GM Automotive Technicians Technical Discussion and Fixes for Oct 11, 2007

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Open Help Requests for GM

	Help Request	Answers
	1988 Cadillac DeVille 4.5L compressor VIN: 1G6CD515XJ Hey you cadi guys out there. I really need some help on this problem child car came in with a/c inop.pulled codes had code for low freon in system. Had r-12 in it talked customer into retro fitting system to r-134-a on initial exam.found evap.leaking and compr...	View
	1996 Cadillac DeVille 4.6L ip panel VIN: 1G6KD52Y4T this vehicle was repossed and a lock smith came out and cut a new key for this and vehicle started fine for a few days and than parked vehilce and it would not start,checked for trouble codes only codes found were p1604 loss of instrument panel cluster serial ...	View
	1998 Cadillac Eldorado ETC 4.6L Poor Idle Quality, high idle VIN: 1G6ET129XW the problem i am having is very randomly the idle will begin to climb to around 2500 rpm. when i say random it could be a month before it happens, or it could be the next day. there are no codes for high idle, or anything else for that matter. every pid looks ...	View
	1999 Cadillac DeVille 4.6L a/c clutch VIN: 1G6KD54Y5X hey caddy gurus, this one came from another shop. they cannot get the a/c clutch to engage. it will only engage if the a/c control relay is grounded (circuit 459 dark green/white). the system has the correct amount of freon in it. they put new gm pcm and a/c m...	View
	1994 Chevrolet K1500 5.7L Excessive Emissions, Poor Idle Quality, Hesitation, Stall VIN: 2GCEK19K4R hello everybody hope u can help me i got this 94 cheve p/k 5.7l the problem is that the vehicle stalls in gear this is what happens i got 15 psi in fuel (tbi) no vacuum leaks good spark. no codes the vehicle would stay running in park but at soon as the vehicl...	View
	1997 Chevrolet Blazer 4.3L No Start VIN: 1GNDT13W2V we got it in off the wrecker and at first it didnt have very hot fire at the plugs, we checked the cap and it was burnt and so was the coil wire, replaced both of them parts and problem is still not corrected.	View
	1997 Chevrolet Express 2500 5.7L Fuel Guage VIN: 1GCGG25R2V This vehicle came into our shop with turn signal and brake lights not working properly, and marker lights partially working. The turn signals and flashers would flash very raplidly on driver side and rapidly on passenger side. The fuel guage was also fluctuati...	View
	1998 Chevrolet S10 2.2L Stall VIN: 1GCCS1444W This vehicle came in running with #2 cylinder misfire. After diagnosing the vehicle we replaced the ECM with a used unit. Now it starts and runs on all 4 cylinders but only for about 6 seconds. We have tried the reprogramming protocol several times. We replace... Trouble codes: U1016 (loss of class two communication), P1629 (no fuel enable signal)	View
	1999 Chevrolet Silverado 1500 5.3L several items Hello, and help! I really try not to post a request until I am bald. I'm there. Truck comes in for MIL. Not on when I get into truck, radio is on(key in hand) but low fuel light is on, gauge reads walk, power windows inop, power mirrors inop. History DTC's are...	View
	1999 Chevrolet C3500 7.4L hard start VIN: 1GBKC34J0X this is a hand me down from another shop (they closed ) ( i am going to work at wendys ) cold it starts fine, after it has been driven it is a hard start truck ( extended crank time ) i put a fuel pressure reg. in it as it was a leaker, there is no codes store...	View
	2000 Chevrolet Astro 4.3L MIL Lamp on VIN: 1GCDM19W6Y all codes set at same time vehicle will go days and run fine then codes set vehicle will not go over 50 mph never happened for us but freeze frame data shows tp voltage 0 checked tp sensor iat sensor evap vent all look good checked over wiring for short to gro... Trouble codes: P0122, P1122, P0112, P1112, P0446	View
	2000 Chevrolet Silverado 1500 4.3L Excessive Emissions, Hesitation, Stall, Poor Fuel Economy VIN: W1YE278955 Being a Dodge tech, I'm stumped. Truck came in for rough running, stalls on accel, has very "ripe exhaust" and very low fuel economy. After repairs, rough idle is gone, but all other problems still exist. Problems occur more frequently when cold and seem to me...	View
	2001 Chevrolet Prizm 1.8L blower motor VIN: 1Y1SK52841 Help we have this prizm that is not playing nice. It came in with only high speed on the blower fan,(does not work on 1,2 settings) inspected and found a burnt blower resistor circuit board, replaced resistor and still only had high blower. Checked fuses good,...	View
	2001 Chevrolet Astro LS 4.3L transfer case VIN: 1GNEL19W11 We have a vibration when turning. transfer case was replaced at customers request based on other shops diagnosis. vibration is not there in reverse and does seem to come and go in drive. mostly when accelerating and turning. suspect encoder motor keeping front...	View
	2002 Chevrolet Impala 3.4L No Start VIN: 2G1WF52E02 good morning techs i have a 2002 impala here with a strange problem. the vehicle will not start after filling fuel tank. wait approx 30 mins car will start and run no problem. no codes found, no tech bulls found. is it possible that it could be as simple as a ...	View
	2002 Chevrolet Malibu 3.1L Battery light VIN: 1G1ND52J72 Vehicle originally came in with a no crank caused by a dead battery. Replaced battery and everything checked out good in the charging system. Vechicle came back with the complaint of the battery light coming on intermittently. Testing the charging system revea...	View
	1996 Geo Tracker 1.6L MIL Lamp on VIN: 2CNBJ1862T Have re-occuring p0400 for egr flow issue. Transducer and bypass vac solenoid are new. Other vac control solenoid is not new, but does function properly ( cuts vac to transducer P port ). Lift valve manually, stalls eng @ idle. Turn egr on w/ scanner, stalls e... Trouble codes: P0400	View
	1995 GMC Jimmy SL 4.3L rear diff noise VIN: 1GKCT18W3S Hello everyone and thanks for the help on this one. I have this 1995 Jimmy 4x4 that was towed in because the customer stated that their was alot of noise(rumbling, clanking) coming from the rear end all of a sudden. My brother drove it onto the lot from the t...	View
	2000 GMC Sierra 1500 SL 4.8L Poor Idle Quality, Hesitation, Misfire, MIL Lamp on VIN: 1GTEC14V1Y Hi group: I've got a dandy on the go. Need some help. Customer brought in truck complaining of rough idle and poor performance until he had travelled about 5 or 10 kms. After that , truck would run OK. He stated that he had the heads redone ,as there was one ... Trouble codes: P0336 (CKP Sensor out of range)	View
	2001 Oldsmobile Aurora 4.0L struts VIN: 1G3G564C01 Having a promblem with the upper strut mounts on this car. WE have orderes mounts, rubber insulators for top and bottom of springs, new gm plastis spacers. What happens the spring is larger than the plastic spacer and the spring will go over the spacer breakin...	View
	1995 Pontiac Trans Sport 3.8L poor power VIN: 1GMDV06L8S This Transport has poor power from a standing start. Has fresh plugs and wires. Fuel filter is new. New Delco pump and strainer. Exhaust system has been checked for back pressure. (OK) Fuel pressure, key on-pump running 41psi.Spec says it should be 41-47psi. A...	View
	1991 Saturn SL1 1.9L Poor Idle Quality, Stall VIN: 1G8ZG5490M In open loop car will die at idle. In closed loop it will idle but it's rough. The car hesitates real bad after it's in closed loop. Have to keep the RPM over 2000 to drive while it's in open loop. It idle fine with propane. There are no external vacuum leaks....	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1995 Buick LeSabre Limited 3.8L HVAC control head VIN: 1G4HR52L6S Thanks to all that tried to help with this buick- after different checks the problem ended up being the A/C heater control head. Tried one from a bone yard and everything is working fine. Thanks once again to all.	11
	1991 Chevrolet Corvette 5.7L Surge, Cuts out VIN: 161YY3386M Thanks to Brain and Lee they hit the nail on the head the timing was off adjust timing to 6 deg. set idle to 675 and cleaned all grounds and adjust tps sensor.Thanks to all the technicians who offer their help. THANKS RAY/ MIREK	9
	1991 Chevrolet Corsica LT 3.1L Cuts out, Stall VIN: 1G1LT53T1M The car is fixed and gone, thanks to all of you guys who took the time to help me, thank you all. Almost all of you nailed it on the head it was the injectors, I checked resistance and found 5.6 ohms, 8.2 ohms, etc, only 2 were ok (12.5 ohms) one of those was ...	22
	1993 Chevrolet K2500 Cheyenne 6.5L glow plug system VIN: 1GCGK24F9P I'm going to close this request and consider it fixed. The customer had not return so I got impatient and called him. He said he was having no problems starting the truck hot and was happy. I appreciate all the replies I recieved and was looking forward to doi...	11
	1998 Chevrolet Express 3500 5.7L Stall VIN: 1GBHG31R1W Thank you to everyone who replied, the answers I recieved were fuel pressure regulator still bad, decarb engine or possible bad gas, plugged return line. The problem actually turned out to be a bad ignition switch, a weird one though figured out that if I tur...	5
	1999 Chevrolet Blazer 4.3L No Start I feel like a dumbass.Replaced the fuel pump. Has 63psi koeo. starts fine now. I thank everyone for their input.Hope i can help someone sometime.	6
	2002 Chevrolet Express 2500 5.7L Engine VIN: 1GCGG25R72 Well since it will take a while to confirm the results, I am going to close this with our plan of action. We will start with inspecting/repairing the PCV system as nec. It was suggested that there could be a common restriction in the system or a collapsed ...	10
	2003 Chevrolet S10 2.2L Poor Idle Quality, Misfire, MIL Lamp on VIN: 1GCCS14H23 we suggested that we needed to check the intke manifold and gasket, for a cracked manifold or blown gasket and the customer decide to drive it the way it is. thanks for all the help and maybe they will get tired of it and let us fix it. Trouble codes: P0304.	5
	2004 Chevrolet Tahoe LS 5.3L Hesitation, Cuts out, MIL Lamp on, Won't exceed 1500RPM VIN: 1GNEK13Z64 First off, thanks to all who replied to this one. This was my first post on here and it feels good to have some help out there. The vehicle set a P1125 this morning before I even started it. I monitored APP and TPS data and found APP1 and APP2 mismatched by... Trouble codes: P1125 (Accelerator Pedal Position APP System Fault).	4
	1993 GMC G1500 Rally 4.3L stays in 2nd gear VIN: 1GTDG15Z2P Sorry for taking so long to close this one out. I had to post it 2 times because I had already added comments. The way that we found the problem was to monitor the output signal from the Drag module. It being a square wave, what i noticed was it would drop 3...	6
	1993 GMC G1500 Rally 4.3L Limp home mode VIN: 1GTDG15Z2P Sorry for taking so long to close this one out. I had to post it 2 times because I had already added comments. The way that we found the problem was to monitor the output signal from the Drag module. It being a square wave, what i noticed was it would drop 3...	3
	1996 GMC C1500 Sierra SL 4.3L Misfire, MIL Lamp on VIN: 1GTEC14W9T Thanks to all that replied . I replaced 1/3 02 Sensor & did Fuel System Service. Raod tested 30 miles aand everything was good. I agree with all that replied to use Delco plugs. We only use Champion in Mopars. Customer said he would replace plugs to save money... Trouble codes: P0143 (02 Low Voltage Bank 1 Sensor 3), P)300 (Multi-cylinder missfire).	9
	2003 Hummer H2 6.0L Rear Air Suspension VIN: 5GRGN23U83 I thank those 2 replies, unfortunately the Tech 2 is the only system that can handle my situation, vehicle is responding fine to repairs that were made weeks ago but service message still comes on (like and oil change lamp) and goes out shortly after.	3
	1998 Oldsmobile Silhouette Premiere 3.4L ABS lite on and RED brake VIN: 1GHDX03E8W Thank you guys for your ideas. Unfortunately I did'nt see the responses till after it was fixed. Don't know if we had scanner problems giving the wrong code or what(we have mentor and modis) they both said lf motor open. well we replaced the motor assy. hile i...	5

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