Please help.I have a 01 with 4 inch exhaust. air cleaner and diablo chip 65 HP setting. My truck wants to limp when i'm pulling a hill while towing a moderate load(28 foot trailer) When I shut it off and wait 30 seconds she starts and runs normal except for the check engine light. The only code it throws is the 0093 which I believe is the "turn on the check engine light on"code. I know it is not the trany thanks to the $3000 trany swap that I thought for sure would fix it. I can say that my EGTs were at 1300 when it limped. I just hooked up my guages. what I read that was normal for pulling a grade at 5000 foot elevation. The truck limped in 5th just prior to a 4th gear shift. Where do I go next? I'm very confused. Thanks for helping. sorry i was long winded. Greg

p0093 fuel system large leak detected. Try getting your programming back to stock and see if it throws the code.

Try using the search function at the top of the page. This seems to be a common problem if I remember right, just find someone who had the same problem as yours and give them a PM about it.

Bad cp3 or air leak somewhere. My money's on the pump.

Wouldn't hurt to reseat the fuel filter either, and check the bleeder screw.

Bad cp3 or air leak somewhere. My money's on the pump.

X2 Mine does the same thing while towing a real heavy load but I don't get a code it just loses power and then it comes back after a couple seconds. Sounds ike you are running out of fuel. My guess would be the CP3 since you don't have a LOSS OF PRIME problem then I would say you have a leak.

I know this is going to sound stupid, but when was the last time you changed you fuel filter?

I know this is going to sound stupid, but when was the last time you changed you fuel filter?
An obvious but not so obvious question

Sounds like air bubbles accumulating above fuel filter change fuel filter and make sure the gasket is oiled before tightening to have good seal

I just got mine fixed from the same problem. It was the CP3. I had a mechanic do the work, but he started with the rubber fuel lines, then the regulator, then CP3. Runs like a champ now.

Thanks for all the great advise. What I gather from this is what a buddy also said. Start with the filter then work towards the pump. I admit that I'm a self taught wrencher that is not high on knowledge about everything. My fuel filter was only hand tight so I put a tool on it and got a little over a quarter turn more on it. Ya my a-- hurts from the boot marks I've put on it. I'll keep you posted on the results. I'm draggin my boat this weekend so I should know soon. If this is common, maybe a sticky would be warented. GT

To answer some of the questions given. I changed the fuel filter about 500 miles ago when a converted it to synthetic oil. I put the truck back to stock and it limped prior to putting a new tranny (ouch) in it. As I stated in my last post, I pulled the filter off,made sure the bottom bleeder and cap was tight. Then reinstalled the filter with an oil wrench. I also made sure the top bleeder was tight. Now we wait til this weekend to see if it is all good. GT

mine threw that code not long ago.....was towing my TT (no tuner).

I cleared it after the truck cooled off a bit and it threw it again, limped then shut itself down. I could smell fuel.

mechanic said back driver side lines were loose...said he got a quarter to half turn on all the lines.

To answer some of the questions given. I changed the fuel filter about 500 miles ago when a converted it to synthetic oil. I put the truck back to stock and it limped prior to putting a new tranny (ouch) in it. As I stated in my last post, I pulled the filter off,made sure the bottom bleeder and cap was tight. Then reinstalled the filter with an oil wrench. I also made sure the top bleeder was tight. Now we wait til this weekend to see if it is all good. GTAnxiously awaiting to hear if tightening that stuff made a difference.

I have had a VERY similar problem, but mine only limps with the Hypertech on level 2 (60 hp???) if I put it back to stock. I can tow up the steepest hills, WOT and no limp (but its slow as shit) but Im not sure if its cause I dont have the power to pull 5th gear or because Its something else. I gotta admit I havent checked that stuff yet, its been a billion degrees here and Im not excited to roll around under my hot truck after work. Hopefully I can get to it tomorrow night. Problem is it will be a couple of weeks before I can test it again.

Sorry I took so long to reply, truck ran great towing the boat. I was in heaven thinking i had my old truck back. Just this week drug the trailer to the ocean. Blew a tire on the trailer going but no truck problems. Still on a high until the trip back home when it threw another 0093 and limped. Blew another tire on the trailer and played the limp, stop, restart, limp... game the rest of the way home. It is getting worst. Any thoughts would be greatly appreciated. GT

ive never came across this problem but i read about here on here a lot. All the answers people are giving are the norm so Id say someones right. I bought my truck with a bad cp3 pump. It started and ran just fun, but it was very VERY slow and low on power. I had a p1093 code (lack of fuel rail pressure during power enrichment) and after a couple months a p1094 code came along (lack of fuel rail pressure at idle.) My truck with the bad Cp3 pump never went into a limp mode even while towing. Have the code ever came up without a tune in it while towing?

Mine did all of the above, but only when towing. Took it to dealer, who said injectors and they were relpaced. That was 45K ago and still running strong.

It sounds like you need injectors and we have been reprogramming the pcm of our customer 2001 trucks to a 02 and the latest updates. This will stop alot of problems when limping while towing. If you want to do this find a vin # off of a similar 02 with the same options as yours and have your local dealer do the reflash as if they were programming a new pcm for your truck. hope this helps:)

Lets start with some answers you all have given me. Before I put a new tranny in I took it back to stock and it limped. I tried the dealer who could not recreate the problem without me dragging my 28 foot trauler 50 miles to him. He then said it was the mass air and "could not find any other problems until that was fixed". I took it back later and again he could not recreate the problem with out the trailer. I told him it was still throwing a 0093 but he had to recreat that limp before he could be sure what was wrong. He did say that the rail pressure was good when he tested it.
Can I have him test the CP3 and would he be able to tell if it is bad with out the trailer? Also, I called him to see what it would cost,ball park, to exchange the CP3. He did not know what that was then could not give me a price just said it was a 6 to 7 hour job. Nice

Anxiously awaiting to hear if tightening that stuff made a difference.

I have had a VERY similar problem, but mine only limps with the Hypertech on level 2 (60 hp???) if I put it back to stock I can tow up the steepest hills, WOT and no limp but Im not sure if its cause I dont have the power to pull 5th gear or because Its something else. I gotta admit I havent checked that stuff yet, its been a billion degrees here and Im not excited to roll around under my hot truck after work. Hopefully I can get to it tomorrow night. Problem is it will be a couple of weeks before I can test it again.
Dear ARZ unfortunatly in my case it did not help. If you read on the thread you will see several other possible cures. I would give anything for someone to say that they know exactly whats wrong so i can fix it once and for all. Not my luck. I'll keep posting till I have an answer. I'm thinking the injection pump now whitch is known as the CP3. Good luck with your demons. GT AKA skicat7

Mine did all of the above, but only when towing. Took it to dealer, who said injectors and they were relpaced. That was 45K ago and still running strong.OK, so you say it ran like shit. Then the dealer "TOLD" you the injectors were replaced and now that they "TOLD" you that they were replaced 45K ago, NOW it runs strong.

Is it just me, or does anyone else have problems understanding what this guy is saying?

I wish someone could tell me Im not haveing troubles anymore and it would all be OK!!! LOL.

mine threw that code not long ago.....was towing my TT (no tuner).

I cleared it after the truck cooled off a bit and it threw it again, limped then shut itself down. I could smell fuel.

mechanic said back driver side lines were loose...said he got a quarter to half turn on all the lines.OK so if you can smell fuel we can ALL agree you have a leak and that is BAD and none of us would be surprised that it would continue to limp. Then you tell us your mechanic got a 1/4 turn on all the lines and YOU didn't tell us WTF happened. Did it fix the problem or NOT????

Am I going crazy or is this the twilight zone?

Sorry I took so long to reply, truck ran great towing the boat. I was in heaven thinking i had my old truck back. Just this week drug the trailer to the ocean. Blew a tire on the trailer going but no truck problems. Still on a high until the trip back home when it threw another 0093 and limped. Blew another tire on the trailer and played the limp, stop, restart, limp... game the rest of the way home. It is getting worst. Any thoughts would be greatly appreciated. GTOK, so you nad 2 blowouts and NO change to your limp condition. Bummer on the trailer flats!!! I feel for you brutha, seriously!

Did you have a tune on it, or was it stock?

That would definitely help us.

ive never came across this problem but i read about here on here a lot. All the answers people are giving are the norm so Id say someones right. I bought my truck with a bad cp3 pump. It started and ran just fun, but it was very VERY slow and low on power. I had a p1093 code (lack of fuel rail pressure during power enrichment) and after a couple months a p1094 code came along (lack of fuel rail pressure at idle.) My truck with the bad Cp3 pump never went into a limp mode even while towing. Have the code ever came up without a tune in it while towing?OK, I can barely understand what this guy is trying to say, but it sounds like I have the same problem. I can tow all day long (up the steepest hills) without a tune, soon as I install a tune AND tow a load and try an incline as steep as a freeway bridge I limp. (while tune is installed, NO LOAD=NO LIMP, stock tune HUGE LOAD HUGE HILL, WOT=NO PROBLEMS)

You never said WHAT, or HOW, or IF, you ever solved your bad CP3 issue. Then you post a poorly worded question at the end of your post. WHO are you asking that question too?!?!?

Have YOU ever installed a tune on your truck? If so, DID it limp? HOW did you know your CP3 was bad?

Thanks in advance for clearing that up!!!

It sounds like you need injectors and we have been reprogramming the pcm of our customer 2001 trucks to a 02 and the latest updates. This will stop alot of problems when limping while towing. If you want to do this find a vin # off of a similar 02 with the same options as yours and have your local dealer do the reflash as if they were programming a new pcm for your truck. hope this helps:)This guy seems to think we all have a friend at the dealership that will gladly install a FREE re-flash when most of us have an issue when a tune is installed. Then, seems to think that ALL of us would benefit from $1300+ (not including the install price) worth of new injectors even though our trucks can pull to the MOON on a stock tune.

I don't know about you guys, but I really don't have the extra money, just to throw some at it just to see if if that works.

Ok everyone, ignore all my previous replies since Im PWI (Posting While Intoxicated). Hope I didn't offend anybody...

But Im kinda serious. LOL. Even when Im wasted I can still understand what Im typing. I guess I will review this in the morning, and see if that still holds true. LOL.

Lets start with some answers you all have given me. Before I put a new tranny in I took it back to stock and it limped. I tried the dealer who could not recreate the problem without me dragging my 28 foot trauler 50 miles to him. He then said it was the mass air and "could not find any other problems until that was fixed". I took it back later and again he could not recreate the problem with out the trailer. I told him it was still throwing a 0093 but he had to recreat that limp before he could be sure what was wrong. He did say that the rail pressure was good when he tested it.
Can I have him test the CP3 and would he be able to tell if it is bad with out the trailer? Also, I called him to see what it would cost,ball park, to exchange the CP3. He did not know what that was then could not give me a price just said it was a 6 to 7 hour job. NiceI didn't do a refresh and notice that you guys had replied. I worked for GM as an Engineer, and all I can say is, I would NEVER trust those dealerships, unless you found a good guy you can trust. Those guys are IDIOTS, Service managers, Mechanics, ALL OF THEM!!! all they are is "parts changers" and they are experimenting with YOUR money. They couldn't diagnose a problem if it was theirs!!! Seriously if you found a good one he would start his OWN shop.

Dear ARZ unfortunatly in my case it did not help. If you read on the thread you will see several other possible cures. I would give anything for someone to say that they know exactly whats wrong so i can fix it once and for all. Not my luck. I'll keep posting till I have an answer. I'm thinking the injection pump now whitch is known as the CP3. Good luck with your demons. GT AKA skicat7I have been following other threads and Im pretty convinced that might be my problem too. Filling out your sig, so we knew what year, miles and mods your truck was/has, is a big help. Sincerely, thanks for your good wishes, I too,will post when I have solved it.

It just pisses me off that you cant tell the difference between a guy that REALLY knows what he is talking about and says in a quick sentence "Its your CP3!!!!" and another idiot that says "hey just replace the injectors!!!"

This week I replaced all of my flexible (rubber) fuel lines and I should be able to test it tomorrow. I will post back either way, test or no test, success or failure.

OK so if you can smell fuel we can ALL agree you have a leak and that is BAD and none of us would be surprised that it would continue to limp. Then you tell us your mechanic got a 1/4 turn on all the lines and YOU didn't tell us WTF happened. Did it fix the problem or NOT????

Am I going crazy or is this the twilight zone?




think you might have some kind of issue bud.....obviously if the guy got the lines tightened down the leak is gone.....if it wasnt I would have said the mechanic was an idiot.....is that clear enough???

I have had the pleasure of finding a very good dealer and their mechanic is top notch from what i can tell....no guess work from them yet. So your wide sweeping nonsense is just that...a silly generalization.

Anything else i can clear up for ya just hollar:)

"I can say that my EGTs were at 1300 when it limped. I just hooked up my guages."

Where are you measuring the EGT? Thinking that 1300 at top of down pipe is an actual EGT of 1500 or more. That temp may trigger the cpu to shut things down and dump heavy fuel to cool EGT's.

I had that happen once towing (12,000 lbs) up a long gravel road at 7000 ft. Lots of black smoke, no power. Stopped, ran engine at 1000 rpm until things cleared up. At that time I was running pretty much the same set up. 4" exhaust turbo back, with Hypertech tune at +70, After market air filter.

How long is the grade when it quits?

Hey man i have an 01 i've been tuning with efi live and pulling did some stuff that caused same problem call me i think i can help. my name is trent. 765-425-1132

OK, so you say it ran like shit. Then the dealer "TOLD" you the injectors were replaced and now that they "TOLD" you that they were replaced 45K ago, NOW it runs strong.

Is it just me, or does anyone else have problems understanding WTF this guy is saying?

I wish someone could tell me Im not haveing troubles anymore and it would all be OK!!! LOL.

OK so if you can smell fuel we can ALL agree you have a leak and that is BAD and none of us would be surprised that it would continue to limp. Then you tell us your mechanic got a 1/4 turn on all the lines and YOU didn't tell us WTF happened. Did it fix the problem or NOT????

Am I going crazy or is this the twilight zone?

OK, so you nad 2 blowouts and NO change to your limp condition. Bummer on the trailer flats!!! I feel for you brutha, seriously! But I have had days much $hittier than that.

Did you have a tune on it, or was it stock?

That would definitely help us.

OK, I can barely understand what this guy is trying to say, but it sounds like I have the same problem. I can tow all day long (up the steepest hills) without a tune, soon as I install a tune AND tow a load and try an incline as steep as a freeway bridge I limp. (while tune is installed, NO LOAD=NO LIMP, stock tune HUGE LOAD HUGE HILL, WOT=NO PROBLEMS)

You never said WHAT, or HOW, or IF, you ever solved your bad CP3 issue. Then you post a VERY poorly worded question at the end of your post. WHO are you asking that question too?!?!?

Have YOU ever installed a tune on your truck? If so, DID it limp? HOW THE #UCK did you know your CP3 was bad?

Thanks in advance for clearing that up!!!

This guy seems to think we all have a friend at the dealership that will gladly install a FREE re-flash when most of us have an issue when a tune is installed. Then, seems to think that ALL of us would benefit from $1300+ (not including the install price) worth of new injectors even though our trucks can pull to the MOON on a stock tune.

SWEET!!! I will get right on that. $1300+installation for new injectors sounds like a GREAT idea. I don't know about you guys, but I really don't have the extra money, just to throw some at it just to see if if that works.

Ok everyone, ignore all my previous replies since Im PWI (Posting While Intoxicated). Hope I didn't offend anybody...

But Im kinda serious. LOL. Even when Im wasted I can still understand what Im typing. I guess I will review this in the morning, and see if that still holds true. LOL.
i wound refrain from drinking and posting in the future if i were you.
makes you look like a -ick

That little fix still hurts. I too hate tossing money at a problem in the dark. If i had a crystal ball I'd open my own shop and hire dealer mechanics to swap parts. If you have a good dealer consider yourself lucky. I know they are out there. I just don't trust mine. My Egt pick up is in the manifold on the passenger side where Kennedy diesel said to put it. I believe i'm getting real temps. The truck has limped at lower temps. The truck threw a code and limped in the stock mode. I plan on checking for a leak in the filter area first because i believe in simple to hardest and I am a dreamer that believes swapping out a bleeder screw or even a filter housing sounds better than a CP3. I just hope crossing all fingers and toes will cast good Karma my way. As always I'll post my results. Could someone tell me how to test the CP3 just in case my karma fails me.

Well ARZ ....considering my first post in this thread was after skicat and you never asked a question i was talking to him NOT you.. You're right I never said what cured my Cp3 issue :rolleyes: pretty simple....CHANGED IT BECAUSE IT WAS BAD. Read my sig. jackass....i spent all that money on a PPE hot+2 to do what? look at it? NO!! i have installed a tune on my truck. I was going to throw some ideas out there because I know how you feel about being in the dark but instead you're going to be a
***** so i guess you can.....CHEW MY BAG

WHOA!!! I really pissed off a lot of people. LOL. I too am guilty of simple typing errors, and Im sure incomplete sentences, but I still find it surprising that in only 20 posts there were at least 5 posts, that were incomplete or that you couldn't understand what they were trying to say and no one called anyone on them.

1LTREATER,
I re-read my posts, and my reference to some saying "Just replace your CP3" is 100% NOT directed at you. I have read at least 6 places where someone said "I just had my CP3 replaced under warranty and its all good now!" That's not the kind of solution that will help any of us. Im very sorry, to offend you, but I could not understand your post. Knowing how you determined your CP3 would have been a great help, but I guess I shot myself in the foot on that one. Again sorry to offend you.

Birddog,
Your right "generalizations" are no good for anyone. Very glad to hear you have a mechanic you can trust.

Raydzi,
Ok I admit to dropping a few too many f-bombs but am I completely wrong?

Sorry to all! On with what I learned this weekend. Sorry I didn't post sooner, I have been swamped and honestly I forgot about this post.

Since I swapped 6 of my rubber fuel lines (I think all) in the engine compartment, and finally got around to changing the ATF, I figured I should go out and see if this fixed my limp. The short is "NO" the lines did not fix it.

The long is I need:
-to have a tune installed
-to be towing a considerable load over 5K
-going up a gradual hill

Odd thing is

There are a few odd things about this limp:
If I use the throttle it seems MUCH less likely to limp.
If I use cruise control it seems to limp much easier, (maybe its the nature of the smoother fuel delivery? (who knows) After the first limp event on a gradual hill (using cruise), also had a head wind (I really didn't notice till I turned around), I decided to keep going and the very next hill was VERY steep and long and it WOULD NOT limp, (not in cruise control) got to the bottom of the LONG downhill and turned around to go back up, (Now this is a BIGGER hill than all previous while testing) Floored it at the bottom and was able to do 80+ up the hill until the curves got to tight. for some reason it WOULD NOT LIMP. If any hill would tax it this would be the one.

Completely mythed (sp) I could not understand why (still don't) all the way back into town is a VERY gradual downhill, 75-85-95 NOTHING would make it limp (cruise, man-throttle, nothing). Almost back to town (15-20 miles or so) I do a u-turn and head back out,(remember gradual uphill and I notice a head wind) and Im using quite a bit more boost to achieve the same speeds. A mile or so from turning around (up to speed 65+ 5th gear) I decide to set the cruise, and within 10-15 seconds, BAM it limps again. Starting to recognize a pattern (I think) I coast down, and wait for it to do what ever it does to clear itself (if you use the throttle it will fight you and keep limping). I come to a steady speed, (40-50 or so luckily very little traffic leaving town) and all seems OK and I stand on it again, get it over 65 and hold the throttle steady and start up another gradual rise, and it limps again. This time I fight it with the throttle, and try to stay in the throttle, and it will continue to limp all the way until I am at 20 some odd mph. I pull over, no SES, no CEL (didn't check the codes) wait a few and it drives away like normal, I do a U-turn head back to town with cruise on and several gradual hills SHOULD have limped it but nothing, she drives fine.

At that point I was getting low on gas and completely fed up and not able to nail down EXACTLY why and when it would limp.

Seemed a giant hill with alot of load and a WOT driving like a maniac would not limp. But a plain old gradual hill with the vehicle set on cruise would limp right away. I am still stumped.

I need to find a local guy that can test my FPR and CP3 and see what is going on with them.

Also: My fuel filter was replaced before I purchased the truck, I have loosened the water bleed on the bottom but I havent ACTUALLY replaced the filter, its got about 7k and 4 months on it. Is there any special instructions to replacing the fuel filter? Anything other to do other than pump the primer? Is there any special bleed procedure I should be doing to get the air out of that bleed port next to the A/C or that plastic hex nut on the filter adapter? Am I missing something OBVIOUS that I just don't know about?

Again sorry for the attitude, Id be glad to buy you each a beer if we ever met in person.

I did the wait a week then open the bleeder on the fuel filter and got steady fuel in less than 1 pump. Shucks!!!!! So I'm breaking down and taking it to another dealer who claims to have a real mechanic. He thinks it's either the cp3 or injectors. That would be my4th set in 120,000 miles. I just want it to end.
ARZ. the 1 thing that is constant for me is in fifth gear. I too am light on the throttle. The dealer wanted it back to stock, so I did and it limped again. Mine needs to be shut down for 20 seconds after opening the door to kill the battery delay then it runs like nothings wrong. Some times it won't even throw a code, just limp. Why do we love these little pieces of s**t so much? I'll let you all know what I find out after the hurt on Monday. Wish me luck.

Please help.I have a 01 with 4 inch exhaust. air cleaner and diablo chip 65 HP setting. My truck wants to limp when i'm pulling a hill while towing a moderate load(28 foot trailer) When I shut it off and wait 30 seconds she starts and runs normal except for the check engine light. The only code it throws is the 0093 which I believe is the "turn on the check engine light on"code. I know it is not the trany thanks to the $3000 trany swap that I thought for sure would fix it. I can say that my EGTs were at 1300 when it limped. I just hooked up my guages. what I read that was normal for pulling a grade at 5000 foot elevation. The truck limped in 5th just prior to a 4th gear shift. Where do I go next? I'm very confused. Thanks for helping. sorry i was long winded. Greg

You shouldn't be towing on the +65 setting. Diablo says you can do 8000lbs or less with that setting but I wouldn't trust it. The fact it limped after shifting to fifth doesn't surprise me. The fifth gear clutch pack is the weakest and will slip when over powered. Change the setting to the tow tune. +40hp. See if that changes anything.

Would modding the cp3 and regulater help or they just go bad?

Thanks for the advise RIGET1, but the thread was long and you missed lots of info. I don't blame you for not trudging through it as ARZ got drunk and littered the post with useless garbage. My added post showing that I put a rebuilt tranny in with a HD shift kit. Also the truck will limp in stock settings when towing anything, IE: trailer or 22 foot bayliner. I checked for a leak in the fuel system by opening the bleeder valve after the truck set for numerous days. I'm frustrated to the point I feel the stealer needs 1 more shot at it. I'll post the result when I have them

just what do you mean by rebuilt tranny and HD shift kit? are we talking a big name like suncoast or ATS orrrrrr some ebay special?

It was bought through Ebay from A&M transmission with the shift kit installed. Had my local tranny shop inspect and install it.

... I don't blame you for not trudging through it as ARZ got drunk and littered the post with useless garbage...Im never going to live that down HUH?!?!? LOL. I guess I kinda deserve some $hit, for that. LOL.

Seriously, only the people who's feelings got hurt and replied with insults were the useless parts. At that point, there were 20 posts, and 5 of them were TOTALLY inconclusive, incomplete, and/or totally confusing. So with 25% of the posts not helping I wanted answers. And was willing to piss people off to do it. Thanks again for keeping us up to date and I will do the same. Seriously, GOOD LUCK.

For what its worth I dont think its your Ebay trans. It would show/store a trans code if it was.

Have you checked your intercooler plumbing or anything for leaks? Just thoughts.

Skicat....thats the only code its throwing?

ARZ It's all good. we need a little shake up every now and then. Some people just can't handle the truth. I also know if you are in my boat, you are getting short from frustration..When my tranny guy did the instal he flushed the hole system including the cooler and lines, checked it for leaks then refilled it with the Amsiol I supplied. He also replaced some sensors. He was a good guy I trusted him completely!!! ..........1LTEATR yes thats all she threw. 0093 was very consistant when it threw a code. sometimes it didn't even when it limped.......
Well I got some good news for you all and some bad news for me today. 1) if you use a dealer ask if they have a "world class" mechanic. Which is first a master mechanic, then with further training and classes becomes a world class. They are not easy to find as it isn't an easy title to get. This dealer had 5. 2 of which they stole from another dealer. He was the first and only stealer mechanic that jumped on and fixed my truck. I did not even have to drag a towable to have him fix it!!!
Now for what was wrong, it was my CP3 also known as the injector pump. He said it would limp in 5th while pulling because the RPM's were low and the pump was not generating enough pressure.......
If for some fate dealt to me this was not the fix, I'll repost with a continued frustrating drudge till a fix is found. I thank all for the suggestions and advise. I will close by saying be good and kind to each other. Add your 2 cents when you can. Nothing is always obvious to everyone so speak up. peace Greg

Good to hear. I was going to suggest getting a lift pump because maybe the CP3 was starving for fuel, but you got it taken care of.

Now for what was wrong, it was my CP3 also known as the injector pump. He said it would limp in 5th while pulling because the RPM's were low and the pump was not generating enough pressure.......
If for some fate dealt to me this was not the fix, I'll repost with a continued frustrating drudge till a fix is found. I thank all for the suggestions and advise. I will close by saying be good and kind to each other. Add your 2 cents when you can. Nothing is always obvious to everyone so speak up. peace Greg

You should be able to get 23,000psi at idle, so the fact that they told you that the rpms were too low and the pump wasn't generating enough pressure while in 5th, is BS in my book.
I have pulled 7000# with my hypertech on stage 3(120hp 180tq or so they say) I haven't limped the trans and I've pulled a few good sized hills and grades. I also pull a sled on weekends on the same power settings.

The fact that a new cp3 didn't fix your problems leads us most likely to your injectors, the injectors may be returning too much fuel. According to the OEM service manual a bad cp3, bad fpr, air leak in the system, or bad injectors may cause the p0093 code.

Mine was doing the same thing. Would go to limp mode and set 0093, under a high demand for fuel. I changed the fuel filter and problem gone. I feel lucky on this one.

ARZ It's all good. we need a little shake up every now and then. Some people just can't handle the truth. I also know if you are in my boat, you are getting short from frustration..Yea when 25% of the responses are impossible to understand, I was kinda surprised no one had been called on it. LOL

When my tranny guy did the instal he flushed the hole system including the cooler and lines, checked it for leaks then refilled it with the Amsiol I supplied. He also replaced some sensors. He was a good guy I trusted him completely!!! ..........1LTEATR yes thats all she threw. 0093 was very consistant when it threw a code. sometimes it didn't even when it limped.......I only experienced a CEL or SES a very few times compared to how many times it limped.

Well I got some good news for you all and some bad news for me today. 1) if you use a dealer ask if they have a "world class" mechanic. Which is first a master mechanic, then with further training and classes becomes a world class. They are not easy to find as it isn't an easy title to get. This dealer had 5. 2 of which they stole from another dealer. He was the first and only stealer mechanic that jumped on and fixed my truck. I did not even have to drag a towable to have him fix it!!!Awesome news, I did not know anything like this existed. If I have to use a dealer, I will definitely look for one of these guys. I too am/was worried that I would have to drag a toy hauler up some big hill and witness it fail before someone would believe me.

Now for what was wrong, it was my CP3 also known as the injector pump. He said it would limp in 5th while pulling because the RPM's were low and the pump was not generating enough pressure.......This makes perfect sense when compared with how several of my limp events did and DID NOT happen. A while back, I went and towed a trailer around just to see if I could make it limp. What I found really ticked me off and didn't make any sense until you posted this with your new found info from your world class tech. Now it makes total sense, read along and see if these events don't put my frustration and confusion in perspective. With this new info it seems to make perfect sense.

I went up and down Bush hwy and the hill from Bush hwy where Power rd turns into Bush south bound turned around and went up that steep little hill, it was tough to get it in to 5th gear before I got to climb it but I usually had to flog it a bit to get up to speed and once I caught a guy cause he was going to slow (and I was towing) UGHHH! did it 2 separate times and NOTHING, it towed/pulled the hills FINE!!! Heres a link to a map of the hill (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=&ie=UTF8&ll=33.505296,-111.67727&spn=0.021292,0.042443&t=p&z=15), its only just over 100 ft climb but its pretty steep.

So I drove a few more miles over to the bottom of Usery Pass road, at the bottom is a 4 way stop so I obviously couldnt hit it in cruise control or at a steady state. Usery Pass Road (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=&ie=UTF8&ll=33.50433,-111.602383&spn=0.085168,0.169773&t=p&z=13) this hill climbs from 1440 ft to over 2300 ft in 2.5-3.0 miles, it is a very steady hill and I was so upset that I never witnessed a limp event towing up that hill. The problem was that i never got to approach it when I was already up to speed. I had to floor it at the bottom of the hill and by the time I got to get it into 5th gear I had already flogged the crap out of it and obviously the rail pressure was already up. Unsatisfied with no limp while towing with a tune (level 2 on a hypertech III).

I drove northeast out to the Beeline and headed north. I hadn't driven 2-3 miles on this smooth gradual climb (northbound on the Beeline, between Bush hwy and 4 peaks turnoff) (<iframe width="425" height="350" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="http://maps.google.com/maps?f=q&amp;source=s_q&amp;hl=en&amp;geocode=&amp;q=&amp;ie=UTF8&amp;ll=3 3.655781,-111.516724&amp;spn=0.085018,0.169773&amp;t=p&amp;z=13&amp;output=e mbed"></iframe><br /><small><a href="http://maps.google.com/maps?f=q&amp;source=embed&amp;hl=en&amp;geocode=&amp;q=&amp;ie=UTF8&amp;ll =33.655781,-111.516724&amp;spn=0.085018,0.169773&amp;t=p&amp;z=13" style="color:#0000FF;text-align:left">View Larger Map</a></large>) put it in cruise and BAM it went into limp mode. Feeling validated I knew a big hill was coming up. I had lost speed so I waited for traffic to clear and got into the throttle to get it back up to speed and set the cruise and climbed this WAY bigger hill, and what-do-you-know it didn't limp.

Completely confused and kinda pissed it didn't react the same I drove to the bottom of this huge hill (notice the turn-around at the bottom "north") (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=&ie=UTF8&ll=33.709633,-111.49724&spn=0.042482,0.084887&t=p&z=14) turned around (now south bound and climbing about 2100ft up to over 2700ft in just over a mile, WAY steeper than the Usery Pass hill) and in frustration floored it all the way to the top. Even more frustration resulted, as I witnessed NO problems, it pulled with tons of power and ease well into 5th gear, (almost 80 mph) then the road got to curvy and I had to back it down, UGHHH!!!

Completely frustrated I set the cruise kinda high (about what had triggered a limp ALL previous times) and NO problems what so ever, I didn't notice until I was almost all the way back to Ft McDowell at the Verde River bridge that we had a SERIOUS tail wind, and its ever so slightly downhill back to Fountain hills/Ft McDowell. I figured, well what if I turn around and go against the wind and back up-hill? So that's what I did just before the bridge, I turned around at the rodeo grounds, (Grindingstone Motocross area). I gradually got it up to speed (into 5th gear) and set the cruise control and within 30 seconds, BAM it limped, I decided to work against it and continued feathering back into the throttle as soon as it exhibited any signs of returning power and if continued to limp in all gears until I couldn't go any faster than 30 or so mph. I pulled over and let it idle and tried it again only this time I went WOT to 5th gear and I couldn't make it limp on a gradual hill that was just a little steeper than the 2 previous limp events just minutes earlier and the one 15-20 minutes earlier.

Completely confused, I was getting low on fuel and turned around and drove home without incident.

This whole effort proved only to be a waste of fuel until this news.

If for some fate dealt to me this was not the fix, I'll repost with a continued frustrating drudge till a fix is found. I thank all for the suggestions and advise. I will close by saying be good and kind to each other. Add your 2 cents when you can. Nothing is always obvious to everyone so speak up. peace GregAmen brutha!!!

You should be able to get 23,000psi at idle, so the fact that they told you that the rpms were too low and the pump wasn't generating enough pressure while in 5th, is BS in my book. Didn't he say anything about pressure at idle, but if the engine is producing 22+psi at such a low RPM, I can believe that if a CP3 or a FPR was not up to the task that this kind of limp might be the result.


I have pulled 7000# with my hypertech on stage 3(120hp 180tq or so they say) I haven't limped the trans and I've pulled a few good sized hills and grades. I also pull a sled on weekends on the same power settings.Ok I will give you that sled pulling creates a load, but I would bet you are at WOT, and not low RPM's (1900-2200) with the cruise control set (which is when ours go into limp). AND since you live in the Dakota's I would be willing to bet you havent pulled hills ANYWHERE near a steep and long as the ones we have out west.

The fact that a new cp3 didn't fix your problems leads us most likely to your injectors, the injectors may be returning too much fuel. According to the OEM service manual a bad cp3, bad fpr, air leak in the system, or bad injectors may cause the p0093 code.Am I missing something? I don't see where he said it "DIDN'T FIX IT"

Well after wading through all of the unneeded posts and replys I feel I can finaly put my 2 cents in.
I have found the exact problems with my rig. Sometimes it limps and some times it does not. But I think that for my rig I have found why and when and have not limped it since. For me it was not about bad injectors or CP3s, or even a bed tranny(I hope not). I currently have about 160k miles on a stock engine with original injectors and a stock tranny. I did change the CP3 when I did the conversion. While towing my #12k Toy Hauler I can limp the truck easily in level 3 on my Banks 6-gun. It can be done in level 2 but can easily be avoided.
So you are curious about the why and when. I believe it is a matter of rpm, demand and torque. With my Banks 6-gun I have a very soft bottom end and it does not really build untill the boost starts climbing around 1600-1800 rpm, after that you get the real kick in the pants acceleration when the fuel starts to pour in. When I am cruising along around 50-55mph and I come onto a hill I can feed the pedal in slowly to climb the hill. If I maintain 5th gear and continue to add fuel to accelerate or if the hill gets steeper then I will limp it every time. But if I stab the pedal to the floor and then release it will shift to 4th gear and I can accelerate as much as I want and I can not limp it. I have tried this many time and can now feel when the truck is about to limp. If I am using the Cruise Control it will limp the truck almost every time because it feed the fuel in slowly to maintain speed. The setpoint for down shift is just high enough. It has to do with the relationship between the boost level, fuel level, gear position, torque output, and load. Unfortunaly this will change with every different programmer, every different driver, and every different hill/trailer so no 2 situations will be the same.
I beleive that a built tranny will cure my situation but have found that if I keep the tunner down and pay attention I can stop it from happening. And I can still fly up and down the mountains with any trailer at any speed I want.
What I am getting at is that we all have a duramax engine but we all drive different trucks and it is the total package that makes our truck what they are. You have to become familiar with your package and find your own solutions. Use the experiences of others to build upon and ask lots of questions. Your solution will probably be as unique as your truck.
Good luck and let us know how your solution is comming.

From looking at several threads, the P0093 code seems to haunt the LB7. I threw the P0093 code for almost two years before I finally got it fixed. When the code trips and throws the truck into limp mode, it is due to a descrepancie between the demanded fuel pressure and provided fuel pressure, i.e. the computer wants 150MPa but the pump is only putting out 115MPa. It is generally caused by the fuel pressure bleeding off through faulty equipment. The previous reply addresses a temporary fix, which worked for me for about 6 months. I would recommend an injector test and fuel rail pressure test; that will narrow the problem down. There are usually 4 common causes of the P0093: fuel filter, injectors/injector cup, fuel pressure regulator, and/or CP3. Luckily, I got my injectors under warranty because they didn't fix the problem. I later replaced the FPR and CP3, which come as one unit, and I havn't seen the code since.

... The previous reply addresses a temporary fix, which worked for me for about 6 months. I would recommend an injector test and fuel rail pressure test; that will narrow the problem down...I agree 100%

Boise, you might have replaced your CP3 but that doesn't mean your FPR isn't having problems. I would be willing to bet you money its NOT your transmission.

Kudos on your engine swap, I know what it takes to swap entirely different powertrains into another vehicle and have done many swaps. That sounds like an awesome swap.

FYI. I replaced my LB7 pump with an LBZ pump. It came with a regulator.Was having very similar issues as you guys. Had pressure checked before replacement. Code was tripped P1093. System was calling for 23000psi and only getting 10000psi. Cost sucked!! Results were fantastic!!!!!!!!!!