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Old 11-13-2012, 03:43 AM   #1 (permalink)
jlwade
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1993 6.5 TD... Lift pump power question

Hello... I'm back.

First I must say this...
A while back when my truck died I had posted about my truck but due to me being a total newbie as a diesel owner and totally NOT knowing anything, I started internet research, came across this site, did a lot of reading before I posted, learned a few things, got totally lost and confused on other things, I posted my post... but... due to my lack of knowledge combined with total confusion I had lots of questions tryed to be thorough in explaining, but instead I became a rambling idiot, was called one (nicely though, without idiot added to it) and in a round-a-bout kind of way, was told to get lost. So if any of you who are reading this now were one of the few who did reply to that post...I do deeply appologize. I am sorry. Did come very close though to totally giving up and just trashing my truck after that. But couldn't do it. I love my truck. I miss my truck. I needs my truck.

Unfortuneatly since then, fixing my truck got put on the "back burner" and has been just collecting dust and spider webs. I can't let her sit no more. I gotta try to get her working again. I needs my truck.

I no expert, never gonna be, but now I know and understand things more (by 100% at my level of knowledge) than I did before. So... enough said. Just wanted to say sorry about my last post. I be smarter now. So this should be easy.

Quick recap...
The day truck died... in morning I started it up. No problems. Other than the normal quirks (to me back then I did not know that the "quirks" were actually warning signs that something was eventually going to go bad) Put her in gear and went. Back country road the speed limit is only 35 so all is seeming ok. 2 miles down the road is the freeway. I am getting onto freeway and I give it the gas and shift and the truck drags. I first thought tranny cause there was no difference in speed when I shifted. Down shifted. No difference. Shifted again and it "kicked" in. About 7 miles down (I have had past experience with other cars to know when an engine gets starved of gas it drags down) all of a sudden the drag down starving engine action starts. I try the pedal to the floor reaction and all that is happening is I am still dragging down. I have to down shift but it blows through soback up to speed I go. About 5 miles down it does it again. And again but this time only about 2 miles and went down to almost a crawl and down into 2nd gear then it broke through so I sped it up but only got 1 mile and this time it quits. I tried a couple times to restart but nothing. Truck did this to me once before (about 5 months prior) and so I just did what I did then, I let it sit for about 5 minutes then retry. It did restart. Quickly got moving (didn't give it chance to want to redie) My destination was just 3 miles to go. but now can't get past 3rd gear. Get to certain speed it dragged. Had to back down to 2nd gear, get to certain speed, it blew through. Repeat that 2 more times. Prayed like crazy to get to where I needed to get. Didn't want to stop till I got into parking lot but I had to turn at a lite... I prayed for green but got the red but truck died before I got to lite but had enough momentum (and luckily no traffic and had a wide shoulder) I blew the red lite and turned onto the shoulder of road and that is where she permantly died. The rest is history...

Not happy my truck has been sitting for so long. My batteries which were good, ended up taking a crap from not being used for so long. Hoping a good charging will revive them. We'll see what happens with that...

The only thing I have done so far is put in a new LP. It DOES work. I did a test after installation of touching a wire from hot on battery right to the fuse and with key in the on position You can hear the LP. 1st question... What is the normal sound (if there is shuch a thing) should a LP make? The one I took out I never heard. Of course I never listened for a sound and didn't know I could've heard or actually should've heard or to even listen for a sound. When I heard the LP I opened bleeder hose and touched the fuse again. Fuel came pouring on out. Closed bleeder hose and cracked open the thingy on top of the fuel filter. Touched the hot wire to the fuse. Man oh man... the fuel that came shooting outta there so fast and so high would have put any fancy high shooting water fountain in the world to shame (in a small fuel filter scale version...lol)

Now question #2... I have read on here throughout the threads you have mentioned that a OP can and most times (depending) will work without the LP working but it won't last for long cause the strain of it working alone will kill it for sure but... can a LP work without the OP? and if it can/does, are there any tell tale signs, signals, actions or reactions between the two. Working LP WITH working OP... Working LP WITHOUT working OP.

OR... for me in my situation, is it just a guessing game? Cause I also read here throughout the threads you all have made mention that there is no way to test an OP to see if it IS a working OP or not. Without knowing if mine is good or not, I did/do plan and still will, just to be on the safe side, putting in a new OP and real soon too. But for right now if the LP will work without the OP, I just want to at least turn the key and have the truck actually start and run for a bit (not driving) and so maybe check for any other (hopefully none) problems that can only be checked for WITH the engine running.

Question #3... can the LP work without the LP relay? Or is that a mandatory my have?

Like I mentioned... New LP installed. LP was tested with hot wire jumper. Can hear LP loud and clear during test and also opened bleeder hose and filter top thingy and fuel flowed fast. Now take away the hot wire jump and "pretend" as if all is working proper. I put key into in, turn it to on position (no cranking over the engine. just on)... LP is dead silent and no fuel flows out the bleeder or filter thingy. Question #4... What am I missing? Other than the OP and the LP relay, what else is there? Well... wait to answer question #4 untill I get question #3 answered. But Question #5 can be answered... The LP relay was a fairly new one (only a few months old). So when the LP quit, could it have blown the relay? I know some relays can be tested but I have no clue how to even do that. If the LP relay can be tested... How do I do that?

OK... that should be all for now. I'm seeing positive good signs that my Big Red will be up and running again and oh so close I am getting the flutterbys in the tummy feeling just thinking about me and her runnin down the road working again. I have had a major financial blow to me the past few months so yea I am being as cheap as I can be. Depending on the answers here... if it's mandatory then yes I will have to get and will. If it is needed but not mandatory just to crank her over and listen to her running for a few minutes, then a few days wait won't hurt. Just want to crank her over for right now. Running down the road will be later.

Thank You all in advance
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BIG RED 93 K3500 6.5 Turbo Diesel 5 speed 4X4 crew cab with long bed.

Rigged for bumper pull and gooseneck ball hookup.
She is a workin girl. and she does it very well. She not all that pretty but then again if she were pretty... she wouldn't be a truck. She is a big girl and she got her big girl pants on and wearing her color beautifully.

RUBI 1999 Jeep Wrangler/Rubicon Sport 4X4 4.0L 6 cyl ragtop and half soft side doors. 3 inch lift. ball hitch in rear. and she can haul with the best of them.

She is dressed to play and she plays dirty. Loves to go topless and is a flasher. She may be covered in dirt and mud but she wears it well. Her good looks come shining through.

Jack of all trades... master of some... Leader of the roost.
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Old 11-13-2012, 09:43 AM   #2 (permalink)
racer55
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Ok got through most of the chapter,LOL.

It is good that you got a new and apparently working LP,here is what should happen and when:

When you turn the key to start the LP relay should activate and the LP should run,test this by putting the gear selector in D or R and turn the key to start-the neutral safety switch should prevent the starter from engaging but the LP should operate.

Once the engine starts and you release the key to the run position the OPS(oil pressure switch) should take over power duties for the LP,OPS's commonly fail and should only be replaced with AC Delco switches-the OPS relay mod is an additional relay you can add or buy a kit from Kennedy Diesel to eliminate OPS failure long term:
OPS relay install
http://www.kennedydiesel.com/detail.cfm?ID=402

Now that you have bled the filter of air-when the fountain happened at the filter,you need to bleed the IP(injection pump).

The way that I do that is to crack loose 1 easy to get to injector fuel line-then crank the engine over for 15 second bursts with a 1 minute starter cool down period between cranking sessions,typically it takes upwards of 3 such sessions to get the engine running.
Once running tighten the loose injector fuel line carefully so as not to get caught in moving parts-done.

If your fuel filter has not been changed for some time you might want to replace it before beginning any of this.

The way to test if the OPS is powering the LP when the engine runs is to open the water in fuel drain(Tee valve by thermostat) and note if the engine stalls.
If it stalls the OPS is not powering the LP and needs replaced-then start the bleeding procedure again because it is as though you ran out of fuel.

The IP can pull fuel from the tank on it's own as long as there are no leaks to break the suction,and as stated it wears the IP much more quickly-the LP should be kept operational at all times.
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Relocated PMD/Heatsink to Front Bumper #9 Resistor
K-47 Standard Duty AC Air Filter And K-47 Housing
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Last edited by racer55; 11-13-2012 at 09:57 AM.
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Old 11-13-2012, 10:08 AM   #3 (permalink)
JMJNet
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LP on a 93-95 does not run when key is to the on position and during cranking.

When the engine is running, the LP will start running due to the oil pressure because the OPS runs the LP when engine is running. If the part of OPS that control the LP is bad, you will not have a running LP during engine run.

You can add a relay that can energize the LP when the key is on before cranking or engine runs.
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Old 11-13-2012, 10:13 AM   #4 (permalink)
racer55
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Quote:
Originally Posted by JMJNet View Post
LP on a 93-95 does not run when key is to the on position and during cranking.

When the engine is running, the LP will start running due to the oil pressure because the OPS runs the LP when engine is running. If the part of OPS that control the LP is bad, you will not have a running LP during engine run.

You can add a relay that can energize the LP when the key is on before cranking or engine runs.
LP should run during cranking otherwise what good is the LP relay?
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96 Chevy C3500 Dually 6.5TD F Engine 4.11 Rear/5 Speed
Relocated PMD/Heatsink to Front Bumper #9 Resistor
K-47 Standard Duty AC Air Filter And K-47 Housing
Kennedy special calibration fan clutch/Kennedy 20" steel fan
LeroyDiesel.com oil cooler kit
Diamond Eye 4" turbo back exhaust
2 1/2" crossover
High Idle Mod
Feed The Beast 2.0
EGT,Boost gauges
Diagnostic Checklist 2.0
OBD1 Codes
OBD2 Codes
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Old 11-13-2012, 10:29 AM   #5 (permalink)
FloridaHorseman
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Ditto what racer said.

To be clear, the OPS has two internal circuits; 1 for the oil pressure sending function and 1 for powering the LP. It's the weak circuitry in the OPS for the LP that fails from continued high amperage (heat) to operate the LP when the engine is running. That side of the OPS fails but you still have indicated oil pressure saying the OPS is working. For newbies that's usually the confusing part of the failed LP equation.

The recommended LP relay mod calls for a new OPS because it must still use a working LP side of the OPS. But instead of sending the high demand voltage/amperage directly to the LP through the weak OPS circuitry it uses much lower amperage through that same circuit to just trigger a higher amp rated 12v relay taking direct battery power to operate the LP. That reduces the strain on the OPS but maintains the original intended safety function of shutting off the fuel supply when there is no oil pressure.

And for test or "emergency" operation you CAN run 12v direct to the LP to keep it running. The problem you describe does sound like fuel starvation under load. A cheap mechanical fuel pressure gauge Tee'd into the fuel line at the IP inlet on a long piece of fuel line that can extend back to the windshield cowl will tell you what the fuel pressure is when the engine starts to bog. The OEM or proper replacement LP on your '93 should produce between 9-15 PSI at idle and no less than 3-4 PSI at full throttle. If the fuel pressure drops below that or even goes to zero with a new functioning LP it indicates the fuel filter sock in the tank is clogged and creating a vacuum in the fuel line. ~FH
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Old 11-13-2012, 01:32 PM   #6 (permalink)
jlwade
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Hi…

Question #3... can the LP work without the LP relay? Or is that a mandatory must have?

Thank you Racer and hey, sorry if it seemed a little long but I did much much better this time ...lol  … Ok so I do need the relay for LP to work. No problem, as soon as I read this I got a friend getting me one right now.

That is one thing I didn’t do (or know to do) was to have it in gear. When I did it I just left it in neutral and depressed the clutch as if I was going to actually cranking it over but not. Only to on position.

And I guess I forgot to mention… my truck is a standard.

So to clarify (make sure I understand right)… Put truck into gear… no depressing clutch… turn key to on… SHOULD hear LP… if I hear nothing when I do it this way, than does that mean the relay is blown?

OOPS… didn’t bleed injectors. Will do that.

Sorry JM but you ALMOST got me and recunfuzzled me but I did a lot of reading here on this site and was also told that my year truck is in a class of its own. Doesn’t run or work like any other year (early or late) engine. But all info from everyone is good to me. I am a learning newbie.

Florida… newbie confusion is an understatement… LOL… and I do believe you in a way answered my #2 question. But forgive me as I clarify and got it right… I WILL be getting a new OPS to put in no matter what but for right now in testing and to at least get her cranked over and run for a few minutes at least, it’s not mandatory at this testing only moment.

Getting a fuel pressure gauge sounds like something for me I’ll need to do. Be my early warning detector…lol. So that will be my next step. First I wanna get her to at least crank over and next week when I go to get the OPS I will squeeze out my pockets and try to get that too.

Thank you all for the input.

These may not be the important questions but could still be useful for me to know. Can you answer my questions #1 and #5 please.

1st question... What is the normal sound (if there is such a thing) should a LP make? The one I took out I never heard. Of course I never listened for a sound and didn't know I could've heard or actually should've heard or to even listen for a sound. This new one is loud. I can step away from the truck 10 or 20 feet and still hear it.

Question #5… My LP relay was a fairly new one (only a few months old). So when the LP quit, could it have blown the relay?

Again… Thank You all
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BIG RED 93 K3500 6.5 Turbo Diesel 5 speed 4X4 crew cab with long bed.

Rigged for bumper pull and gooseneck ball hookup.
She is a workin girl. and she does it very well. She not all that pretty but then again if she were pretty... she wouldn't be a truck. She is a big girl and she got her big girl pants on and wearing her color beautifully.

RUBI 1999 Jeep Wrangler/Rubicon Sport 4X4 4.0L 6 cyl ragtop and half soft side doors. 3 inch lift. ball hitch in rear. and she can haul with the best of them.

She is dressed to play and she plays dirty. Loves to go topless and is a flasher. She may be covered in dirt and mud but she wears it well. Her good looks come shining through.

Jack of all trades... master of some... Leader of the roost.
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Old 11-13-2012, 01:47 PM   #7 (permalink)
racer55
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You need to turn the key to start position without touching the clutch for the LP to run.

The clutch switch is your neutral safety switch.

LP's often make a rapid clicking sound when working.

It is unlikely that a bad LP would burn out a relay but a dead short could do it.Check the LP fuse as well-it powers the relay.
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Relocated PMD/Heatsink to Front Bumper #9 Resistor
K-47 Standard Duty AC Air Filter And K-47 Housing
Kennedy special calibration fan clutch/Kennedy 20" steel fan
LeroyDiesel.com oil cooler kit
Diamond Eye 4" turbo back exhaust
2 1/2" crossover
High Idle Mod
Feed The Beast 2.0
EGT,Boost gauges
Diagnostic Checklist 2.0
OBD1 Codes
OBD2 Codes
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Old 11-13-2012, 02:59 PM   #8 (permalink)
JMJNet
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Quote:
Originally Posted by racer55 View Post
LP should run during cranking otherwise what good is the LP relay?
Not on the 95's LP until I added the KD harness aka relay.
In theory, it should run but the stock relay is useless and never works as it is supposed to.

Does not mean to create a confusion or disrespectful to racer and FLHorseman.

My dad bought a 96 and LP runs during cranking.
My brother have a 94, and LP does NOT run during cranking either.

If nobody believes me, then so be it.
Again, not trying to create an argument or disrespectful to other member or confusion.
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Heath Turbo-Master
Chevron's XLP Diesel Additive

Last edited by JMJNet; 11-13-2012 at 03:06 PM.
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Old 11-13-2012, 04:25 PM   #9 (permalink)
racer55
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test procedure:
Fuel Pump Relay not working
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96 Chevy C3500 Dually 6.5TD F Engine 4.11 Rear/5 Speed
Relocated PMD/Heatsink to Front Bumper #9 Resistor
K-47 Standard Duty AC Air Filter And K-47 Housing
Kennedy special calibration fan clutch/Kennedy 20" steel fan
LeroyDiesel.com oil cooler kit
Diamond Eye 4" turbo back exhaust
2 1/2" crossover
High Idle Mod
Feed The Beast 2.0
EGT,Boost gauges
Diagnostic Checklist 2.0
OBD1 Codes
OBD2 Codes
6.5 FAQ
Carcode & TDCO Instructions

Last edited by racer55; 11-13-2012 at 04:26 PM.
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Old 11-13-2012, 04:28 PM   #10 (permalink)
racer55
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Quote:
Originally Posted by JMJNet View Post
Not on the 95's LP until I added the KD harness aka relay.
In theory, it should run but the stock relay is useless and never works as it is supposed to.

Does not mean to create a confusion or disrespectful to racer and FLHorseman.

My dad bought a 96 and LP runs during cranking.
My brother have a 94, and LP does NOT run during cranking either.

If nobody believes me, then so be it.
Again, not trying to create an argument or disrespectful to other member or confusion.
96 was a transition year where early models were like 95 and later models were like 97,eg dual and single stats,LP operation ect,although I have not heard any were OBD1 that model year?
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96 Chevy C3500 Dually 6.5TD F Engine 4.11 Rear/5 Speed
Relocated PMD/Heatsink to Front Bumper #9 Resistor
K-47 Standard Duty AC Air Filter And K-47 Housing
Kennedy special calibration fan clutch/Kennedy 20" steel fan
LeroyDiesel.com oil cooler kit
Diamond Eye 4" turbo back exhaust
2 1/2" crossover
High Idle Mod
Feed The Beast 2.0
EGT,Boost gauges
Diagnostic Checklist 2.0
OBD1 Codes
OBD2 Codes
6.5 FAQ
Carcode & TDCO Instructions
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