Hello everyone. Marc here. Love the s/c 3800. Have had it in GPs and Ultras. Never had a Riviera before so its a
learning experience. Got a few issues that I have resolved and some I can't seem to nail down. I purchased this
one a few months back but have not driven her much because she seems menopausal.
First off I discovered a few codes in the pcm. Previously somewhere along the way someone removed the CEL and ABS lights. Reinstalled to find the CEL was illuminated, no surprise. Had two codes. Quad driver failure, Had to replace pcm, that code was solved. I got a reman pcm, and with those you have to reuse the prom chip. Next code was a knock sensor code. Changed the sensor to no avail, I traced the circuit to find to short to ground issues. Later found that the prom chip I had to reuse was in fact bad as well.
So what I did was return the reman pcm, got my old one back then got a pcm from a local junk yard prom chip and all, installed it and check engine issues where gone. Interestingly enough while I had the knock sensor code and the timing was retarded 20 degrees had no other drive train issues. Afterwards however, when the engine issues were resolved I started to loose my overdrive after about a mile in each drive cycle. Thinking maybe tcm or tcc solenoid. Other than that the trans shifts and pulls great. No slipping and bumps or thumps. Just loss of OD after about a mile.
Next issue and I have read about them with no real remedy is the temperature gauge stays on 100 and never moves. According to the scan tool I have it gets to temp, fans come on and cycle. Temp sensor has been replaced before I got the car. And what seems to happen to others is the temp and gear indicator go about the same time. The cluster I beleive has been swapped and I can see where the has been repair work attempted on the right hand ipc plug.
Fianlly she is hard to crank. I tested the fuel pressure to fine it was about ten, so I installed a new fuel pump. That helped the fuel pressure but it was still dropping with the key on engine off. That called for a fuel pressure regulator. The fps still drops and the car is still hard to crank. I pulled the intake only to find that the wonderful built quality of the gm intake gaskets had failed, now granted the car has 192k miles on it so I'll be lenient. Not too sure if they are factory or there had been an attempt to replace. I can tell that someone has been in there and I corrected the mistakes that they had made.
So complete update is no coolant temperature gauge or gear indicator. No overdrive past about a mile and still hard to crank.
Sorry for the novel but I wanted to give all the details I can think to give. Not ready to give up on her not to mention I have a pile of cash tied up in this Riv. Thanks for your help in advance