Allante Friends,
I am writing because I am practically at my wits-end with my 1992 Allante. Three weeks ago I decided to finally fix that pesky oil leak at the oil cooler line near the filter by replacing the o-ring seal, per my factory service manual's suggestion. The repair went flawlessly. However....to get to the line...the inside, hardest-to-get-to line, I had to remove the top of the air cleaner and rubber tube that the went to the throttle body, the cruise cable and one electrical conncter, then the outer cooler line and the oil pressure sensor. I think that's all I removed or disconnected.

While I could see inside the throttle body, I noticed the two butterflies had a small bit of dirt around the outside edges, so I used some Gumout carburetor cleaner I had on hand to knock-off that little bit of dirt. I could not have used much more than an ounce or so, as my can was almost empty and I had trouble getting hardly any to come out of the can. I did this with the engine running and it nearly killed the engine several times as I sprayed the cleaner. When I was done and tried to drive the car it ran Horrible! I had never had a single drivability issue before and was quite disturbed. At first I had an E017 code (left 02 sensor not ready). I clerared that code and it came back one time. I thought maybe I washed the dirt into an injector, so I got a can of seafoam and put it in the fuel tank and ran it through, then filled with fresh 91-Octane gas. No help whatsoever. The E017 code has not come back again, but because I got it twice, I replaced both O2 sensors. again, no help. One of the tests point to the PCM, but that's ridiculous, unless all this is just a great coincidence, which I doubt. I do get random codes once in a while on the tailights and other sensors, and I just clear them and they stay away causing no problems.

I little more detail on my drivability issue: The engine misfires, seemingly on one cylinder. It will cut in and out, running fine for short times then drop back out to a misfire. I am about out of ideas short of replacing the PCM. The O2 sensors were relatively inexpensive, but the PCM is more and more work as well. Given your collective level of genius, I thought I might ask for even a guess that might help.
JB

 

Okay gang! It took me over two months but I finally fixed my '92 Allante. It was the Engine Control Module. I knew there was a good chance it was the ECM, but could never prove it. Finally I saw a guy on youtube use a Noid light to test injector pulse in his 1992 Deville. He said no flashing light meant no signal from the computer so most likely a bad ECM, which he claimed did fix his car. He also had an intermittent like I did. So I rented a Noid light and it was on, then it was off, then it was on again! That was it for me. $100 for a reman ECM and I'm back cruising the Caddy.

Noid light! Who knew?

Oh yeah, about my claim that this all started with spraying the carb cleaner. Well, it kind of did, although I remember now I had seen some check engine flashes, but had no drivability problems. I wonder if spraying the cleaner with the engine running made so many parameters out-of-whack at once that the ECM overheated trying to compensate everything? It was on the verge and kablooey! I may never know for sure, but I like the theory.

Thanks for all the posts and thoughts about this. It was a challenge for me to say the least.

Thanks,
Jeff

 

Nice suggestion about to completing or solving this issue.I really like it and now i think it properly diagnoses.Be careful in this type of hazards it may cause serious problem with you.