1998 6.5TD Running rough (checklist inside)

[cnysix5]

Hello all,

First time posting here. Have been scanning the forums a lot, and read through many many posts on here, and other places on the net.

I have a 1998 k1500 6.5TD I bought it, and it wouldn't start. Had it towed home, and below is a list of everything I've done to this point, and my problem now.

I'll try to be as specific as possible, and give as much info as I can, so you guys can help me out!

Let me give you a little background of what I was told from the PO.

Truck was from Texas. (I'm in NY, and bought if from NY). PO ran a bio diesel blend I guess. (50%veggie/50%diesel) Drove it fine for a couple of years then it quit when he brought it up here. (I'm assuming because of the weather) He said everything was all gummed up which lead him to the dealer. He had replaced brand new tank, filters, brand new turbo (all from dealer, and new GM passlock2... irrelevant?). They had checked lift pump and it was functioning. They told him it needed an injection pump.

This is when I acquired the truck. (btw PO had already done the PMD relocation.)

Here is what I did from the get-go.

1. Brand new starter and, starter wire (battery - alternator - starter)
2. Brand new batteries fully charged.

At this point I "sort of" got the truck to be able to start. Took a VERY long time to crank in order for truck to start. I have a video which I can post if necessary.

I realized if I losen the bolts on the EGR truck would start right up. Lots of smoke though up near the intake. This lead me to... (as I read in the checklist) clogged up cat. Took a saw-zaw down there and sawed off my cat. Viola! truck starts up right away no problem.

Drove it down the street to my friends shop to get a straight pipe welded on.

Here is what I noticed.

Throttle is VERY touchy; Tons of power upon immediate take off, then it falls on its face. Lots of smoke. (gray). No smoke any other time. Took it very easy, and brought it back to my garage.

Now when I would start the truck it sounded like a very bad missfire on a gas engine. The whole engine would shake very violently like it's going to rip itself out of the frame. Occaisionaly it would surge up then go back down. It idled very high ~1500+

I thought maybe it was a PMD. So I bought a brand new PMD, and swapped them. Same thing.

Next I scanned the computer and pulled two codes. No check engine light. (well 3 actually 3rd for EGR not really my problem now. It was unplugged)

P0251
P0370

P0406

Optical sensor bad... Hmmm I read all about this on the net. I started the truck, unplugged the sensor and idle becomes steady, immediately drops. Then if I put it in gear, and then back in N or P it slowly goes back up to high idle.

So at this point I opened up the top of my pump, marked where the OS was, took it out and cleaned it. Put it back in. Started the truck, and it was great fro maybe 2 minutes. Perfect idle, ~750 - 800 no shake or surge in rpm. I got too excited. Immediately all the above symptoms returned. If I unplug it, then truck runs fine.

Attempted to clean it out again, but it wouldn't change anything this time. I tried to bump it to see if the disk that the OS actually reads from was not too dirty. I retarded it, and it was definitely noticable. Advanced it, and it just ran like garbage. So I put it back.

Next I purchased a used good condition Injection pump. I just finished swapping them. I turned on the truck for the first time and it was great for maybe 1 minuted this time. Then it went back to the same exact issue.

I do not have access to a scanner to even know where my timing values are, but at this point I'm really stuck.

I have 3 PMDS, two injection pumps, a whole lot of cuts on my skin etc. The snow is coming, I would love to have this thing on the road! PLEASE HELP!

1. Describe the problem you are having in detail:

see above

2. Year of truck/engine.

98 k1500 6.5TD

3. Odometer reading (indicate miles or kilometers).

132k

4. Indicate the model number on the Injection pump (starts DS4 or DB2......).

DS4

5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD.

1500 on the doors 4x4

6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit)

Yes

7. Air Filter condition (visual check).

Clean

8. Fuel filter condition (freshly changed, mileage since changed).

Freshly changed >100

9. Location of PMD/FSD? (ex. on pump/remote over intake, behind bumper).

Inside cab under seat with heat sink, and fan PO

9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor).

Not sure looks like not homemade. Again PO

9b. Indicate the location and condition of the FSD/IP grounding wire.

Ontop of the IP

10. Outside Temperature (C or F). _____ °

Today 40° F

11. Service Engine Light while running?- on/off/intermittent

No

11a. Service Engine light does glow during start/cranking/bulb check:

Yes

12.Have you scanned for engine codes?

Yes 1st time before IP r&r

12a. List exact results on engine codes.


P0251
P0370

P0406

13. Condition of Battery terminals (removed, cleaned and tightened).

Good, yes to all above

14. Known condition and age of Batteries.

New, very good


14a. Are batteries a matched set of same age?

Yes

15. Condition of Major Grounds (removed, cleaned and tightened)

Yes the ones I could see.

16. Does engine crank, or "turn over"?

Yes

16a. Does engine start and run?

Yes

17. If engine does not start- Crack injector line: do you have fuel? Yes/No

NA

18. Does your Wait To Start light come on?

Yes

18a.Number of seconds WTS light is lit.

Depends on temp Very cold maybe 10 - 15secs?

19. Engine Cranking speed (if you have an accurate tachometer).

Fast

20. Are you experiencing Stalling?

No

20a. Describe the event (upon startup only, down the road, hit a bump, etc...)

All the time

20b. Do you notice loss of dash or instruments?

No

21. Check turbo inlet and air filter for obstructions.

None

22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?

NA


23. Lift pump test - Describe results.

Plenty of fuel from t-valve and top of fuel filter

24. Upon cold start, does the radiator hose get hard quickly?

No

25. Upon cold start, do you have excessive white smoke?

No

26. Do you have excessive cranking time before the engine starts?

No

27. Have you used the block heater? Does it affect engine starting? (only try for starting problems).

NA

28. Are all glow plugs in proper working order?

Yes I presume so. No white smoke at startup

29. During hard acceleration, do you have excessive black smoke?

Haven't really had a chance to drive truck

30. Do you have any unusual exhaust smoke issues?

31. Turbo check out - Pass/Fail

Right now I'm having an issue after IP replace. It was working fine before.

32. Indicate fuel that you are using: Bio-Diesel, #2 Diesel, SVO/WVO, other

Regular pump Diesel

32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system).

NA

33. Are you using any fuel additives? If so, please list.

Just put fresh 5 gals of diesel with Diesel Kleen

34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank?

Today first time I did notice a lot of air come out.


35. Do you have any service history available that might pertain to the problem you are having?

See above

36. Please indicate any modifications to the vehicle that might help us diagnose better.

None

[JMJNet]

I feel your pain!!!

Try to test with the different PMD and see if one can get you starting again.

[cnysix5]

Originally Posted by JMJNet

I feel your pain!!!

Try to test with the different PMD and see if one can get you starting again.

Thanks for your reply. I will try that tomorrow. When you mean starting again do you mean running correctly? Is that PMD related you think? The truck starts up fine right now...

Do they have to be properly mounted, or can I do a quick swap without it being mounted?

Also w/ or without resister?

Thanks.

[cnysix5]

Update:

Wow... It seems that I was so caught up in this whole mess I overlooked a very easy solution lol.

I did just what JMJNet suggested, and whadya' know? It worked! Perfect!! Let's hope it stays this way.

Just in case anyone else comes upon this thread later with the same problem here is exactly what I did.

I replaced my PMD with another Stanadyne used PMD with a #5 resister. I plugged it in and mated it to the surface of my heatsink. Turned the truck on, and it seemed to work okay so far.

[racer55]

You should still get the TDCO checked,and I would also replace the IP return line with clear diesel rated tubing and watch for bubbles-your symptoms sound a bit like air intrusion as well.

[cnysix5]

Thanks racer55. I will try to get that done A.S.A.P. Hopefully I may be able to get my hands on a scanner soon, and will post back here for help and such.

Also I will to the return line clear tubing suggestion as well. Any idea where to get such tubing? Also what size?

Thanks.

[racer55]

Most small engine repair shops have the line-size is something I am unsure of at the moment.