1988 GMC 4×4 350 cold running problems
Question:
My computer was acting up and driving me nuts. I in a fit of desperate rage started smacking it with a stick one day while driving down the road. (I had the glove box out to mess with it) A GM tech told me afterwards it was probably dirty and I dislodged the dust. I really felt like the master of my truck that day : )
Response:
not yet, but then it’s only got 220,000 miles on it . Jack – Hide quoted text — Show quoted text – > Jack…do you have the same grief????? > Rene… >Please let all us 88 owners know. >Jack >> Hi Dave…I have ordered an after market chip. I have like I say run >> out of options..and am willing to see if this cures my troubles. >> Thanks >> Rene >> >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– >> >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! >> >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
i have an 88 tbi 350 with same symptoms. my ads chip didn’t fix. i will be replacing o2sensor next. speed shop tells me fuel pressure regulator could be another contributing factor. also, oxygenated fuel seems to be part of the problem in cold weather. if you are not already try using shell or amoco for couple of tanks, see if that helps. good luck – Hide quoted text — Show quoted text – > Actually now that you mention that, it makes me wonder about > the prom…I have the GM factory manual, I followed the trouble > shooting tree to try to figure out this condition.I double checked > everything and was sure it was the computer…as was described in the > manual. Upon replacing the comp…the problem was there the next day. > I did not replace the prom tho…had to pry it out of the old one and > install it in the new one. I have noticed that upon disconnecting the > battery for any reaon…that the truck does seem to run quite > nicely..even from cold…but the symptoms soon return the next time I > start it after letting it sit overnight. > Like I said…now I am wondering if the prom might be the problem…. > My next question is.. would I be better off to purchase an after > market chip…or would good ol’GM be the place to buy one????? > Thanks > Rene >Just a thought from an "old" GM guy, ther were a lot of tsb’s in the >middle 80’s about this type of condition on tbi engines, they used to use >up dated ecu proms to correct warm up transition lean conditions, look into >this. > . >> > Hi …. >> > My pickup is getting close to being torched….runs like a piece of >> > shit when its cold. Has been like this since I bought it 4 years ago. >> > Symptoms….starts fine…seems to fast idle as it should…sometimes >> > has a bit of a miss sometimes not….once it starts to warm up and >> > goes into closed loop mode and drops off fast idle…the engine idle >> > goes stupid…and sometime will actually quit. Seems to have a slight >> > bit of hesitation or bogg when driving it when its cold…pauses as >> > you apply throttle from a stop sign..but once you put your foot into >> > it off it goes….all this shit goes on till its warmed up and once at >> > proper operating temp seems to run just fine. Has all kinds of power >> > too. >> > I have replace the tbi with a new one…throttle shaft had too much >> > play on the old one. I have replaced every sensor on the engine…new >> > module….and pick up coil…..I have even checked the iac to make >> > sure its working fine on the new tbi. I have checked the egr to make >> > sure it is sealing properly. Engine has never set a code and a buddy >> > at a local auto repair shop has checked out everything with his >> > Snap-on scanner and it does not show any problems >> > I replaced the original engine 2 years ago with a spanking brand new >> > Goodwrench engine and the troubles still followed. >> > The embarassing part of the whole deal is that I am a heavy duty >> > mechanic and just can’t seem to figure this flippin thing out….I can >> > make a diesel engine purr like a kitten…but this gas engine has me >> > pulling my hair out. >> > I am hoping that someone on here has had or heard of similar problems >> > like this…..any help would be greatly appreciated…. >> > Thanks >> > Rene >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Don’t feel bad.. My cousin is a heavy duty mechanic as well. I ask him any questions about a car engine or such and he looks at me and says "I dunno.." 
Seems there are a lot of differences between the two. Cheers, Evan
– Hide quoted text — Show quoted text -> Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
Response:
Please let all us 88 owners know. Jack – Hide quoted text — Show quoted text – > Hi Dave…I have ordered an after market chip. I have like I say run > out of options..and am willing to see if this cures my troubles. > Thanks > Rene >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Jack…do you have the same grief????? Rene… – Hide quoted text — Show quoted text ->Please let all us 88 owners know. >Jack > Hi Dave…I have ordered an after market chip. I have like I say run > out of options..and am willing to see if this cures my troubles. > Thanks > Rene > >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– > >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! > >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Hi Dave…I have ordered an after market chip. I have like I say run out of options..and am willing to see if this cures my troubles. Thanks Rene – Hide quoted text — Show quoted text ->Those old prom updates corrected many driveability woes,you might have >trouble getting the right one at this time, without a part number, and >availability, this is a problem. I would think, if all else is right with >the engine, an perf. aftermarket prom would work. > Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Actually now that you mention that, it makes me wonder about the prom…I have the GM factory manual, I followed the trouble shooting tree to try to figure out this condition.I double checked everything and was sure it was the computer…as was described in the manual. Upon replacing the comp…the problem was there the next day. I did not replace the prom tho…had to pry it out of the old one and install it in the new one. I have noticed that upon disconnecting the battery for any reaon…that the truck does seem to run quite nicely..even from cold…but the symptoms soon return the next time I start it after letting it sit overnight. Like I said…now I am wondering if the prom might be the problem…. My next question is.. would I be better off to purchase an after market chip…or would good ol’GM be the place to buy one????? Thanks Rene >Just a thought from an "old" GM guy, ther were a lot of tsb’s in the >middle 80’s about this type of condition on tbi engines, they used to use >up dated ecu proms to correct warm up transition lean conditions, look into >this.
. – Hide quoted text — Show quoted text -> > Hi …. > > My pickup is getting close to being torched….runs like a piece of > > shit when its cold. Has been like this since I bought it 4 years ago. > > Symptoms….starts fine…seems to fast idle as it should…sometimes > > has a bit of a miss sometimes not….once it starts to warm up and > > goes into closed loop mode and drops off fast idle…the engine idle > > goes stupid…and sometime will actually quit. Seems to have a slight > > bit of hesitation or bogg when driving it when its cold…pauses as > > you apply throttle from a stop sign..but once you put your foot into > > it off it goes….all this shit goes on till its warmed up and once at > > proper operating temp seems to run just fine. Has all kinds of power > > too. > > I have replace the tbi with a new one…throttle shaft had too much > > play on the old one. I have replaced every sensor on the engine…new > > module….and pick up coil…..I have even checked the iac to make > > sure its working fine on the new tbi. I have checked the egr to make > > sure it is sealing properly. Engine has never set a code and a buddy > > at a local auto repair shop has checked out everything with his > > Snap-on scanner and it does not show any problems > > I replaced the original engine 2 years ago with a spanking brand new > > Goodwrench engine and the troubles still followed. > > The embarassing part of the whole deal is that I am a heavy duty > > mechanic and just can’t seem to figure this flippin thing out….I can > > make a diesel engine purr like a kitten…but this gas engine has me > > pulling my hair out. > > I am hoping that someone on here has had or heard of similar problems > > like this…..any help would be greatly appreciated…. > > Thanks > > Rene >—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– >http://www.newsfeeds.com – The #1 Newsgroup Service in the World! >—–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Those old prom updates corrected many driveability woes,you might have trouble getting the right one at this time, without a part number, and availability, this is a problem. I would think, if all else is right with the engine, an perf. aftermarket prom would work.
– Hide quoted text — Show quoted text -> Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
What would cause this on a carburated motor? Thats my 85 to a tee.
– Hide quoted text — Show quoted text -> Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
Response:
Just a thought from an "old" GM guy, ther were a lot of tsb’s in the middle 80’s about this type of condition on tbi engines, they used to use up dated ecu proms to correct warm up transition lean conditions, look into this.
– Hide quoted text — Show quoted text -> What would cause this on a carburated motor? Thats my 85 to a tee. > Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
—–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– http://www.newsfeeds.com – The #1 Newsgroup Service in the World! —–== Over 80,000 Newsgroups – 16 Different Servers! =—–
Response:
Hi Dean…thanks for your reply…..I have already done just what you have said….the engine produces lots of vacuum and I have looked for vacuum leaks in the past……the engine does not have the characteristic idle associated with a vacuum leak….does run quite hunt when started cold…..thats like my trouble but just when it goes from the rich open loop mode to the closed loop mode when the computer takes over. Ahhhh,,,,yes..diesel injector pumps are a bit pricey alrighty…..I know very few people who have had problems with them….whether they be on pickups or a 550 hp Cat engine…and the ones that I do know who have had troubles are their own worst enemies when it comes to keeping their fuel clean and filters changed on a regular basis….:))) Rene…. – Hide quoted text — Show quoted text ->Rene’, >Next time it happens, squirt some carb cleaner right down the TBI throat. >If the idle improves, I’d be looking for a vacuum leak. The TBI gasket at >the manifold and any vacuum line is suspect. Again squirt carb cleaner at >them while the engine is running rough; you should find the leak. Also >check the vacuum at idle. It should be something like 17-21 and very >smooth. The service manual has the spec. An irregular or very low vacuum >usually means a vacuum leak. >Yeah, I know, diesels don’t have to worry about this silliness. But then >gas engines don’t have thousand dollar plus injector pumps either! >Good luck! >Dean > Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
Response:
Rene’, You most likely did this but O2 sensor and throttle position sensor were also changed? Dean – Hide quoted text — Show quoted text – > Hi Dean…thanks for your reply…..I have already done just what you > have said….the engine produces lots of vacuum and I have looked for > vacuum leaks in the past……the engine does not have the > characteristic idle associated with a vacuum leak….does run quite > hunt when started cold…..thats like my trouble but just when it goes > from the rich open loop mode to the closed loop mode when the computer > takes over. > Ahhhh,,,,yes..diesel injector pumps are a bit pricey alrighty…..I > know very few people who have had problems with them….whether they > be on pickups or a 550 hp Cat engine…and the ones that I do know who > have had troubles are their own worst enemies when it comes to keeping > their fuel clean and filters changed on a regular basis….:))) > Rene…. >Rene’, >Next time it happens, squirt some carb cleaner right down the TBI throat. >If the idle improves, I’d be looking for a vacuum leak. The TBI gasket at >the manifold and any vacuum line is suspect. Again squirt carb cleaner at >them while the engine is running rough; you should find the leak. Also >check the vacuum at idle. It should be something like 17-21 and very >smooth. The service manual has the spec. An irregular or very low vacuum >usually means a vacuum leak. >Yeah, I know, diesels don’t have to worry about this silliness. But then >gas engines don’t have thousand dollar plus injector pumps either! >Good luck! >Dean >> Hi …. >> My pickup is getting close to being torched….runs like a piece of >> shit when its cold. Has been like this since I bought it 4 years ago. >> Symptoms….starts fine…seems to fast idle as it should…sometimes >> has a bit of a miss sometimes not….once it starts to warm up and >> goes into closed loop mode and drops off fast idle…the engine idle >> goes stupid…and sometime will actually quit. Seems to have a slight >> bit of hesitation or bogg when driving it when its cold…pauses as >> you apply throttle from a stop sign..but once you put your foot into >> it off it goes….all this shit goes on till its warmed up and once at >> proper operating temp seems to run just fine. Has all kinds of power >> too. >> I have replace the tbi with a new one…throttle shaft had too much >> play on the old one. I have replaced every sensor on the engine…new >> module….and pick up coil…..I have even checked the iac to make >> sure its working fine on the new tbi. I have checked the egr to make >> sure it is sealing properly. Engine has never set a code and a buddy >> at a local auto repair shop has checked out everything with his >> Snap-on scanner and it does not show any problems >> I replaced the original engine 2 years ago with a spanking brand new >> Goodwrench engine and the troubles still followed. >> The embarassing part of the whole deal is that I am a heavy duty >> mechanic and just can’t seem to figure this flippin thing out….I can >> make a diesel engine purr like a kitten…but this gas engine has me >> pulling my hair out. >> I am hoping that someone on here has had or heard of similar problems >> like this…..any help would be greatly appreciated…. >> Thanks >> Rene
Response:
Rene’, Next time it happens, squirt some carb cleaner right down the TBI throat. If the idle improves, I’d be looking for a vacuum leak. The TBI gasket at the manifold and any vacuum line is suspect. Again squirt carb cleaner at them while the engine is running rough; you should find the leak. Also check the vacuum at idle. It should be something like 17-21 and very smooth. The service manual has the spec. An irregular or very low vacuum usually means a vacuum leak. Yeah, I know, diesels don’t have to worry about this silliness. But then gas engines don’t have thousand dollar plus injector pumps either! Good luck! Dean – Hide quoted text — Show quoted text – > Hi …. > My pickup is getting close to being torched….runs like a piece of > shit when its cold. Has been like this since I bought it 4 years ago. > Symptoms….starts fine…seems to fast idle as it should…sometimes > has a bit of a miss sometimes not….once it starts to warm up and > goes into closed loop mode and drops off fast idle…the engine idle > goes stupid…and sometime will actually quit. Seems to have a slight > bit of hesitation or bogg when driving it when its cold…pauses as > you apply throttle from a stop sign..but once you put your foot into > it off it goes….all this shit goes on till its warmed up and once at > proper operating temp seems to run just fine. Has all kinds of power > too. > I have replace the tbi with a new one…throttle shaft had too much > play on the old one. I have replaced every sensor on the engine…new > module….and pick up coil…..I have even checked the iac to make > sure its working fine on the new tbi. I have checked the egr to make > sure it is sealing properly. Engine has never set a code and a buddy > at a local auto repair shop has checked out everything with his > Snap-on scanner and it does not show any problems > I replaced the original engine 2 years ago with a spanking brand new > Goodwrench engine and the troubles still followed. > The embarassing part of the whole deal is that I am a heavy duty > mechanic and just can’t seem to figure this flippin thing out….I can > make a diesel engine purr like a kitten…but this gas engine has me > pulling my hair out. > I am hoping that someone on here has had or heard of similar problems > like this…..any help would be greatly appreciated…. > Thanks > Rene
Response:
Hi …. My pickup is getting close to being torched….runs like a piece of shit when its cold. Has been like this since I bought it 4 years ago. Symptoms….starts fine…seems to fast idle as it should…sometimes has a bit of a miss sometimes not….once it starts to warm up and goes into closed loop mode and drops off fast idle…the engine idle goes stupid…and sometime will actually quit. Seems to have a slight bit of hesitation or bogg when driving it when its cold…pauses as you apply throttle from a stop sign..but once you put your foot into it off it goes….all this shit goes on till its warmed up and once at proper operating temp seems to run just fine. Has all kinds of power too. I have replace the tbi with a new one…throttle shaft had too much play on the old one. I have replaced every sensor on the engine…new module….and pick up coil…..I have even checked the iac to make sure its working fine on the new tbi. I have checked the egr to make sure it is sealing properly. Engine has never set a code and a buddy at a local auto repair shop has checked out everything with his Snap-on scanner and it does not show any problems I replaced the original engine 2 years ago with a spanking brand new Goodwrench engine and the troubles still followed. The embarassing part of the whole deal is that I am a heavy duty mechanic and just can’t seem to figure this flippin thing out….I can make a diesel engine purr like a kitten…but this gas engine has me pulling my hair out. I am hoping that someone on here has had or heard of similar problems like this…..any help would be greatly appreciated…. Thanks Rene
