GM Automotive Technicians Technical Discussion and Fixes for May 3, 2007

Join Now

Prev	Professional Automotive Repair Technical Discussions for May 3, 2007 International Automotive Technicians' Network (iATN) - Members Only	Next
(Also Available: All, Asian, Chrysler, European, Ford, GM.)
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Open Help Requests for GM

	Help Request	Answers
	1987 Buick Riviera Luxury 3.8L Excessive Emissions VIN: 1G4EZ1139H hi all, need a little info on this one.car has a code 55 ecm failure.michell has no info other than "replace ecm"did that and no help.car came in for failed emission.hc failed i know i can fix this emission problem with cat convertor. car has fuel control and ... Trouble codes: 55 (ecm failure)	View
	1987 Buick Century Limited 3.8L No Start VIN: 1G4AL5139H I have spark, fuel pressure, injector pulse and good crank signal. ECM does not show rpm change while cranking, it stays at 0. I can scope signal going into ecm at ppl/wht wire and looks fine. I can view data with scanner and see maf values change while cranki...	View
	1994 Buick LeSabre Custom 3.8L Stall, Poor Fuel Economy VIN: 1G4HP52L22 this is for a different shop so i will apologize for lack of information this car will die while driving and when you try to restart it it seems like it is flooded you hold the accelator to the floor and it will refire and then clear up no specific time for it...	View
	1996 Buick Century Custom 3.1L Poor Idle Quality VIN: 1G4AG55M3T Hi all of you out there I have one that is making me pull my hair out hear this Buick when you start the car it will idle up and then down to around 700 Rpm with a iac count of 29 to 30 but if you put it in gear or turn ac on Idle will go up and and not back d...	View
	1996 Buick Skylark Custom 3.1L Theft system VIN: 1G4NJ52M3T Hi Guys I'm sure someone has run accross this. The car will start sometimes and not others. Have performed key learn procedure multiple times. Sometimes Theft light is not illuminated at all. Not even at prove out. Code 1629 stored in memory haven't had much l...	View
	2002 Buick LeSabre Custom 3.8L Misfire VIN: 1G4HP54K92 This is a first time post for me. Any help would be greatly appreciated. Vehicle came into our shop from the dealer which was diagnosed as a valve problem. The customers complaint is a rough idle. No misfire can be felt on acceleration or when cruising. Found ... Trouble codes: P0300, P0301	View
	2000 Cadillac Seville STS 4.6L Alternator VIN: 1G6KY5490Y Vehicle quit going down the road. Battery waas dead. We charged battery and found alternator was not charging. Only code was low battery voltage. The diagnostic we found stated that if you had 12 volts at the alternator output, a good case ground and either 5,...	View
	1981 Chevrolet C10 Custom 4.1L lifters VIN: 2GCEC14D6B When first started the truck runs good (for as many miles). The longer it runs, the lifters on a couple cylinders (particularly #1 & #2) start to clatter, eventually to where it misfires & runs like crap. Let her sit for a while & fire it up & it runs good aga...	View
	1981 Chevrolet Corvette 5.7L door locks VIN: 1G1AY8769B This is the 1/4 mile drag car that I asked for a vacuum diagram on an earlier post ...I am putting every thing back to stock to make it road ready...I am all most done with this project all I have left is getting the power door locks to work , I have no power ...	View
	1991 Chevrolet V3500 Silverado 7.4L transmission VIN: 1GCHV33N3M Hi guys and girls.I need help fast from all the GM trans techs.I am planning an engine swap in my own truck.I will be removing the gas hungry 454 and putting in a non turbo 1994 6.5 gm diesel with a mechanical inj pump.Now I have been told that I have to use t...	View
	1994 Chevrolet Cavalier Z24 3.1L Misfire VIN: 1G1JF34T2R Thank you all for your help in advance. This is my wife's car, so I'm in trouble. This has been going on for several months now. She will be driving at almost any speed, and will experience a set of misfires for about 5-10 seconds, then it goes away. Sometimes...	View
	1996 Chevrolet Cavalier 2.2L starts & dies VIN: 1G1JC1248T Vehicle will start & dies right away .p1629 VTD code is set in the PCM. Go through flow chart & says Pcm replacement .When I looked at VTD codes in the IPC there were 13 present(history codes none current) . I cleared all codes in both IPC & PCM. Then i tried ... Trouble codes: P1629	View
	1996 Chevrolet S10 2.2L No Start VIN: 1GCCS1448T this truck has no spark, and no injector pulse. it will not comunicate with scaner and the check engine light comes on for a split second and gose out.what could make the ses light come on and go out so quikly. cam and crank signals are good. i have unpluged e...	View
	1996 Chevrolet Camaro 3.8L Poor Idle Quality, Surge, Cuts out, Stall VIN: 2G1FRP22K1 this car will run good cts reads normal up to about 226 degrees tyhen all of sudden it will jump straight to 287 to 300 deegrees and starts running bad, idle surge and stalling. then cts will go back to normal reading. and run great. customer stats that there ...	View
	1998 Chevrolet Venture 3.4L No Start VIN: 1GNDX03E3W vehicle towed from other shop not running, ckd fuel pressure within factory spec, checked for spark good, checked for injector pulse as best as we could with out removing intake none detected. spray combustable in intake engine will run. check modis trouble s...	View
	1998 Chevrolet Venture 3.4L MIL Lamp on VIN: 1GNDX06E3W hello, I have a 3.4 liter running on -14% to -16% LT fuel trim. It runs with a slight flutter at idle, after a while it sets a P0172 code. When you command open loop with the scan tool, the oxygen sensor sits at 800mv. In closed loop the fuel trim compensates... Trouble codes: P0172 (fuel system trim bank1 rich)	View
	1999 Chevrolet Metro LSi 1.3L Cylinder Head VIN: 2C1MR222XX Hello all. This Metro was having a misfire for cylinder #2 coming up. Suspected something wrong with a valve in the cylinder head. Removed cylinder head & sent to machine shop & found bad exhaust valve & guides. Had machine shop repair head & installed cylinde...	View
	1999 Chevrolet K1500 Suburban 5.7L Misfire VIN: 1GBFK16RXX This 99 Suburban came in wanting plugs to solve a missfire at idle. i insatalled the plugs and noticed number four had some build up on it. but it did not solve missfire. # four cylinder misses at idle only. It has great acceleration and runs great off idle. I... Trouble codes: P0304	View
	1999 Chevrolet Astro 4.3L Poor Idle Quality, Hesitation, Misfire, MIL Lamp on VIN: 1GNDM19W3X van came from another shop with rebuilt engine complaining about hesitating,no start and idle.they installed cam,crank sensors.i scoped and scaned engine,everything looked good except idle,too high.I changed cap,rotor,wires,that seemed to remedy the no start t... Trouble codes: P0300, P0335	View
	2000 Chevrolet Blazer LS 4.3L Leaking fuel VIN: 1GNDT13W6Y Thanks for looking . This Blazer will leak raw fuel from the canister vent solenoid when parked in the sun for an extended period of time . Customer swears that she doesn't overfill the tank , but it happens soon after fill up . Not fully understanding the ven...	View
	2002 Chevrolet Tahoe LS 5.3L courtesy lights VIN: 1GNEK13Z92 customer complains of the interior lights not coming on when door handle is pulled.in fact they dont when the door is locked. they do come on when door is open. also the head lamp switch gets too hot to handle after the head lamps have been on for some time. t...	View
	2003 Chevrolet Tahoe LS 5.3L Battery drained VIN: 1GNEK13293 Truck came to shop with dead battery, customer said battery dies after one dday or three days of sitting, had battery installed at other shop. I tested the charging system and battery draw with a amp meter. charging system ok and battery draw is 0 amps. I swit...	View
	1982 GMC C2500 6.2L glow plug VIN: 2GTFC24C2C I hope someone has a miracle for me. I just replaced a tank & sender, breaking the budjet on this worthless truck. Now I have to put glow plugs in it & had the tip of one break off & fall in. About 7/16 or 1/2" of it. I REALLY don't want to pull the head. Any ...	View
	1998 GMC Sonoma SLE 2.2L Misfire VIN: 1GTCS1945W Truck came in for chuggs on accel I test drove and all seemed ok at first then noticed when taking off especially when in second or third light to medium throttle would miss and buck once or twice but sometimes not at all. No miss under hard accel or heavy loa...	View
	2001 GMC Savana 3500 5.7L MIL Lamp on VIN: 1GDHG31R81 we install new reman. engine complete with all sheet metal. after install check engine light flashed then came on solid. tested ignition sytem with scope could see no problems, replace cap and rotor second time and retest drove with same results, scope tested ... Trouble codes: P0300 (missfire detected)	View
	1929 Oldsmobile roadster 196CID Mechanical VIN: 1070931011 Dear friends, I have in my shop a old olds, 29´and the engine is incomplete, I need to kowm about diagram of oil pump,shaft distributor and pressure system.The engine is a 6 cilinder,(195 CID).Thanks a lot	View
	1990 Pontiac Grand Prix LE 3.1L Poor Idle Quality VIN: 1G2WJ14TXL car would not idle when brought in. Did smoke test,no leaks found. Checked iac and replaced. Car idles now but is still running lean and low vac. With vac gage at idle it registers fairly steady( not what you would expect if bad valve)at 8 or 11 inches.I block... Trouble codes: 44 (lean exhaust)	View
	1997 Saturn SL1 1.9L Cooling system VIN: 1G8ZH5288V This Saturn was left here. OIl is getting into the cooling system some how. Pressure testing the ccoling system overnight revealed nothing. It is not transmission fluid some one else said that was the problem and replaced radiator to no avail. Color of coolant...	View
	2001 Saturn L300 3.0L coolant VIN: 1G8JW52K01 this car came in with complaint of oil in the coolant, brown milky looking stuff. the customer had been dealing with this for some time now and had changed radiators twice, thinking the tranny cooler was the culprit leaking trans fluid into the coolant, they f...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1955 Cadillac Sedan 390CID r12 VIN: 5562120017 Thanks for all your help. 6lbs of R-12.. W/sight glass, Great imput on the vacumme control eating freon -Would not of thought of that, been awhile since I used a propane leak tester..But I Recall A Whiff or two of the gas put off by it.. Thanks all! Andy	12
	1994 Cadillac DeVille Concours 4.6L Unknown VIN: 1G6KF52YIR All replies to this situation indicated that the problem was internal to the transaxle or its harness. If the harness checked out ok the only repair would be an overhaul of the transaxle. There is no way to check the harness without almost removing the transax...	4
	1997 Cadillac Eldorado 4.6L oil pressure light VIN: 1G6EL12Y5V Thank you for all the help from the IATN members that offered help on this vehicle. I have found a broken wire (black) in the wiring harness close to the oil pressure switch. I put in a new pigtail harness connecting to the oil switch and all is well! Thanks a...	8
	1998 Cadillac DeVille d'Elegance 4.6L high beams, windows, radio, fuel door VIN: 1G6KE54Y2W Thanks to Brent, Steven, Dennis and Ronald for taking their time to reply to my call for help. I did not do my homework on this one and posted too early. We all get lazy sometimes. Brent was right as the splice under the left side of the rear seat (S305) was t...	4
	1930 Chevrolet 2 door coupe 5.7L Alignment VIN: 1A2B3C4D5E Thank you to all. I ended up using CAMBER-0, TOE-0, CASTER-+4. The veicle is very easy to steer and flies straight as an arrow.	17
	2000 Chevrolet Blazer LS 4.3L 4wd VIN: 1GNDT13W1Y Hello. I have not been able to relook at this Blazer since my first post. The cust took it and said they did not have the funds to look at it now but will bring it back when winter starts again. I did notice though before I let it go that if you let it sit for...	9
	2002 Chevrolet Trailblazer LS 4.2L Transfer Case VIN: 1GNDT13SX2 I believe that the problem is in the transfer case, had dirty oil with debris, but am still waiting for a go ahead to take it apart. Thanks for all the replies, they were very helpful	11
	2005 Chevrolet Silverado 1500 LS 5.3L 4 x 4 VIN: 2GCEK13T45 We installed an encoder sensor and problem was solved! Thanks for immediate attention and sorry for taking so long to close. Bruce [...]	8
	1994 GMC Olympia 5.0L co VIN: 1RC9408367 Thank you everyone for your help, Michael from Oklahoma and Ronald from Michigan had some very helpful tips. The base timing was at 6 degrees and I set it at TDC (according to the book) and set the idle at 500D (according to the book). Now I'm getting a IAC re...	14
	2004 GMC C5500 Topkick C5C042 6.6L No Start, Hesitation, Misfire, MIL Lamp on VIN: 1GDE5C1254 Hi everybody. All of you nailed the problem. I replaced number 4 injector and vehicle starts and runs like dream. Thanks alot. IATN is very good. I appreciated one more time all of you who responsed to me. Trouble codes: P0522 (Oil pressure sensor circiut signal low), P0304 (cylinder 4 misfire detected), P2228 (Baro sensor circuit signal low).	5

(Also Available: All, Asian, Chrysler, European, Ford, GM.)