DIS Failure symptoms?

[tccrab]

Lee:

This might be a long shot, but I had a similar heat related misfire. I discovered that the female pin sockets in the ECM plug for the fuel injectors had been stretched by my volt meter and the corresponding male pins on the ECM weren't making good contact. Temperature and vibrations would cause a misfire that would clear again with no obvious clues.
Took me a dog gone long time to figure it out.

Good luck.

'Crabs

[scottfab]

Originally Posted by LGAFF

Having an issue, when I first start driving my 90, the car will miss and sputter for a short time(10 seconds) then run fine, no related codes..... as the exhaust is poping its unlikely fuel.
...snip.....
It also waits to present itself between a shift...1-2 etc

So it happens when the car is warmed up and turned off then restarted?
That is the issue presents again for the first 10sec?

[LGAFF]

Usually its after the car has sat:

Start the car, drive it down the block turn on the main road....bad shuttering popping. Always shortly after a startup, have not had it occur when its warm or being driven.

[scottfab]

Originally Posted by LGAFF

Usually its after the car has sat:

Start the car, drive it down the block turn on the main road....bad shuttering popping. Always shortly after a startup, have not had it occur when its warm or being driven.

Sure sounds like it's OPEN LOOP related so yah I agree with others, fuel related. With the popping it sounds rich when in open loop. Maybe a nasty sticking open injector. Could be very time consuming to isolate. If you have a way to, find out what block/trim looks like on both sides.
Also comes to mind is the O2 sensor heater. It is suppose to bring the sensor up to temp fast. If the element is blown then it'll be slow to respond until the exhaust heats it up. Just some ideas, food for thought

[LGAFF]

I think its the calibration; its fairly generic and I did not run the car in cold weather, car seems better today but its warmer and sunny.

[XfireZ51]

Lee,

If the car is cold and your hitting the accelerator and it stumbles, then the likelihood is the AE is too lean. There's a table for AE Comp v CTS or possibly
MAT that may need tweaking. At operating temp sounds like its ok.
I keep saying you can't expect a modded motor to behave without doing some custom tuning for it. It's not a question of just sticking in a chip and go.

[LGAFF]

Tested the fuel pumps each put up 50psi and held pressure....given the consistency between the two I think they are fine.

[LGAFF]

While I agree, this was not present last year with the same tune....trying to rule out mech issues....thought maybe weather, not sure thats it

Originally Posted by XfireZ51

Lee,

If the car is cold and your hitting the accelerator and it stumbles, then the likelihood is the AE is too lean. There's a table for AE Comp v CTS or possibly
MAT that may need tweaking. At operating temp sounds like its ok.
I keep saying you can't expect a modded motor to behave without doing some custom tuning for it. It's not a question of just sticking in a chip and go.

[-=Jeff=-]

Originally Posted by LGAFF

While I agree, this was not present last year with the same tune....trying to rule out mech issues....thought maybe weather, not sure thats it

Did you check too see if you have fuel in the tank?

I had a problem with my 90.. in Open loop car ran like crap, once in Closed Loop it was fine, it did similar things your car is doing. I swapped the ECM and it fixed it.. since you have a few cars, swap the ECM into another car and see if the problem follows, you could do the same with the Ignition module, move the one you think has issues into a car that runs fine. That is one way to narrow it down for you

[LGAFF]

Well not too bad today, buts it warm...I had the tech 1 on and noticed the BLM Int went to 70 when it stumbled....