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Buick LeSabre Starting/Stalling Problems



  • bildabonebildabone Posts: 4
    Before I go any further .Please tell me if this is possible,with all of the injecters out but connected to the fuel rail,if I crank the engine will the injecters fire off and release fuel,ifr everything is working correctly.And by the way its a 94 lasabre
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    edited May 2013
    The injector is grounded through the black wire to the connector and gets power on the other line, so it should spray fuel: doesn't need to be connected to engine. But I don't know if that's safe, because it will be spraying out fuel in a vapor in a very explosive form if it finds a weak plug wire, etc.

    But since the car runs with ether, you're doing the right kind of troubleshooting.

    If you have a voltmeter try testing for a pulse when the PCM grounds each injector while cranking. Did you read the link I put in the prevous post? Is your injector fuse okay providing power? Note that you have a 94 with the higher failure rate on PCMs.

    BTW, did you disconnect the MAF sensor to see if the car would run with it off putting the car back in a different mode? MAF sensors get replaced because they are easy to blame. I've never had to do one on 4 cars that have had one even with high mileage. I read more about problems with replacement brands in Bonneville and leSabre discussions. AND disconnecting it and the car working in a limp mode does not mean the MAF is bad. It's only a diagnostic step. A longtime shade tree mechanic up the road from me worked on another neighbor's Monte Carlo, 95, and symptoms of running rough and occasionally dying. Disconnected MAF, ran. Replaced. Still had problem. Disconnected MAP. Ran. Replaced. Still had problem. Took to transmission buddy who knows diagnostics and had engine tools, and it turned out to be something else. But they had put hundreds into the MAF and MAP sensor on the 24-valve engine.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • bildabonebildabone Posts: 4
    edited May 2013
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    edited May 2013
    The PCM is the computer controlling the powertrain.
    It's under the air intake or inside the air intake in the engine compartment.

    Or it's against the passenger side of the A-pillar inside the car under the dash.

    Without rereading all your posts, remember if the crankshaft position sensor is not sending certain pulses, there will be no spark and no injector pulses.

    I'm beyond my troubleshooting ability here, so I may not be able to be of help. But are you getting spark on a plug when you lay the wire against metal on the engine or you lay an old spark plug with the plug wire attached against metal, do you get the spark across the gap?

    When you say your car runs if you use ether, that would indicate it's getting at least a weak spark.

    I gave you one test for pulses to an injector using a 194 bulb wires plugged into the injector lead.

    I forget what year your car is now... aaah, 1994.

    The problem with just replacing parts, is you can spend up a lot of money with guessing. And it requires a test device to really see what's not happening that is giving you the problem.

    Does someone you know have a 94 where you can switch the PCM to see if yours is the trouble?

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • Kirstie_HKirstie_H Posts: 11,042
    It's awesome, patient, and comprehensive responses like this series that got you the "Spotlight Member" nomination & win.
    Thanks for all you do to help!


    Need help navigating? - or send a private message by clicking on my name.

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  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    On the injectors with the key ON, there should be voltage to each of the pink w/black stripe wires. You will need a cheap voltmeter to verify that. The PCM will ground each of those to fire the injector. The PCM may be defective in the circuit for the ground for those (called quaddrivers If I Recall Correctly). Or the process that tells the PCM when to fire which cylinder may not be working right.

    When the PCM senses the engine starting to crank, all injectors are fired in unison one time to put some fuel into the intakes to be ready for the first firing cycle.

    This is getting beyond my ability level. I think it needs some circuit checking and probably needs a TECH II scanner that dealers use and some shops have equivalents for.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • tndayotndayo Posts: 4
    This recently just started happening.
    I have a 1991 Buick LaSabre with 76k miles. The car turns on just fine, it drives just fine, but when the car becomes idle, as in I stop at a red light or stop sign, the engine just cuts off. I took it to an autoshop and they told me it was the Idle Air Control Valve so I got it replaced. Drove it down the street and it stalled again. The mechanic did a power check on the valve and says there's some electrical issues short circuiting the valve. They put the old valve back in and I took it to another auto shop because they don't deal with electrical issues. The second auto shop told me just by looking at the engine that it seems like there's a vacuum leak but didn't know where. I called the first auto shop and they didn't believe that it was a vacuum leak. Has anyone else had this issue or may know what the issue is? I'm not that savvy with cars.

    The engine doesn't cut off every time when I'm idle. When it doesn't cut off, it sounds like the car is struggling to stay running, like you can hear the engine drop then go back to normal. I have changed the oil, refilled the coolant, and changed the car battery. My next step is to get the car tuned up because it has been a while. Another thing I noticed is that my temp light would flicker whenever I have the AC on.. I don't know if they're related or not. At first I thought the car was overheating but it doesn't seem like it since my radiator fan is working and its taking the coolant. Anywho, does anyone have any ideas or suggestions?
  • I am currently going thru the same problem.The guys here have given plenty of suggestions and they have been really helpful.For me the mass air flo senser ,fuel pressure regulater the crank shaft position senser no doubt were all excellent suggestions,but didnt solve the problem.the fuel punp puts out 43lbs at time of initial start up d rops to 35 while running.I dont know if thats sufficient .I'm frustrated and now the gas tank is out and I'm changing the pump.I'll be pissed if it still doesn't solve my problem
  • sandismomsandismom Posts: 1
    I also own a 1997 Buick Lesabre & have had very similar problems. I would be driving 35 mph and it would just cut off. when it first started doing this last year, after sitting for 5 minutes it would crank back up. It started happening more frequent and then wouldn't start back up. I had to call aaa to come tow me. 2 different mechanics could not find the problems. then the car would act like it wasn't getting gas & then would cut off. the steering wheel wouldn't turn for me.I eventually parked it, not knowing who to take it to. I got tired of donating money to mechanics. from what I hear on this discussion board it is a major problem with buicks. was there ever a recall on anything pertaining to this "problem"
  • bobbydingbobbyding Posts: 7
    Yep. My Buick would just die while driving and would typically restart within a few minutes. In my case it was the crank sensor. My mechanic did not find this issue, it was predicted here on this forum and I had to specifically request it be replaced. I don't remember how much it cost but it wasn't more than $200 (maybe around $150) for the time and parts. Of course it may or may not be what's wrong with yours, but it may be worth a try.

  • tndayotndayo Posts: 4
    It has been a month now and I still haven't found the solution. Neither has the autoshops. Shortly after my last post, the brakes went out so I had to get them replaced.. along with a new heater core because there was an anti-freeze leak in the dash. As for the stalling issue, it has still not been resolved yet. I gave the autoshop in the condition they wanted it: The point where it would just shut off whenever I turn it on, like, it starts up fine then a second later, cuts off. I had to push the car into the parking spot because I just wasn't able to drive it.

    The autoshop is doesn't know what to do. They put all their test equipment on the engine and everything checks out fine. They said something is causing the car to produce rich air, or something like that. Basically the car's air is too rich and causes it to stall. Note this only happens when the car is HOT. When it is cold, it runs just fine. They tried swapping out the CPU and the ignition module and that did not help. Frankly, they have no idea and its driving them nuts and its driving me nuts too.

    Has anyone had similar issues or have any suggestions? Would replacing the crank sensor work out?
  • ytdh314ytdh314 Posts: 1
    I've been down this same road, and it turned out to be the fuel pressure regulator, do some research on it and it might just be your issue too.
  • I have had many of the same issues that seem to be floating in this forum with my car stalling. Since May, it has stalled more than I care to think so towing bills have been outrageous. It started while I was traveling at 30 mph on a major street. The car turned itself off while driving. It started and then stopped. The intake valves were replaced and other items under the hood but that did not help. It ran for several days and then started again. It ran for a week and stalled again while driving. Then it would not start. I have been to 2 mechanics and nothing shows up on the computer. Coils were changed. It started and ran without hesitation for several weeks. The CPU was checked. That is not the issue. I have taken notes on what others have said to see if we can find what is wrong. My engine light and gas tank lid light have stayed on for two years. I have replaced the gas tank caps from both generic and dealer and nothing works. This all began after Pep Boys changed my spark plugs in May 2010. Problems started in summer 2011. Could it be the key? The irony is that both times the car was towed, after it cooled down for over 4 hours, it started. I can't continue this hesitation as I travel and it causes me money to tow and the possibility of a major accident could occur.
  • tndayotndayo Posts: 4
    By any chance, did you get the crank sensor replaced? That seemed to be the problem with mine. Except my problem was that my car stalled when I was idle and not while driving. Whenever I stopped at a red light, the car would stall. I caused so much traffic that way, its quite embarrassing. Whenever I let it cool down for a couple of hours, it would run fine. It did stall on me when I was driving sometimes though. But anyways, after spending tons of money at the car repair shop. They figured out it was the crank sensor. After they replaced it, the car ran has been running fine and it has been a couple of weeks now. I hope I didn't jynx it. The crank sensor won't pick up on their testing equipment. They tested everything, even the CPU and for vacuum leaks. As for your engine light and gas tank lid, I'm not sure what those are. The whole time I was having issues with mine, no lights were on. Well good luck.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    The gas cap loose is probably a P0440 which means a leak in the tubing when the car tries to check for a leak by pulling a vacuum on the tank and watching how fast the air moves in to replace the lower pressure. It requires having someone trouble shoot the exact code and then checking the rubber parts of the vacuum tubing on the top of the engine to the purge valve. There are parts that crack as they harden with age. When Pepboys worked around the engine they may have wiggled the tubes and caused the cracks to leak. ONe part is a U-shaped turn on mine. I ended up putting a heat shrink tube around it to seal it.

    The leak can also be some other tubes such as the rubber tube from the carbon canister to the vent valve which closes so the vacuum can be drawn OR the vent valve itself may not be closing. That would set a different code.

    Not sure what the "intake valves" are that you mean. But I vote for the crankshaft position sensor. The test is to pour cool water over the sensor which is under the edge of the large pulley low on the engine with the belt around it. If that cools it quicker when your car shuts off, then the $40 part can be replaced by taking off that large pulley--maybe a maximum 1 hour job.

    The other could be the Igniton Control Module which is under the 3 coils. It has wires to the end of it. You might wiggle them to see if that improves contact, but they were very well held in place. The module might be getting hot and cutting out.

    The real test for the last two is to test a plug wire to see if you're getting spark while the car is cranked when it has just cut off. That requires having a spark plug wire you can pull of and lay on top of the metal to look for spark.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • THanks for your email advice. This is one piece I saw on the forum that people recommended. I am talking to my mechanic today to see how we can get that done. Someone also suggested a new key but that is expensive. My car went through four different computers and everything tested well and working. I hate the fact that Buick does not see this as a major issue as it could cause an accident or death if it happens at a high speed. I will try that.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    I did forget to mention an ignition switch contact may be the problem. But those would often fail at random times or when a sharp bump affects the switch. Now I'm talking about the actual ignition switch with the electrical contacts and _not_ the key cylinder itself, unless those are the same on our 2000-5 cars. I haven't checked my factory service manual.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • where is the vat modual located on 92 la saber
  • I am not sure if they are the same or not. I will check it out in my manual. Thanks. I talked to my mechanic and we have replaced some of the parts you suggested. The crankshaft sensor has not been replaced. It is the cheapest to try as the ignition switch is $125 to replace. I appreciate your help. I love my car but stalling is costing me money and time.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    Does the Security light come on when you turn the key to ON?
    Does it start flashing for 3 minutes? If so, then you know the computer did not read the right resistance for the chip in the key when it's in the lock cylinder.

    Search for VATS (vehicle anti theft system) on the internet and how to bypass it. Use an ohmmeter and measure the resistance of the chip in your key. There are lists of the 15 possible resistances that GM used on the net. Get resistors at Radio Shack in pack to put in series to equal that resistance. Solder them together and then solder the ends onto the wires from the computer instead of the key in the lock.

    Be sure to cut the wires high up on the steering column to get extra lead to work with. You are looking for the yellow tube that looks solid until it goes to the connector group up on the firewall by the left foot and instead becomes two tiny white wires that go to the pins in the connector.

    Search for some articles and videos. Here's one.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • I have a 99 Buick Lesabre. I was having the same problem. We were told it was the security system. So we got a new steering column - still happened. Ended up fixing several small stupid things, and it was stillhappening. One day I was stuck, and just started messing with things. I turned the heat/vent on HIGH, started the car and BAM, it worked. The car will be fine for weeks, then do it constantly for a week. And the heater/vent trick works every time. Sometimes I have to do it 2, or 3 times - but it works. Not sure what it is, but whatever, it works! Good luck!
  • tndayotndayo Posts: 4
    I tried the same thing when my car was having the issue. Turning the heat on high helps the engines air flow in r something like that. It didn't work too well for me too though. I got the problem fixed though. Turned out to be the crank sensor. It only took them a grand later for them to figure it out -_-
  • So here is another problem that has started, maybe you might know.. The car is chugging HARD, and will stall out of no where. Started the day after a coolant flush. Oh, and PS: I bought the car for 2k about 18 months ago - I've put about 1500 into it. Its ridiculous.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    >I bought the car for 2k about 18 months ago - I've put about 1500 into it. Its ridiculous.

    When you bought it, what did the mechanic say that you took it to for inspection before purchase? That inspection will tell you likely problems coming ahead for that model.

    A prepurchase inspection is really important. You can't trust the used car salesman or lot or curbstone seller to be honest about a vehicle's past and future.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • I have a 1993 Buick LeSabre (150,000 mi.) that has run very well for years. Never stalls. Til now. I was idling the other day and the car died out with black plumes of smoke coming out of the tailpipe. I can restart it, but within seconds the car dies out. The mechanic has tried fixing the problem by replacing the computer. He's tried three so far thinking the first two may be faulty. We tried different keys in the ignition. He's also tried several other "fixes". Now he's going to check the harness wiring. Are there any other things you might suggest? In case this may have any bearing on the problem I want to mention that we recently had a new starter put in. Thanks.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    If your mechanic is trying different keys as a remedy for black smoke out of the tailpipe, you need a different mechanic.

    And insisting that 2 replacement computers must both be bad when they don't fix a symptom is another problem.

    Time to move on to a different mechanic.

    Also, I'd look for leaking injectors along with the injectors commanded ON all the time to give too much fuel. That might lead back to the drivers in the computer, but I"m not seeing how the current fellow is coming up with computer as the problem.

    And I'd check the indicated temperature from the temperature sensor that the onboard computer uses. If it is telling the engine that the temp is COLD, the computer puts too much fuel in and you would be running rich. My scanner can tell me the temperature--your current or future mechanic should have one capable of that. The temperature gauge in the car may give a different reading from another sensor so the computer's temperature gauge needs to be checked.

    My places to start would be too look at the fuel pressure regulator on the fuel line that can leak fuel through its diaphragm and suck that leaked fuel into the intake manifold directly, richening the mixture.

    I'd also try starting it without the MAF sensor connected. If it runs then, the Mass Airflow Sensor might be bad.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • I am going to make sure that what you have suggested gets checked. Thanks so much for the time you took for such a detailed response. I really appreciate it.
  • buickjenbuickjen Posts: 1
    edited September 2013
    92 buick lesabre with 144k. Doesn't leak oil. The spark plugs are new. Its never happened while driving only when I park turn it off and come back out to start it. And its random but sometimes it will turn over but chug and the whole car shakes and it turns off. I wait 30 mins and itll start up and run fine.and i thought it had something to do with the key cause my chip on my key was worn down so I replaced it. Ran fine for a few days but now its doing it again. Any ideas? Thanks
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 21,502
    edited September 2013
    Since you don't mention any running symptoms at any other time, I assume there are no other periods of rough running, stumbling, etc..

    My _guess_ would be crankshaft position sensor_. Usually people have the car stall on them and it won't restart for 10 or more minutes until the engine cools and the sensor is able to operate correctly.

    Watch the tachometer when it starts to stumble. The tach should go to zero because of the lost signal to the ignition system. Or it will swing wildly from 0 to 500 or more on the cycles where it's catching an electronic signal.

    The position sensor (CPS) is under the edge of the harmonic balancer. That is the lower pulley on the engine with the serpentine belt. It has a couple of wires and is about the size of a thumb under the edge of the harmonic balancer.

    Your sensor, I believe, has to be positioned using a gauge for the right air gap. Later ones just fit into a positioning hole.

    An anecdotal test is to pour cold water on the sensor which cools it down quicker. The magnetic effect returns and if will start the engine. You might carry a thermos of water with you on a trip or a large cup of ice water.

    See if you can locate the CPS on the back side lower of the lowest pulley. Engine off, of course... :)

    Could also be the ISC, ignition spark control, under the 3 coils on the front of the engine top. You could also try cooling it with water; water over the coils and the metal unit under them will not hurt anything.

    Good luck.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • travis236travis236 Posts: 2
    edited May 2014

    Hi i have a 92 buick lesabre custom 3.8 first of all when starting i have to give it gas to keep it running but only usally for 15-30 secs then its fine also when driving at 55+ it will randomly stutter only a few times and its completely random and usally goes away but check engine light doesnt usally come on while it does this. but i do have a randomly occuring check engine light any idea what this could be? and now it sometimes doesnt want to stay running but starts every time no problem just as soon as i let go of the gas it stalls out until i get it just right or something and it stays running after letting go of gas pedal. just recently replaced plugs and wires and fuel filter ** figured out to make seprate discusing not sure how to delete**

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