Racetronix Pump Still Kicking My A@@!!

[tatasta]

Well, I took the car out again today to try and get my target AFR. I have 33# LS1 injectors which ran perfectly prior to installing a Racetronix pump. Naturally, before the new fuel pump, the fuel pressure was ~58#. After the install of the pump the car runs at 70-72#, which threw my AFR off by nearly a full number, I mean before I had 12.8:1 @ WOT and now it is ~11.9:1 @ WOT. I used the IFR spreadsheet and input the new values but still too rich.

I am to the point of asking for assistance because I am sure the remedy will cost some money so I would like to go the right way the first time.

My first choice is to install an external pressure regulator because I am sick of tweaking a tune that was great before the new fuel pump. Attached is a tune and log to look at but mostly I just need pointed in the right direction.

With this tune it was lean at idle to the point of nearly dying and at WOT the AFR was ok but it was missing/stuttering at high RPM. Never had this trouble before the high fuel pressure.

PLEASE HELP!!!!!

Thank you!!

[DrkPhx]

70-72 psi fuel pressure is too much for a LS1. Like you mentioned, you need to install a fuel pressure regulator to get it back in line to what is was before.

[joecar]

Post your spreadsheet.

[tatasta]

Joecar,

I haven't pestered you for a while.

This is the spreadsheet I used to calibrate the IFR for my injectors when I first installed them. It worked great until I put the Racetronix pump in.

Thanks

[mr.prick]

What's the part number on these injectors are they re-sized?

[tatasta]

What's the part number on these injectors are they re-sized?

Not sure of the part # at the moment. They are Bosch LS1 Design 3 flow tested at 33#. They came from FIC. As mentioned before, they were easy to tune for at 58psi with the stock pump and the car ran great. I was running at 95% + on duty cycle with the stock injectors is why I put the FIC injectors in.

Attached is a tune and log from the car before the fuel pump install. It was a bit rich but on N2O it was good.

I can get the part # in the morning.

Thank you

[joecar]

Joecar,

I haven't pestered you for a while.

This is the spreadsheet I used to calibrate the IFR for my injectors when I first installed them. It worked great until I put the Racetronix pump in.

Thanks

No worries...

When you measure rail pressure, is it constant 70-72 psi, does it deviate from that...? Is it 71±1 psi or better...? Is this what you used to recalculate the spreadsheet...?

[tatasta]

No worries...

When you measure rail pressure, is it constant 70-72 psi, does it deviate from that...? Is it 71±1 psi or better...? Is this what you used to recalculate the spreadsheet...?

It is a pretty steady 71#. I used 70 or 70.5 in that spreadsheet to calc the new IFR. So, yes this all I used to come up with the values.
Did I miss something?

[tatasta]

joecar,

Also, they are 33# injectors.

[ND2RACE]

If all you did was install a pump and the fuel pressure went up why would you tune around that? Am I missing something?

Sounds like you knocked the fuel pressure regulator loose in the tank.