Running lean but high fuel psi

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Dec 18, 2018 | 10:40 PM

Jobobcat

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Staging Lane

Joined: Sep 2018

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Running lean but high fuel psi

For my swap I'm running a tre performance 340 lph pump with a vette filter regulator then to my upgraded selector valve then to the fuel rail/injectors. I measured the pressure after the valve and its bouncing between 80-90 psi. I realize that the pump is out doing the filter regulator and I am installing a new system Thursday with a different regulator and filter. However while running this high pressure my tuner says the motor is incredibly lean. I tested all the injectors, they're good. I also cleaned out the rail and it's fine too. Now how would the truck be running lean with that much pressure? It's a l96 6.0 with the 52# flex fuel injectors. The only think between where I checked and the rail is a stainless braided 6an line.

Thanks!

Dec 19, 2018 | 09:23 AM

33willys

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From: Alamogordo, NM

Get with your tuner and see what LB injector he used to program, then check to see if what you have matches. In other words did he use 28 lb and you actually have 22 lb.

Dec 19, 2018 | 09:39 AM

Jobobcat

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Staging Lane

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Quote:

Originally Posted by 33willys

Get with your tuner and see what LB injector he used to program, then check to see if what you have matches. In other words did he use 28 lb and you actually have 22 lb.

Will do. Thanks!

Dec 19, 2018 | 10:43 AM

wave1957

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What about an accidental air intake after the MAF? Such as a bad/ripped/ damaged vacuum line, or a vacuum port left open or with a damaged cap (I had that on my Magnacharged 6.0, the PCM kept throwing a Lean Bank code))... Or a bad intake gasket... Or even an air intake in the exhaust, between the engine and the O2 sensors: with this one, the engine is not actually running lean, but the PCM sees a lean exhaust...

Dec 19, 2018 | 10:50 AM

Jobobcat

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Staging Lane

Joined: Sep 2018

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Quote:

Originally Posted by wave1957

I'll check out these ports. I have the vacuum port at the back of the intake going to my brake booster, and the other vacuum port going to my vacuum ball for my heat and the other goes somewhere, I cant remember. But it shouldnt cause a big air intake thing. If I unplugged the maf would it default to the map and I be able to drive it then? The issue I'm having is when driving and I go to barely crack open the throttle more than 10% it will backfire out the exhaust and go into limp mode and will continue to backfire. Sometimes when I first start it, it will backfire through the intake and when it's cold (under 130 degrees) and I go to open the throttle the engine will die.

Dec 19, 2018 | 05:15 PM

Jobobcat

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Staging Lane

Joined: Sep 2018

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I unplugged the maf so it ran all calculations off the map. And it ran pretty rich instead of lean, I'm saying largely due to 80-90 psi of fuel pressure. The maf is in the correct direction. I'm supposing the MAF is the issue here.

Dec 19, 2018 | 07:41 PM

Jobobcat

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Staging Lane

Joined: Sep 2018

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Dang it. Maf didn't do anything. Unplugged the map and it ran great! Tested the map on another vehicle and it worked fine. Seems like yet another tuning issue I've had with this thing.

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