i have a 94 k1500 with 220000 on it and it just started having a little smoke hase blowing from the dipstick tube. it has had the injection pump done about 25000 ago new tranny and i also relocated the pmd. it has a bad exhaust leak on the crossover pipe from the driverside manifold to the turbo,i just ordered a new 2 1/2" pipe of ebay going to install as soon as possible. i just hope i didnt waite too long, ive been reading around on internat and cant really get a solid anser on my specific question. ive read so many things from head gasket to holes in the piston to injectors or even lift pump. oh i forgot to mention because of my ignorce with typeing that while idleing sometimes it will feel like the truck got bumped lightly from behind and the motor sounds like you cut the fuel real quick and let it back on,also it will rev up on its own and spit black smoke out it only has done this once going dow the road but frequently does it when first started. i also read about it could be the injectors not holding vacum and fuel running back to the tank and a way to tell is to take the fuel cap off and listen for suction. or it could be lift pump.,or oiloil getting past the turbo shaft. well i feel like im talking in circles hope its not to confuseing and ive been clear enough its hard to explain seeing that none of this happens exspecdly its alawys random any insite would be a great help, thanx

I'd just start with the CDR...

I would start by changing the crossover.
2) check that CDR for being open.
3)check for air in the fuel system and check fuel pressure.

what exactly does the cdr do? and what does the provent crank case oil seperater ventilation valve do,and how costly is it? how would i check for air in the fuel system, i thought that all you had to do was open the t valve on top of the motor until you get straight fuel with no air is that right? what should the fuel pressure be between 5&7?
how bad did it hurt it running it with the hole in the crossover pipe? i hope not bad i love this truck for some reason besides power i like driving it better than my duramax! id also like to know how you went about your high idle and foot dimmer? thanx

CDR = Crankcase Depression Regulator valve

Similar function to a PCV valve.

The Crankcase Depression Regulator (CDR) Valve maintains crankcase pressure. Pressure must be regulated to prevent oil consumption through the intake system, and to prevent oil leaks due to excessive buildup of pressure. Control is accomplished by regulating the blow-by gases into the intake system to be reburned. Inside the CDR valve, a spring holds open a valve plate that connects to the CDR valve body with a flexible diaphragm. The valve plate is capable of restricting the outlet passage to the turbocharger air inlet duct when airflow pulls it closed against the force of the spring.

what exactly does the cdr do? and what does the provent crank case oil seperater ventilation valve do,and how costly is it? how would i check for air in the fuel system, i thought that all you had to do was open the t valve on top of the motor until you get straight fuel with no air is that right? what should the fuel pressure be between 5&7?
how bad did it hurt it running it with the hole in the crossover pipe? i hope not bad i love this truck for some reason besides power i like driving it better than my duramax! id also like to know how you went about your high idle and foot dimmer? thanxThat POS called the CDR is supposed to keep the crank case under a slight vacuum and burn the crank case vapours in the engine.A novel idea,but less effective if you have a lot of blow by on a somewhat worn engine,this will cause excessive oil consumption ( a new CDR wont solve that problem)Or the thing is plugged shut. In the latter case to much crank case pressure will cause leaking seals and/or gaskets.

Running with a leaking crossover will make the turbo less effective cause that is driven by exhaust gas pressure,resulting in less power. it wont kill your engine though.

bleeding the fuel system is done by opening the bleed screw/plug on top of the filter and starting the LP till only fuel runs out.
The T-valve is primarily for water draining from the bottom of the filter,only bleeding there will leave the filter still full of air.You can use that T-valve drain hose to hook up a pressure gauge for checking pressure .min 5 psi at idle and at least 1 psi WOT.

high idle set up can be found in the stickies,PM me for the dimmer switch.

The provent does the same as the CDR,only it filters the oil out and puts it back where it belongs.

A little bit of blowby is not a problem. Fuel gets past the piston seals and is common, happens on anything, especially with 21:1 compression ratio.

If it were caused by the CDR it would be because its stuck closed, so if you can blow through it that aint causing you to see it now. If you used a lighter oil, or one with more detergent or something, who knows, just a little blowby could be a number of things. It might just be oil mist.

Thanks a lot guys I appreciate the information, it was really helpful. I just got my crossover pipe today. I gotta talk to my buddy about using his fuel pressure gauge, I'm thinking about changing the filter and starting from scratch now that I know the proper ay to bleed it. I cant believe how helpful you guys have been, I posted 3 threads on my Duramax and only got one reply. Do either one of you know how to block off the EGR? Does anyone know what the plugs on the drivers side valve covers go to? When I bought the truck two out of three were unplugged, when I plugged the other two in all it did was set of the check engine light.
I was wondering what the story was with blow by coming out the dipstick, I read on Heath Diesel if you have blow by coming out the oil filler tube its not a good idea to modify the worn engine. But seeing as though it only coming out the dipstick do you think it would hurt the engine to add injectors and a chip? Do you know how much power the chip gives at the wheels? I know from experience, buying for a Duramax, its easy to put numbers on the box but what it actually puts out is different. Who would you recomend going threw Heath, Kennedy, or SS Diesel?
Thanks a lot for your help!!

Heath, Kennedy, Westers, Engh Motors.

pull the CDR hose off and see blowby is coming out there, if not CDR is stuck closed. I have a good amount of vapor/mist, still runs awesome and hard.

a compression test will give an good indication of the condition of the rings and valves.
anything between 350 to 400 psi with no more than 20/25 psi spread between high and low across all 8 is OK.

My wife's 95 has over 350 k on it and starts and runs very good,but blowby was so bad that i vented the CDR to the world,that cut the oil burning to allmost zero.Been running like that for 40 K

How old are your fuel injectors? If pushing 100K on the injectors, I'd replace them. This single item made the biggest difference in my truck at 120k miles. White smoke at startup went away, and all startups were quick and easy after that.

I had blowby from the filler cap at idle before and after, but not while running, and used lots of oil even though I experienced very little black smoke.

Shortly after that I suffered a blown head gasket, so I pulled the engine and am currently rebuilding it. Found stuck rings in 3 cylinders during the rebuild, and a crack running down along the #4 main crank shaft bolt hole.

At 250K, you really have gotten your money's worth. But, it could run alot longer.

One word of caution, I have seen a fair number of cracked & rusted crossover pipes working in michigan. Even a small crack drastically lowers the amount of boost. Low boost usually means high exhaust gas temp, so it is possible there is engine issues due to high egt. Compression test would be at the top of my list before I replaced any parts other than the crossover.

i hope its not injectors the truck has 221,730 miles now and the pump and injectors were supposodly done at 197,???. but who knows it could be with fuel the way it is now. i think it could be something to do with air in the lines because it started acting bucking and sputtering twice the other night so i pulled over and loosen th filler cap and waited till i heard the tank expand put it back on and it was fine. kinda lost does this make sense to anyone else?

Yes, here's some ideas from another thread.

Put a piece of clear tubing in the injector return line path. After the fuel starts to flow well, look for bubbles passing through the system. Also, the fuel between the tank and the lift pump is normally under vacuum pressure and air can be sucked in to the system there with no sign of a fuel leak.

Pressurize the tank lightly with an air hose (15 lbs or less, engine off of course) and look for fuel leaks.

Yes, here's some ideas from another thread.

Put a piece of clear tubing in the injector return line path. After the fuel starts to flow well, look for bubbles passing through the system. Also, the fuel between the tank and the lift pump is normally under vacuum pressure and air can be sucked in to the system there with no sign of a fuel leak.

Pressurize the tank lightly with an air hose (15 lbs or less, engine off of course) and look for fuel leaks.A better way is to replace the IP return hose permanently with clear tubing,one can observe for air at all times

i replaced the crossover pipe,took out the cat and muffler, replaced with 3 1/2" striaght pipe in front of tire exit,and replaced fuel filter and fuel cap. the truck was fine for a day then started agian but worse with the bucking and puking gray and black smoke.
its weird because it sounds like its missing one minute when it does it then it will do it again and feel like you just gave it a 100horse shot off the bottle. sometimes if you rev it up it will go away sometimes it will stay at the same rpm or at other times it will rev up higher, one time i was out of the truck and it started spitting and sputtering while it was idleing as i opened the door to shut it off and it was like it spiked itself and did a runaway to 5 grand, before i got to the key to shut it down. it was scary seeing the tach at that rpm but strangly it didnt sound that rough, i know that it isnt good for them but i was exspecting to see parts flying i never heard of a 6.5 hitting that high of a note. well thanx for all the other info very helpful anymore lol. im getting a appiontment to get a compression test and fuel pressure test done but any info is always good.
thanx again

do that IP return clear hose swap.

Correct me if i'm wrong but isnt arent run away events associated to IP failing?

Correct me if i'm wrong but isnt arent run away events associated to IP failing?Yes it could be The IP itself,but one has to trouble shoot other possibilitys first.A engine running out of fuel often speeds up just before stalling.

.....A engine running out of fuel often speeds up just before stalling.

Having run out of fuel in 3 different vehicles i have never noticed this to happen.

There are a couple different things going on here it seems. One: your injectors are totally warn out (like mine) and have caused holes in your pistons (like mine, though its possible that its the rings). two: the injector pump is screwing with your timing, at times not firing and sometimes you have a run away rpm event. THESE ARE DANGEROUS! Even if you did have air in your lines, bad injectors, failing pmd, massive blowby, and were low on fuel i doubt those symptoms could cause a run away event.

Hate to sound like a GM repair tech, but i think your IP is on the way out. A quick way to check is to try out your cruise control. You will not have a functioning cruise control without a normally functioning IP.

*All of this info provided is an opinion, it is what i know to be true. And is certainly open to debate*

Having run out of fuel in 3 different vehicles i have never noticed this to happen.

There are a couple different things going on here it seems. One: your injectors are totally warn out (like mine) and have caused holes in your pistons (like mine, though its possible that its the rings). two: the injector pump is screwing with your timing, at times not firing and sometimes you have a run away rpm event. THESE ARE DANGEROUS! Even if you did have air in your lines, bad injectors, failing pmd, massive blowby, and were low on fuel i doubt those symptoms could cause a run away event.

Hate to sound like a GM repair tech, but i think your IP is on the way out. A quick way to check is to try out your cruise control. You will not have a functioning cruise control without a normally functioning IP.

*All of this info provided is an opinion, it is what i know to be true. And is certainly open to debate*Well,I guess i aint young enough to know it all,I been a diesel mechanic for only 40 odd yrs yet.
So, mebby i should just replace parts and forego trouble shooting like a proper technician does these days:rolleyes:

Well,I guess i aint young enough to know it all,I been a diesel mechanic for only 40 odd yrs yet.
So, mebby i should just replace parts and forego trouble shooting like a proper technician does these days:rolleyes:

Did i not mention to test the cruise control?? Sounds like trouble shooting to me. I never said to replace the IP, i said thats what needs to be checked.

Maybe i've been a diesel tech for 100 years, who cares. Try answering his problem not getting nit picky with me. I said i was up for a debate and all you do is try and throw some lame experience story in my face, get a life.

Had a bad IP, or part thereof, on my truck that was still under warranty. The ECM was throwing a code about cyl. off balance or something like that, intermittently. Every time the code was thrown, my cruise control would shut off.

Took awhile, but my troubleshooting charts led me to the fuel solenoid on the IP. The dealership argued with me awhile on that, first replacing a glow plug, then the ECM board and chip. Nothing worked until they replaced the IP. Somehow the cruise and the IP are tied together, probably for a safety reason.

Runaway could be IP or could just be the PMD, when it was relocated was it new???

oil in bad blowby can be fuel in the engine and cause a runaway. Did you ever check out to see if the CDR is at least open?

The rest of your symptoms seem like an air leak, like rusty fuel lines above the fuel tank or a bad PMD or bad PMD extension cable.

Did i not mention to test the cruise control?? Sounds like trouble shooting to me. I never said to replace the IP, i said thats what needs to be checked.

Maybe i've been a diesel tech for 100 years, who cares. Try answering his problem not getting nit picky with me. I said i was up for a debate and all you do is try and throw some lame experience story in my face, get a life.
You musta shorted a fuse,better look for the cause.;)

both the pmd,cooler and pig tail are new so it shouldnt be that,hopefully. a guy that is working on the same jobsite as me said he thinks its air in the fuel system until he saw it act up today, and change his mind to it looks and sounds like something electrical like circuit board. he also said to check the grounds.
i put in a clear piece of hose the ij. and dont see any air,but is it possible that thier is air getting in before the lp. and not see it in the clear line? the reason i ask this is because i got under the truck when it was acting up and put my hand on it and it felt like it wasnt running consistinly but when it straighten out it ran constant.the guy that said to check the grounds said that after it biulds pressure it shuts off,but another guy told me that he wired his trucks to the key and has never had a problem.so once agian im stuck,i feel like were getting closer though keep the info coming please. also there is that round piece on th ip with a bolt head on it could that have any thing to do with it?
thanx again everybody

The round piece is the fuel/engine shutoff solenoid. It comes on with IGN and if it wasnt working it would start or it could cause a stall, but not likely your issue.

No codes at all??? If there are no codes for the APP or anything, and you dont have a lot of oil in the intake (have you checked??) then the runaway must have been caused by IP or PMD. 5000RPM is too high to be anything else like the CTS.

If yo dont see any air bubbles in that clear hose,then the fuel supply system is OK.
As long as you got consistent steady fuel press 4-5 at idle.
A bad APP would set a code.
It may be the IP after all,sticky fuel solenoid maybe,or the advance.

what does cts stand for? i didnt think it had anymore oil in the intake than it ever has like you could run ur finger around it and have oil on it but it isnt exactly saturated.
i did check and you can blow through the cdr both ways. the cruise control never worked anyway and i never checked why so i cant tell that way.
do you really think it could be a bad fuse? what is the advance your talking aboit some of the abreveations you guys use i dont know is there a dictionary on the sight for them?
i cant see bubbles in the line so does that mean there isnt any behind the lp.? nobody commented on wireing the lift pump to the key and if the lp kicks of after it builds up pressure. so is it possible that if there isnt bubbles in the line it could still be rusty fuel lines above the tank, or would the air show up there from that too?
the dealership i got the truck from said that the ip were so famous for going that they warranty them 100k has anyone else heard of this because if that is true mine was done at 197k im under the 100k to get anew one right?

what does cts stand for? i didnt think it had anymore oil in the intake than it ever has like you could run ur finger around it and have oil on it but it isnt exactly saturated.
i did check and you can blow through the cdr both ways. the cruise control never worked anyway and i never checked why so i cant tell that way.
do you really think it could be a bad fuse? what is the advance your talking aboit some of the abreveations you guys use i dont know is there a dictionary on the sight for them?
i cant see bubbles in the line so does that mean there isnt any behind the lp.? nobody commented on wireing the lift pump to the key and if the lp kicks of after it builds up pressure. so is it possible that if there isnt bubbles in the line it could still be rusty fuel lines above the tank, or would the air show up there from that too?
the dealership i got the truck from said that the ip were so famous for going that they warranty them 100k has anyone else heard of this because if that is true mine was done at 197k im under the 100k to get anew one right?CTS-coolant temp sensor.Its in the stickies some where.

The CDR is normall open,closing only under high boost levels,letting blow by vapours including oil suspended in there go in the intake most of the time.

No bubbles in the line means no air pre or in the IP, that dont mean the LP is putting out even if it is running.A fuel press gauge is your friend here.

The advance is a mechanical gadget in the bottom of the IP that is driven by a stepper motor to advance or retard the injection timing.

The IP's arnt that bad,its the PMD thats the issue. Dealerships used to replace the whole IP instead of just trying a new PMD. More money that way. IMO,A bad LP kills the IP internal organs faster than anything else
If your IP was replaced under the 11 y warranty before,your outa luck cause they do it only once.

could oil be leaking past the turbo down the intake and causing the problem?

could oil be leaking past the turbo down the intake and causing the problem?

:agreed:
Complaint of runaway, missing, and lots of blow by. It doesn’t take much raw engine oil to have a diesel runaway. The more RPM the more airflow and more of the pooled oil that is sucked or blown in for combustion.

Your ignition switch will not shutdown the runaway engine if it is running on engine oil. Safest place to stand is in front of it or behind it as parts scatter out the sides including but not limited to the cooling fan. Best to quickly slam the hood if it starts to run away.

Time to look at the CDR hose for the amount of oil and the turbo compressor outlet pipe to the intake. The CDR is the round gold can on the passenger side of the engine. It has a pipe going to the turbo intake. You may want to leave this pipe disconnected and do a bypass as described elsewhere. This is really only a band aid for lots of blow by. (I have had diesels with extremely bad blowby towed to another shop to have the engine rebuilt rather than risk it running away. Aka draining the oil out of the intercooler on a Powerstroke...)

Then you need to check the turbo for a bad oil seal on the compressor side. You can disconnect the turbo to intake tube and start the engine. Powerbrake in reverse and have a friend watch the output air from the turbo to see if it is blowing out a bunch of oil or oil mist.

This is in addition to the above suggestions.

the turbo seals can go bad on both sides,but that situation would cause black smoke and oil consumption,i dont think it would cause a run away.
you can test that by running the engine with the intake elbow removed from the turbo.
if you see oil radiating out from behind the impeller,it leaks.

i might just be trying to aviod the fact it could be the lift pump with wishful thinking so im really hoping the turbo just needs to be rebuilt! but of course it probaly isnt. everybody seems to be on the run away not being caused by the turbo and i understand that. but the reason im leaning tords the turbo is it makes sense to me if oil is getting by into the intake into the combustion chamber it seems it cause the reving and spitting the black and grey smoke seeing thoogh it would take up more room in the chamber causing more pressure and if the intake is on a different cylinder each time it would cause it to run rough and seem like the motor is out of balance until the oil that got in is out.it does have quite a bit of oil in the intake but doesnt seem like it really uses that much. i not trying to disagree with anybody cause it could be the way i explained it the runaway i guess isnt really a runaway if you can turn the key off is it? the reason i called it that is because it reved to the top of the tach on its own with out me doing it but i guess its really not a runaway if i could stop it with the key right? it has only done this twice but the spitting and sputtering and slight revving[2500] and down happen quite frequently and sometime while it is just idleing sitting still. sorry for the missunderstanding i hope this is more clear. dont take this like im trying to say anybody is wrong and i know everything otherwise i wouldnt be asking questions this just a thouht of mine. ass always thanx for the help please keep it coming

Of course you mean 'fuel injection pump' not 'lift pump' as you wrote in you most recent post.

Bison, is there any chance a runaway can be caused by contaminated fuel or maybe a bad ECM?

I still think its the fuel injection pump, or IP for short, or the PMD since it will shut down when keyed off. I am told that anything, including a PMD, can be bad right out of the box. And anything can fail at any time, even a relocated PMD.

the turbo seals can go bad on both sides,but that situation would cause black smoke and oil consumption,i dont think it would cause a run away.
you can test that by running the engine with the intake elbow removed from the turbo.
if you see oil radiating out from behind the impeller,it leaks.

It can. Rare and usually scatters expensive parts... Although I knew of blocking the intake the CO2 fire extinguisher idea is new.

Symptoms described:

http://en.wikipedia.org/wiki/Diesel_engine_runaway

Check the turbo and get the CDR away from the intake!

Smoke...
Black is fuel
White is unburned fuel
White that fades away can be water.
blue is oil.

Sadly you may have more than one issue here.

Of course you mean 'fuel injection pump' not 'lift pump' as you wrote in you most recent post.

Bison, is there any chance a runaway can be caused by contaminated fuel or maybe a bad ECM?

I still think its the fuel injection pump, or IP for short, or the PMD since it will shut down when keyed off. I am told that anything, including a PMD, can be bad right out of the box. And anything can fail at any time, even a relocated PMD.I dont think the ECM is the culprit,a faulty APP may have some to do with it.A broken IP shaft has caused that problem too.

Bad fuel wont have a bearing on it IMO,it usually dont run good on it.

It can. Rare and usually scatters expensive parts... Although I knew of blocking the intake the CO2 fire extinguisher idea is new.

Symptoms described:

http://en.wikipedia.org/wiki/Diesel_engine_runaway

Check the turbo and get the CDR away from the intake!

Smoke...
Black is fuel
White is unburned fuel
White that fades away can be water.
blue is oil.

Sadly you may have more than one issue here.Yes i can happen under certain conditions in diesels,never heard of,or seen it happen on a 6.2/6.5 though. There just aint enough air or atomatization to sustain combustion IMO.

want to tps. cts. and map. senser. i know where there is a truck i could get some parts off from its a 95 and mine is a 94 will any of theese work?

now it quits again like the pmd did before hope you guys are right its warrentied! still think it could be that?