1998 Suburban Hard Start When Warm

1999silverado1500z71 · October 1, 2013

Hey everyone, I've got a 98 Suburban with the 5.7 Vortec 350 with 157,000 miles. It starts just fine when its cold or has been sitting overnight. However when you go to start it when it's warm it has an extended crank, eventually fires and runs at really low rpm. Once it gets running at low rpm you have to push down on the gas pedal and it'll rev up fine and then run normally but sometimes it will die when you put it in gear then you have to start it again and rev it then it'll be fine. It also smokes a little while it's trying to start but clears right up. Once you get it started and running it runs just fine. There is a service engine soon light on but I don't know exactly what's causing the engine light. From what I've been reading it sounds like it might be a bad fuel pressure regulator or possibly an injector leak but I'm not sure. Was wondering if anyone on here could shine some light on my problem and how much it might cost to fix.

gmtech4 · October 1, 2013

we cant do the how much thing ,,,,first off the truck needs to be scanned fir the DTC then go from there

things you can do is clean the MAF sensor,,,check fuel pressure,check fuel filter if plugged by blowing thru it ,,,,you;ll know if its plugged

other than that,take it in

just dont do any guessing or shot gun any parts at it

Duelin · October 1, 2013

Also it could be the fuel pressure regulator on the CPI leaking and causing a flooding condition. When you try and start it when it is hot and it finally fires do you get a puff of black smoke out the exhaust ?

1999silverado1500z71 · October 2, 2013

yes there is a little puff of black smoke that comes out of the tail pipe.

Duelin · October 2, 2013

You or someone is going to have to check and see if the regulator is leaking. A lot of the time one side of the valley will be cleaner than the other. That is where the gas is spraying out and washing down that side.

1999silverado1500z71 · October 3, 2013

Its going in next Wednesday to get looked at. I hope the damage isn't too bad. Until then I'm just going to leave it parked.

Duelin · October 3, 2013

Well Good Luck. Keep us posted.

1999silverado1500z71 · October 12, 2013

Got the problem fixed. Turns out the temp sensor and an oxygen sensor were bad. The temp sensor was thinking it was -40 degrees and supplying the engine with too much fuel which was causing the hard starts. Turned out to be a fairly easy fix.