slight skip problem

[TFaucette]

my truck has started to have a slight skip in it so I crack lines to at least determine which cylinder and if I can tell anything and on I belive 4 when you crack it, it spits a bubblely air fuel mix. I assume if I am experiencing this on one injector then I am having a injection pump failure if it's not delivering solid fuel?

 

[JWiegel]

What truck the 90 or 06?

 

[TFaucette]

its on the 90

 

[JWiegel]

Open the same line from the pump and see if your still getting air if so most likly a IP

 

[TFaucette]

talking to my injection shop they suggested pulling the injector that fires before the one skipping that sometimes a bad injector can rob from the next so it's on the 5 and i'm going to pull the 1 and see.

 

[HHhuntitall]

?? Maybe, but it shouldn't rob enough to make it misfire at an idle. The turning of the rotor shuts off fuel for a fraction of a second between injections to allow the rotor to fill back up before the next injector sequence..... If it's got air coming out of the pump, I'd wager the rotor is galled and the pump will need RxR... . I'm curious how the air is getting introduced into the system. Is your lift pump working correctly? Have you checked for fuel pressure to the inj pump from the lift pump? If air is coming in from the lift pump, it could be just showing up on the one if it's a minimal amount of air... ...

 

[TFaucette]

that's what I can't really figure out but it looks kind of bubbly but haven't checked lift pump pressure for this but not so long ago it was running a healthy 5-8psi pulled both 1 and 5 (the one it was skipping on) and get them checked out but i'll let you know when I figure it out

 

[HHhuntitall]

Also, have you checked the fuel feed line. IF there is a crack somewhere, it can ingest air, which can translate to air in the pump.....

 

[TFaucette]

I sent the number 1 and 5 one the nozzle was leaking and other had trash in one of holes of other

 

[AEdelheit]

Or the injector is bad and compression is being pushed back through the injector, sounds odd but ive seen it happen