GM Automotive Technicians Technical Discussion and Fixes for Apr 28, 2005

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	Help Request	Answers
	1997 Buick Park Avenue Ultra 3.8L air vents VIN: 1G4CU5212V this is a regular customer of ours...we have verified complaint and customer is accurate...drivers air vents are running 15 degrees warmer(57 vs 42) when a/c is on...passenger temp slide has no effect..we feel sure it is bad...but customer is not complaining a...	View
	1984 Cadillac Eldorado 4.1L Poor Idle Quality, Surge, Stall, MIL Lamp on VIN: 1G6AL5788E hello to all, i have a good customer that had this eldorado in the family since new, he brought it in and stated the when he drive, sometime the blower motor would start to blow and the car would run bad. brought the car in the bay scanned for codes #52 ecm lo... Trouble codes: 52 (long term memory has been reset)	View
	1989 Cadillac Fleetwood 4.5L runs rough VIN: 1G6CB5150K Originaly came in with charging probles. Vehicle had defective alternator. We replace and problem was fixed. Customer came back in complaining of running rough. If we unplugg the alternator vehicle will smooth out and have no problem. Vehicle has a high amp af...	View
	1990 Cadillac DeVille 4.5L exhaust leak VIN: 1G6CD533IL I have a 1990 Cadillac Deville here. In the leftside(front) bank exhaust manifold, there is a suppose to be a plug that lead out of the manifold. Customer came in with missing component. In that spot there is a threaded hole similiar to where the o2 goes into ...	View
	1999 Cadillac DeVille 4.6L No upshift VIN: 1G6KD54YXX Strange problem with this Deville. If you try to accelerate it will stay in 1st gear, rpms go to 3900-4000 no upshift and it just hangs there doing 3900 rpms at won't shift or gain any more rpm. Testing a like vehicle, engine will run to 5800 and shift into se... Trouble codes: P1527	View
	1990 Chevrolet C3500 Cheyenne 5.7L alt VIN: 1GTHC34K2L Hello fellow warriors,we have a 90 c3500 2wd p\up,with a electric hydraulic dump box.Our situation is this:When the dump box without a load is raised,it pulls the charging system down to 12.2 volts,eventually killing the engine(based on the time it takes to ra...	View
	1991 Chevrolet K1500 Cheyenne 5.0L Front wheels VIN: 2GCEK19H6M If I could get some input on this truck,good customer of mine had problems front wheels locing up,He replced calipers(one was seized) and brake hoses.The front wheels will lock up once or twice a day without applying the brakes,does not matter what speed and i...	View
	1992 Chevrolet Astro CL 4.3L MIL Lamp on VIN: 1GNDM15ZXN client brought in this van after having it at another shop. snap on scanner will not communicate. other shop already installed reman ecu. vehicle does seem to be running okay most of the time, has intermitant engine running problems. service engine soon light ...	View
	1995 Chevrolet K2500 5.7L transfer case VIN: 1GCFK24K6S This truck makes a bearing whine noise only in 4x4 hi. It does it accelerating and decelerating. When cruising @ say 45mph, the noise is there somewhat. If you let off the gas the noise goes away for about 2-3 seconds and then returns. When the gas is applied ...	View
	1995 Chevrolet K1500 Cheyenne 5.7L Hesitation VIN: 1GCEK19K7S Have a 95 Silverado,5.7 TBI When you apply light throttle when leaving a stop the EGR valve will open up and cause engine to hesitate. I know that the ECM is commanding the EGR solenoid to open and send vacuum to EGR valve but why. Thought that is might be a c...	View
	1997 Chevrolet K1500 Suburban LS 5.7L fuel pressure VIN: 1GNFK16R5V We need help on this one, luckily this one belongs to a relative so they have been congenial about the problem. Originally truck came in with no start. Diagnosed as bad fuelpump replaced pump with a/c delco from the zone, strainer and rebuilt sending unit {lin...	View
	1998 Chevrolet Lumina 3.1L MIL Lamp on VIN: 2G1WL152M4 The cooling fans work with engine temp and the a/c. I have a feeling there is a wire that is comming in contact with ground somewhere but I can't see to find it. According to alldata, the computer is looking to ground the fan relays if the voltage is correct c... Trouble codes: P1652	View
	1999 Chevrolet Venture LS 3.4L camshaft VIN: 1GNDU0EE9X we found a broken camshaft in this vehicle. before we get to a teardown mode of the engine, i was hoping someone else has found a reason for the broken camshaft. if so, would anyone out their please let us know what you have found. EXAMPLE: SEZED OIL PUMP, DAM...	View
	2000 Chevrolet Blazer LS 4.3L Fuel Gauge VIN: 1GNCS18W7Y hello all, we did a simple fuel pump job on this one and now the fuel gauge isnt working right. it will stay on full for about 200 miles the all of the sudden it will drop to 3/4. costomer brought it to us full so i unpluged the unit and it went to empty. so i...	View
	2000 Chevrolet Silverado 1500 5.3L Fuel Gauge VIN: 1GCEK19T1X Hi everyone, I've got this pickup here with cust complaining of eratic fuel gauge. He says that sometimes when he knows he has a full tank of gas the gauge will stay on empty for a while and then make it's way up to full. Or it will sometimes read more than wh...	View
	2000 Chevrolet Impala LS 3.8L tcc VIN: 2G1WH55K3Y customer complains that tachometer "jumps" when going up hills. Can duplicate concern and have monitored TCC duty cycle and slip speed with scan tool. the duty cycle will vary between 35% and 65% and the slip speed is anywhere from 150 to 450 RPM. The car has ...	View
	2000 Chevrolet Silverado 1500 5.3L 1-2 shift VIN: 1GCEK19T2Y Have a harsh 1-2 shift and the 2-3 and 3-4 shift are not as hard as the 1-2 shift. No Codes. As vehicle warms up the shifting gets better. All shifts feel on time. I checked the actual amperage draw of the Press Control Sol valve on the red/blk wire and it re...	View
	2002 Chevrolet Impala 3.8L warning ligh VIN: 2G1WF55K92 Vehicle came in with battery light on and low charge rate. one week later car came back with complaint of battery libgt, security light and ses light flashing intermittantly. Codes present in all control modules is u1064, loss of comm with body control module....	View
	2003 Chevrolet C4500 Kodiak C4C042 6.6L adapter plate VIN: 1GBC4E1163 Hey, I need some help from you heavy duty truck techs. I entered this one in as a 3500, but it is a 4500 cab and chassis. The problem is that the adapter plate between the engine and transmission is cracked and leaking coolant.This is a 6.6l Duramax with a fiv...	View
	2003 Chevrolet Silverado 1500 5.3L MIL Lamp on VIN: 1GKEK19T83 i've tracked down plenty of EVAP problems but this is a new code. p0455 is evap but no description is given in my techII. pressure builds in the tank as the truck is driven. i will hunt down the problem but i saw no other posts for this code so i want the reco... Trouble codes: P0455 (i dunno)	View
	2005 GMC Yukon 6.0L Reverse This truck came in with a slip,shudder followed by a harsh bump or two when backing up a grade. There was no codes. The fluid was dark already(7600kms) So I pulled it out and found the reverse input clutches black. When airing the rev/input drum up while it wa...	View
	1989 Oldsmobile Cutlass Supreme International 3.1L No Start, Poor Idle Quality, Cuts out, Stall VIN: 1G3WR14T4K Hi Techs, I have this 89 Olds Cutlass Supreme 3.1L that will hardly idle and I cannot give it any throttle at all or it will stall out. Fuel pressure is good fuel volume is good,no codes. I can hardly keep it running to use the scanner but the map sensor looks...	View
	1996 Pontiac Sunfire SE 2.2L Hesitation, Stall, MIL Lamp on VIN: 1G2JB1241T vehicle came in with 2 injectors leaking, so we replace #2 & #4 injectors and changed oil. upon start up vehicle started missing on #3 injector tested good but we replaced it. seemed ok on test drive started missing on #1 so we replaced it as well. car runs go... Trouble codes: P0172	View
	1997 Saturn SL1 1.9L Stall VIN: 1G87H8283V Engine Dies At Random,Looses Fuel Injector Pulse. Always Restarts In About 5-10 Minutes.	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1979 Cadillac Seville 5.7L Stall VIN: 6S69B99440 I decided to replace the transmission oil and filter, it was very dirty(muddy), also tried dico the Lock up solenoid , but the car keeps the same. After rechecking everything again I found vacuum leak in the vaccumm hose inside the ECM. This improve the engine...	15
	1996 Cadillac Seville SLS 4.6L clock VIN: 1G6KS52Y6T Thanks to those of you who responded, and I tried all suggestions which included disconnecting the battery once again to reset the system. The vehicle needs a new clock ( which comes with everything else).	3
	1990 Chevrolet R1500 Suburban Silverado 5.7L Surge, Cuts out, Misfire, MIL Lamp on VIN: 1GNER16K4L Sorry for the delay, we replaced dist shaft with new delco and nothing changed. We finally replaced the MSD coil and the prom chip and the sucker ran just fine. What ever, we'll take it. Thank to all who helped. Trouble codes: 42 (est problem).	22
	1993 Chevrolet Camaro Indianapolis 500 Pace Car 5.7L No Start, Poor Idle Quality, Stall VIN: 2G1FP22P5P hey all. thanks for the info. i am taking everything into consideration. you cannot move the plug wires in a different order on this dist. i am going to put this thing back together with a new dist. and see how it works. i also plan on pulling o2s out to see a...	17
	1993 Chevrolet C1500 Cheyenne 5.7L reverse binds VIN: 1GCDC14K0P Hello everyone and thanks for the help on this one. The problem ended up being that the low reverse snap ring that holds the clutches and rear sprag in the case had popped loose. It wiped out the case. I got a case and transferred things and its working fine. ...	10
	1994 Chevrolet Camaro Z28 5.7L MIL Lamp on VIN: 2G1FP22P7R First off thanks to all of the techs that responded. The car is fixed. I rechecked engine grounds and everything was good to go. I checked body gounds and found one loose ground point on RF strut tower by the Power Steering reseviour. Fixed it but the codes st... Trouble codes: 36 (Loss of high resolution distributor/crank signal), 41 (voltag high on the ignition module circuit 423), 46 (VAT Code), 51 (PCM Program Fault).	6
	1995 Chevrolet Lumina 3.1L Starting VIN: 2G1WL52M1S Thanks to everyone for your replies. I checked everything over again. I replaced the oil pressure switch and inspected the connector, the connector was ok. Sent the car on its way. Problem fixed.	11
	1996 Chevrolet C60 Kodiak C6H042 6.6L starts and dies VIN: 1GBG6H1J1T Had some replys on this one and all were most helpful.None hit it on the head,but most of us are AUTO techs eh?The wildly fluctuating fuel pressure at low rpm was the route to the answer.Problem is the injector seats are pitted/corroded and are allowing engine...	3
	1996 Chevrolet Tahoe 5.7L Cuts out, Misfire, Poor Fuel Economy, MIL Lamp on While not a widespread issue, it has been seen numerous times. More responses than expected were received. {BTW, for those who asked, a VCM is a Vehicle Control Module, the designation that the 'General' has assigned to their Gasoline Tight engine control syst...	15
	1997 Chevrolet C1500 Cheyenne 5.7L Unknown VIN: 1GCEC19R5V We suspected that the converter clutch had been damaged when it was slipping before we replaced the valve body. There was no paint burned off of it, and no sign of it being hot, so we tried the TCC solenoid first as it can be changed just by dropping the pan. ...	26
	1999 Chevrolet Silverado 1500 4.8L power steering VIN: 1GCEK14V2X Thanks to all who replied to my request. I installed a Cardone steering box and flushed the system. Problem solved. Thanks again, Joe	28
	1999 Chevrolet Venture 3.4L MIL Lamp on VIN: 1GNDX03ESX as far as i know vehicle is fixed replaced fuel filter and customer has not returned Trouble codes: P0171.	10
	2003 Chevrolet Express 2500 5.3L Poor Idle Quality, Misfire, MIL Lamp on VIN: 1GCFG29T03 To make a long and painfull story short. #2 cylinder had a problem with the valve seat. Here is where life gets real fun. The machine shop failed to properly repair the #2 seat when the heads were serviced. The result of this faulty machine shop repair was ton... Trouble codes: 300 (random miss), 753 (tranny solonoid).	8
	1991 GMC S15 Jimmy 4.3L starter VIN: 1GKC11829M i had replaced both battery cables and problem went away!!positive cable had a lot of corrosion under insulation. thanks everyone!!	17
	1996 GMC C1500 Sierra SL 5.0L Brakes Thanks a ton for all who replied, I tried the ABS stops on a dirt roas, but there was not even enough to get the wheels to come close to lock, made sure adjustment of drums was good, then re-pressure bled the system. The same day I pressure bled it I was able ...	11
	2002 GMC Savana 3500 5.7L high idle VIN: 1GTHG35R92 found defective iac. talked to my delco warehouse and found he is having a very high failure rate for these. he had 50 on order and 44 already spoken for.	15
	2004 GMC Savana 2500 4.8L Stall, MIL Lamp on VIN: 1GTGG29V24 Thanks for all the replies;I was glad to learn that the redesigned throttle body would fix this problem. I just like to besure before ordering these hi dollar parts The throttle body fixed the problem.	5
	1992 Pontiac Grand Am SE 2.3L Excessive Emissions, Poor Idle Quality, Hesitation, Poor Fuel Economy VIN: 1G2NE1438N Thanks group. It was something I should not have missed. Reading your thoughts helped back me up and open my eyes. It was the o2 ground. Looks like upon motor installation they had missed some grounds. Repaired grounds and o2 sensor worked correctly and fuel t...	6
	1995 Pontiac Firebird Formula 5.7L Excessive Emissions, Poor Idle Quality, Poor Fuel Economy VIN: 2G2FV22P9S i truly appologize for not getting back to close sooner this was an incredibly hard problem to diagnose. i had to leave town on an emergency an was having to diagnose this car by cell phone! because everything was working like it should but acting like a misfi...	9
	1999 Saturn SC2 1.9L Surge, Stall Thanks to all who responded. The shop that installed the plug wires had switched nos.1 and 4 on the coils. I had a reply from Dave [...] that suggested this. I'm not sure how this causes the surge. Maybe it messes up the sequential firing of the injectors bu...	5

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