NightHawkR

My car started running very lean all across the power band since last week and the rear rotor stopped running (both the primary and secondary injector for the rear were clogged). Changed band new injectors ( all 4 of them, 720/720 got a good deal on them ) and now i am having extremely hard time to start the car and getting the smell of being too rich but once the car started it gets lean again until 3k (AFR reading is jumping randomly from 14-16). But once the turbo kicks in it runs very smooth and getting a flat 11.8 all the way to 7k (didn't floor it to redline not knowing what might happen). And right after i came out from Walmart the car won't start at all (flooded) i tried to unflood it at the parking lot, I filled the parking with white smoke but still won't start, it cranks and just starts up for 1 second then die again. The cops came so i had to stop and explain and ended up having to tow it home.

Heres the current setup:

88 T2 with S5 engine/turbo/wastegate, all stock no porting
720 primary 720 secondary
Stock TMIC running on stock boost
S4 ECU/TPS/Boost Sensor/etc...
3" single full exhaust catless
rewired FD Fuel pump
AEM Wideband + AFR Gauge
SAFC neo (correction disabled)


thinking about it, with 720 primary is there anything that needs to be done for the ignition for the car to start up properly compare to having 550?

I also think compression should be out of the question since i had a compression test done couple months ago and all 6 faces is giving good numbers, and after that i had put less than 600km on the car until now all running on stock boost and only pushed the car couple times without flooring it either. Unleast i somehow messed something up within that 600km.



Anyone got any idea on this?

RotaryRocket88

iTrader: (7)

You can't just throw 720cc injectors in w/ a stock ECU and have it work. As far as I know, an SAFC has no ability to adjust start up fuel, so if that's the case you're out of luck. The start up map determines the injector pulse width based on engine temperature. When cold, more fuel is injected than when warm. By throwing 720cc primaries in there, you've just increased the amount of start up fuel by ~30% across the board. The start up maps are too rich to begin with, so an extra 30% will pretty much guarantee it not to hot start, and have trouble cold starting too.

To fix this, you'll need to put stock 550cc injectors back in for at least the primaries. The secondaries only run at high RPMs, so you can adjust fuel with the SAFC to compensate for them.