GM Automotive Technicians Technical Discussion and Fixes for Apr 15, 2004 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	1987 Buick Century Custom 2.5L cooling fan VIN: 1G4AH51ROH Greetings fellow Techs,.. I'll try to remember to list everything here, because I swear we've checked everything. Cooling fan does not come on when engine reaches temp. This system is pretty basic, there's the fan motor, fan relay, coolant temp sensor, ECM an...	View
	1990 Buick Electra Park Avenue 3.8L MIL Lamp on VIN: 1G4CW54C5L Vehicle came in with the complaint of the check engine light. We tested the original EGR valve and the large orifice solenoid ohm tested bad. So it seemed obvious that was the problem. After replacing the valve, we test drove and no more light, so we shipped i... Trouble codes: 65 (Large Orifice EGR Solenoid Failure)	View
	1994 Cadillac Seville STS 4.6L oil leak lower block VIN: 1G6KY5296R I am the lucky tech working on this fine traveling American oil slick on 4 wheels. I have gotten conflicting info on this car. My question is not on the oil leaks itself but the assembley of the job and I do mean job!!! #1 the divider plate between the lower ...	View
	1987 Chevrolet Celebrity 2.5L Excessive Emissions, Poor Idle Quality, Hesitation, Surge VIN: 1G1AW51R8H Hi group, This Celebrity came in running poorly, just like plugged exhaust or very late timing. I scanned it and cleared the codes, none of them have returned, all the readings on the datastream look reasonable given how poorly it runs, next we undid the exha... Trouble codes: 13 (O2 sensor ckt open/short/bad), 42 (EST problem)	View
	1988 Chevrolet Camaro Iroc-Z 5.7L Excessive Emissions VIN: 1G1FP2185J The egr only will get a signal when the car is first driven off idle up to 15, the duty cycle is at 100 percent and then drops within 5 seconds to 0 percent once the speed is set at 15 mph. The same thing happens when we take it up to 25 mph. O2 sensor is new ...	View
	1993 Chevrolet Lumina Euro 3.1L No Start VIN: 2G1WN54TXP Good evening fellow techs. this one hasgot me a little stump. Hope someone can help. This vechile has a no start customer thought it was a fuel pump. upon diagonis the fuel pump came on and 45psi still didn't start. hooked up scanner found 19 codes stored trie...	View
	1994 Chevrolet Cavalier RS 2.2L Poor Idle Quality, Surge, Stall VIN: 1G1JC1440R CHANGED THE SPARK PLUGE,CLEANED THE THROTTLE BODY,R/R THE IGINITION MODULE AND THE FUEL FILTER.I HAVE BEEN DRIVING THE CAR FOR A FEW DAYS AND EVERYDAY WHEN I DRIVE IT TO WORK (15+ MILES) ITS FINE BUT WHEN I GOING BACK AFTER WORK (DURING WHICH TIME THE CAR IS P...	View
	1995 Chevrolet Astro 4.3L Front Drive shaft VIN: 1GBEL19W5S This Chevy Astro van came to us on a flat bed wrecker. The customer thought the transmission was "out". We discovered that the front drive shaft had been removed (stolen?). It was not with the van. The owner claims no knowledge of its MIA ststus. When all fo...	View
	1996 Chevrolet S10 LS 4.3L 1-2 4 VIN: 1GCCT19WXT I need some tranny experts here. this vehicle shifts OK untill it warms up. Lose low gear and high at the same time. I replaced the 1-2 solenoid and 3-4 solenoid at the same time. My transmission shop in town said to start there.I checked for voltages at the c...	View
	1997 Chevrolet C1500 Suburban 5.7L No Start, MIL Lamp on VIN: 1GNFKI16R9 fuel Pump Replaced, works when jump wire in relay box pin 30 to 87. Have no power on pin 86/85 power on pin 87 Any Ideas why no power to entegize relay? Thanks! Mike	View
	2000 Chevrolet Impala 3.8L fuel gauge VIN: 2G1WF55K9Y hi all, we got this car in for a complaint of fuel gauge reads full at all times except when you stop driving vehicle and put in park. when you open drivers door the gauge will read to correct level. we checked this car to duplicate complaint. the fuel gauge r...	View
	2000 Chevrolet Silverado 1500 4.8L abs module VIN: 1G6EK14T8Y the abs system works normally at higher speeds, but is very erratic at a speed under 5 mph. when coming to a stop the abs motor comes on and the brake starts pulsing. checked for wheel sensor faults, but can't find any. the scanner doesn't show any codes. on t...	View
	2001 Chevrolet Express 3500 5.7L Poor Idle Quality, Stall, Low Idle Speed VIN: 1GCHG39R41 This Chevy van intermittently dies at idle unless you keep the throttle opened slightly, like it is running at base idle only. It is quite intermittent, but seems to occur most often after a hot soak of a few minutes. We did catch it on the scan tool once and ...	View
	1999 GMC Sierra 1500 SL 4.8L Cooling Systems VIN: 2GTEC19V9X Vehicle has been using coolant, is very well maintained, the only way I could determine where the coolant was going was to do the taste test on the bottom of the oil fill cap. Upon removing the valve covers there is significant coolant on the underside of the ...	View
	2000 GMC Safari SL 4.3L No Start Need some help guys. This van was towed in for a no start. Checked for codes. None found (current or history). Tested fuel pressure - 65 lbs key on. Removed pressure regulator, pressurized and pulsed each injector. No problems noticed. Removed spark plugs, eac...	View
	1994 Pontiac Firebird 5.7L Hesitation, Misfire opti.distributor may be the cause ? but i dont have good known subtitute. Trouble codes: 18 (ignition signal)	View
	2001 Pontiac Firebird Formula 5.7L MIL Lamp on VIN: 2G2FV22G71 Need Help on this one , this is one of 2 firebirds we have with same problem. No driveability problem? We scanned system and activated air pump as told and checked for vacuum leaks, none found.O2 shows correct fluctuation??? need GM Expertise on this also addi... Trouble codes: P1415 (Air System Fault Bank 1), P1637 (Generator L Terminal Circuit)	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1994 Cadillac DeVille 4.9L MIL Lamp on VIN: 1G6KD5287R Thanks for all the replies, it was a great help. To fix this thing, I reset the min idle as someone had previously adjusted the min idle to about 350 RPM. Then I re-adj. the TPS and performed the idle learn proceedure sent by Mark [...], thanks Mark. And tha... Trouble codes: P0085.	8
	1989 Chevrolet C1500 Cheyenne 4.3L Misfire VIN: 1GCDC14Z3J hello guys, thank you all , many responses but only three got it right on the nose. i started over with diagnosis and found that with ecm out, i used termial from tester lead and found passenger injector wire at ecm terminal was worn out.i kicked my own ass af...	16
	1990 Chevrolet C1500 Cheyenne 5.0L compressor clutch VIN: 2GCEC19H5L First, I would like to thank all of the members who have responded. I saw that the different types of responses were grouped into three catagories. I will list them and tell how I was able to weed out the problem: The first catagorie is the responses to sugges...	14
	1993 Chevrolet C1500 Suburban 5.7L pulling right VIN: 1GNEC16K4P Guy's thanks for all the help on the brake pulling problem. It's still not really fixed but now when the customer brakes normally it will track straight. He still says that is pulls to the right but everytime we would brake hard it pulled to the left after the...	20
	1993 Chevrolet Astro CL 4.3L 3rd gear VIN: 1GNDM15Z9P thanks for the expert help and suggestions for the van! I will live with the drunk squirrel in the torque converter until it dies. God Bless & happy wrenching!	7
	1997 Chevrolet Cavalier 2.4L Misfire VIN: 7979851557 The problem was the coil module i put the ignition scope on it and the spark patterns was erratic.I went to the junkyard and bought one for 20 bucks.Thanks guys for your help. Trouble codes: P0300, P0303, P0304.	32
	1998 Chevrolet K2500 Suburban 6.5L Poor Idle Quality, Surge, Cuts out, Misfire, Poor Fuel Economy, Engine Races VIN: 3GNGK26F2W Thanks for all the replies, and all were on the right track. The fuel injection pump had given up. After I called the customer with an estimate, the customer called the local dealer because the truck had less than 100k, and the dealer supplied the new pump und...	6
	2004 Chevrolet Silverado 1500 4.8L new cruise switch VIN: 1GCEC14V44 Thanks to Martin, from British Columbia for his help with wiring details. Unfortunately, GM has changed the 04 trucks to be not cruise control ready if the factory did not install it. It has a different wire harness and who knows what else. This may not be tru...	4
	1995 GMC Yukon SLE 5.7L bottom end bearing failure VIN: 3GKEK18K7S My dad's boss used to say, 'Never start a letter with an apology.' I'm terrible at following directions so I apologize for my slow response to this excellent organization whose members have been so generous in helping me with my problem. I'm a one-man show in ...	12
	1998 GMC Jimmy Envoy 4.3L Starting VIN: 1GKDT13W4W Thanks a lot everybody!!! 98% of you were right on the with what I was thinking. I replaced the ignition switch and it's been starting every time. I'm guessing that I don't need to reprogram the Passlock because it started right up the first time. Could GM com...	25
	1990 Oldsmobile Delta 88 Royale 3.8L timing chain VIN: 1G3HY54C9L Hi Gang, Finally, FINALLY got the correct part. Get this, according to the part numbers on the boxes, the part that matched the tensioner I removed was for a 1977 3.8 liter engine. I might have guessed that in a million years, but it would have been at the l...	10
	1993 Oldsmobile Achieva S 3.3L MIL Lamp on VIN: 1G3NL14N6P I was able to call this one a wrap after cleaning the fuel system. I found the fuel filter disintegrated to the point that it had allowed sediment and paper into the injector screens. After cleaning the vehicle ran perfect. Thanks to those who took the time to... Trouble codes: 44 (lean exhaust).	5
	1990 Pontiac Grand Am LE 2.3L Excessive Emissions, VIN: 2G2JB34K9L Hi guys and girls.Thank you so much for everybody's time and proffesional advice (Jim,Pat,Kent,Hyperfly,John,Neal,Keith,Scracr,and TnT).Yes Kent [...] have ordered the book you have suggested and it should be a good read.I have started to build the header and it w...	10
	1999 Pontiac Montana 3.4L abs & tcs light VIN: 11GMDX03E2 HEY found the problem. First thanks goes out to Brian in Wesconsin, Bob in Texas & Richard in Ontario. Where the problem lies is a wire that had been rubbing another power wire from the fuse block to the Brake Modulator. Circuit 855 {orange wires} have been ru...	3

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