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6.5 has me lost

H

Hammerhead

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94 chevy 2500, hard to start, when it does start it blows black and gray smoke. While driving it will sputter. Can’t go over 55mph, as soon as I do the check engine light comes on( as soon as I let off the accelerator check engine light goes off.I unplugged the coolant temp sensor and it did help with the smoke but not the sputtering or the CEL
This is a list of things I have done to it over the last year.
1. New fuel tank, sending unit, fuel lines, fuel filter, and lift pump
2. New injectors
3. New PDM
4. New donut gaskets
5.new batteries
6. Started on glow plugs( got 3 in before one broke off,so I do have a broken one still to get out)
7 new coolant temp sensor
At this point I have more money in it than it’s worth so I guess I gotta figure it out

Any help is appreciated
 
Welcome. Wish you found us beforehand.

Leroydiesel.com sells a glow plug remover tool for the swelled glow plugs.
ONLY use AC Delco 60G plugs. They are self limiting and won’t swell up. There is one made by Bosch but their quality went to garbage and is a huge mistake to buy along with any other non regulated one.

Video of it running might help- post to youtube, bitchute, etc and post link here.

Black smoke is most commonly air flow problem.
Secondarily can be over fueling.

Plugged AIr filter, rag getting in the air plumbing, turbo not functioning from loss of vacuum system, etc.

If you are burning engine oil- that can be an issue as well. This can lead to engine run away and be very dangerous.

Are you getting any codes?
Does the smoke smell like oil, or fuel?

Please fill out your signature line with truck details and any modifications done. It will pop on each post you make automatically and help us a ton with diagnostics as this goes through. There are several things that can cause this so expect a descent amount of back & forth here. Check the thread frequently- definitely the best and most active 6.5. Group around.
 
Get You a vacuum gauge and see how many inches of vacuum the pump is producing.
Buy about 6” of clear fuel hose and install that on the top of the lift pump to the return tube, with the engine running, watch for air bubbles flowing through the clear fuel hose.
An electronic fuel pressure gauge is also a big help in diagnostics. Leroy diesel sells a FP tap that fits atop of the fuel filter where that bleed screw is. Ideally a FP gauge where the pressure fitting plumbs into tue top of the injection pump is the best location.
I had a live gauge hooked to the filter location then I learned that it could be very dangerous if the tube springs a leak or cracks then it could become a fire hazard.
Welcome to the forum HH.
 
So much help and advice in a short period of time! I’m liking this forum already . I just ordered the hook ups from Leroy diesel .I will go down these list and check all items , probably be next week sometime being that it’s fair demo derby season and I have some destruction to inflict. I’m sure I will have additional question, but thanks for all the help so quickly.
I know very little about diesel but decided to buy 2 of them! Probably not my smartest move
 
There is lots here on the forums to read about and learn from on these 6.5 engines. Great group of guys and gals here too! stick around and you'll be an expert on these old rigs! lol.

since yours is a 94, how well versed are you with a PC or laptop? there are very few scanners around that can actually read codes and data properly on these rigs. if you plan to keep your rig and want to invest into a scanner to read codes and data, along with set the timing if it's a DS4 electronic injection pump (no throttle cable to the go pedal) you basically have two tried and true choices... well three if you want to spend more money lol.. there is the genuine GM tech2 scanner (big money), a Chinese copy of the GM tech2 that does just as good so long as you never update it, and a laptop with some software and a USB cable.

if you know your way around a windows laptop I can help get you started with some free software (paid version gets you more functions) and share some knowledge on how to build your own USB cable to connect to the truck saving you some funds. the cables already build sell for around $50-$75 and if you need to set timing or other more in-depth diagnostics, the software will do everything a GM tech2 can but you'll have to invest another $100 for a licensed version.

Just to be clear, I'm not selling anything, just sharing some knowledge. since you check engine light (SES) is turning on, even when it turns off the code will still show up on a scanner and might help point you in the direction where you need to start looking. I am almost certain you have a boost solenoid code. but until you can read them, we are only guessing and will be pointing you to eliminate issues like fuel and vacuum issues.

A lot of these guys are well versed in what to look for without even seeing what codes are showing up, so take their knowledge in as much as possible. @Will L. and @MrMarty51 gave you some great suggestions to start with.

as far as reading codes, there is also the old paper clip method too. just shorting out two pins in the connector and counting the SES light flashes. But I am not certain that this method will show historical codes if the SES light is not currently staying lit.

if your interested in the PC software and making your own USB cable, I can post up the info and how I built mine.

and sorry for the long winded post, I usually don't post them this long but I think @Will L. is rubbing off on me here. HAHA!
 
Check the injection pump and see if its original. GM issues a TSB for all the issues you are having. The fix was an updated injection pump. 99% of the ones I get in the shop end up needing a pump. Double check the lift pump and supply fuel system before you throw any more parts at it.


Here is the TSB


#67-63-04: HARD START, NO START, START STALL, ROUGH IDLE - (Oct 30, 1996)

SUBJECT: HARD START, NO START, START STALL, ROUGH IDLE, STUMBLE AND LACK OF POWER (NEW OPTICAL SENSOR AND CERAMIC ROLLERS)

MODELS: 1994-96 CHEVROLET AND GMC C/K, G, P TRUCKS WITH 6.5L DIESEL ENGINE (VINS F, S, P--RPOS L65, L56, L49)

CONDITION: SOME OWNERS MAY COMMENT ON THE FOLLOWING CONCERNS: HARD/NO START, START STALL, ROUGH IDLE, AND ENGINE STUMBLE WHEN OPERATING UNDER HIGH TEMPERATURES AND LOAD CONDITIONS. RELATED DTCS: (1996: P0251, P0370, P1216, P1217), (1994-95: CODES 17, 18, 35, 36).

CAUSE: A DISTRESSED OPTICAL SENSOR CIRCUIT BOARD MAY CAUSE NO OR IMPROPER CAM SIGNALS WHICH AFFECTS PUMP TIMING. ALSO, LOW LUBRICITY FUEL MAY RESULT IN WORN INJECTION PUMP CAM ROLLERS CAUSING LOW FUEL OUTPUT.

CORRECTION: AN ENHANCED FUEL INJECTION PUMP WAS RELEASED BEGINNING WITH THE 1997 MODEL YEAR THAT CONTAINS AN IMPROVED OPTICAL SENSOR. IN ADDITION, NEW CERAMIC ROLLERS ARE ALSO RELEASED WHICH WILL HELP PREVENT ROLLER WEAR DUE TO LOW LUBRICITY FUELS.

SERVICE PROCEDURE AS WITH ANY COMMENT, THE CONDITION MUST BE DUPLICATED BEFORE ATTEMPTING TO DO ANY REPAIRS AND A THOROUGH INVESTIGATION DONE TO DETERMINE THE PRIMARY CAUSE OF THE CONCERN. IF DTCS ARE PRESENT, REFER TO SECTION 6E OF VOLUME 2 OF THE SERVICE MANUAL TO TROUBLESHOOT ANY/ ALL DTCS. FOR OTHER DRIVEABILITY SYMPTOMS, USE THE SAME MANUAL.

1994-96 MODEL YEAR SERVICE INJECTION PUMP 1. 1996 MODEL YEAR 0-12 MONTHS, 50,000 MILES. WILL BE SERVICED USING A NEW REPLACEMENT PUMP, PART NUMBER 12558156- MODEL NO. 5288 TO REPLACE A PART NUMBER 10225930 INJECTION PUMP (REFERENCE BULLETIN 57-63-04A FOR 1996 INJECTION PUMP EXCHANGE PROGRAM POLICY).

2. PART NUMBER 10225930, MODEL NO. 5067. INJECTION PUMP WILL BE REBUILT BY THE STANADYNE DEALER AND IDENTIFIED BY STAMPING MODEL S5288 AND PART NUMBER 12558156 ON THE MANUFACTURER'S PLATE. IN ADDITION A "GREEN" TAG WILL BE ATTACHED TO THE FRONT OF THE PUMP.

3. PART NUMBER 10225929, MODEL NO. (5068). INJECTION PUMP WILL BE REBUILT BY THE STANADYNE DEALER USING THE NEW OPTICAL SENSOR AND CERAMIC ROLLERS. THE PUMP WILL NOT BE IDENTIFIED WITH A NEW MODEL NUMBER BUT WILL HAVE THE "GREEN" TAG ON THE FRONT OF THE INJECTION PUMP AND STAMPED (S5068) ON THE NOMENCLATURE LABEL.

4. ANY NEW INJECTION PUMP (PART NUMBER 10225930) WILL BE SUPERSEDED TO THE NEW PART NUMBER 12558156. HOWEVER, IF A NEW PUMP PART NUMBER 10225929 IS ORDERED IT WILL BE AN UPDATED MODEL 5068 WITH THE "GREEN" TAG HUNG FROM THE FRONT OF INJECTION PUMP.
 
Hammerhead said:
So much help and advice in a short period of time! I’m liking this forum already . I just ordered the hook ups from Leroy diesel .I will go down these list and check all items , probably be next week sometime being that it’s fair demo derby season and I have some destruction to inflict. I’m sure I will have additional question, but thanks for all the help so quickly.
I know very little about diesel but decided to buy 2 of them! Probably not my smartest move
Click to expand...
Eventually you will want to do the lift pump relay upgrade on any 6.5. 1995 and older.

Leroy sells a plug and play lift pump relay upgrade.
If you make your own, make it plug and play.

Where did you get the injectors?

There's a lot of garbage parts out there.

In my opinion any injectors need to be tested & balanced before installing.
 
Keep in mind these pumps were never designed to run on ULSD. They eventually updated some parts top handle it better. So if you have and older style pump that wasn't upgraded to the current standards then it could have failed again. That TSB we pre ULSD so even the upgraded optical sensor and ceramic rollers don't cut it with todays fuel standards. Fuel additives are a must on a DS4. The DB2 on the other hand can be fully upgraded to handle anything thanks to the US military.
 
That is something that I didn't think about. it was being mentioned in another thread here too. on the injection pump (IP) optical sensor connection there was a connector with a little black box inline, then another connector to it. this will be the big connector on the top of the IP housing. if you see what looks like a sort of extension harness with a squarish black box in line on the wires. unplug it from the harness and toss it in file 13 (trash) reconnect the optical sensor without that extension. that little thing is a resistor type noise filter that can give you fits.

Mine had one on it and it would randomly start fish biting and sometimes just flat stall out. removing this fixed the issue.
 
jrsavoie said:
Eventually you will want to do the lift pump relay upgrade on any 6.5. 1995 and older.

Leroy sells a plug and play lift pump relay upgrade.
If you make your own, make it plug and play.

Where did you get the injectors?

There's a lot of garbage parts out there.

In my opinion any injectors need to be tested & balanced before installing.
Click to expand...
I want to say they were Bosch but I’m not sure that was a year ago. I do know the problem was before the injectors and there was zero change after the new ones were installed.
 
Hammerhead said:
I want to say they were Bosch but I’m not sure that was a year ago. I do know the problem was before the injectors and there was zero change after the new ones were installed.
Click to expand...
If you can spare the time, I'd pull the. Injectors and have them tested and balanced by a trusted shop. Unless you're set up to do it yourself
 
I remember mine had one when I first bought it, one day it started randomly fish biting. I started one day finding it by mistake while I was messing with stuff while idling. barley touching it and the truck just died! you guys here on the forum told me to toss it. after that I have never had that issue again! :)
 
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