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Help please got code 88

625fireman

625fireman

I have injecter-itis
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Location
NE Ohio
I trying tset my tdco and i got a damn 88 code. No matter what i have tried i cant get it to clear.
1 tryed thru GMTD scan
2 jumped pins and held throttle and brake
3 unhooked batteries overnight
4 changed ECM but not chip
5 pulled ecm fuse for 5 min

nothings working cant get it to clear...............
 
Try and get ahold of Buddy, he knows the OBD1 ecms pretty well. Shoot him a PM , he was online earlier. I'm not sure why. So it's not that it keeps throwing the same code, it's that you can't erase the existing one ?
This will sound dumb but you had the motor not running when you tried right ?
 
Try unplug the connectors on the top of the injection pump be sure there is no corrosion or water in them. I got code 17 and 18 and couldent do a TDC relearn until I tinkered with the harness. Been working fine for 2 months now. And X2 for buddy. He knows the OB1 very well
 
This code cannot really be erased, when you do, it comes back next time you check it until the timing is set right. So you need to run the TDCO learn procedure and get a value between -2.02 and +2.02, if either of those values show then its out of tolerance, but doesnt go any higher or lower than that regardless of how far out you are. If the TDCO shows 0 then the PCM has never learned a TDCO value or the memory got erased.

With GMTDScanTech, the full version you can momentarily delete it and immediately run the TDCO learn procedure. But if you were to go back and check codes before getting a good TDCO it would just be there still.

If its out of tolerance youll have to physically move the IP.
 
Ok that dosent change anything. No matter where i physicaly put the pump i get a -2.02. It definatly changes what the engine sounds like though.

I have a thought though could I have a bad stepper motor????
 
Can you step us through what you have tried each time. Are you running the TDCO learn procedure or just trying to clear the code?
Assuming you have the full version of GMTDScanTech and no other codes
should be something like this.
Warmed up truck
Ran TDCO learn, have -2.02 with the DTC88, shut off truck
loosened IP nuts and moved towards passenger side, tightened top nut
Ran Time Set, and got about 3.5 degrees average in the actual injection timing window while desired was 0 degrees.
At this point you could go over to codes and temporarily clear the DTC88
Ran TDCO Learn and .........
Got -2.02 again, so shut down truck, loosened IP again, moved further towards passenger side......

Attached in this file is the procedure I use, and a picture of about how the IP mounting flange should line up with the timing wedge on the timing cover. Also explain some of the common issue you encounter with this.
 

Attachments

  • Mnx&Mods info.pdf
    1.7 MB · Views: 20
Last edited:
Hmmm...IIRC there is a separate button in GMTDscan to erase historic codes. If it's there but no light it's a historic code. I don't have an OBD1 truck anymore to try it on but I seemed to remember having that issue getting rid of a code 41.
 
Big T no I never touched the crank position sensor.

AS for what I did.

I plugged into the truck and the setting in the truck was +8.5 +8.5 -0.7
set the time set and it was set to +8.5 +8.5 -2.02

the reason I asked about the stepper motor is that the rpm never changes or does the motor sound any different during the entire process while time set or tdco learn.
Temp is up above 175 every time it was done, codes were cleared with engine off.

Its wierd while doing the time set it is 0 in the first box, the center box has NEVER gone below 5.8 and has gone as high as 13.4 but it always goes to set at 8.5 +,- 1.0.

I have tried running the tdc time set, and TDCO with it in the center where it was, moved to passenger side at three differnet spots, then moved to the drivers side at three different spots.
Again no matter where the pump is physicaly on the truck the times set and the TDCO numbers ahve not changes since the first time I ran it.

However listening to the engine it does not sound the same when I move the pump so I know I am changing the timeming but I have no clue where it is at.
 
625fireman said:
the reason I asked about the stepper motor is that the rpm never changes or does the motor sound any different during the entire process while time set or tdco learn.
Click to expand...

My engine didn't change sounds or speeds any either while doing time set or TDCO. My timing and TDCO did move however.
 
So after reading Buddy's attachment I need to crank the pump towards the passenger side.
 
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