GM Automotive Technicians Technical Discussion and Fixes for Jul 25, 2007

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	Help Request	Answers
	1999 Buick Regal LS 3.8L Misfire VIN: 2G4WB52K4X This buick is now in for the second time for a poor run condition, it sets a p0300 missfire code and the customer complains of a lack of power. this is the only code set and i have not experinced the complaint. however in the p0300 freeze frame data i noticed ... Trouble codes: P0300	View
	2001 Buick Regal LS 3.8L Misfire VIN: 2G4WB55KX1 At approx 4000 rpms, the motor stumbles and looses power considerably. Idles fine. Test drove vehicle with scanner hooked up. Misfired in cyl 1- 14 times, cyl 4- 6 times, and cyl 6- 4 times, on acceleration. Does the vehicle have a rev limiter at 4000 rpms? Cu... Trouble codes: P0300	View
	2004 Buick Rendezvous CX 3.4L compressor VIN: 3654FYJ546 car came in with weak ac and overheating, i changed the t stat and scanned,found high side at 400,compressor cycles on and off ,low side is @49	View
	1989 Cadillac DeVille 4.5L Fuel data display VIN: 1GCD5155K4 The Fuel Display Center is erratic. It will change between Avg. & Instant Mpg, Range, & Gallons used by itself. I replaced the FDC but the customer called back and said the display was changing again by itself. I lab scoped circuits at the FDC but it was not f...	View
	1997 Cadillac Eldorado ETC 4.6L Dash,Instrument cluster VIN: 1G6ET1293V Intermitantly applying brake pedal the climate control will go blank,instrument cluster will set every light possable,multiple body codes, then it will be fine for hours,days min and reoccur. Eng. runs fine. Alt and all body grounds cleaned and replaced. Bat. ...	View
	1999 Cadillac Catera 3.0L Surge This car came in with multiple misfire codes and running lean. Found intake manifold gaskets leaking. Removed upper and lower intake manifolds and replaced gaskets. Replaced thermostat while we were in there. Reassembled, engine ran fine in shop. Test drove an...	View
	2005 Cadillac SRX 3.6L Cabin Air Filter VIN: 1GYEE63715 The service information makes it look easy but the cabin air filter does not want to pull out. I have never done this style before, any ideas how this pulls out? Anything I should be careful of?	View
	1968 Chevrolet Corvette CID wipers VIN: 025194678S car came in after body shop did a "restoration" on it. The wiring to the wipers was cut. I don't have a good schematic to tell me where the wires go on the motor. If anyone has this info in the form of a schematic or just memory I would greatly appreciate it. ...	View
	1984 Chevrolet Corvette 5.7L performance A/C not cold enough. The door in heater box feels like it switches all the way from cold to hot. It is not retrofitted still charging with R-12 confirmed to be quality freon other R-12 jobs work great. Car calls for 2.75 lbs and I'm positive I have enough freo...	View
	1986 Chevrolet Sprint 1.0L turn signal switch VIN: 1G1MR0858G in kind of a pickle here guys,customer brought in this throwaway car for complete paint,body,interior,rebuild motor..everything.huge bill.everything came out great till somebodybumped,and broke the turn signal switch.if anyone knows where i can lay my hands on...	View
	1997 Chevrolet P30 Chassis 6.5L tps VIN: 1GBKP32Y9V I scanned this vehicle because the owner complained of excessive shift "hunting". It came up with a code for low TPS voltage, a backprobe of the sensor showed a 5 volt reference as well as the feedback voltage being responsive to adjustmemt. When the scanner ...	View
	2000 Chevrolet Suburban 2500 LT 6.0L Rear differential VIN: 3GNGK26U9Y Every 50-75 miles when coasting to a stop light there will be a loud bang in the rear end when down shift occures. Everything in the drive line is tight and this only happens randomly - you cannot make it happen. I sent this to a transmission shop and he drove...	View
	2001 Chevrolet Suburban 1500 5.3L Compressor VIN: 3GNEC16T71 Greetings fellow techs, This vehicle's compressor will not engage when vehicle is started with the a/c switched already on. In scanner it is showing to be receiving A/C request signal, but computer is not grounding relay when it sees A/C request signal. It ha...	View
	2001 Chevrolet Cavalier Z24 2.4L abs / traction control / brake light VIN: 1G1JF12T11 customer came in with no door remotes working and dash lights on for abs / traction and red brake light / replaced bcm and had dealer flash / left dealer 1/2 mile lights back on door remotes still work / snap on scanner co communication with abs / u 1000 code ...	View
	2002 Chevrolet Impala LS 3.8L Compressor VIN: 2G1WH55KX2 A/C is inoperative, checked all fuses and relays, good, hvac control lights but no compressor engage, follow alldata diagnostic chart for compressor clutch does not engage. lead me to replace pcm. replaced with GM reman unit. reprogrammed started car still no ...	View
	2002 Chevrolet Avalanche 2500 8.1L rear main seal VIN: 3GNGC23G82 I am replaceing the rear main seal,my j42849 installer tool was stolen in a recent break-in, my new tool will not be here for another 2 weeks, has anyone ever succesfully installed one of these rear main seals with out the proper tool, tanks for any help.	View
	2003 Chevrolet Suburban 1500 LT 5.3L compressor VIN: 1GNFK16Z93 AC system appears to be fully charged... has front and rear AC.. Has not been serviced according to cust. Gets cold when turned on.. But makes a terrible chattering noise when RPMs are raised... Belt tensioner starts vibrating (slapping up and down) at 1500rpm...	View
	1995 GMC Jimmy 4.3L Hesitation, Cuts out VIN: 1GKCS13W6S this vehicle cuts out as if its breaking fire. has new plugs, wires, cap, rotor, and distributor. it idles fine, but under a load it cuts out real sharp as if its a fire issue. fuel pressure okay, all data on scanner seems fine.	View
	1998 GMC Jimmy SL 4.3L No Start i got this truck from a wholesaler and the problem is with key on,you press the gas pedal and the fuel pump will not turn on.sometimes when you try just to start the vehicle the fuel pump will not come on but definitely when you touch the accelorator you can m...	View
	2003 GMC Envoy XL SLE 4.2L Fan clutch VIN: 1GKES16S33 This vehicle just started within the last two days of the electronic fan clutch engaging at various times when it shouldn't. The customer left her house on a cold start and it engaged full boar and stayed engaged for about 3 miles. It does quiet down some the ...	View
	2004 GMC Envoy SLE 4.2L speedometer VIN: 1GKDT13S64 Still having trouble with irratic readings. Speed is off. Sometimes goes to max and causes a clicking noise. Varies at times.	View
	2000 Oldsmobile Bravada 4.3L Cuts out VIN: 1GHDT13WXY hello guys, this car is my son's. on a 40 min. trip it will start to lose power on acceleration start to pop and then die. it will crank and not start. has fuel pressure. if you let it sit for several hours and return , it will start right up. it just had a n...	View
	1991 Pontiac Grand Prix SE 3.4L charging VIN: 1G2WP11X6M alt charges fine,during normal operation with ac off,with ac on charging system volts low [...].2v,new battery,new alt??help.p.s.-has new monster stereo,seems not to affect-isolated from car,during testing.	View
	2001 Pontiac Montana 3.4L ac VIN: 1GMDU23E51 Customer complains at times going down the highway every other day or so the AC will just quit cooling. I cannot duplicate this. The other complaint is that the blower motor is weak coming out the front vents. I saw a bulletin on the door but it was only perta...	View
	1999 Saturn SL2 1.9L front crank seal VIN: 1G8ZJ5275X Saturn techs HELP, we swapped engines and now have a front crank seal leaking. We are using OE seals and Harmonic balancers from both engines are like new, oil drain back behind seal is clean and clear into oil pan, we pulled the pan. Oil pressure is normal co...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1987 Chevrolet Caprice 4.3L Poor Idle Quality, Hesitation, Surge, Cuts out, Stall VIN: 1G1BL51Z7H Thanks to everyone who said 9-10 Lbs of fuel pressure just was not enough. Who would of thought the the factory spec's could be wrong!! That never happens. After I replaced the fuel pump the fuel pressure whent from around 9 psi to 15 psi and when I pinched of...	25
	1994 Chevrolet S10 LS 4.3L #10 fuse VIN: 1GCDT19ZXR First of all I would like to thank everyone for reading the post and replying. The fix was just as Tim had said the pink and black wire had rubbed through on a firewall screw I was able to repair the wire and the fuse stopped blowing. Most replys pointed to tb...	13
	1995 Chevrolet Caprice Classic 4.3L coast VIN: 1G1BL52W75 With the help of one of our other customers (and a free olf) with the same vehicle we were able to monitor the data on his vehicle. After road testing there was no difference between the two vehicles, the sensation or the data. It also stayed in third gear u...	4
	1997 Chevrolet Malibu LS 3.1L ABS module VIN: 1G1NE52M5V Well I think we got this one. I had chcked the groung curcuit with an ohms meter and it showed ok but when I pulled the wire harness apart the ground wire had a brake in it and had only about three strands holing it together. I suppose this was enough for the ...	6
	2001 GMC Sierra 3500 SL 6.6L air bag lamp on VIN: 1GTJK39191 hello everyone and thanks for the replies. Bob from canada you was correct. the fix was to replace the sensor. I know the code is for left side impact sensor but this truck does not have side sensors. This truck only has one sensor in the front. I replaced...	7
	2002 GMC W3500 Forward W3S042 5.7L power steering VIN: 4KDB4B1R52 Found that the king pins were so frozen, that it took away the power assist due to the fact that the pump could not overcome the mechanical problem. We heated the pins to finally take grease, and the problem was cured!!! Thanks for your suggestions, Men!!!	7
	2003 GMC Envoy SLT 4.2L electo viscous fan clutch VIN: 1GKDS13SX3 thank you for all of the replies as most said there is a tsb actully a couple of them explaing diffrent situations that the fan cluthc can be engaged on start up expecially in high humidity areas when the ac is on when car is shut off well i was going on what ...	10
	2003 GMC Sonoma SL 4.3L drive shaft VIN: 1GTCS19X63 after many attemps, we've resolved the vibration. the rear drive angle was wrong, it was at pos 5.5 degrees. we ordered shims for the rear and install a 6 degree shim, that improved the vibration and brought the drive angle to neg 2.5 degrees. we changed that ...	10
	1998 Oldsmobile Cutlass GLS 3.1L MIL Lamp on VIN: 1G3NG52M2W From the 12 replies we were able to determine that relay was improperly installed that got compressor working with atm tests but not from control, tested all powers and grounds at control and believe problem is in control head as we get no a/c request at pcm o... Trouble codes: 1641 (no def found).	12

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