HELP! Please

[dhmarkley]

Hey guys, I need some assistance. I have a 1995 GMC Sierra K2500 with a 6.5 and a 5 speed. The problems started about 3 weeks ago, the truck started loosing power and being harder to start. After that I noticed that the check engine light started to come on and go off as it pleased.

I took it to the dealer to see if they could diagnose the problem or not and they said that they retrieved 7 codes from the computer. They told me to drive it around until the light came back on and then bring it to them ASAP. I drove it home and by the time I pulled in to my drive, that dam light was back on. I found my code reader and read the codes and they were that same 7 that the dealer found.

I told the dealer what had happened and they said the only thing that I could do is drop it off for a week or so. I would rather not have to do that because their rate for diesels is 85/hr.

My question to you guys is, what do you think it could be?

ERROR CODES: 19,34,49,57,62,84,99

Thanks and any help would be greatly welcomed.

[Chevylover]

DTC 19 - Crankshaft Position Reference Error

DTC 34 - Injection Timing Stepper Motor Fault

DTC 49 - Service Throttle Soon Lamp Circuit Fault

*DTC 57 - PCM 5 Volt Shorted

DTC 62 - Turbo Boost Sensor Circuit Low

*DTC 84 - Accelerator Pedal Position Circuit Fault

DTC 99 - Accelerator Pedal Position 2 (5 Volt Reference Fault)

All DTC(S) with the * sign are automatic transmission (4L80E) related


Looks like a massive electrical problem. First you should check ALL grounds but seems to me more that there is a short anywhere in your harness. Perhaps made by a little animal, we call in germany a "marder".

Cu,
Sven

[3bals]

I had a "marder" take the insulation from the firewall and build a nest under the intake manifold, but luckily didn't eat any wires or fuel lines.

Jody

[jdogg00074]

I had an old 6.2 no-turbo that sat for 7 years and i finally got around to gettin her up and running. took a little while to start but when i got her running it shot mice and their nests out the dual exaust. bad place to make a home. truck ran great though even after sitting that long

[Husker 6.5]

Marders are a ferret like creature indiginous to the European continent. Saw a segment on I believe 60 Minutes a year or so ago where they were in Denmark filming with night vision cameras. The varmits would walk up under a parked car, then proceed to climb up into the engine compartment and completely trash anything they could gnaw on, wire harnesses, fuel lines, they even had an underhood camera that caught one little S.O.B. chewing through an A/C line! He got his when it let loose!

Husker 6.5

[3bals]

Marders are a ferret like creature indiginous to the European continent. Saw a segment on I believe 60 Minutes a year or so ago where they were in Denmark filming with night vision cameras. The varmits would walk up under a parked car, then proceed to climb up into the engine compartment and completely trash anything they could gnaw on, wire harnesses, fuel lines, they even had an underhood camera that caught one little S.O.B. chewing through an A/C line! He got his when it let loose!

Husker 6.5


Marder, mouse, same thing, or so.

Jody

[Husker 6.5]

Marder, mouse, same thing, or so.

Jody

Sshhhhh. We got to be vewy, vewy quiet. We'we hunting wabbits. Ahahahahah.:D :D :D

Husker 6.5

[TedReminder]

Try taking off the filter in the optical sensor harness and plugging it in without the filter. You might just have a bad filter. Just a guess but worth a try.
I second the suggestion to freshen up all the grounds too.
Ted

[dhmarkley]

Thanks for all of the sugestions, i will try them this weekend and let you know how i make out.

THANKS! :)
Derek

[dhmarkley]

Ok, I was onder the hood looking around and i found an orange plastic vacuum line that was pinched shut. I traced it and it goes from the vacuum pump to a sensor and then a black vacuum line goes from the sensor to the wastegate. So I fixed the line, ran the truck for a cupple of mile to get her hot and then came back and tested for codes again. To my suprise, I am down to 3 codes now. 18, 19, 34. Any more ideas?

THANKS!:D
Derek

[dhmarkley]

Try taking off the filter in the optical sensor harness and plugging it in without the filter. You might just have a bad filter. Just a guess but worth a try.
I second the suggestion to freshen up all the grounds too.
Ted

:confused: Where is this located? Sorry if it's a dumb question, but i just recently started working on 6.5's. I am used to working on little isuzu and VW diesel motors.

[Chevylover]

it is plugged in the wire harness directly at the injection pump.
have look here : Optical_Sensor_Filter_Harness (http://www.ssdieselsupply.com/product_62_Optical_Sensor_Filter_Harness.html)

Cu,
Sven

[Husker 6.5]

:confused: Where is this located? Sorry if it's a dumb question, but i just recently started working on 6.5's. I am used to working on little isuzu and VW diesel motors.

Based off the codes you're throwing, I'd look at the cranshaft position sensor and/or for a failing harmonic balancer. Your codes are referencing the inability to accurately determine the position of the crankshaft (either because the balancer is failing and the reference magnet is "wandering" or the CPS (pick-up sensor) is failing. This gives a signal for crank position that the stepper motor in the IP can't compensate for and hence the 34 code for the stepper motor fault. Use search mode to find references for these problems that have already been addressed in the forum previously.

The optical filter harness has a flat plug on each end with a "Black box" in the middle. One end plugs into the IP, the other into the engine harness.

Husker 6.5

[dhmarkley]

I just looked at the site and it said "Will require a TDC Learn Procedure to be performed after replacement to "zero" everything back up." How do i do this? I am going to order one today.

Thanks for all of your help!
Derek

[Husker 6.5]

I just looked at the site and it said "Will require a TDC Learn Procedure to be performed after replacement to "zero" everything back up." How do i do this? I am going to order one today.

Thanks for all of your help!
Derek

You will need a Tech II scanner to perform the procedure. Not cheap. See if you can rent/borrow one from a GM dealership or mechanic friend.

Husker 6.5

[TedReminder]

There is a very good program available for use on a laptop computer. Go to www.enghmotors.com and check it out. It is the GMTD Scan Tech program. $200 US including the plug to interface with your truck computer. It is for 1994-95 years only. Does everything the tech 2 does. Times the pump, sets TDCO, reads and clears codes, and reads every sensor your truck computer reads. I have it and love it. One trip to a dealer for a scan or pump timing would cost much more than the program.
Ted

[dhmarkley]

I just checked my codes again and they are all gone, well except code 12 of course. Thanks for the link to that code reader/reprogramer! I just ordered one. I also just got the new marine injectors and i am off to find the #9 resistor.

It is amazing how one little vacuum line can cause all of them codes to come up.

Thanks again for all of your help!

Derek

[grancito]

I looked at that site and it quoted $85, is that right?

[dhmarkley]

I looked at that site and it quoted $85, is that right?

$85 for just the dongle, $199 for the software and the dongle.

[Craig]

Wow, This GMTD Scan Tech program looks awsome. I am going to get one. I just put in a new motor and was going to the dealer to perform settings. I will just get this instead. Thanks for the heads up.

[Craig]

I got the Engh Motors kit and it is fantastic. I set my TDC and TDCO. It has so many features. Thanks for the recomendation.:)

[dhmarkley]

Ok guys, I thought that i made some progress, but i think i spoke too soon. New/Old Problems:

Error Codes:
19 - Crankshaft Position reference error
18 - Pump cam reference puls error
34 - injection timing stepper motor fault

Code 34 seems to come up whenever the motor is under load. Ex:Idleing with the air on, 4th gear going up a steep hill (lugging a little)

NEW PROBLEM:
I am now having starting issues. It seems to hapen the most when the motor is warmed up. It has gotten really bad here lately with 90+ days here. It will crank, fire and run for about a second then shut off. When i try to restart it will only start if i give it about 1/4 throttle and then it just gives a big puff of black smoke and is ready to be driven.

Another thing i just remembered is that when i was driving up a hill the other day in 4th it started to miss and carry on a little.

Thanks for all of your help guys!

Derek
95 GMC 6.5