Anybody,

Maybe some one can help me with this. I replaced my injector pump and need to time it. I have Auto Tap with the GM enhancements. I can read all the data needed to do the timing and set back but I can't reset the computer to do the initial pump timming to 3.5 degrees. Do you know of any way of resetting the computer so I can set the pump timming and offset without the Tech-2 scan tool?
MFParker
:help:

I wish Big Brother would stay out of my trucks computer. You OBD-II guy's have worse than me.

Does auto tap have a time set command? and is idle timing displayed what value do you have for that?

If you know somebody with a MT2500 I can help you there, many shops have a MT2500.

Also any shop with a MATCO or MAC is a T2 clone, MT2500 works but takes some doing. Does it not run at all or hard starting and idle stumble

Tim,
I install a rebuilt injector pump and got readings of > 12.5 for actual and desired injection timing. The reading for the TDC offset was >5700 degrees. Without being able to use time set command to command timing desired to 0 deg., I believe I am just getting bad readings or at least ones I can’t use to time the pump. Auto tap doesn’t have a time set command. Do you know of any other programs that can be used with a lap top that can access these functions?
The Suburban idles and runs but smokes more than it should. I’m trying to fix a problem where the truck just shuts down on me like I turned the ignition off. I replaced the PMD with no success and now am replacing the pump to see if this solves my problem.
Blaine (MFParker)

Pump is too advanced - rotate IP 1mm to passenger-side - should retard timing to within what is considered 'hi-performance' area, giving about +8.5deg and about 5 to 5.5deg TDC offset on your scantool, which would be -1.5deg TDCO on TechII.

Then do key-on-key-off procedure for TDC Learn, in FAQ section, above.

First thing to do when your resetting TDC offset, is make sure when you install the pump, that the pump is as close to a vertical position as you can, if anything, just a hair to the driverside to compensate for timing chain slack.
Next, operate the vehicle to get the coolant temp to > 170F (77C).
Clear ALL codes.
Shut the vehicle off, Turn the key on, hold the gas pedal to the floor for 45 sec. Release the pedal, and turn the key off for atlease 30 sec. Restart the truck, you should hear the engine get quiet or stumble for a second, this tells you the PCM is trying to relearn the offset and has commanded the stepper motor to full retard position for comparison to crank signal.
Go to the data display on the scanner. First check TDC offset to see if it is in spec, and that it has relearned. If the pump is too far advanced for the PCM to relearn, then you will notice that the Actual timing will read a few degrees less than Desired. This means the PCM set the IP to full retard, but it is out of the acceptable range and the pump needs to be retarded, and the procedure repeated. This is a common occurance, if this happens the truck will smoke white, A LOT!
If the pump is too far retarded, then usually the PCM will be able to relearn a new offset, but it will be a positive value, or >-.25. and the pump should be advanced accordingly.
Hope this helps ;)

Texas Diesel Guy,
Can the above procedure you mentioned be done without being able to use the “time set command to command timing desired to 0 deg.” as called for in the shop manual timing set procedure?

The time set command you are referring to, is a tool to help set TDC offset, it is quite handy, and can speed things up a bit, but this procedure can be done without it.

The truck still stalling?
Are you sure of your fuel supply pressure?