Fuel Issue

[gcsd3742]

Has anyone changed out there Fuel Pump or added a 2nd pump?

[qwikredline]

yes why?

[Steddy]

Why do you think you need to on your LNF?

HPFP is the issue with E, not the in-tank pump

[gcsd3742]

So Quikredline what did you use? I'm having fueling issues? HPFP Speak english?

[qwikredline]

I dont have an LNF and Steddy is right... in my case I use the in tank pump as a lift pump, but it doesnt matter in this case your car is completely different from mine, for needs/concerns/issues/solutions.

[gcsd3742]

OK so I'm still lost you use the OEM but then what else do you use? Do you use an inline fuel pump as well as the OEM? is there a drop in that will replace the OEM? what has someone else with the LNF used to fix this issue or does no one have this issue yet?

[Steddy]

John has an LSJ, and HPFP is referring to the cam driven high pressure fuel pump, which an LSJ doesn't have

What makes you think the HPFP is being starved?

[gcsd3742]

I keep getting the code for low fuel pressure, it backfires I believe the code was P0081.

[Steddy]

It's the HPFP, not the in tank pump.

An easy fix with someone who knows what they are doing with HPTuners, your fuel rail pressure is low due to the stock limitations in the calibration.

And if it's P0081...that a code for the intake valve control solenoid...which the HPFP is ran off the intake cam...proof that it's not the intank pump

[gcsd3742]

Hum interesting so back to the drawing board then, Obviously....It's strange because this just started it was running fine Thanks

[Steddy]

No prob, and I'd give you a call if I wasn't at work.

Also it takes a while for problems to show up sometimes.

Basically, you need to raise the max rail pressure a smidge so that doesn't happen when you go wide open because the stock limits are set at a point where a larger turbo can possibly move enough air for the injectors to put out more than stock-tuned cam-pump can supply

IIRC the stock limits are 2500 psi in the midrange and it tapers off to 2200 up top

A slight raise by your tuner should fix it.

[qwikredline]

Steddy the latest Equinox must be DI ecotec, and I have had a bunch of these vehicles go through the training I am doing so far this month. Wow! Noisy like a diesel from the DI pump makes an LNF sound quiet and the pinging on initial tip in/accell is also loud. The sound of fuel economy? Lots of timing for sure lol

[Steddy]

Steddy the latest Equinox must be DI ecotec, and I have had a bunch of these vehicles go through the training I am doing so far this month. Wow! Noisy like a diesel from the DI pump makes an LNF sound quiet and the pinging on initial tip in/accell is also loud. The sound of fuel economy? Lots of timing for sure lol

It is DI, it comes with a noise cancelling subwoofer and sound tuned front glass to help cut the sound down a bit.

And most of the DI cars are running a lot less timing than the MPI cars. It's not uncommon for an LSJ to run upwards of 20-something degrees of spark advance...stock they run something like 18...I think

I know stock LNF runs 10, and with the turbo upgrade it bumps it up to a whopping whole 11.

[rallycobalt06]

Hum interesting so back to the drawing board then, Obviously....It's strange because this just started it was running fine Thanks

I believe that Bart and I have told you that you need to find a tuner who knows what their doing with HPTuners. All the fueling maps are now open and that shop you're going to obviously doesn't know what to do with them.

[qwikredline]

It is DI, it comes with a noise cancelling subwoofer and sound tuned front glass to help cut the sound down a bit.

And most of the DI cars are running a lot less timing than the MPI cars. It's not uncommon for an LSJ to run upwards of 20-something degrees of spark advance...stock they run something like 18...I think

I know stock LNF runs 10, and with the turbo upgrade it bumps it up to a whopping whole 11.

crusing constant throtle the LSJ runs 47-50 degrees of timing .....GM does it that way for mileage..

[Steddy]

crusing constant throtle the LSJ runs 47-50 degrees of timing .....GM does it that way for mileage..

Oh yeah...well I was talking timing up top

[gcsd3742]

already bumped up the pressure on the high pressure side in the HPT. It can't hold pressure on the high side if there's not enough volume feeding the low side. This is what I was told

[USMCFieldMP]

These guys know what they're talking about. I'd listen.

I think I have a HPFP in my garage too, if your's shyt the bed.

Also, do you want that .63A/R Turbine Housing, still?

[cubaniche]

This is an old thread and Im sure you guys know this by now. His tune may be trying to bring in boost too quick for that turbo hes running and thus popping the low fuel pressure at WOT, most probably in the medrange. ZZP has CAMs for the LNF that offer an enlarged fuel lobe, basically 'stroking' the HPFP to keep up with fueling demands in the midrange. LNF owners on a larger turbo or trying to run full E85 on the stocker often run into this issue. Its not the intank pump thats the issue.