GM Automotive Technicians Technical Discussion and Fixes for Apr 28, 2006 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	1996 Buick Century Special 3.1L fast idle VIN: 1G4AG85M9T Work order say's "engine races cold". Spent some time trying to verify complaint. Finally figured out the symptom is the rpms will stay at the highest setting untill the key is cycled. If you start it cold, it will run at about 1150rpm. It will stay there thru...	View
	1999 Buick Park Avenue 3.8L air bag VIN: 1G4CW52K6Y This Buick came in with a service vehicle soon light on. Found DTC U1064 loss of communication with BCM. I checked power and grounds all good. Checked continuity on serial data line also good. I replaced BCM cleared all codes and sent the car on it's way. Came...	View
	1996 Cadillac Seville SLS 4.6L cooling fans VIN: 1G6KS52Y1T The cooling fans never come on, jumping the coolant temp wires does nothing, can anyone tell me if they have encountered one of these( Thanks	View
	1995 Chevrolet Corsica 3.1L No Start, Poor Idle Quality VIN: 1G1LD55M4S This Corsica came from the machine shop for a no start. The customer drove to the grocery store and when he went to leave it didn't start. got it home somehow and then the parts throwing began. Finally he decided it needed head gaskets and took it up to the ma...	View
	1995 Chevrolet Lumina LS 3.1L Excessive Emissions, Hesitation, Poor Fuel Economy VIN: 2G1WN52M8S this one came in with the converter glowing cherry red...inspection revealed check engine light on code 17 ect low input, found ect unplugged , spoke with customer and found that he unplugged it because fan was not working?.. plugged it back in and tested work...	View
	1998 Chevrolet S10 LS 2.2L Rediness Monitors VIN: 1GCCS1949W This vehicle came in for Emission Test Failure. CMP Failure code P0342 and Rediness Monitors Catalyst and Evap Not set. Code was easy, defect cam shaft pos sensor. Replaced, MIL off after 2 starts. No other codes or pending. Ran Drive Cycle 3 times with cooldo...	View
	1998 Chevrolet Corvette 5.7L Fuel Gauge VIN: 1G1YY22G7W Fellow Techs, This customer called to tell me his fuel gauge is not working properly, and was wondering if I'd heard of this before. He says it is full of fuel, but the Driver's Info Center says only 200 miles left in tank and fuel gauge shows about 5/8. I ha...	View
	2000 Chevrolet Venture 3.4L MIL Lamp on VIN: 1GNDX03E1Y Well it came in for engine light on, runs fine. Found two codes 131 137 both sensors low voltage. Test drove after clearing the codes saw open loop not only at wide open throttle but also at closed throttle sometimes. At one point we went to open loop and the ... Trouble codes: P0131, P00, 137 (sensor 12 low voltage)	View
	2001 Chevrolet Silverado 2500 6.0L Poor Idle Quality, Poor Fuel Economy, MIL Lamp on VIN: 1GCHK29U71 cutomer customer changed plugs and wires him self , truck seems to run fine until you get on freeway going about 60 and the check engine lite starts flashing, check for codes and it has code p0300 it says random missfire. checked missfire data and shows cylind... Trouble codes: P0300 (engine misfire)	View
	2003 Chevrolet Silverado 3500 6.6L No Start VIN: 1GCJK33193 Customer brough vehicle in after diag at dealer to replace 8 injectors. After replacing all injectors vehicle will not start. Is there a special way to prime these injectors, or what am I doing wrong to get this vehicle to start?	View
	2003 Chevrolet Avalanche 1500 5.3L Misfire VIN: 3GNEK13T42 hello, and thanks for reading.customer said fuel pump was "whining", and a couple of days later the noise went away. next day the misfires started,multiple cyls,particularly 2 and 7,under all conditions.fuel filter was restricted,then exploded,causing the soun... Trouble codes: P0300	View
	2004 Chevrolet Silverado 1500 4.3L major leak VIN: 1GCEC14X64 Vehicle came in today with fuel leak at injector assy. Removed connector and foudn fuel spraying out of housing. What im wondering i did not replace the fuel pressure regulator when i replaced housing is it possible its sticking? And i was also wondering about...	View
	1992 GMC C1500 Suburban 5.7L No Start VIN: 1GKEC16K1M Hey guys, I have a big problem with this Suburban. The customer towed it in three days ago with a no start. He says it just died while driving. He was here 8 days ago and had codes for the tps and many others too, I didn't save them and he has since cleared th...	View
	1994 GMC Safari SLE 4.3L No Start VIN: 1GKEL19W3R blows ecmb fuse when shifted into reverse. checked fuel pump amps (9)amps checked fuel pump rpm around 6600rpm checked wires and relays going to fuel pump look ok the only thing that i see going to the ecmb fuse is the fuel pump,and ecm. runs great all the ti...	View
	1994 Oldsmobile 88 Royale 3.8L No Start VIN: 1G3HN52L8R My first post to IATN for help was very surprising of the amount of help offered, and indeed a real fix was determined from the help received. Thanks to all who helped. Now I have another real bad problem with a 1994 Olds. 88, 3.8L, vin code (L). This vehicle...	View
	2000 Oldsmobile Silhouette GLS 3.4L abs VIN: 1GHDX03E0Y to all gm techs, help. i have this 2000 olds silhouette with an intermitant abs light coming on and the abs pump intermitanly activating. the customer is worried because sometimes the pump activates when she needs to stop and the pedal starts moving down with ...	View
	2001 Oldsmobile Alero GX 2.4L anti theft system VIN: 1G3NK12T01 Hello group and thanks for your time. This Olds Alero has been a problem for quite a while. It came to me after the dealer through up their hands. The vehicle will intermittantly not start and have to be towed in. Cranks, no start. Code p1632, Anti theft alar...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1996 Cadillac Fleetwood 5.7L Misfire, MIL Lamp on VIN: 1GC6DW52PO Thanks to all who replied. The fix ended up being the computer. Right off of throttle the ecm would command the egr solenoid duty cycle to 99%. This would open the egr valve prematurely and create a misfire. This in return would create the p0300 that I had on ... Trouble codes: P0300.	8
	1985 Chevrolet Corvette 5.7L Hesitation, MIL Lamp on VIN: 1G1YY0783F again, many thanks to all those who replied, although some responses didn't quite understand that i had information for a 86' vette, this was an 85' vette, and the maf system is completely different. the burn module on the 85' is located directly behind what l... Trouble codes: 33 (maf sensor signal voltage high).	8
	1996 Chevrolet S10 LS 4.3L readiness monitor VIN: 1GCDT19X2T thanks for all the replies, since we were advised to replace PCM we tried to Flash it first, it already had the current update so we VCI'd it, test drove it and all went ready within minutes except the EVAP and Heated O2, dont know why Cat went ready but we hu...	7
	2002 Chevrolet Trailblazer LS 4.2L no 3rd gear VIN: 1GNDT13S32 Many thanks everyone who answered my help request. The general consensus was a clutch pack for third gear was burned out. My shop does not do transmission overhauls so I am subleting the repair.	14
	2005 Chevrolet Silverado 1500 5.3L fuel tank VIN: 1GCEK14V05 SPECIAL THANKS TO EVERYONE of you who responded, pretty much everyone hit the nail right on the head. After receiving the wrong but then the right part, I replaced the canister vent valve for my friend as recommended and you can refuel to your hearts content. ...	17
	2005 Chevrolet Corvette 6.0L unk VIN: 1G1YY32G62 thanks for all the help-some iatn members gave great advice but the problem turned out to be something you will likley not see again. the pcm was dented from the impact and the circuit board was touching the case. a new pcm corrected the problem- thanks again ...	4
	2005 Chevrolet Uplander LT 3.5L vibration VIN: 1GNDV33L35 Soory for the delay GM Stil says this is ok to happen over night I Have given up This is my owen van and i can't wast ant ymore time i think that is what GM Whrats jason	10
	1997 Geo Tracker 1.6L Hesitation VIN: 2CNBE1869V Thanks for the help! Ken hit it on the head, Crank Sprocket was moving. Crank bolt seemed tight as I had turned the engine backwards with it. I replaced the sprocket, key & bolt, epoxied the key & used part of a DrPepper can as a rolled shim on the bottom. Adv...	4
	1988 GMC K3500 Sierra SLE 6.2L No Start, Hesitation, Cuts out, Stall, Poor Power VIN: 1GTGK34J0J Big thanks to the iATN members who helped...This vehicle is fixed and on the road. After reviewing the replies I got I knew where to start. Special thanks to Ken [...] from Iowa and Brent from Michigan who both mentioned the tank as being the problem. I remove...	8
	1998 GMC Jimmy Envoy 4.3L keyless entry VIN: 1GKDT13W7W iATN is great.It even works while you sleep.I posted Saturday night then went to bed.I woke up Sunday morning and had the fix. The fix was two things.First,after a closer look,one of the solder joints was broken on the battery holder,as some of the responses...	14
	2001 GMC Sierra 2500 HD SL 6.0L Alternator, PCM, Wiring VIN: 1GTHK23U31 Many thanks to all those who replied! Lot's of people told me alternator should be replaced by delco oem (cause GM has 7 regulator model and jobber only 3). Unfortunately, I won't have the chance to fix this one, since the alternator charges good and the probl...	7
	2000 Oldsmobile Alero GL 2.4L Poor Idle Quality VIN: 1G3NL52TOY well i could not come up with a reason that the computer was holding the iac at 50 to 56 steps at idle, so i thought we would try a new pcm, but customer declined at this time.	7
	1997 Pontiac Grand Am GT 3.1L abs VIN: 1G2NW12M2V car dealer declined any more costs for abs system. all circuits ohmed good all the way back to the battery cables. tried two used ebcm's and diagnostics always came back to bad ebcm. good wheel sensor readings from all wheel sensors on scanner, but short circu...	3

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