GM Automotive Technicians Technical Discussion and Fixes for Feb 16, 2004

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Open Help Requests for GM

	Help Request	Answers
	1988 Buick Regal Limited 2.8L Cuts out VIN: 2G4WD14W3J vehicle came in for hesitation on accel and could go past it if gas was feathered,went immediately to maf and tps and scoped for glitches and found voltages to computer lower than normal for specific condition,scoped grounds=ok,scoped reference voltage and fou...	View
	1990 Buick LeSabre 3.8L No Start VIN: 1G4HD54C8L I have this Le Sabre that does not want to start when the coolant temperature is at [...] fahrenheit or lower and only for less than a minute. It will start every time over 56 degrees. What I noticed is that the injector pulse is at 90ms when this is occur...	View
	1996 Buick Skylark Custom 3.1L MIL Lamp on, Blown Fuse VIN: 1G4NJ52M9T Help; Vehicle came in ABS and Check eng lamps on. Multiple codes in PCM for trans, evap, egr,abs and a/c. Traced prob to blown "ERLS" fuse in eng. comp. fuse box. Tested draw, 13 amp OK. Installed new fuse, checked harness for shorts, none found. Ohmed solenoi... Trouble codes: P0753, P0758, P1573, P1654, P1655, P1675	View
	1994 Cadillac DeVille 4.9L MIL Lamp on VIN: 1G6KD52B2R scan this cad,had code 48,perform tests&it points to the computer that we replaced before for this code,when you do the tests it says to open egr valve manually and the car will run rough,but it will not turn out the test light like the test says it should.i w... Trouble codes: 48 (no egr flow)	View
	1997 Cadillac Catera 3.0L oil leaks VIN: W06VR52R2V My customer purchased this vehicle recently, and is regretting it. It leaks oil from every seam. The spark plug tubes are filled to overflowing with oil. It appears to leak from a seal or seals under the timing cover. It also leaks from the lower oil pan gaske...	View
	1993 Chevrolet Astro CL 4.3L No Start, Flooding VIN: 1GNDM19W1P Hello Guys I have a Astro Van that came to me for no start. The owner had been here about a month ago telling me about it , I could not work on it when he was here . He returned a month later telling me of what was done to the vehecle. It would not start and h...	View
	1988 Chevrolet G30 Beauville 5.7L No Start, MIL Lamp on VIN: 1GAFG35K9J The van i am working on is a 1988 chevy full size van, It will not start unless you hold the gas pedal to the floor, upon starting it sets a code 15 i checked for 5 volt reference that was good, so i checked ground and that was good,i first replaced the sensor... Trouble codes: 15 (coolant temp)	View
	1991 Chevrolet C1500 Cheyenne 5.7L Dash lights VIN: 2GCEC19K2M Hi Techs, I have a 91 Chevy 1500 pickup with inoperative dash lights. A new headlight and dimmer switch were installed with no fix. When the headlights are turned on, the turn signal indicators both come on and if I adjust the dimmer switch down to its lower p...	View
	1996 Chevrolet Blazer 4.3L Fuel gauge VIN: 1GNDT13W9T Hello everyone, thank you for taking the time to read my post. We have a 96 Blazer with a fuel gauge the fluxtuates when it is half full almost a half a tank,(it will go from 1/4 to 3/4 as you accel. then slow down. When it is full it does not move around. We ...	View
	1996 Chevrolet Blazer 4.3L Ignition Switch, Shift Indicator Light VIN: 1GNDT13W8T Hello, I have a 96 Blazer that I just replaced a Heater core in. When I went to make sure everything was correct, I noticed that the key would not return to the lock position, and with the key in the start position, it would not show park, Neutral, Drive and F...	View
	1997 Chevrolet Express 3500 6.5L Poor Fuel Economy, low power VIN: 1GCHG35F8V This truck came in for poor performance and poor mileage. Two codes found were P0216 (injection timing control system)and P1214 (Injection pump timing offset). We tried to reset the TDC and the timing but it wouldn't reset. We found the injection pump stepper ... Trouble codes: P1214 (Injection pump timing offset), P0216 (Injection timing control system)	View
	1998 Chevrolet Astro 4.3L fuel gauge VIN: 1GCDM19W4W Hello techs. After fuel pump module replacement for pump failure / no start, fuel gauge reads past full mark at all times. Gauge will respond to float arm movement. When float arm is at "empty" position, gauge reads closer to full(but still past full)than when...	View
	1999 Chevrolet Blazer 4.3L Flasher Unit VIN: 1GNDT13W9X Problem: Flasher unit clicking when key is on. Symtoms: ignition on, both signal leaver and 4 way switch is in off position, turn signal flasher clicking. But both 4way and turn signal lamps not flashing. Move either 4way switch on or turn signal leaver left o...	View
	2001 Chevrolet Venture LS 3.4L MIL Lamp on VIN: 1GNDX03E41 Hello again This time the problem is a Venture with a 3.4 The EGR valve has been replaced with a dealer part. The EGR port at the bottom of the throttle body has been cleaned out.code still sets. If I understand correctly the PCM determines EGR performance us... Trouble codes: P1404 (EGR performance)	View
	2002 Chevrolet Trailblazer LS 4.2L engine VIN: 1GNDS13S82 we currently have a 2002 chevy trail blazer that has a serious vibration at just off idle & continues as you continue into the throttle. the vibration in the engine compartment seem to be right at the air intake box if you hold your hands on the air box the vi...	View
	1995 Geo Tracker LSi 1.6L Poor Idle Quality, Misfire VIN: 2CNBJ1865S Vehicle is running on cyl 1 and 4 only, cly 2 and have spark and injector pulse, plugs are not wet with fuel	View
	1991 GMC V2500 Suburban 5.7L Poor Idle Quality, Hesitation, WILL NOT REV VIN: 1GKGV26K3M This vehicle will not rev up over idle - falls flat on its face. When carb spray is introduced the engine will rev. None of the work performed thus far has changed the problem. This model (4L80-E transmission) does not have the ECS control module. Trouble codes: 43 (Electronic Spark Control Circuit)	View
	1996 GMC Yukon SL 5.7L transfer case VIN: 3GKEK18ROT I recently had a 1996 GMC Yukon with the transfer case stuck in 4WD LOW. This vehicle has the NP 243 electronic push button shift transfer case with the transfer case encoder motor, tccm, and push button switch. The customer says that he was sitting at a stop ...	View
	1997 GMC K3500 Sierra SL 7.4L line pressure VIN: 1G3K300J97 After an overhaul for converter failure(highly metalized oil-no other hard parts affected)I now have very low line pressure(45 psi)and am unable to command higher pressure with Tech-2.When commanded the PCS is following the commands but not increasing pressure...	View
	2001 GMC Sierra 1500 SL 4.3L No Start VIN: 1GTEC14W51 Truck is not firing/No spark	View
	1999 Oldsmobile Intrigue GLS 3.5L Security keyfob & Locks VIN: 1G3WX52H9X This is a situation that we here at the school are trying to work with... The car keyfob and keys were stolen along with another complete 2003 GMC pickup ..With the help of ONSTAR the pickup was found but ...The thief/thiefs still have both sets of keyfobs and...	View
	1991 Pontiac Grand Prix GT 3.4L Poor Idle Quality, Surge, Stall VIN: 1G2WP14XXM car has a bad rolling idle when hot in park,put the car in gear and it will idle ok,have tried resetting idle with scanner,replaced idle air control actuator,every thing on scanner looks ok,can't find any vaccum leaks,i am at the end of my rope with this car,t...	View
	1994 Saturn SL 1.9L clutch VIN: 1G8ZF5595R we replaced clutch , plate, bearing, slave cylinder, and know cant not get any clutch pedal. no bleeder valve on slave cylinder.. thank you	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1987 Cadillac Seville 4.1L Speedo Illumination VIN: 1G6KS518XH Thanks to Tom, Chet & Roger [...] likely fault is in the dash unit. I had time only for a quick look, and saw that the unit had been out before and was broken in a few spots (plastic housing)I have put this repair on hold for the moment and will see this car ba...	3
	1993 Cadillac Eldorado 4.9L oil pump VIN: 1G6EL12B2P thanks to all who replied. the general consensus is that this thing needs a motor. customer opted not to pursue the issue. so did we since we specialize in transmissions.thanks again for all your time and trouble.also a special thanks to k.p.@juno for the pres...	10
	1990 Chevrolet Cavalier 2.2L Cuts out VIN: 1G1JC11G7L Well after 3hrs finaly was able to make this thing happen in the shop was able to whatch injector in action and spark at the same time well a moduale fixed this one I never seen a moduale this interment and start right up after.Does GM not know there is a bigg...	11
	1995 Chevrolet Lumina 3.1L temperature/heater VIN: XX1WXXXMXS I greatly appreciate all the replies I received regarding my cooling system issue. In the end it turned out to be a head gasket/head integrity issue. I closed my mind to the fact that I may be dealing with one of these issues due to good compression readings a...	14
	1996 Chevrolet C1500 Cheyenne 5.7L No Start VIN: 1GCEC19R0T thanks for the replays, finaly after I scoped injector and ignition system, i took the desicion to remove upper intake manifold and found 6 injector clogged, there was enough fuel pressure, injectors were opening electricaly but spring were clogged at the end ...	4
	1998 Chevrolet Astro 4.3L Misfire, MIL Lamp on VIN: 1GNDM19W7W I apologize for not getting back with you all on this help request sooner I have been having problems with my computer. Anyhow I don't quite understand how this fixed it but I replaced the egr valve and now all is good thanks to all who replied with ideas. Trouble codes: P0121.	15
	2000 Chevrolet Silverado 1500 4.8L Mechanical VIN: 2GTEK19V6Y hello to fellow members, this truck has consumed more time than any other in my past. i had sent the heads to the machine shop for a leak test but forgot to mention to you. turns out the left head had a crack around the center head bolt hole. customer thinks i...	5
	2000 Chevrolet Venture Warner Bros. 3.4L rear video sys VIN: 1GNDX13E4Y Well I got three responses for this problem. First one was from Charles [...], he suggested that I may have a power and ground problem. I checked all vehicle grounds and related power sources but found no problem. Second help was from Timbotech, he suggested ...	3
	2000 Chevrolet K3500 5.7L Fuel Tank Leak VIN: 1GCHK34ROY The fix for this one was to replace the vapor canister and gas tank. The vent on top of the canister gets plugged. I did cut a crankcase filter foam and put it in the vent cap then sealed the cap to the canister so dirt could not get into the opening. Had one ...	11
	1995 GMC Jimmy SL 4.3L No Start VIN: 1GKDT13W7S Hello Group, I want to give thanks to all who took the time to reply to this post. This Vehicle was In my bay way to long and I'm glad to see it go. I took the advice of many to replace the ICM module to regain injector drive from my VCM.This did fix my pr...	6
	1988 Oldsmobile 98 Regency Brougham 3.8L No Start, Misfire VIN: 1G3CW51C8J I got burned by just checking resistance of the coil pac, just because it check out the coil was breaking down inside, I installed a new AC Delco and it ran fine. thanks for all the replies!!! Trouble codes: 43 (Knock sensor threr isnt one on this used engine), 42 (EST sets during cranking and it back fire in the air box).	15
	1992 Pontiac Bonneville SE 3.8L abs module VIN: 1G2HX53L8N thanks for the helpfule replys,fred and damon hit it right,the brake pressure modulator valve contains the control solenoids and is not seviceable,replaces as a unit.i checked the abs relay as per pete and the relay operates normally,i also checked the l.f. se...	6

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