Timing or air seepage??

[evo rider]

Ok, so I got my newly rebuilt injector pump installed and have checked all the fittings. The truck runs but is hard to start and the rpm's surge up and down until the rig is fully warm. Even once its running ok, the first incline I drive it on (top of my driveway) it bogs and then stalls unless I give it some gas. Im leaning towards the notion that there is air in the fuel lines somewhere or the timing of the IP is off.. What are some symptoms of faulty timing? also there is a little bit of white smoke noticed at when the truck is idling

[DmaxMaverick]

Sounds like air. Timing issues are much more consistent than that, and won't cause a racing engine after a start. You may have a timing issue, but you at least have air or another issue at work.

[evo rider]

yeah. I attached some clear tubing to the return hose coming out of the pump and let it run for awhile and there were definitely small air bubbles the whole time gathering in it. Next on the list is pressuring the tank slightly and checking for leaks. Is there anything I can eliminate after seeing bubbles come straight out of the pump? I have a feeling there isnt haha

[DmaxMaverick]

Nothing conclusive you can eliminate. If you have no external leaks, it usually means a leak between the tank pick up and fuel lift pump, or the lift pump itself. However, if it is a small leak, it can be large enough to suck in air, and small enough to not leak fuel externally, that you notice, anyway.

[evo rider]

yea Im still stumped. Ive checked all fittings multiple times now. I dont want to think its the pump itself but that possibility keeps growing in my mind

[Robyn]

If the IP was done by a reputable shop then I would not cast stones at it just yet.

I am assuming this is a 6.2 with a mechanical lift pump??

Place a piece of clear hose between the filter and the IP and run then beast.
If you see bubbles then the issue is farther upstream. and likely on the tank side of the lift pump.

The pump could be sucking air internally but generally this is not the case.
You can hook the clear hose betwen the frame mounted hard line and the lift pump and run it to see if there are bubbles there.
If bubbles then its possible that the tank pickup or the jump hose from the tank to the frame lines has a hole.

A small hole can allow air in and not fuel out.
If you get bubbles try removing the fuel cap and see if the bubbles go away.
I poorly vented cap can casue issues.

The tank pickup can also be a place of issue.

best

Robyn

[Warren96]

What year is it?