Mulvarney

iTrader: (1)

Hi this is my first thread here so hopefully someone can help.

My car is an 04 model Blob eye WRX. It has been mapped by me via tactrix ecu flash software. It has a VF24 turbo running 18.56 psi max (mapped to tail off higher RPM), Pink injectors, High flow 300LPH fuel pump, Decat up pipe, 3" downpipe - 2.5" back exhaust. Up until a long 500mile drive last week the car has been performing faultlessly. The car now under full load is starting to show reduced AFR's of 12.4. The car was mapped by me to 11.76 with EGT measured at 835 degrees max on 99 Ron fuel (pre turbo). The timing is pretty conservative and not at all aggressive. I have a V8 STI intercooler and K&N panel filter. Under load the MAF flow is always regular and consistent like before on previous logs at max flow achieved of 215g/rev. My target AFR of 11.76 was always achieved until last week.

My question is would a faltering and slowly dying fuel pump cause an issue where afr would not be achieved causing the afr to lean out to 12.4 from the target of 11.76? To counteract the issue and for piece of mind I altered the map last night but I have dropped the target open loop map to 10.94 to achieve a target of 11.7 AFR I have fitted a new wideband sensor to make sure the sensor is okay and it is working perfectly as the last one did also. Thing is I haven't got my wideband hooked up to Romraider to log but you can see when under hard load the AFR is not right.

Any pointers would be helpful. The fuel pump is an automotive solutions high flow unit but I will probably change it out for a Walbro just to make sure. The only thing that is strange is the fact the IDC doesn't go above 77% regardless of what the target AFR being asked in the Primary open loop tables are set to. The mapping software uses a AFR target based setup but the standard front O2 sensor is only a narrowband so it is pegged at 11.25 AFR regardless so I can only see my actual AFR on the Innovate display when driving under load at high revs in open loop conditions.