1998 crew cab long bed dually 4x4 454 big block cranks but won't stay running. Crank, vroom, dies. Have replaced fuel pump (new connections), new plugs (it has 140,000 miles on it), crank position sensor and now this. Does not seem to be a problem when it's cool. When it gets hot outside or even warm, it does the crank, vroom, dead routine. It has a GM dealer installed anti theft system. When I'm cranking the security dash dummy light flashes. HELP. What could be causing this. It's not like it does it all the time and those intermittent issues are the worst. Have taken it to the dealer twice and of course, they can't reproduce the problem so no fix.

 

These motors have a known issue with the fuel injectors and with your mileage if they haven't been replaced it might be time to think about it. They act up worse on a warm engine so it kind of makes sense on your truck. I am getting ready to change mine because every once in a while it will take a little longer to start when warm and has shut off immediately like your describing. New injectors are supposed to increase performance too! Which will be great because my truck already pulls like a Mac truck!

 

HAHAHAHAHAHAHA.....LOL MAC Truck......good one Shamrock...lol

 

OK maybe that was a slight exaggeration, but it pulls SOOO much better than my 6.0 HD truck that I just got rid of. We had 6 people in it and a loaded down pontoon boat behind it a week ago and it was a if the boat wasn't there for 90% of the trip. There was only one steep incline that made it rev up a bit to 3000 RPM - when my 6.0 would hit about 4500 RPM on that same stretch. I am a true believer that there is no replacement for displacement!

 

Thanks to your input and some from other blogs, websites the most probably culprit is the fuel pressure regulator, a part I ordered on line for about $50 (local chevy dealer quoted me $126). I will also do some cleaning around the throttle body, area sensors, etc. and see what happens. I'll let you know.
Thanks for the input.

 

I saw you said you replaced the pump but did you replace the inline filter?

Do those trucks use a MAP sensor?

 

Sounds like a issue with the security. That system will shut down fuel if the wrong signal is received from the passlock sensor. If the truck starts then stalls leave the key on until the security light goes out. Once out try to start it. Sometimes this works. Can take up to 20 min for the light to go out. I have replaced lock cylinders and ignition housings for security issues.

 

First I'll respond to dedge...yes we did replace the inline filter when we replaced the fuel pump together with new electrical connections. We're gonna install the new pressure regulator, do a fuel injector clean up service and throttle body cleanup service, which hopefully will correct the problem.

To respond to Acnas, we had considered the possibility that the security system may be either the whole problem or part of the problem but this really is my dad's old truck and to him the security system is a sacred cow and he won't allow anyone to mess with it. We're gonna have to have iron clad proof that the problem involves the security system and your suggestion will help.

Many thanks to both of you. Will keep you posted after we do the work this weekend.

 

There were 6 shade trees working on this truck prior to my dumb*** saying "I'm a retired mechanic. I can fix it. First things first. Checked rail pressure, 60 psi then slight drop. FPR was my first thought. Changed and checked vacuum hose. No pressure. Checked relays. Relay box looked like blind meth-head spiders did the wiring. Sorry spiders. Straightened that out only to find more wiring issues. Check. For good measures, I made sure throttle body was clean and change TPS.
Firing order was corrected. Starts for a brief second then dies. Primed with gas and its actually ran for a minute. Distributor and rotor good. Not convinced its the crank sensor but can't think of anything else.
I've never had this problem before