Engine/Transmission (1998.5 - 2002) Can't figure out the smoke?

[Doughboy21kd]

When i start the truck and step on throttle quick like it will sputter and blow either blue or white smoke, almost like a small backfire. If i let idle in "P" or "N" once its up to operating temps or or when its HOT outside the idle will flucuate up and down about 50 rpm's not much... Kinda like the timing is out of wack. When in drive it's fine and at WOT it runs GREAT. It's just at idle that it blows smoke and sputters and it only does it for split second and clears itself up. It Runs and idles fine when cold outside.



Just wonderin if anyone else has anything else i should try.



So far i have Replaced:



I have changed the fuel filter

Intake air temp sensor

APPS sensor and my voltage is . 665. low as i could get it.

I have 17 psi fuel pressure at idle and WOT is about 13 psi.

AFE Drop in filter

I have cycled key and checked for codes as well as useda SMARTY and checked for codes and got nothing.



I've done some reading and calling around. And some of the places i have called seem to think the VP is on it's way bye bye. They think the diaphrame or plunger is messed up or something like that. The pump has been run dry once that I KNOW of but not for more than a couple secs to where i noticed NO fuel pressure.



So what else should i do to narrow it down? Any suggestions? THANKS

 

[DSeamans]

Smokin

I'd start by cleaning connectors to the vp and ecm. Try to see if you have a bad injector(s) that is leaking down. But, that sounds like how my vp started. It did that for over a year and 30k before anything changed. I just changed mine, and it was still running. I was getting gradually more white smoke at startup, more black stepping on it, and a mileage drop of 5mpg when I finally changed it. Also, the egts were running 1-200* higher than normal. The way it was explained to me is the timing piston wears the chamber and fuel starts getting around it. That messes up timing that causes the other symptoms. If it is the timing piston, I was told you won't see sudden death. Drive it and watch for other symptoms. Mine never threw a code, but I didn't wait til it was dead to change it.



Good luck,

Dave

 

[Doughboy21kd]

I'd start by cleaning connectors to the vp and ecm. Try to see if you have a bad injector(s) that is leaking down.

The injectors are new about a month ago. So i kinda have been watching the oil to see whats going on. And everything seems to be on the up and up. I'll check the connectors and see. I think its the pump myself cause it runs and idles like a champ when its not HOT.

 

[Graphic man]

sounds like VP timing to me and my guess it's on it's last legs

 

[Doughboy21kd]

Another thought? Anyone think that i could have a bad or stuck injector? Doesn't white smoke and occasinal backfire(not often though),mean raw fuel? Just a thought.



Only reason i was thinking that is cause it only does it sometimes.

 

[PRout]

Another thought? Anyone think that i could have a bad or stuck injector? Doesn't white smoke and occasinal backfire(not often though),mean raw fuel? Just a thought.

Maybe im wrong, but I take it you have recently changed injectors. That's interesting point number one.

If that is when the problems started occurring then you surely cant rule them out. Almost sounds like you could have a "dribbler" in there, or one that is at best, not seated or sealed correctly or have a real outta spec pop off setting.

If it were me, Id swap them with known good ones, run with those for awile until you can have the suspicious ones checked out by a VERY reputable shop and set up correctly for you rig as well. Then you will pretty much be rest assured with them being validated (with new copper washers - and a touch of oil around the rubber o-rings, you should be good to go)