Hello:


I'm having a difficult problem with my 1992 Buick Regal. From time to time while driving I notice the "Check Engine" light comes on for a minute or so, then goes off. Since this problem has appeared there has been another problem which occurs every 5-6 weeks. That problem is that the car refuses to start or even "hit" likes it trying to do so. After a few days it starts and the above process starts all over again.I bought one of the Actron Diagnostic Code Scanners and followed the instructions on scanning for code failures. The results yield:


CodeMeaning


23 Manifold Air Temperature (MAT) sensor- high or low voltage
OR
Throttle Position Sensor (TPS) sensor error
OR
Mixture Control (MC) solenoid- open or short circuit problems





43 Electronic Spark Timing (EST) circuit- low voltage detected
OR
Electronic Spark Control (ESC)- circuit problems



66 Air Conditioner (A/C) pressure sensor- circuit problemslow charge
OR
Electronic Control Module (ECM) computer circuit problem-internal resetoccurred
OR
(Transmission) 3-2 shift control solenoid- circuit problems



So, I've discovered all three diagnostic problems. Thankfully, every time the car has refused to start it has been at home. I would like to ask a couple of questions about this situation. When the above problem was noticed (the refuse to even try to "hit") could I have disconnected the power from the computer (by disconnecting one of the battery cables) in order to reset the computer would if have probably started after this reset? The obvious question- what would be the best way to narrow it down to the exact problem(s)?


Thanks for your helpEdited by: gciuser

Well, I'd say there is no chance unpluging the battery and reseting the computer, all of those sensors are scanned like every 200ms. The only thing I could see it being is the 43 and 23 as your AC wouldn't cause your cut outs.


as far as 23: I'd have to rule out the mat, cause from a cold start it shouldn't make a diffrence, unless the thing is physicaly dammaged. I'd also have to rule out your TPS, cause when that goes (and it goes slowly(months - years)with a eratic RPM as a symptom) A TPS is just a Rhiostat (Variable resistor) that is connected to your throtle plates, these wear out cause you are a creature of habbit and so is your car, when the throttle plates stay in a cirtain range (Like idle, or 40mph) for most of the cars driving time. the rhiostat wears in those spots. usualy at the bottom (idle) or mid point around the RPM/speed you normaly drive. needless to say you would have noticed something wrong way before this compleatly died, again unless it is physicaly damaged. as for MC selenoid, these Almost never go, usualy if something's wrong with it, it is wiring.


So In short I'd say for code 23, when the car runs if it has an eratic idle, it's your TPS (not the cause of your car not starting).


43: this is prolly where your problem is. Ether one of those will stop your car from running, new plugs n leads maybe, but maybe also a new coilpack (cha ching)


66: they shoulda called this one 666: basicaly if you get a code 66, you're not going anywhere for a long time. I'm talkin about the ECM not the AC,I've never heard of a fried ECM SOMETIMES working, they ither work of they don't that's why I think that code is blowing for the AC. But if not, Your ECM (computer) is internaly resetting mosy likely due to shortage or bad sensory input.


But now that I've commented on all the codes, I'm starting to see a pattern, Like alott of BAD wiring, shorts or otherwise, one short/bad wiring job wouldn't cause an internal reset, but many could. First thing would be first, I would locate each sensor as per the codes, trace the wiring for them back to thair sources, and maybe you'll find something you can fix with just a little tape or wireloom, if not then, do the next cheepest thing, plugs and leads, still hooped? coilpack (the pack of coils (dist) that your leads for your plugs come from).


These OBDI's are prety good, you can trust em so if it's blowing 3 diffrent codes, you more than likely have 3 or more problems. price them all out, test the ones you can (TPS) with a VOM (multi meter) then start replacing them, in Cashological order :) 1 by 1.


Hope this helps.

Thanks so much for the help. You've given me a great head start. I have noticed that there has been some hesitation in the acceleration during a hard pull. I think that may have resulted, at least in part, in that 43 error code. What books/service manuals do you recommend for finding out where these sensors are physically located and for a wiring diagram?


Thanks again so much.

sure thing, Haynes is my favorite publisher of automotive manuals. sometimes I'd swear they have every car coverd.. but sadly this is not the case.. But lucky for you they cover all domestic modles since the 70's ish...


http://www.haynes.com/na101.html#anchor561259


Scrool to the GM section, you'll find your car.


38010 - Buick Regal, Chevrolet Lumina, Oldsmobile Cutlass Supreme & Pontiac Grand Prix all front-wheel drive models. Buick Regal ’88 thru ‘02, Olds Cutlass Supreme ’88 thru ’96, Pontiac Grand Prix '88 thru '99, Chevrolet Lumina '90 thru '94. Does not include information on supercharged engines.


So your next step would be finding a place to buy the book.


http://www.amazon.com/gp/product/B0002KKRPQ/qid=1150259098/s (http://www.amazon.com/gp/product/B0002KKRPQ/qid=1150259098/sr=8-1/ref=sr_1_1/102-5556038-0500141?%5Fencoding=UTF8&v=glance&n=15684181) r=8-1/ref=sr_1_1/102-5556038-0500141?%5Fencoding=UTF8&v= glance&n=15684181


I found you one on sale :) or you could just try your autozone or some place like that.


And hey, no problem man..Edited by: Harley