b16ef

My friend has a 1.5l jdm zc in an 89 ef converted to obd1 that he turboed, on 7lbs. Once it starts to build boost it leans out and starts stuttering. We tried two different fmus,It has a missing link, we changed the fuel filter, and fuel pressure regulator ,we put a walburo fuel pump in it, colder spark plugs that we gaped to .30. I just doesnt seem like its getting enough fuel when it gets out of vaccum and into boost. We have tried everything we can think of.....this is the first turbo we put on also.

hondub

you tried everything but ditching the fmu. At the very least get a safc and run a map hack. Missing links and fmu's are trash.

b16ef

yea i know, but it still shouldn't lean out in boost though. We have tried everything that we can think of.

hammeredgsr

get a tune that would solve ur problems

CavemanRacing

How did he tune it?

nismo

what tune?

lol

CavemanRacing

Thats what I was hinting towards.

DAintegra90

internal or external waste gate, if the vacume hose is wrong than it will do that

TurboEG8

come on people tell this guy he didn't retard the timing far enough
duh.............
retard the timing dude and you'll be ''GOLDEN''..........if not more retarded

BAD4DR

It wouldn't hurt! As it's already lean, and severely prone to knock....

More likely, it's caused by the FMU not providing any additional fuel for the first 3-4 psi of boost. I highly doubt they spent the additional $$$$ to get a spring-loaded FMU that doesn't have that problem. And, with little or no tuning, and most likely a T3/T4 57 trim, and stock injectors.....
The poor thing wouldn't have enough fuel if they ran 100% duty @ 100 psi....