I'm going to try and describe this as best as possible, as my tuner is having problems on a new engine build.

Everything seems to be working properly except they cannot add spark. If they try and modify the spark tables, the ECM simply doesn't respond; timing stays at whatever it's manually set at with the distributor. Apparently it is also not even adding spark based on the STOCK spark table, either. There is simply no spark advance. They tried using a different ECM, and two different ignition modules with no change. All other tuning changes work fine, fuel, thresholds, etc. so it's not a prom or software issue.

I admit to not understanding how spark control works very well, so I hope I've described this as best I can. suggestions?

 

Not sure what EFI system you are using, but most have a forced timing setting. Check and make sure your Calibration software is not set at a forced timing setting

 

Sorry, it is the stock ECM and EFI system. ECM 1227165 on an 88 T/A.

 

ESC, electric spark control or wiring to it ??

Later

 

Yes. probably the wire to ESC that is unplugged.

/N.

 

No, the wire is plugged in. And it tests fine. Trust me, if it was that simple we wouldn't have been fighting with it for three days. If I remember correctly if the ESC wire is bad/unplugged you get a code, there are no codes, which is what led them to believe it was the ECM in the first place. But a new ECM didn't help.

 

I'd try a different ESC anyway, what have you got to lose?

I try not to take anything for granted or face value and
been down that road before
5 minutes work

good luck

 

Here's where my inexperience shows....

It's my understanding that the ESC is, well, the ECM. Yes? This has been replaced with no change. What I thought was the ignition module, or whatever its called that recieves these signals and controls the physical advance/retard in the distributor has also been replaced. Again, no change.

Sorry if I'm sounding like a total newbie, Ive spent the last two years learning about heads/cams/intakes and haven't yet got to the ignition system.

 

The ECM is the computer.
The Electronic Spark Control is your spark control device.
The ignition module is located inside the distributor.
The ESC should be located on the firewall on the pass side of
your brake booster.

Just unplug it and try another one.
Don't know, if you leave the old one in place you may have to ground it to the firewall but may have plug ground.

HTH

 

Update:

replaced the stock ignition module (again) and also the ESC module. No change. The only thing that has not been replaced at this stage is the actual stock prom/memcal that we are piggybacking the tune on. Again, I'm not sure this is the cause as all other changes that have been ordered (fuel, EGR deactivation, injector size change, etc) take just fine. Again, the car adds 6 degrees to whatever the base timing is set to and that is it. So it is adding some timing, but not at all responding to any changes made to the spark table.

It's as if the car is in limp home mode...sort of. No code 42, no dumping gas, but the EST is bypassed. We're thinking of possibly swapping out proms, which presents it's own set of difficulties as 87-88 proms are very difficult to find.

 

When you say you are piggybacking your new tune
on a stock memcal and prom

Do you have a adapter like the Moates HDR1 where you can physically remove the chip and reprogram the chip
with your new info ??

If you can program other items like fueling, temp, ect,
the complete Memcal unit wouldn't be the problem.

What programing equipment and software are they using
to make bin changes??

You don't need the stock chip to burn new bin to.
256-512 chips work fine with the correct offset or stacking
employed.




Later

 

Found it. It was in the stock chip PROM.