GM Automotive Technicians Technical Discussion and Fixes for Aug 16, 2005 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	1973 Cadillac Coupe DeVill 7.7L Rear Lighting VIN: 6047R3Q278 Hello everyone and thanks for any help on this old doll. I have this 73 Caddy in with all sorts of rear lighting problems. When you turn on the turn signals in the rear, they flash dimly or not at all. Also, with the brakes applied, things like the license pl...	View
	2002 Cadillac Escalade 6.0L turn signals VIN: 1GYEK63N32 Well this simple problem is not so simple-turn signals flash too fast on both sides-have replaced the flasher,the turn signal switch,ext turn signal bulbs-no help!!!-What am I missing???I see the bcm is involved in the circuit,but I don't see how that could ca...	View
	1993 Chevrolet G20 Chevy Van 5.7L brakes VIN: 2GBEG25K1P Van came in with complaint of pull to right when brakes applied. Van was in desperate need of brakes all around, the rotors were shot and we felt we could eliminate pull with new calipers. Van still has pull- but to clarify it a bit- it is an initial pull when...	View
	1993 Chevrolet K1500 Cheyenne 5.7L Petal Feel VIN: 1GCEK14K8P This vehicle came in with a spongy pedal/low pedal concern. The frong and rear brake linings were all in bad shape (cracked, thin, etc.) I did a complete rear brake job with wheel cylinders, bleed the system, and adjusted them up tight. Front recieved new lini...	View
	1993 Chevrolet G20 Chevy Van 4.3L no speed signal VIN: 1GBEG25Z1P have speed signal, speedometer works fine, scanner shows no speed output. tested at buffer with a/c voltmeter, shows signal at speedometer and at output signal same readings. must be bad ecm but I first can't find the ecm as this is a conversion van [it should...	View
	1993 Chevrolet S10 Blazer Tahoe 4.3L Excessive Emissions, Poor Idle Quality, Surge, MIL Lamp on VIN: 1GNDT13W8P Vehicle runs good when warm, but idles rough when cold.Customer says it acts like it is getting too much fuel. I havent had a chance to check it when it was cold. customer is from out of town and hadnt been able to leave it. Check engine light seems to only c... Trouble codes: 45 (rich exhaust)	View
	1995 Chevrolet Astro CL 4.3L Hesitation, Cuts out VIN: 1GNEL19W6S This van has a severe hesitation on start up. It will only last for a mile or so. To keep it running you need to keep feathering the throttle. Fuel pressure is good, and increases when throttle is depressed. It is hard to diagnose because of the limited time f...	View
	1999 Chevrolet Tahoe LS 5.7L Misfire, MIL Lamp on VIN: 1GNEK13R9X vehicle has 2 dead cylinders #5 and #7 always. complete compression check shows 120 or very close to it on all cyls. fuel psi and volume are good. inj. pulse is also good. we took off valve cover and checked for rocker movement and cam shaft wear. all looks ok... Trouble codes: P0300	View
	1999 Chevrolet Silverado 2500 6.0L oil pressure VIN: 1GCGC29U5X Removed old oil pan and found a small amount of grit and slight sludge build up, less than you would expect to find if the engine milage is correct at 235,000. Inspected oil pick up screen and found it clean. Replace oil pan and gasket with oe parts, installed...	View
	2001 Chevrolet Cavalier Z24 2.4L high idle VIN: 3G1JF12T61 Car came in idling at 1400-1500 rpm.No apparent vacuum leaks.IAC is @ 60 counts,purge solenoid slowly rises to 100%,LTFT is at 25%,disconnected purge vavle made no differance,disconnected IAC made no differance,disconnected TPS and idle went down to 850-900 rp...	View
	2002 Chevrolet Silverado 2500 HD 6.6L no power VIN: 1GCHK23162 Starts and idles fine. No hesitation but it feels like you are running out of fuel under acceleration. Hooked up Snap on scanner it reads 3,059MPa with key on engine off, my Motor manual says it should be 1.1 to 1.4MPa. If I disconnect the fuel rail pressure s... Trouble codes: P1093, P1094	View
	2003 Chevrolet Express 1500 4.3L Distributor VIN: 1GCFG15X93 Van came in for no start. We found distributor not turning smoothly. Removed distributor and found severly damaged/worn drive gear. We inspected cam gear and can't see any runout or damage, but before we install new dist. we would like to know what caused it, ...	View
	2004 Chevrolet Astro 4.3L awd VIN: 1GCDL19X14 Vehical came in with AWD light on scaned codes determanied bad Accuator motor. We replaced accuator motor code would not clear. We inspected and tested all wires all test good. When we try to clear the code the light comes back on immediatly. Tried to reset wi...	View
	1994 Pontiac Firebird 5.7L No Start VIN: 1G23456789 Hello fellow Techs. Knowing that this vehicle came from another shop It will be a challenge. I noticed a lot of parts has already been replaced. ECM, DISTRIBUTOR, IGNITION MODULE, ALL SECONDARY IGNITION,FUEL PUMP AND FILTER. Current fuel pressure at 39 psi, sp...	View
	2000 Pontiac Sunfire SE 2.2L No Start, Cuts out, Stall, MIL Lamp on VIN: 1G2JB1245Y customer came tonight as I was closing with the car on a hook. dropped it, then I went in and it started and drove it in the garage. she said it was cutting out for the last two days and today it stopped. hooked up the scanner and there was no communication. t...	View
	1997 Saturn SC2 1.9L Stall VIN: 1G8ZN1287X Found out Crank Position Sensor was bad and replaced it. Drove about ten miles and it stalled out again. Wait about 30-45 minutes and let the engine cool off and start back up and drive all the way back to the shop. I put a second Crank Position Sensor in it... Trouble codes: P1599 (Stalls with ingition system enabled and loses crank position signal)	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1989 Chevrolet S10 Blazer Sport 4.3L No Start, Stall, smokes ignition coil VIN: 1GNCT18Z0K First I would like to thank everyone for the excellent responses. A lot of people mentioned the ignition module, I'm sorry I failed to mention that we replaced the module with the tune-up parts. [...] hit the problem right on the head, What we found was the...	17
	1992 Chevrolet C1500 Cheyenne 4.3L Hesitation, Stall VIN: 2GCEC1925N well, we did check all connections and plugs carefully, and i did pinch terminals to injectors at ecm. so far it has not acted up again. thanks for the help.	7
	1994 Chevrolet Caprice Classic 5.7L engine VIN: 1G1BL52P7R Thanks for all the help We used what was sent to us in the emails. What we came back to was a bad #7 wire and a small broken vac line. we found the small line cracked but that did not fix the problem. So we went back to the wires & plugs because the car did ru...	17
	1996 Chevrolet Cavalier 2.2L ignition cylinder VIN: 3G1JC5245T Thanks again to all who replied. Since the cyclinder was shot anyway, I tried Rickey from Florida's method of driving the lock tab into the cylinder and that did the trick. I had one of my fellow techs pull on the cylinder as I drove the tab and it slid out af...	11
	1998 Chevrolet Tahoe LS 5.7L Surge VIN: 1GNEK13R7W Customer came back yesterday for a recheck & was happy- if he's happy I'm happy! I pulled the upper plenum & watched the injector spray pattern- we decided on 3 that had poor atomization, also changed FPR while there. Thanks for the three responses!Sherman [...]...	3
	1998 Chevrolet C1500 Cheyenne 4.3L MIL Lamp on VIN: 1GEC14WZ24 Many thanks to all that replied (27 of you!) all confirming my suspicions about needing a factory converter. The customer returned to the muffler shop and had them install a new converter from the local GM dealer. he brought it back to us to recheck and clear ... Trouble codes: P0420 (Catalyst below efficiency).	29
	2000 Chevrolet Silverado 1500 5.3L Poor Idle Quality, Misfire VIN: 1GCEK14T5Y Customer picked up truck, declining additional repairs and inspection/testing. What I found was the computer wire harness connectors plastic holders are chiped, cracked and broken. Serial wire spliced with but connector. Other wiring found in poor condition. T... Trouble codes: P0300 (random missfire 4 cylinder has highest counts).	10
	2001 Chevrolet Impala 3.4L power VIN: 2G1WF55E11 thanks for the replies from paul,david [...],paul nailed it with a bad cat. gm is have issues with these on all cars and now the trucks thank to all chad	5
	1988 GMC Safari 4.3L engine swap VIN: 1GKDH15Z3J Most replies said to take it out the front end. The van was older one...I could not lower it with the sub-assy. The job was not a real tough one, but I was barly able to beat the clock...after removal of front stuff and throttle body, swap went smooth...I stil...	20
	1994 Oldsmobile Cutlass Supreme S 3.1L Poor Idle Quality, Stall, MIL Lamp on VIN: 1G3WH15M4R Thanks to all that responded. I noticed the block learn pid being lower than I would have expected, I also noticed the O2 pid reading .000 volts to .720 and switching. I didn't remember ever seeing O2 voltage go to zero before! Since I had an O2 sensor error c... Trouble codes: 13 (o2 sensor error), 33 (map sensor high).	10
	1997 Oldsmobile Cutlass 3.1L hvac VIN: 1G3NB52M9V first off i would like to thank those who took the time to reply it takes all of us to make this industry work . this was a non cycling variable compressor that should regulate itself to a low side pressure around 30 psi . what was happening was the low side w...	7
	1998 Oldsmobile Intrigue 3.8L a/c switch VIN: 1GCEG25H4S i want to thank all the people that helped with veh. good help... the problem ended up being a faulty compressor. thanks again for the help. iatn is the best...	5
	1989 Pontiac Grand Prix SE 2.8L Cuts out VIN: 1G2WP14W4K Thanks to all my fellow IATN mechanics for posting possible help fixes. Sorry this fix took so long to post, but I have been moving and they have not hooked up my computer or phone lines til just recently! I received a wide variety of fixes, all of which were ...	21
	2000 Pontiac Grand Prix GTP 3.8L evaporator housing VIN: 1G2WR1218Y Thank you for all 11 replies. Stuart, Rick, Kyle, Glenn and all the reat of you said said to check the 90 degree elbow that was not there. Stuart [...] even gave me the correct part number. When he was driving around town, the condensate would flow out of the d...	11
	2001 Pontiac Grand Am SE 2.4L high idle speed VIN: 1G2NE52T81 thanks for your help, especially greg from IL. I performed all available resets and IAC tests on scan tool, cycled ign sw and tps % was at 0. did drive cycle and idle SLOWLEY began coming down a little more every mile. I noticed IAC counts would be a couple co... Trouble codes: P0122 (tps voltage low).	8
	1996 Saturn SC2 1.9L Accessories VIN: 1G8ZH12711 Another member reported what we suspected; that the switch testing information in Mitchell and Alldata was incorrect. We did have varied resistance in all positions, we're sure it's the motor but customer has declined repairs at this time. I suspect when it st...	4
	2001 Saturn SC1 1.9L MIL Lamp on VIN: 1G8ZN12801 Greetings, I want to thank the 12 techs who replied to my request for this Saturn issue. After replacing the intake gaskets I found a few more vacuum leaks which were enough to cause a higher than normal idle. However I also found that when I installed the IAC... Trouble codes: P0500, P0507, P0509.	12

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