GM Automotive Technicians Technical Discussion and Fixes for Jul 15, 2004

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Open Help Requests for GM

	Help Request	Answers
	1994 Buick LeSabre Custom 3.8L battery light VIN: 1G4HP52L2R Charging system and battery tested ok. Alternator was charging and but battery light in dash was still on. Replaced the alternator... no change in light. When the car is started light is out and stays out of 15 seconds. From what I have found out so far the re...	View
	2002 Buick Century Custom 3.1L MIL Lamp on, service engine soon VIN: 2G4WS52J22 Here we go . First thing to know is this is a salvaged car. When this car initially came in we found the harness in the colum causing the horn to int. go off. This was one of his complaints. secondly was the service engine soon and security light on. Unknown w... Trouble codes: U1064, P1626	View
	1997 Cadillac Catera 3.0L Heater core VIN: WO6VR54R9V Hello to all We have this catera in that needs heater core is there a short cut to this job. 7-8 hr job. any help would be great Thanks Ken	View
	1969 Chevrolet camaro 357CID Mechanical I am working with a good friend on his 69 camaro, we built a .060" over 350 with all new parts topped with an edlebrock carb and pertronix converted distributor. The problem that we have is 2 of the header tubes #5 and #8 are getting dull red in about 4 min of...	View
	1987 Chevrolet V20 Custom Deluxe 5.7L Poor Idle Quality, Hesitation, Stall VIN: 1GCEV24K7H The symptom we have is stalling when putting vehicle in gear. The IAC appears to be the cause of the stalling. If we watch IAC counts, they stay high and slowly drop to 40 PSI and never goes lower than that. There is an exception, when you put the vehicle in g...	View
	1987 Chevrolet R10 Custom Deluxe 5.0L brake pedal VIN: 1GCDR14H4H Need some help. Vehicle came to me with customer complaint brakes do not want to stop. Roadtested apply brakes hard panic stop pedal hard vehicle slows down gradual.Ck brakes front ok rear had grease seals leaking,shoes where covered. replaced both axle seals,...	View
	1990 Chevrolet BOUNDER 7.4L power steering VIN: 1GBKP37N8L this motorhome came in from another shop . the power steering pump is very noisy and fluid leaks out of resvoir through the cap,the pump has been replaced with a gm pump,when you drive down the road fluid is forced out of the resvoir, this motorhome is equipt ...	View
	1990 Chevrolet Lumina 3.1L No Start VIN: 2G1WL54T4L Well after reading all the posts I felt a little better about this one but still have not fixed it. We have a no start with no spark or fuel injectors, no ref to the ecm no rpm on scaner no codes,Have good crank sensor pattern on scope with .8 volts Have 12 vo...	View
	1993 Chevrolet S10 Blazer Tahoe 4.3L Poor Fuel Economy, MIL Lamp on VIN: 1GNDT13W3P The code resets immediately. Engine off, on, or under accel. We have looked for broken wires, bad sensors, and nothing is checking bad. We really need help on this one. There is only one knock sensor in this vehicle. Trouble codes: 43 (esc)	View
	1994 Chevrolet P30 7.4L hydroboost VIN: 1GBKP37N1R well everyone this is good this is not what im used to working with or on.this is a hydro boost system it also has a valve that is used for the e-brake while servicing the a/c a line and im not sure witch sprung a leak (not the first tech on this one other tec...	View
	1995 Chevrolet K2500 Cheyenne 6.5L clutch pedal VIN: 1GCGK24FE3 truck was towed in with no fluid in hyd. system, filled up and found fluid leaking from where steel line goes into slave cyl, could'nt buy sealing ring seperatly so replaced slave cyl, when test driven, found I hade to pump clutch pedal to get a smooth shift, ...	View
	1998 Chevrolet Metro LSi 1.3L Hesitation, Cuts out, Misfire VIN: 2C1MR5229W Hi all. I got a funny one here. This metro has a hesitation/missfire between 1500 and 2000 rpms hot or cold. Idles normal and once past about 2000 it runs normal. In park or neutral there is no problem accelerating. Only under load. Feels like an EGR problem b...	View
	1998 Chevrolet C3500 Cheyenne 7.4L system voltage VIN: 1GBKC34J5W Truck came in with complaint of voltage guage dropping and battery light coming on when voltage gets low enough aprox 12.1 volts , this only occurs when being driven (at any speeds) at idle or when revved in shop will function fine ,we replaced alternator (max...	View
	1998 Chevrolet Metro LSi 1.3L fuel injector VIN: 2C1MR5228W The vehicle was towed into our shop, with the vehicle not being able to start. I checked the sparks, and it came out ok. Then, the cylinder compressor, and it was also fine. The signal from the computer to the fuel injector showed that #1 and #4 operates OK, b...	View
	1999 Chevrolet Astro 4.3L oil pressure gauge VIN: 1GNEL19W4X This van has had a intermittant problem with the oil pressure gauge dropping off and the check gauges light coming on. this happens under normal driving conditions and is quite intermittant. We're pretty sure pressure is good when it occurs.Gauge or dash probl...	View
	2000 Chevrolet Prizm 1.8L Lighting VIN: 1Y1SK528XY Lights change between high and low beam by themselves. Car has automatic headlamps and DRL does not flicker the dash lamps, but does change the high beam indicator as lamps change beam. DRL seems to work normally	View
	2000 Chevrolet Impala LS 3.8L pcm VIN: 2G1WH55K1Y I am looking for a diagram to locate the source of the pcm ac request signal.Iam not sure if it is requested by the bcm or the ac contoller.GM SERVICE info doesnt indicate or supply this part of the diagram.Youre help will be appreatiated greatly.	View
	2001 Chevrolet Tahoe 5.3L Evo VIN: 1GNEK13T91 Can not read the evo data or codes in this vehicle, although we can read the abs data from the bcm. Disconnected the remote start and no change. According to new car sticker truck came with variable assist steering, however it steers easy at any speed which wo...	View
	2002 Chevrolet Impala 3.4L engine VIN: 2G1WF52E33 Vehicle has squeal/hiss at rear of engine. Only happens when in passing gear or hard goose. It does it with belt off also. Used hose and traced noise to rear of engine, mabe exhaust, dont know. I dont want to tear everything apart and find nothing wrong. Has a...	View
	1996 GMC C1500 Sierra SL 5.0L Brke petal VIN: 1GTEC19M5T 2 wheel drive, extend cab, front disk, rear drum. Replace front brakes. machined rotors, Replaced calipers, rear brakes, wheel cyl, axle seals, (lr shoe was 1/2 missing on primary, ) shoes at 60%. Replaced master cyl due to soft petal tha you could push throu...	View
	1967 Pontiac GTO 6.6L Powersteering Bracket VIN: 237677B104 I have questions regarding the placement of the front p/s bracket. Specifically it has none. Ordered a replacement part from AMEs(Pontiac specialist) and it is not clear how it fits. Problem could be wrong pump, wrong rear bracket, or... I have pictures that d...	View
	1994 Pontiac Grand Am SE 3.1L Hesitation the main problem is that "THIS VEHICLE SHUDDERS GOING INTO FINAL GEAR". A complete tune-up has been performed. Torque converter replaced, lock-up solenoid has been replaced. Check engine light is OFF. Intake plenum and throttle plate cleaned. This vehicle will...	View
	1998 Pontiac Grand Prix GTP 3.8L fuel related VIN: 1G2WP5211W this is something if have never seen before. when i put the hand brake on the vehicle will crank but will not start.i have checked all wiring around the hand brake and everything seems to be fine. if i disconnect the park brake switch everything works fine. i ...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1991 Buick Park Avenue 3.8L charging system VIN: 1G4CW53L6M thanks to cw truck and auto and most others, this car is fixed, w/fuses behind the glove box. thanks again john	9
	1992 Buick LeSabre Custom 3.8L Cuts out, Stall VIN: 1G4HP53L8N I'd like to thank everyone for their input. It was greatly appreciated. Curt [...] hit it right on the head. Put a new crank sensor in it and never missed a beat. Customer is happy and I'm happy. I was overlooking a small glitch in the waveform that i mi...	14
	1992 Chevrolet K1500 Cheyenne 5.7L No Start, Poor Idle Quality, Cuts out, MIL Lamp on VIN: 1GCEK14K7N thanks to all who posted for me.all the grounds checked out normal, but now they are very clean. it turns out it was the distributor. even after pulling the old one and inspecting it, the magnets look fine but, the air gaps are wide on 2 of them and almost tou... Trouble codes: 42 (est).	14
	1995 Chevrolet Blazer 4.3L No Start, MIL Lamp on VIN: 1GNCT18W2S well i called the customer and he had just put a installed a new cpi and then i checked the distributor and it was off a tooth, i found a bad wire in the harness for the injector, ultimatly the problem lied in the ignition module, i got 3 bad ones out of the b... Trouble codes: P1351 (est output high or pulses detected when open).	5
	1995 Chevrolet Blazer 4.3L No Start, interminttent VIN: 1GNDT13W65 This is my 3 rd time to try to reply. My computer keeps locking up. did not fine any broken wires. did ck for pulse at computer none there. got a reman computer. But when hot still would not start. did set a code p1351 EST output high. went thru tests came to ...	7
	1996 Chevrolet K3500 7.4L Brake pressure VIN: 1GBJK34J5T Thanks 'much' gang for the info... Terry,Rick,Thomas, Richard..BUT!!! this truck has been driven for a few weeks now with no more failures.. Good solid peddle.. The only thing that was replaced here was the peddle switch/sensor that showed the brakes to be bei...	5
	1997 Chevrolet K1500 Cheyenne 5.7L Steering Effort VIN: 2GCEK19R7V Thanks For The Help, Check For Handwheel Speed Sensor Problems, Found Low Voltage Code, Replaced Sensor, All Is Fixed	22
	1998 Chevrolet K2500 Cheyenne 6.5L No Start VIN: 1GCGK29F2W Well what a fun one this one was! It turned out that the ordinary looking (no wires or key chip)ignition lock cylinder has some kind of hall effect. The security system must recognize it or it shuts down the fuel supply! I left the fact that I replaced it out ...	5
	1998 Chevrolet Cavalier Z24 2.4L timing chain VIN: 1G1JF12T6W This vehicle left here 2 weeks ago and I have not heard what the final verdict was. 2 replies got me thinking more about an oil supply problem when it was mentioned that the exhaust cam may have froze up and caused the chain to jump.I appreciated all replies t...	6
	2001 Chevrolet Impala 3.8L Poor Idle Quality, Stall VIN: 2G1WF55K61 Finaly The system was really rich, i take off the two O2 sensor and the reading of the two sensors was about 450 mv. The source of the rich condition in the exaust was the purge valve leaking in the intake at all time. Thank to all of you, one of Ivan [...]...	6
	1997 GMC Jimmy SL 4.3L MIL Lamp on, trans complaints VIN: 1GKDT13W0V First of all, thanks for the suggestions given. One member suggested to check the egr pintle position valve to see if it was sticking from excess carbon buildup, to address the egr code that stored. Another suggested that I try a different scanner to make sure... Trouble codes: P1406, P0122, P1122.	3
	1997 Oldsmobile Silhouette GL 3.4L 1-2 Shift Solenoid VIN: 1GHDX03E3V After all the shift solenoids and torque convertor solenoids were replaced, problem still existed. Much time wasted and testing later, one of the new solenoids was defective. The shift solenoid that is located at top of valvebody above the axle was the culprit...	6
	1999 Pontiac Grand Prix GT 3.8L Surge, Poor Fuel Economy VIN: 1G2WP52K4X thanks to all that had helped, small o-ring on pcv valve was torn causing the vacuum in valve covers replaced o- ring and valve with kit from dealer and all was great	14

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