97 buick wont start when hot
rickcg31
07-07-2009, 10:44 AM
Got a big problem with my 97 buick lesabre. Ive put new water pump and hoses on and have put new fuel filter, spark plugs ,wires and a new radiator cap and thermostat. The car runs great but the temp gauge still reads above 200 slightly and when you turn it off it will not start back for an hour or so. What can be causing this, please help my wife is about to drive me nutts
thisnametooktolong
07-07-2009, 11:38 AM
Well that could be an out of range engine temp sensor, a stuck air bypass valve. That is assuming that you have fuel and fire at the plug and the fuel rail. If it is not any of those it could be a heat sensitive crank or cam sensor.
rickcg31
07-07-2009, 12:22 PM
will hooking this car ro a computer dianostic machine tell me which sensor is bad if any. Thank you for all your help
imidazol97
07-07-2009, 08:04 PM
Got a big problem with my 97 buick lesabre. Ive put new water pump and hoses on and have put new fuel filter, spark plugs ,wires and a new radiator cap and thermostat. The car runs great but the temp gauge still reads above 200 slightly and when you turn it off it will not start back for an hour or so. What can be causing this, please help my wife is about to drive me nutts
You're going to have to determine if you have air, fuel and spark.
The air is pretty obvious something is blocking your air intake.
The spark can be determined by pulling off a spark plug cable or two in advance while cold and lubing it with dielectric grease so it comes off easily when you can won't start. Use an old spark plug, put it in the cable and lay it on a metal part of the motor for ground. Have someone crank. You should get a nice hot blue spark. If no spark, it could be crankshaft position sensor or the Electronic spark control underneat the coils. It sounds like you're not getting any spark so individual coil failure is not a problem here. The cable connector on the botton of the ESC has lost ground contact for at least one poster I've read. It would make and break contact on a random basis. The ESC units can be tested but the problem is they need to be hot to fail sometimes.
If you have spark, then you have to determine fuel pressure. Do you hear the fuel pump run when you turn the key ON?
Since you don't mention any kind of firing like it has slightly low pressure, I would suspect a real pressure problem. You need to borrow a fuel pressure gauge. Some of the same stores that do free code checks also loan things like fuel pressure gauges. You need to test fuel pressure if you do have spark. You don't give the number of miles on the car. If you don't hear the fuel pump when the key is turned to ON, try hitting the bottom of the tank with a rubber mallet while someone cranks the car. That has been know to jiggle a dying pump loose. But it's only temporary.
Good luck and post to let us know what you find.
You're going to have to determine if you have air, fuel and spark.
The air is pretty obvious something is blocking your air intake.
The spark can be determined by pulling off a spark plug cable or two in advance while cold and lubing it with dielectric grease so it comes off easily when you can won't start. Use an old spark plug, put it in the cable and lay it on a metal part of the motor for ground. Have someone crank. You should get a nice hot blue spark. If no spark, it could be crankshaft position sensor or the Electronic spark control underneat the coils. It sounds like you're not getting any spark so individual coil failure is not a problem here. The cable connector on the botton of the ESC has lost ground contact for at least one poster I've read. It would make and break contact on a random basis. The ESC units can be tested but the problem is they need to be hot to fail sometimes.
If you have spark, then you have to determine fuel pressure. Do you hear the fuel pump run when you turn the key ON?
Since you don't mention any kind of firing like it has slightly low pressure, I would suspect a real pressure problem. You need to borrow a fuel pressure gauge. Some of the same stores that do free code checks also loan things like fuel pressure gauges. You need to test fuel pressure if you do have spark. You don't give the number of miles on the car. If you don't hear the fuel pump when the key is turned to ON, try hitting the bottom of the tank with a rubber mallet while someone cranks the car. That has been know to jiggle a dying pump loose. But it's only temporary.
Good luck and post to let us know what you find.
thisnametooktolong
07-08-2009, 12:39 AM
As long as you have a graphing scanner and not just a code reader. Hooking it up when it won’t start should give you a good idea. But remember that it could also be the ignition module, and or the coil pack. You can actually see the pulses from the cam and crank sensors. If it does not have fuel when it is hot my best guess would be the fuel pump relay. If you do have a good cam and crank signal when it is hot my best guess would be the spark control module
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