99 Silverado hard hot start


Old 06-05-07, 08:43 PM
Thread Starter
Join Date: Jun 2007
Location: Milwaukee
Posts: 1
Arrow 99 Silverado hard hot start

Have a 1999 Silverado,48k, with a 5.3 that starts immediately when engine is cold but 3 to 4 seconds of cranking required with a warm engine. Been working on diesels so long the later model gas engines are becoming like a foreign language to me. Was thinking possibly a fuel pressure problem, but just guessing here. When running, runs and idles like when it was new. There are no codes in ECM. Thanks for any help you may have.
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Old 06-06-07, 02:25 PM
Join Date: Dec 2001
Posts: 2,538
checking fuel pressure would probably be a good start you might also see if it starts quicker if you hold the gas pedal down aways if it does would suspect engine is flooding due to the fuel pressure regulator.
Old 06-10-07, 04:52 PM
Join Date: Oct 2006
Location: Wilmington
Posts: 4,219
Holding the throttle down while cranking does nothing on an FI engine. When was fuel filter last replaced?? Throttle valve cleaned?? Air filter checked/replaced.
Old 06-10-07, 07:00 PM
Join Date: Sep 2004
Location: Brandon, MS
Posts: 174
my 2000 sierra does the same thing, but sometimes it takes 2 or 3 tried to get it to crank and i have to have the gas all the way to the floor. ive changed out plugs, and air filter. also, i smell gas when it does crank up, is that normal?
Old 06-10-07, 09:00 PM
Join Date: Dec 2001
Posts: 2,538
holding the gas to the floor actually shuts off the injector pulse so a flooded engine will start easier even if you dont hold it quite all the way to the floor it still allows alot more air versus leaving the throttle closed.
fuel pressure regulator failure is very common on these models have changed a bunch even on low mileage pickups. pull the vacum line off the regulator and cycle the key on and off about 10-15 times while having somone watch the regulator if it spits any gas out its bad and needs replaced.
Old 06-11-07, 07:42 AM
Join Date: Sep 2004
Location: Brandon, MS
Posts: 174
thank, ill check that.
im guessing a bad one wouldnt make it run bad, cause it runs like brand new.
Old 06-11-07, 10:51 AM
Join Date: Dec 2001
Posts: 2,538
the typical complaint is hard start or longer cranking times usually on a warm engine occasionaly you may smell gas but they generally do not leak enough to cause running problems.
Old 06-11-07, 05:12 PM
LouBazooka's Avatar
Join Date: Dec 2005
Posts: 553
Hey Bejay

Im having the same problem on a 2000 suburban 6.0 L, can you tell me where the fuel press. reg. is located ? thanks

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