Lift pump fuel pressure

[chumwon]

Howdy everyone, my truck seems to vary on performance day by day. I notice my fuel pressure gauge varies between 4-6psi and I swear when it's near 6psi it runs better. Then days where it's near 4psi it's more sluggish. Something is varying and the only 2 things I could think on this old mechanical girl would make that happen would be the lift pump or the injection pump. I replaced the lift pump years ago with I'm sure a cheap one from the parts store and the injection pump was recalibrated back in the 90s when it got it's 088 kit installed.

Any advice or 2 cents would be greatly appreciated! Thanks

 

[Clb]

On the psi I believe you are in the sweet spot for delivery pressure.

On the I.P. "recalibration "
Yea NO..
It's either been rebuilt or not cuz none of the "quality builders" do a "recalibration " just rebuilt units...
Do you mean the timing was set/reset?

Also hit the tech section and the stickies....

 

[chumwon]

I redid the timing with my mt1480 when I did injectors. I guess I was just referring to it'd been rebuilt to turbo spec.

Dang I was really hoping it was getting low and it was just a mechanical pump problem.

 

[Clb]

Ok, better...
Go read mels ( agnem) delivery pressure thread.
Brb
I'm on my fone, and cannot access my watched/bookmarked threads.
Perhaps someone will bump/link mels talk on delivery pressure and internal ip timing.
Foundit...

Official test results of fuel inlet presure/timing

There was some debate a while back about the effects of fuel inlet presure on timing. I had negative experiences with a gas EFI pump, and others were running pumps greater than 7 PSI, but less than the estimated 50 PSI that the gasser pump was pushing. Somewhere in between... I said, must be a...

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