Trouble with Buick
joe dunham
01-01-2002, 09:07 PM
Iam having trouble with my 87 Buick LeSabre. It ran fine but then after I shut it off it wouldn't start. There is spark at the plugs, but it will not start. It will might fire for just a quick moment as you first turn the key, but not afterwards. The plugs are wet with gas after that and I cannot figure it out. There is plenty of fuel pressure and I replaced the pressure regulater with no change in the problem. please help!
Joe
Joe
xivera
01-02-2002, 12:56 AM
Moving to the proper forum... ;)
The Bartender
01-02-2002, 05:25 PM
Ooof. Talk about an industrial sized can of worms.
The 3.8 is a reliable motor, but the early to mid '80s GM Computer Control Systems aren't.
Okay, you have spark. Do you have good spark to all 6 plugs? When it "tries" to start, does it seem rough? Will it restart after it sits for a period of time, and if so, how long does it have to sit? Is it hard to start cold (after sitting for 8 or more hours) ? WHile running, does it appear that the timing could be off (rough running)?
At this age, the pressure regulator is'nt a bad place to start. You have fuel, but have you actually checked the pressure? The regulator prevents excessive pressure, but if the pump in the tank isn't holding the proper pressure, it doesn't matter what the regulator does.
The suspect items for this system are:
In Tank fuel pump
Camshaft sensor
Crankshaft sensor
Ignition Module
Ignition Coil
ECM
Checking the pump isn't too hard. If it's putting out good pressure cold, let it run for a while and then recheck it. After that, check the igitnion coils for resistance, and check check the module. Check the cam shaft and crankshaft position sensors for obvious damage or problems, and check all the wiring leading to them. There's a simple test for a bad ECM. With the car running, in park, at idle, LIGHTLY !!!!! tap on the ECM case with your knuckles or a plastic screwdriver handle. If the car stalls, the ECM is probably bad. (This test may not help in your case, since you have a no start, not a stall problem. But this test can still help identify an ECM problem, which you COULD have.) This tap test is a semi official GM devised test, for those who laugh!
The proper tests for the above items are in the service manual under the applicable sections.
GM issued a large "bulletin" in the late '80s specifically about the proper diagnosis and repair methods for this computer system. If you have a way of getting info, such as a friend at a GM dealer, it could help to ask him/her if they have a copy.
The 3.8 is a reliable motor, but the early to mid '80s GM Computer Control Systems aren't.
Okay, you have spark. Do you have good spark to all 6 plugs? When it "tries" to start, does it seem rough? Will it restart after it sits for a period of time, and if so, how long does it have to sit? Is it hard to start cold (after sitting for 8 or more hours) ? WHile running, does it appear that the timing could be off (rough running)?
At this age, the pressure regulator is'nt a bad place to start. You have fuel, but have you actually checked the pressure? The regulator prevents excessive pressure, but if the pump in the tank isn't holding the proper pressure, it doesn't matter what the regulator does.
The suspect items for this system are:
In Tank fuel pump
Camshaft sensor
Crankshaft sensor
Ignition Module
Ignition Coil
ECM
Checking the pump isn't too hard. If it's putting out good pressure cold, let it run for a while and then recheck it. After that, check the igitnion coils for resistance, and check check the module. Check the cam shaft and crankshaft position sensors for obvious damage or problems, and check all the wiring leading to them. There's a simple test for a bad ECM. With the car running, in park, at idle, LIGHTLY !!!!! tap on the ECM case with your knuckles or a plastic screwdriver handle. If the car stalls, the ECM is probably bad. (This test may not help in your case, since you have a no start, not a stall problem. But this test can still help identify an ECM problem, which you COULD have.) This tap test is a semi official GM devised test, for those who laugh!
The proper tests for the above items are in the service manual under the applicable sections.
GM issued a large "bulletin" in the late '80s specifically about the proper diagnosis and repair methods for this computer system. If you have a way of getting info, such as a friend at a GM dealer, it could help to ask him/her if they have a copy.
gloria
06-14-2002, 07:10 PM
have you checked your codes ?
when i had that trouble i wired a switch to the plug under the dash--now if i have a problem i turn the key on and flip the switch for the code.
if you have a pair of wire pullers(coated handles and tips) pull one wire at a time at the ignition module to check for spark.
you can use a timing light to see if you are somewhere in the ballpark , if so then your crank and cam sensors must be sending a signal
plugs are wet so you must be ok on gas
computers are about 25 - 30 $ in the junkyard---if you get one be sure to take off your cover and match up numbers unless you get it from the same exact model car.
i am not positive but i think when you jump the plug to retrieve code that it puts the computer in the manual mode so that some sensors dont depend on the computer such as gas and the timing retards and may start like that
my car is getting old now,started bucking on hills,i unpluged the tcc
for lockup and it runs perfect little less gas milage may last me 3-4 more years--hate to part with it
when i had that trouble i wired a switch to the plug under the dash--now if i have a problem i turn the key on and flip the switch for the code.
if you have a pair of wire pullers(coated handles and tips) pull one wire at a time at the ignition module to check for spark.
you can use a timing light to see if you are somewhere in the ballpark , if so then your crank and cam sensors must be sending a signal
plugs are wet so you must be ok on gas
computers are about 25 - 30 $ in the junkyard---if you get one be sure to take off your cover and match up numbers unless you get it from the same exact model car.
i am not positive but i think when you jump the plug to retrieve code that it puts the computer in the manual mode so that some sensors dont depend on the computer such as gas and the timing retards and may start like that
my car is getting old now,started bucking on hills,i unpluged the tcc
for lockup and it runs perfect little less gas milage may last me 3-4 more years--hate to part with it
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