brianbarnesevo8

Hey guys i recently just completed the build of my 03 evo 8 that took me over a year to finish. The car got a built short block,head, trans, tcase with an FP green with all supporting mods making 420WHP on 93 oct on speed density. My question is, on hot start i have to hold throttle or else it will die until it warms up a bit (i have seen this be common) and after a bit of cruising to stop at a light i get the infamous idle drop and almost stall then the car catches itself. The weird part is, it did not do this when i picked it up from being tuned it started after about 2 hours of driving. I replaced ISCV with OEM and got same result, fine for about 2 hours of driving then started again. I have boost leak tested which had no leaks and i have re coated throttle body with Molykote 321. I am at a loss here as i am out of ideas! and i find it hard to believe it would be in tuning since it doesn't happen once ecu is reset but maybe I'm wrong. Please help me out guys!

Thanks

2006EvoIXer

iTrader: (1)

Assuming your fuel setup has not been rewired, try pulling Fuel Pump Relay #3 when this happens again. Once it starts up normal, plug relay back in and feel/listen for click.

hutch959

iTrader: (18)

probably tune.

LetsGetThisDone

iTrader: (1)

This. Needing pedal to idle, then it doesn't after a 30-45 seconds can mean the base map is off, but once the front O2 sensor turns on and it goes into closed loop it's ok.

OR, you need to adjust the BISS.

brianbarnesevo8

will try adjusting BISS first then have tune looked into. thanks

brianbarnesevo8

fuel pump has not been rewired, what would this tell me?

2006EvoIXer

iTrader: (1)

​​​​​​​On my car, I rewired my fuel pump and retained the OEM dual stage. I noticed that when engine is hot and I reatart engine, some of the time, fuel pump relay #3 doesn't want to turn on (to break the 14V circuit). This causes my idle to run really rich since my fuel return is still the OEM -4an and can't flow the volume needed at idle. How do I know this is my problem? I installed a volt signal wire from the fuel pump and I can see that for some reason, when engine is hot, Relay #3 doesn't switch on to break the 14V circuit. I know it is my ECU because I wired in a relay to control 2 relays in addition to the OEM Relay #3.

2006EvoIXer

iTrader: (1)

​​​​​​​If you have an AFR gauge, what is your reading at idle when idle is choking?

2006EvoIXer

iTrader: (1)

I just reread your post. I didn't read it all the way through. If you are getting this after heating up engine, then it is likely the partial throttle tune. I had same problem like these guys said, when I upgraded to FIC1650, it ran too rich on partial throttle. My tuner drove my car around and kept tuning it until it ran great. And he didn't charge me for the fix (he said that was his responsibility and should have been tuned that way).

brianbarnesevo8

you sir were correct! BISS needed re adjustment now returns to idle perfect!

brianbarnesevo8

Thanks for your reply AFR was choking around 10.9 afr at like 300 rpm with s2 cams but, i tried adjust BISS in SAS mode and the adjustment was off and now after re adjustment idle is great! Thanks for the suggestions