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Sometimes when the engine is cold and temp is cold it will start just fine warm up to operating temp and be fine all day! The next day same start up condition starts fine run it for 5-10 minutes with out driving, shut it off come back later in the day will not start have to give it full throttle to get it to run but runs like **** back firing rough and runs really really rich!
I bought this car for my son it's a 1991 Oldsmobile 98 regency elite with 220000 miles with the best motor that ever came out of GM the 3800 Buick motor which I love to death that is saying a lot since I was a certified Mopar tech! Which was a long time ago and before I had a SAH type brain aneurysm that ruptured and ended up bleeding for almost 5 days so my mind is not what it used to be, so please help me for my son! I have just about revamped the interior with a 70's flair (a lot of velvet, I love messing with my son! It's so FUN! lol) which looks great, but for this problem I have installed a new computer, coils, ICM (Magnavox), Timing chain since I was there to replace the cam sensor and magnet which I epoxied in and the O2 sensor just tuned up new fuel filter spark plugs etc.. It has 2 codes related to this I am assuming that. The other codes are related to ac and cruise control and anti theft. 42 Electronic spark timing which is intermittent and does not light up the SES well not long enough to notice it and the big one 65 rich exhaust right bank which I am assuming it is a misprint since I only have 1 but I do believe it has something to do with this and might be causing it along with something else maybe a Fuel pressure regulator or a throttle body issue. Am I on the right track? I want to clean the TB which should have been done during a tune up, but only if it was done by a Pro and upsold. the other is the fuel pressure regulator can the GM version get locked into place and act like its a wide open throttle when it's actually trying to idle so the throttle would need to be depressed so it could run or do you think the TB IAC system is so clogged it's jamming up the IAC or interfere with something else to do with it or a combination of both or something else Any help would be great since I am a brain dead dumbass now! Thanks to all who decide to help me!!!!!
 

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Update did not start as normal even with a cold engine and cold ambient temp like it usually does. Since this was weird for the car I ran self diagnostics well I tried it did not go into self diagnostics, disconnected the battery and tried again. I know that GM uses a prom or chip unlike Mopar can a bad chip or prom do this and if it can is there a chance a bad prom burned out my new computer. When I first bought this car it had bad coil pack and ICM replaced both, once running again I ran self diagnostics and it had a MEM-CAL, cam sensor code so I replaced the cam sensor which led to the magnet which was not there which led to the timing chain and gears. Should I have replaced the prom?
 

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Wish I could help, but not much help on this one:
A) my eyes started bleeding trying to read your story inter-twined with actual car notes
B) not too much experience with pre-OBDII stuff, aside from some Fiero work to eliminate/upgrade from it

From what I did read, it seems like you've got a bunch of oddball factors you're trying to discuss all at once, which is a nightmare to troubleshoot in-person, let alone help thru the internet.
 

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Wish I could help, but not much help on this one:
A) my eyes started bleeding trying to read your story inter-twined with actual car notes
B) not too much experience with pre-OBDII stuff, aside from some Fiero work to eliminate/upgrade from it

From what I did read, it seems like you've got a bunch of oddball factors you're trying to discuss all at once, which is a nightmare to troubleshoot in-person, let alone help thru the internet.
If I were in your shoes, I would get hold of a GOOD(professional) diagnostic scanner. Using that you would be able to see all the necessary parameters and if they are normal and then correct the issues as required.. GOOD LUCK! Mister Goodwrench...... Get back to us on the forum with your findings.....
 

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Sometimes when the engine is cold and temp is cold it will start just fine warm up to operating temp and be fine all day! The next day same start up condition starts fine run it for 5-10 minutes with out driving, shut it off come back later in the day will not start have to give it full throttle to get it to run but runs like **** back firing rough and runs really really rich!
I bought this car for my son it's a 1991 Oldsmobile 98 regency elite with 220000 miles with the best motor that ever came out of GM the 3800 Buick motor which I love to death that is saying a lot since I was a certified Mopar tech! Which was a long time ago and before I had a SAH type brain aneurysm that ruptured and ended up bleeding for almost 5 days so my mind is not what it used to be, so please help me for my son! I have just about revamped the interior with a 70's flair (a lot of velvet, I love messing with my son! It's so FUN! lol) which looks great, but for this problem I have installed a new computer, coils, ICM (Magnavox), Timing chain since I was there to replace the cam sensor and magnet which I epoxied in and the O2 sensor just tuned up new fuel filter spark plugs etc.. It has 2 codes related to this I am assuming that. The other codes are related to ac and cruise control and anti theft. 42 Electronic spark timing which is intermittent and does not light up the SES well not long enough to notice it and the big one 65 rich exhaust right bank which I am assuming it is a misprint since I only have 1 but I do believe it has something to do with this and might be causing it along with something else maybe a Fuel pressure regulator or a throttle body issue. Am I on the right track? I want to clean the TB which should have been done during a tune up, but only if it was done by a Pro and upsold. the other is the fuel pressure regulator can the GM version get locked into place and act like its a wide open throttle when it's actually trying to idle so the throttle would need to be depressed so it could run or do you think the TB IAC system is so clogged it's jamming up the IAC or interfere with something else to do with it or a combination of both or something else Any help would be great since I am a brain dead dumbass now! Thanks to all who decide to help me!!!!!
I'd be willing to bet you have a few or more bad fuel injectors. Very similar issue happened to me.
 

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I would recheck any electrical components that you replaced, especially aftermarket. You really should put oem acdelco coil packs and replace all 3 at once along with icm. I think humidity causes wonky behavior too with bad coils. Id also check plug wires for leaks. Then move on to tb. Dont think any sensor except the maf maybe would cause a nostart. Crank/cam sensors could cause a nostart. Might be worth looking into last.
 

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11yr old post... Oops, read the wrong thing. Pre-coffee eyes
 

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Well I do not have anything to really update with the car, but I found and bought the OEM GM shop manual for this car. I have no doubt that I will eventually find the problem since these type of manuals are the Holy Grail of car manuals even though the writers and engineers who design and build these cars and write the manuals use way to much illegal substances! LOL I do want to let everyone know where I found this manual I bought it off of ebay but the company specializes in all automotive literature. They say they either have or can get anything from 1920 till now when it comes to manuals and lit.. The company is Faxon Auto Literature in Riverside, California I hope this helps you Guys and Gals. I will let you know what the problem is with the car when I find out!

Steve
 
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