GM Automotive Technicians Technical Discussion and Fixes for Oct 11, 2005

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	Help Request	Answers
	1990 Buick Riviera Luxury 3.8L Cuts out, Stall VIN: 1G4EZ13C3L hello everyone this buick came in with a intermittent stall. fuel pressure ok, acts like a crank sensor issue as it will start to spitt and sputter and backfire up intake. noticed that when it would start to act up that the headlamps and tail lamps would flash...	View
	1991 Buick Park Avenue 3.8L Misfire VIN: 1G4CW53LXM This vehicle came in as a no start, it had no spark . The harmonic balancer was loose and hitting the crank sensor we replaced both. The vehicle then started but had a miss fire on two cylinders #2&#5 . We went througt trouble shootig in all data and replaced ...	View
	1997 Buick LeSabre Custom 3.8L Poor Idle Quality, MIL Lamp on, idles to high VIN: 1G4HP52K8V Replace upper intake with updated plenum, Customer came back complaining of check engine light on & High RPMS. PO121A Code Reoccurs. Have tried adjusting TPS , Cleaned the throttle plate, Added additional ground to ground wire on tps. Disconnect to see if idle... Trouble codes: P0121	View
	1997 Cadillac DeVille 4.6L Hesitation, MIL Lamp on VIN: 1G6KD54Y6V Severe hesitation and boggs on WOT. Replaced MAF sensor. Condition did not change. O2 sensor readings appear to be switching normally. On light acceleration, problem does not occur, only when mashing on throttle. Any help would be appreciated. Trouble codes: P0131 (O2 signal low B1S1), P0151 (02 Signal low B2s1)	View
	1992 Chevrolet S10 Blazer 4.3L abs lite VIN: 1GNPT13W5N vehicle came in for brake lite and abs lite, replaced abs module and brake lite off but abs lite on. scaned system and lr wheel sensor short appeared. replaced sensor and retested (same code appeared) tested ohms in wiring and all is good. i can't seem to find...	View
	1992 Chevrolet K1500 Cheyenne 5.7L defrost VIN: 1GCEK14K5N Hi I am working on a 1992 Chevy C1500 With EATC everything works good except I have no air flow out of the defrost ducts. The air flow out of all other settings works Great. When I put it in defrost mode the blower motor speeds up but the air comes out of The ...	View
	1995 Chevrolet Monte Carlo LS 3.1L Misfire VIN: 2G1WW12M9S This car will run perfect in a no load situation. When you feather the throttle the car will accelerate fine until approx. 2800 RPM after that it begin to cut out a cylinder. Also, once in a while the car will accelerate fine and if you take your foot off of t...	View
	1998 Chevrolet Blazer 4.3L No Start VIN: 1GMDT13W5W Hi Techs, I have a 98 Chevy blazer that after running for 20 minutes or longer and letting it set for 15 minutes or up to a half hour is hard to start. Fuel pressure is 62 Lbs. and holds when this happens but I am losing spark at the plug. I pull the coil wire...	View
	1999 Chevrolet K2500 7.4L Brake Pedal VIN: 1GCGK23J5X Customer came to us with complaint of vehicle not stopping. He said he had to stop hard and then brakes didn't work rightand ABS light on. Went to a shop and they replaced all wheel speed sensors, front pads and rear shoes, turned drums & rotors. He said it st...	View
	2000 Chevrolet Suburban 1500 LT 5.3L Electronic VIN: 3GNFK16T6Y This chevy has me in a spin. The front ac is perfect, but the rear will only blow out heated air and vent but it wont allow the ac to blow in the back half of the truck??? The controls seam to be working because you can feel the temp go from cool to heat but n...	View
	2000 Chevrolet Suburban 2500 6.0L Poor Idle Quality VIN: 3GNGC26U3Y Good morning. I have this 2000 Surburban that has a rough idle and what sounds like a vacuum leak. This problem started after I replaced a leaking radiator and hoses. It idled fine when I finshed. As the coustomer was driving away he said there was a small pop...	View
	2004 Chevrolet Silverado 3500 6.0L Blend doors VIN: 1GBJC34U94 Hello fellow techs: We have this 2004 Chev stake truck which has no AC. Customer said the mechanical heater control would not go to the defrost position. He broke the knob trying to force it to the defrost position. We put a vise grip on it and forced it a ...	View
	1990 GMC G3500 Magnavan 5.7L Main Bearings VIN: 1GTHP32KXL Well guy's, here is one that I'm at a loss at. we got this vehicle in about a month ago with a seized engine. Being that we are a full line machine shop we sold an engine rebuild. rebuild engine, bored .030 over, machined crankshaft .010 mains, .010 rods. repl...	View
	1993 GMC Jimmy 4.3L No Start, Cuts out VIN: IGKDT13W9P Hi Techs, Vehicle came into the shop not running. fuel pressure was checked and had 52psi and would not maintain pressure. installed new pump & regulator now we have 62psi & it will not bleed down. It will run untill it gets hot and just shut off and not resta... Trouble codes: 22 (TPS Sensor too low), 34 (MAP Sensor or circuit too low)	View
	1995 GMC Yukon SLE 5.7L Excessive Emissions, Hesitation, Cuts out, Misfire VIN: 1GKEK13K5S Looking for any ideas that can help.I've beat my self up good on this one.Is there a GM lord out there! This Yukon boggs down when accelerated, like running out of fuel, or plugged exaust.You can accelerate moderately to heavily and it will bog down, when heav...	View
	1996 GMC C1500 Suburban 5.7L MIL Lamp on VIN: 1GKEC16R5T If you clear the code on this truck the MIL light will stay off for approx. 4 days and then it will come back on. Checked grounds and fuse as stated in the manual and they are fine. Any idea's? Thanks, Kerry Trouble codes: P0161	View
	1996 GMC C1500 Sierra SL 4.3L Misfire VIN: 1GTEC14W8T Hi GM Techs.Vehicles misfires on accel. idles ok but when you give it gas it misfires on all cyls. fuel pressure spec is 60-66 psi . key on eng off fuel pressure is 58 psi . running about 55-56 psi . Is this low enough to cause a misfire? I have heard the popp... Trouble codes: P0300	View
	2001 GMC Savana 2500 4.3L No Start VIN: 1GTFG25W11 intermittent crank, no start. fuel and spark ok. using tech 2 scanner only code which returns is u1016 when i go into passlock system. all powers and ground checked good. does this mean the passlock module is defective?	View
	2002 GMC Safari SLE 4.3L abs VIN: 1GKEL19X42 came to us from a body shop, had been in a minor accident. damage was to left front area. after accident car started pulling right on stops but only when you get down to 7 or 8 miles an hour.looked for physical damage, none found. scanned system, had no codes,...	View
	1999 Oldsmobile Aurora 4.0L hd-a/c VIN: 1GBJ6J1C23 no defrost-no heat-only a/c comes on.when selector turned to heat a/c stays on, all air comes out a/c vent	View
	1990 Pontiac Bonneville SE 3.8L drums VIN: 1G2HZ54CL1 the vehicle needed wheel cylinders,they were stuck, and brakes almost worn out, it had a brake noise when applying the brakes at lower speeds, like the shoes were moving or binding, I did a rear brake job, machine drums, clean and lube all hardware, replace an...	View
	1998 Pontiac Bonneville SE 3.8L interior & parking lights VIN: 1G2HX52K5W When the interior light or parking lights are cut on both come on and stay on. If one comes on they both come on. We have unplugged the bcm, lamp control module, head light s/w. This car does not have remote entry or anything fancy. (doesn't even have a button...	View
	1998 Pontiac Grand Am SE 2.4L steering wheel VIN: 1G2NK4DTYW to all you pontiac techs. this vehicle has a plastic or rubber noise when turn steering wheel. saw gm bulliten stating about the pinion shaft on the rack is that a good proven fix. got a bearing and a seal too fix per bulliten. what im asking is there a shortc...	View
	2002 Pontiac Grand Am SE 2.2L alarm system VIN: 1G2NE52F82 alarm light blinks how can i reset it unhooked batt for 15 min and put back put key on for 15 min no change light still blinks	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1998 Buick Regal LS 3.8L MIL Lamp on VIN: 2G4WB52K0W first off thanks to those who responded. several dealt with spark plug wire routing. they were in the factory position. p.c.m. was o.k. dave [...] from delphi sent me an excellent description of the system and an approach to testing. a special thanks to him fo... Trouble codes: 1361 (1362 -), 1362.	7
	1999 Buick Regal LS 3.8L MIL Lamp on VIN: 2G4WB52K0X Sorry about the delay in closing the customer took the car for the weekend and did'nt bring it back for a week and a half. It turned out to be the MAF after all. Tried cleaning it initally with no change. Bought a new one and put it in and the warm idle readin... Trouble codes: P0171.	14
	2000 Cadillac Escalade 5.7L No Start, Engine dies @ 50mph VIN: 1GYEK63R1Y Thanks for all the replys. The connection for the fuel pump inside the tank was the culprit in this case. Replaced the unit and the vehicle has not been back.	10
	1992 Chevrolet kodiak 8.2L Poor Idle Quality VIN: 1GB6H1J1NJ hello everyone, I had 5 good replies on this one. Ed from Idaho said the quick fix on these engines is to leav the block warmer pluged in while not in use. After i have pluging in the block heater every night the truck starts good and very little smoke wen col...	5
	1999 Chevrolet Blazer 4.3L Cuts out VIN: 1GNCS13W7X The fix for this vehicle was to replace the ign switch. After reading several post stating that they had fixed vehicles with the same symptoms with a new ign switch, we started to wiggle the switch ever so lightly. Nine times out of ten, the vehicle would die....	16
	2004 Chevrolet Aveo LS 1.6L MIL Lamp on VIN: KL1TJ62654 It appears any time that a power train componet is changed on these cars ie:crankshaft, torque converter, flex plate, transmission, engine you have to perform a crank position relearn. It can be done with gensiys or snap on red brick with at least 2004 softwar... Trouble codes: P1781 (engine torque control circut).	3
	2001 GMC Sonoma SLS 4.3L No Four Wheel Drive high or low VIN: 1GTDT13W91 Thanks to all who responded. Ricky from florida on the terminal identification,Chris from colorado,Martin from Maryland on the regular failure of the switches,Rollin from Illinois on the ground location on the system and the likelyhood of problems with them. E...	5
	2004 GMC Yukon Denali 6.0L dash VIN: 1GKEK63U24 Thans to all who replied. I fixed the Denali this morning. After 30 years in this business I thought I 'd seen it all. All but this one. The fix goes like this. It was a missing ground or should I say a removed ground by another shop that did a temp fix. I fou...	4
	1998 Oldsmobile Aurora 4.0L Stall, MIL Lamp on VIN: 1G3GR62C5W thanks to eveyone for their insights i rechecked the air filter & housing for correct fit and for no kinks in snorkel to maf the maf was new but checked for debris in screen, sweep tested tps and baro on lab scope could not find any glithes there did a smoke t... Trouble codes: P0101 (maf).	6
	1992 Pontiac Grand Prix SE 3.1L Poor Idle Quality, Surge, Stall VIN: 1G2W314T6N most replys are for vac leaks or internal engine problems. reran all tests including running comp tests all cyls at 110 lbs + - 5 pounds,engine static comp 170 +-5, and no exhast back pressure left up to owner to decide on engine tear down. will not get answer... Trouble codes: 44 (lean exhast).	28
	1995 Pontiac Sunfire SE 2.2L rear brakes VIN: 1G2JB5245S New rear brake shoes fixed the problem! Sorry for the delay in response but we were waiting for the customer to reply to make sure we fixed it. Thanks for all your help	19
	2000 Saturn SL1 1.9L daytime running lights VIN: 1G8ZH5289Y Thanks to both of the guys that responded. Dave from WA stated there is a wire chafing problem at the headlight and it will inadvertently ground the DRL's. Jim from NY stated that there might be a fuse problem allowing the power to back feed to the DRL's. They...	4

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