Finally used brake parts cleaner to get the nozzles out... Not advisable for several reasons, but it worked.

As far as I can tell, none of the poppets leak... So what is next on the diagnostic chart? I verified that the manifold does loose pressure within 30 seconds of the pump going off...

Thanks!

 

"Fuel pump holds 50+ for 10 minutes. No visible leaks in fuel lines from tank to manifold. Replaced regulator. Replaced lines, (nut kit). I verified that the manifold does lose pressure within 30 seconds of the pump going off..."

Either the regulator is leaking internally, (bypassing the valve) or one or more poppets are leaking.

 

The poppets do not appear to be leaking... I guess there is a problem with the regulator... It's a brand new regulator though... what can be wrong with it?

 

If the valve plate does not seal against the outlet tube, fuel will leak past causing the excessive leakdown, without leaking externally.

 

Is there anything you could do about such a problem or does it require replacement of the regulator?

 

The regulator is a sealed unit, there is no "fixing" it. If in fact that's the problem, the regulator needs to be replaced.

 

Hmm... It's a brand new regulator too...

I noticed in poking aroud last night that the return seems to be full of air bubbles when the pump runs... Is this normal?

 

Just because the regulator is new, doesn't necessarily mean it's good. If there was a leak in the "nut kit" lines you'd see it. If there was a leak in the lines that run from the injector to the nozzles, the poppets, or the injector housing, you'd see that as well. The regulator is the only possible place for fuel to leak, without seeing an external leak.


Return line full of air bubbles... Whenver the pump runs, it constantly circulates fuel which removes air bubbles. If an air bubble reaches the poppet valves, it will cause a lean misfire, stumbling, hesitation on acceleration, induction, (intake backfire) hard starting or even stalling if the bubble is big enough. When air enters the pressurized portion of the fuel delivery system, (whether the engine is running or not) it is quickly pushed through the fuel filter and pressure lines, past the injector, through the regulator and back to the tank. If the fuel delivery system holds pressure like it should, no air can enter the system... no bubbles. If there's a leak, you might hear the bubbles being pushed through the system.

 

I'm inclined to replace the spider assembly. It comes with a regulator IIRC and that will eliminate everything inside the manifold...

I say that because I can't figure out where the air in the return line is coming from... There is no air visible in the pressure side, but the return line is full of air...

 

Replaced the spider. When I took the old one out the bodywas visibly cracked and showed evidence of leaking. It now holds ~50psi for 10 minutes throughout the system.

But the problem remains. And it runs really rough now, so I guess the excess fuel was masking whatever the main problem is.

If you add more air by unhooking the pcv, it no linger acts properly like before (850 rpm and smooth). I gets about 500 rpm idle and very rough.

I got a p0122 code initially again (TPS) but wiggling the plug again cleared that... Could this be an indication that the TPS is malfunctioning or?

IAC not working properly?

I'm kinda stumped again. It runs quite rough, and will not idle on it's own... if you take your foot of the pedal it dies immediately... Sounds almost like a vacuum leak, but if you create a vacuum leak, it runs better, which makes me rule out a vacuum leak...

I like this truck alot and want to get it running... but am having a hell of a time.

Thanks in advance for the help...