I've got a stock Greddy turbo with AP tuned by MM. The last 10k miles have been pretty problem free. Over the summer, I had an issue where the car was running rich. Jeff suggested I check for a boost leak before re-tuning and sure enough, the other end of the jet air had popped off. Reset the AP and all was good.

Recently, the car has been running lean under boost...quite lean (see attached before/after logs). I've reflashed the map a few times and tried a slightly different map. My innovate shows similar #s so the O2 is probably fine. I also cleaned the maf and I'm planning on changing the plugs as they probably got fouled when the car was rich. What else I should be looking at? Exhaust leak before the O2 maybe? Bad gas?

-mileage 51k
-smooth idle with vac -19/20
-engine temps are fine
-changed to walbro fuel pump 10k miles ago.
-injectors are reds and uncapped yellows.
-oem plugs/coils/wires also have about 10k on them

Any help is greatly appreciated. Thanks.

 

how long ago did you discover the leak at the jet/air hose? miles?

 

maybe 5-600 miles ago. I should also add that I changed out the battery recently. Not sure if that matters though.

 

was the car running lean before the battery change?

 

not that I noticed and I'm pretty good about watching the afrs. The previous battery was kinda weak even when it was new. The new battery is a little larger with more cca. Maybe a bad ground?

 

still have the same cell #?

 

I do. Thanks for the help Greg.

 

It appears your ignition timing is bit more advanced than before. Calculated Load is down too.

new


old

 

timing is more advanced because calc load is lower. hard to judge between the two files. gear is different as well. both runs at the same psi?

I hate when problems rise randomly after a while of problem free boosting.

have you checked your fuel pressure?

has your trims changed at idle and cruise? leak pre-turbo/post-maf?

 

Suggest a large air leak pre turo , post maf ........

 

Both your calc load and maf numbers are down after than before, so this is not an apple to apple comparison

I would guess a mechanical issue of some type