1986 LeSabre LTD problem

Me again...

Is there an easy way to tell if the signal sent by the computer to advance the spark is being used by the ICM? Been trying to figure out an easy way to tell.

My laptop is connected to the serial data on my ALDL, and in 10k test mode the computer says it's sending the spark advance signal, and my engine performance increases slightly. Enough to increase the top speed on about 1/2~3/4 mile stretch of road from 89 mph to 93 mph (I discovered a 15mpg gas mileage decrease a few weeks before the cheesy turbo I had went kaputt. It was old, and I didn't expect it to last very long).

Taking it out of the 10k mode, performance decreases, and I can't monitor the spark advance. EVERY other sensor is reading correctly, and EGR solinoid (which I found unbelievable) is properly functioning. The TPS was reading very low, but I fixed that. This didn't effect the performance, only the idle (as noted by road test and failed gas mileage test).

I have both type 1 and 2 ignition systems (backwards compatable), but am currently using the type 2 (the original factory ICM). I think this may be improperly functioning, so will put the other type on. If this doesn't fix the problem, then I don't know what else to do but start focusing on mechanical failures. (the current motor has 120,000 miles on it. There shouldn't be any problems, but wouldn't be surprised if there were at this point).

I have an '87 driveline in, which is the same as the '86 (except the MAS). The exhaust is white, even after warm-up. Not just a little, either. I also noticed fluid on the vacumnline to throttle body connector (should be dry). Not sure, but I think it smelled like tranny fluid, but fluid level had been fine in the tranny for a while now.

No other car that I have come across has had the same problem. Any ideas? Know any shortcuts to see if the ICM is using the ESA signal?

How about putting your own mark on the harmonic balancer and then using a timing light on it. If the mark jumps around as you rev it, it should prove the advance is being used?

tranny fluid will burn white out the exhaust. You should see a count figure for the IAC during diagnostic, if you switch from park to drive or activate the a.c the count should change.

I found that the P/N switch wasn't reading correctly, occationally getting bumped, and causing the EGR to "malfunction". The computer sensed vacumn in "neutral", even though I was cruising down the road in drive. Pop it down to third, and the SES light turned off. Diagnostics showed that the P/N switch was sending a signal to the computer, which consequently thought the car was out of gear, sensed vacumn, and triggered the light.

Still working on the other stuff. Started misfiring yesterday, so just another thing to fix...

Update:

Earlier I said that putting a 10k resistor over the ALDL terminal A and B (putting the car into the factory 10K test mode) and leaving that in made the gas mileage go up. Well, that lasted for 2 fill-ups on the gas tank, and now back down to 20- mpg.

So, I finally got to changing the Ignition Control Module. Believe it or not, the white exhaust went away...again.

The count for the IAC does change when change from park to drive, or accelerate.

Going to put an scilloscope (i think it's spelled like that) on the fuel injectors to be sure they are getting the proper signal.

Oh, and I noticed that my diagnostic program was showing a rich flag (running rich) even though the ECM doesn't catch it.

Man, my car is beating me. Not cool. This is almost as bad as when I first got it running. Ran horrid for about 10 minutes, then stopped running. Then, it wouldn't run or start at all. Spend two months reading sensor data, ect. Everything was good. Turned out the Cat. converter was plugged up from all the backfiring that had happened when it was first started (which was caused by a bad coil in the first place).