I have a DTC code 88 that I can not get to clear. My tdco always reads -2.02 and will not learn no matter how I move pump because this code will not clear. I have it even when engine is not running I know this code is because of offset error but do I have another problem causing this.

 

Hi JJ-

I have a 1995 GMC 6.5 Diesel. I have a DTC 88 and no matter what I do I cannot clear it and consequently....I cannot set the timing.

I have swapped PMD's, I have swapped ECM's, I have turned the pump back and forth a ZILLION times, I have disconnected the batteries over night. No matter what I still have the DTC 88 and the timing is on -2.02

I own the Enghs motors software so I can clear the code, but it comes right back and so it will not set the time. It even sets the code when the engine isn't ON!!!

I seen you post with a similar problem and I am wondering if you found a solution? Any tricks or tips before I just start the truck on fire?

Much appreciated. Will from Minnesota

 

Yankee, My pump was just to far out of time. I could not rotate it enough with injection lines tightened down. So you may have to loosen them in order to rotate easier. Code will not clear until you are within timing limits. Make sure you are not going from -2.02 to 2.02 while rotating as a little changes timing a lot. Start with shutoff solenoid vertical or slightly toward drivers side.

 

Thanks JJ for the reply. I will try again today, but I have to admit.....I go in without a lot of hope. I have placed the pump back (several times) exactly where it was before I moved it and it still comes up -2.02. Not once has it showed any other numbers, I would be relieved to see +2.02 just because it would tell me that at least the computer is seeing movement!

The joke to all this is that on several moves, including the spot where it is now.......the truck has never run BETTER. For the 1st time in a DECADE, it doesn't smoke up on a cold start. Drives like it has nitrous.

I have already paid over 300 dollars by 2 different dealerships over the past 5 years to set the timing and all of it was a waste on money. I don't believe the Techs at GM know how to set the timing anymore if they ever did. I always get the truck back with lower power and smoking rough starts.

I wonder if the timing chain could have skipped a tooth? I am probably just grasping at the "replace something" mentality at the end of my frustration. I wish I could live with the SES light ....but I can't do that either. It's has to be right or it will bug me.

It's only a matter of time at this point before I round off the nuts that hold the pump down after so many movements.......

Thanks again.

Will

 

HELLO JJ and GOOD TIDINGS TO YOU!

I stand here before you on a field of victory drinking a cold Bell's cutthroat pint of beer........and I wish I could buy you on as well.

Thanks for the advice. I will be honest, like I had mentioned....I had very little hope today of curing this DTC 88 HELL problem. But I took your advice to the truck with me and really turned the pump the other way. BOOOM!! I finally got off the -2.02!! End up hitting -1.14 and cleared my 88 code. Turned it off and bumped the truck just a teeny tiny bit towards the drivers side and it went back to -2.02....then I barely feathered the pedal and it flashed to -1.94 for a couple seconds bouncing around.....waiting patiently again....and BAM! Nailed -1.94 and shut the LEARN off.

WHOOOOO HOOOOOOOOO!!!!!!!

Can NOT believe how the truck runs now. I repeat...CAN NOT BELIEVE IT. Can't wait to run into my 1st unsuspecting Ford 7.3.......

Now the Heath Max-E-Torx prom, HX 35 Turbo, 4 inch diamond back exhaust, open air filter, and duramax cooling fan are all working together properly and it feels real good.

Thanks for the direction JJ, it sure makes a difference just talking things through with someone else. (I will write you back when I blow the heads off. )

Will - Minnesota

 

Great to hear it worked for you. I admit they can be a pain in the rear, but when right they do run good. Good luck. Any more questions just ask. This is where I learned. JJ