GM Automotive Technicians Technical Discussion and Fixes for Sep 7, 2004 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	2002 Buick Century Custom 3.1L Hesitation, NO POWER VIN: 2G4WS52J52 this car has got me.car came in with no power all the time. when road test the car seem to labor, like pluged cat.took cat out and was good. checked air intake and that was clean. map and baro working with rpm. mass air flow new 7gps at idle and about 110 at w...	View
	1990 Cadillac Fleetwood 4.5L Poor Idle Quality, Hesitation, Misfire VIN: 1G6CB5334L I need a little help on this one. The car has misfire under light load and idle. The block learn at idle is 108 and during cruise it will stay about 120. Will run better under heavier acceleration, and trims will go to 128. Fuel pressure is 32 to 40. The vacuu...	View
	1979 Chevrolet K20 Cheyenne 6.6L Temp gauge VIN: CKR249J158 Haven't been able to find a voltage spec for the temp gauge Or a trouble shooting chart.	View
	1993 Chevrolet Astro 4.3L Excessive Emissions, Poor Fuel Economy, MIL Lamp on VIN: 1GBEL19W5P Greetings to all,this van is running very rich,basic testing of the following sensors all showed good,o2,map,coolant and air temp sensors we even disconnected the charcoal cannister to see if it was saturated.I removed the intake manifold twice just to see if ... Trouble codes: 45 (rich exhaust)	View
	1996 Chevrolet Corsica 3.1L MIL Lamp on, comes back on VIN: 1G1LD55M4T on this vehicle we have replaced the MAP sensor and the EGR everything else has tested good on this vehicle but the code keeps on coming back. Trouble codes: P0401 (EGR flow)	View
	1997 Chevrolet C2500 5.7L gauges(fuel, charge,oil, temp.,odometer and tacho VIN: 1GCEC34K3V Hello everyone, I received this vehicle with the problem in the gauges. When you start and run the vehicle at the idle speed, the gauges that control temperature, charge, oil,odometer,tachometer start to oscilate . First I messure the voltage without any acces...	View
	1998 Chevrolet K1500 Cheyenne 5.7L No Start, Stall VIN: 1GCEK19R3W To All Fellow Mechanics, I need help. Car came in on a hook, customer stated vehicle was running fine before this problem, came to stop sign, it shut off. He was able to restart but the car ran like crap, limped it home, shut it off and was unable to restart ...	View
	1999 Chevrolet Astro 4.3L abs VIN: 1GNEL19W0X A.B.S. activates at low speed on all stops. Vehicle is A.W.D. there are a lot of posts in the archives for front wheel speed sensor/reluctor ring corrosion, presumably on rear wheel drive vehicles, this is all wheel drive and sensors are integral to hubs. Ohm ...	View
	2000 Chevrolet K2500 5.7L 4wheel drive VIN: 1GCGK23R9Y Sure could use some input on this one...The 4 wheel drive selector switches aren't doing anything. I checked the switch and it is passing voltage like it should. The transfer case module will click simular to a relay. This is even with switch disconnected. It ...	View
	1993 Oldsmobile Bravada 4.3L oil filter to engine adapter VIN: 1GHDT13W4P greetings fellow techs this vechicle was towed in to my shop partially dismantled, customer stated vehicle had severe oil leak at oil filter to block. checked truck personally, adapter bolts removed, adapter hanging from lines. there is very little room to get...	View
	1994 Oldsmobile 88 Royale 3.8L MIL Lamp on VIN: 1G3HN5213R Hello there, The mil light is on and i am trying to get the codes but i can't. The DLC connector is for OBDII when i hook up the scaner i get the masage no communications. I have snap on scaner when i input the vehicle info scaner tells me connect GM 12 pin co...	View
	1996 Oldsmobile Achieva SL 3.1L door locks, radio, interior lights VIN: 1G3NL52M0T Customer complains about the door locks erratically operating while going down road. Same with interior lights.These symptoms started when they wiggled wiring to rear speakers in trunk. Radio hasn't worked properly in a "long time". I notice that when you turn...	View
	1986 Pontiac Firebird Trans Am 5.0L Poor Idle Quality, Hesitation, Surge, Cuts out, Stall VIN: 1G2FW87F8G Car came in for a surge complaint at higher cruise speeds.Found fuel pressure low and would drop off to nothing after key shut off. Replace fuel pump and pulsator. Road test and car lost power and would hardly move. Recheck fuel pressure and delivery o.k. Insp... Trouble codes: 42 (Electronic spark timing)	View
	1987 Pontiac Fiero GT 2.8L Flywheel VIN: 1G2PG1193H Hey folks, the engine in this Fiero was rebuilt and somehow, someone lost the flywheel. We bought a reground crankshaft from NAPA, and our local Pontiac dealer is confused about which flywheel to replace it with. Apparently, somewhere between 87 and 88 Pon...	View
	1995 Pontiac Bonneville SE 3.8L battery gauge VIN: 1G2HX52K3S This Bonneville is quite odd. From time to time the headlights will dim and the battery gauge will drop to about 12v unprovoked just driving along. BUT When you start the car there is a delay from the time the car starts until the battery gauge gets to 14v. AN...	View
	2002 Pontiac Sunfire SE 2.2L air bag lamp VIN: 1G2J37TD88 Air bag lamp on .I think its something to do with the communication between the two modules ? probably relearning their ids but how ? I tried to program for new BCM but it said speedometer locked why is that ? And if I replace the BCM how do you reprogram when...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1987 Buick Regal GNX 3.8L fluid leak at breather tube VIN: 1G4GJ1174H ok so i did not fix this car yet. I am almost sure that the problem is the pump gasket. the customer wants to fix it but the local transmission shop says that it cannot be the pump seal. their lead technician for 20 years says that he has never heard of a pump...	16
	1992 Cadillac Fleetwood 60 Special 4.9L No Start VIN: 1G6CG53B4N Eh Folks I've got this Caddy fixed but I don't know how it was able to drive into the shop! This must have been a problem vehicle before! I found one of the two VATS wires was cut from a previous alarm system (which has been removed ), yet it ran to get here... Trouble codes: 52 (ECM reset).	6
	1998 Cadillac DeVille 4.6L Poor Fuel Economy, MIL Lamp on VIN: 1G6KD54YXW Well I think my wifes car is fixed. Thanks to the 7 of you that replied. The fix was to replace the harness wireing connector(pig tail) for the b2s1 o2 sensor.Even though the wireing checked good every time I checked it must have had an intermitant problem. I ... Trouble codes: P0154 (lack of o2 switches b2s1), P0151 (o2 low voltage b2s1).	7
	1994 Chevrolet K2500 Suburban 7.4L coolant VIN: 1GNGK26N4R first let me thank all who responded. after talking to cust. found that a performance chip had been installed requiring a lower temp. t-stat also after rechecking fan clutch found not holding as it should. replaced both items and fixed. thanks again to bkbauto...	16
	1995 Chevrolet K1500 Cheyenne 5.7L No Start, Stall VIN: 1GCEK14K9S this one turned out to be a real stumper!thanks for all the help.what i ended up doing was pulling the throttlebody assembly off and cleaning the whole thing.i blew through all ports and fuel lines,put the throttlebody back on,not finding anything out of the n... Trouble codes: 54 (fuel pump relay or circuit problem).	10
	1997 Chevrolet Blazer 4.3L Pressure Control Solinoid VIN: 1GNDT13W4V Hello everyone, I received several replies to this problem and most said they have seen the ignition switch cause this and simular problems. I could not duplicate the stall but about one time per day, I tried tapping on the steering column and it would not sta...	5
	2000 Chevrolet Impala LS 3.8L rpm flares up VIN: 2G1WH55K6Y as i had suspected the replies pointed to the tps intermittantly droping out. the tps is of the non-adjustable variety that auto zeros with the lowest voltage seen during operation. i special ordered one and installed it. the customer is returning to college a...	4
	2001 Chevrolet S10 4.3L No Start, Stall VIN: 1GCCS14W21 Most of the replies received helped to confirm what we suspected, a failed PCM. When light tapping on the PCM shell causes bad data to become worse, you have a pretty good suspect. My hesitation was due to the fact that a PCM replacement was going to require a... Trouble codes: P0101 (MAF signal out of range).	6
	1996 Geo Tracker 1.6L MIL Lamp on VIN: 2CNBE1868T Replies suggested that I did actually have a misfire causing the code, or a worn crankshaft timing belt gear. After tests, no misfire existed and the crankshaft was not worn or loose. After reaching 1500 rpm, the timing mark on the crank jumps back to 0, and t... Trouble codes: P0330 (Multiple Misfires Detected).	4
	1997 Geo Prizm LSi 1.8L MIL Lamp on VIN: 1Y1SK5283V thank you to all that wrote in and all your helpful suggestions, however the problem is a mystery to this day. And maybe someday we will learn this mystery. Trouble codes: P1780 (park/neutral position pnp switch).	3
	1996 GMC K2500 Suburban 7.4L cv AXLE VIN: 3GKGK26J3T The best suggestion that we've had is that a retaining ring in the front differential may be broken. To investigate this possibility, it will be necessary to remove the front differential. This is the course that we have decided to pursue. Unfortunately, or fo...	5
	1994 Oldsmobile Cutlass Ciera 3.1L MIL Lamp on VIN: 1G3AG55M3R Hi All, I did get the scan tool to read. I wiggled the harness right behind the OBD connector and was able to interface. I found a loose wire under the dash that prevented me from reading codes. It turns out that some GM vehicles do not have a B terminal to fl...	14
	1994 Pontiac Firebird 3.4L Wipers VIN: 2G2FS22S4R Thanks for the help guys. Most folks said the problem was in the park relay in the wiper motor cover assembly. We changed that little goodie but the problem remained. However, [...] Auto Electric in Kokomo Indiana said to check for a loose nut on the transmiss...	8
	2000 Pontiac Grand Am SE 2.4L Key/ thumbler VIN: 1G2NE12T3Y Hello All Tech, Thanks to All, Lots of responces and all helpful.I finished it today. I got new switch and thumbler but it did not come with Key. I have to sent it to locksmith with the old key.I guese they changed what inside the thumbler to make the old key ...	8

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