99 Suburban Starts…Won't Run
Question:
Ok…this has been a reoccuring problem for little over a year now. It first happened in July 2002, again in June of this year and yet again this past weekend. In all instances the Suburban was driven over 100 miles the day before and then allowed to sit outside overnight. In the morning the Suburban starts instantly, but then cuts-out and dies immediately after start-up. This start-up then die sequence will happen for almost exactly two hours before the truck will finally start and run fine. I have replaced the oil pressure switch as someone has suggested recently. As the key is turned you can hear the fuel pump run and see oil pressure guage move. But, just after the engine starts it dies…it does not stall as if from a plugged fuel filter, injector, etc. Is there any computer input, sensor or signal that would shut down an engine right after it has started? It seems to me that a sensor has become damp from either weather or condensation and the signal from this sensor is required to allow the engine to run once started. The engine starts instantly and strong…there is no hesitation on the start…it just doesn’t want to run. When the truck finally runs, it starts and runs perfectly for months on end. Like I said it tends to do this after a long trip where the truck then sits overnight outdoors. Any thoughts? Would the Helm shop manual be a good place to start diagnosing this type of problem? Thanks! Mike S. Kalamazoo, MI
Response:
It sounds like it runs on the initial prime relay pressure then when the ecu takes over the pump quits. Try to get a test lite on the power wire to the fuel pump and see if there is current to the pump during the event. Of course this will be tough if it is this intermittent. Or just replace the fuel pump relay and see what happens.
– Hide quoted text — Show quoted text -> Ok…this has been a reoccuring problem for little over a year now. > It first happened in July 2002, again in June of this year and yet > again this past weekend. > In all instances the Suburban was driven over 100 miles the day before > and then allowed to sit outside overnight. In the morning the > Suburban starts instantly, but then cuts-out and dies immediately > after start-up. > This start-up then die sequence will happen for almost exactly two > hours before the truck will finally start and run fine. > I have replaced the oil pressure switch as someone has suggested > recently. As the key is turned you can hear the fuel pump run and see > oil pressure guage move. But, just after the engine starts it > dies…it does not stall as if from a plugged fuel filter, injector, > etc. > Is there any computer input, sensor or signal that would shut down an > engine right after it has started? It seems to me that a sensor has > become damp from either weather or condensation and the signal from > this sensor is required to allow the engine to run once started. The > engine starts instantly and strong…there is no hesitation on the > start…it just doesn’t want to run. > When the truck finally runs, it starts and runs perfectly for months > on end. Like I said it tends to do this after a long trip where the > truck then sits overnight outdoors. > Any thoughts? Would the Helm shop manual be a good place to start > diagnosing this type of problem? > Thanks! > Mike S. > Kalamazoo, MI
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Response:
Forgot to mention this is a K1500 with the 5.7L gas engine. Vehicle has approximately 95K miles. Mike S. Kalamazoo, MI
Response:
Same thing I was thinking… Turn the key on and it primes for a few seconds, start it and the pump should run full bore till you turn the Sub off. I would do the relay swap first. You also might wanna check the box on the steering column that is run by the ignition switch via a rod. When the key is released from the start position it might cut out enough to turn off the fuel pump. – Hide quoted text — Show quoted text -> It sounds like it runs on the initial prime relay pressure then when the ecu > takes over the pump quits. Try to get a test lite on the power wire to the > fuel pump and see if there is current to the pump during the event. Of > course this will be tough if it is this intermittent. Or just replace the > fuel pump relay and see what happens. > Ok…this has been a reoccuring problem for little over a year now. > It first happened in July 2002, again in June of this year and yet > again this past weekend. > In all instances the Suburban was driven over 100 miles the day before > and then allowed to sit outside overnight. In the morning the > Suburban starts instantly, but then cuts-out and dies immediately > after start-up. > This start-up then die sequence will happen for almost exactly two > hours before the truck will finally start and run fine. > I have replaced the oil pressure switch as someone has suggested > recently. As the key is turned you can hear the fuel pump run and see > oil pressure guage move. But, just after the engine starts it > dies…it does not stall as if from a plugged fuel filter, injector, > etc. > Is there any computer input, sensor or signal that would shut down an > engine right after it has started? It seems to me that a sensor has > become damp from either weather or condensation and the signal from > this sensor is required to allow the engine to run once started. The > engine starts instantly and strong…there is no hesitation on the > start…it just doesn’t want to run. > When the truck finally runs, it starts and runs perfectly for months > on end. Like I said it tends to do this after a long trip where the > truck then sits overnight outdoors. > Any thoughts? Would the Helm shop manual be a good place to start > diagnosing this type of problem? > Thanks! > Mike S. > Kalamazoo, MI > —–= Posted via Newsfeeds.Com, Uncensored Usenet News =—– > http://www.newsfeeds.com – The #1 Newsgroup Service in the World! > —–== Over 100,000 Newsgroups – 19 Different Servers! =—–
Response:
- Hide quoted text — Show quoted text – > Same thing I was thinking… Turn the key on and it primes for a few > seconds, start it and the pump should run full bore till you turn the Sub > off. I would do the relay swap first. > You also might wanna check the box on the steering column that is run by > the ignition switch via a rod. When the key is released from the start > position it might cut out enough to turn off the fuel pump. > It sounds like it runs on the initial prime relay pressure then when the > ecu > takes over the pump quits. Try to get a test lite on the power wire to the > fuel pump and see if there is current to the pump during the event. Of > course this will be tough if it is this intermittent. Or just replace the > fuel pump relay and see what happens.
Although we tried jumpering the fuel relay to directly connect the fuel pump, the same problem occured. I will still replace the fuel relay and may even change the fuel pump. I even thought in the back of my mind that it could be the ignition switch too. We even tried holding the key in the start position and let the truck crank for about 30 seconds. Here it would start normal, instantly die and while the starter was cranking, every once in a while it would momentarily catch for 1/2 second…but not enough to start the engine. Thanks for the suggestions guys! Mike S. Kalamazoo, MI
Response:
. . . . It sounds like it runs on the initial prime relay pressure then when the ecu takes over the pump quits. Try to get a test lite on the power wire to the fuel pump and see if there is current to the pump during the event. Of course this will be tough if it is this intermittent. Or just replace the fuel pump relay and see what happens.
Same thing I was thinking… Turn the key on and it primes for a few seconds, start it and the pump should run full bore till you turn the Sub off. I would do the relay swap first.
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