VPC Leaning out HELP!

5uprahboy

New Member
Aug 22, 2005
343
0
0
Auckland
The VPC has the correct chip in it. When running 7psi or 11psi on WOT after 4,500rpm the fuel leans right out to 15:1. I've tried turning the gain to max rich, all that does is gives me 11:1 lean/cruise and brings the air fuel @ 4,500rppm to 14.5:1. Its like the VPC just isn't going into open loop and doesnt realise that the car is reving.....

http://www.supras.co.nz/pics/finished/dyno_lean.pdf

The steady curve lines are boost and the giggly ones are the air fuel.

I have an OBX FPR on running 38psi @ idle with the car running and fuel pressure rises on boost to 42psi @ zero boost/vacuum and then 1:1 from then on up.

I am running stock injectors and as you can see from the dyno only making 138rwkw before it starts to lean out. Previously I have made 188rwkw on 9.5psi and the only thing different between then and now is the VPC and a new intercooler/piping.

Could the VPC be bung?

I have tested the MAP sensor and it tests fine.

Please help! :(
 

Bondango

Supra Specialists Ireland
Have you tried running without the VPC and running the AFM? This is the only way to eliminte it as a problem.
did you witness fuel pressure rise on a 1:1 on positive boost? If not you could be looking a a fuel pressure issue - Fuel Pump/resistor/regulator ?
 

hottscennessey

DONT BE A BITCH!
Jun 3, 2005
3,137
0
36
37
Richmond, VA
Do you have an FCD installed? If not, double check and make sure, this sounds just like there is an FCD installed, especially when you're upping the airflow signal, but not seeing a change in the AFR.