1999 Suburban Is Hard Start

[cwh]

I have a 1999 Suburban K2500 with the 454(125K miles) and auto transmission. I had the fuel pump replaced with a delco unit in November and the truck fully serviced and tune-up at the same time. If the truck sits overnight it fires right up(garaged or out in the cold, I live in Alaska), but if I drive it and shut it off for a short time it is difficult to start. Short time defined as 5 minutes to an hour or so. By difficult I mean it cranks for maybe 3-6 seconds, runs real rough and then starts to run fine. I do notice a little black smoke during these extended cranking times. Most of the time this is the case but every once in a while it will fire up just fine after a short off time. The engine seems to idle a little rough as well. My mechanic, who I trust, told me that the GM manual says the rough idle is within acceptable range. I've actually never had any of my big block trucks idle as rough as this one, most of them idled as smooth as silk. I've ran some techron through the engine recently and it did help it a little. I may need to feed a couple more bottles through it. Any ideas? No trouble codes have been triggered and the "check engine" light is not on. Any help would be appreciated as this 'burb has milked my wallet from the day I bought it. I'm almost ready to dump it and buy the wife a SS Trailblazer.

 

Thanks in advance,

 

Chris

[markw8]

It sounds like you might have a bad fuel pressure regulator, or an injecter leaking. Mark.

[cwh]

It sounds like you might have a bad fuel pressure regulator, or an injecter leaking. Mark.

 

I would have guessed that it would take a few leaking injectors to make it start tough. I have another set of injectors that I can use to swap a few out. Is there a way to tell which is the trouble injector? I'll put a fuel pressure gauge on the system and see what the regulator is putting out.

 

Thanks,

 

Chris