My buddy has an STI with the following mods:
FP RED 3" inlet
850cc
Walbro pump
Perrin fuel rails
UTEC
TGV Delete
Big MAF
Big Inlet
ect...

So far the car wants TONS of fuel to idle and free rev. Way tooo much its not normal. Once we cross over into the 20-30 load collums around 3500-4000 rpm's it goes way lean(via w/b) around 5-7 psi of boost and jerks like crazy and wont rev any further. We tried to add a little bit of fuel at a time untill we were maxing out the injectors at only 8 psi! we are also maxing out the MOD MAF because we are trying to add so much fuel but its the only way the car will run or idle. We have steady idle and vaccum but Im talking we are adding like 20-30 more fuel just to get it to idle??? Anybody got any ideas or a base map to send me?? We have had these injectors on before the FPRED and the car ran fine. Im leaning towards a bad MAF sensor????
Idle AFR is around 14.5-15.5 when we add 20-30 more fuel!????

Anybody got any ideas????

anybody???

bump.

well...

sounds like your injector scaling is way off...

do you have a scan tool to read fuel trims...you need that in addition to the wideband...

remember to reset the ecu and utec each time u make an injector value change.....

cb

well...

sounds like your injector scaling is way off...

do you have a scan tool to read fuel trims...you need that in addition to the wideband...

remember to reset the ecu and utec each time u make an injector value change.....

cb

You ready for a really dumb question? How do you PROPERLY reset the ecu and utec? Just want to make sure we do everything right cause this car is a pain in the a$$ right now.

Bump. we tried scaling the injectors a bunch of different ways and still nothing has changed??? Anybody?

To reset the ECU, unplug the negative battery cable, step on brake pedal until the odometer clears. To reset the UTEC, it does it everytime you turn the power off but it takes a few seconds. If you had the UTEC exposed there's a red LED that will stay lit until the power is completely off. I usually just count it out in my head (1/1000, 2/1000, 3/1000) and turn the key back on. UTEC is now reset ;)

I too think the injector scaling is way off coupled with the fact that you guys aren't reseting the ECU through any of this.

If you guys are using a 3" MAF housing I would try this scaling config: stock STI injector size/ scale Mod injector size (add 220 on the scaled size over stock). Reset the ECU with 0's in the 0% column. This should work. If you're using a smaller MAF housing than 3", I would add about +30 to your scaled injector size and go from there.

To reset the ECU, unplug the negative battery cable, step on brake pedal until the odometer clears. To reset the UTEC, it does it everytime you turn the power off but it takes a few seconds. If you had the UTEC exposed there's a red LED that will stay lit until the power is completely off. I usually just count it out in my head (1/1000, 2/1000, 3/1000) and turn the key back on. UTEC is now reset ;)

I too think the injector scaling is way off coupled with the fact that you guys aren't reseting the ECU through any of this.

If you guys are using a 3" MAF housing I would try this scaling config: stock STI injector size/ scale Mod injector size (add 220 on the scaled size over stock). Reset the ECU with 0's in the 0% column. This should work. If you're using a smaller MAF housing than 3", I would add about +30 to your scaled injector size and go from there.


we tried scaling the injectors many different ways last night and reset both the tuec and ecu after each time. Car will idle fine when scaling is at 550-750 and 0% collums are +5 but once we free rev it just spudders and wont go pst 2000 rpms....

we tried scaling the injectors many different ways last night and reset both the tuec and ecu after each time. Car will idle fine when scaling is at 550-750 and 0% collums are +5 but once we free rev it just spudders and wont go pst 2000 rpms....

Has the distance of the MAF sensor to the turbo compressor inlet changed from the old setup? This would create a condition like you're experiencing. Also, make sure that you've got no post-MAF vac and/or boost leaks. That might be another problem.

Has the distance of the MAF sensor to the turbo compressor inlet changed from the old setup? This would create a condition like you're experiencing. Also, make sure that you've got no post-MAF vac and/or boost leaks. That might be another problem.

Yes, it went from a CIA to a Big MAF intake , but I did this same set-up with my car and never experienced these problems. There is no Vac-leak and the car idles very steady but just wont free rev unless we add 20+ fuel then it wont drive past 4000rpms/ 8psi( 2nd gear) , it just jerks and bucks like its way too lean but we add more and more fuel to the point were the mod maf is maxxed and so are the 850cc injectors...

Have you checked the codes for the car? Start by doing that. Also, how much has the distnace of the MAF to the compressor inlet changed? BTW, that major bucking can also be timing or rich AFR conditions, not just lean.

Have you checked the codes for the car? Start by doing that. Also, how much has the distnace of the MAF to the compressor inlet changed? BTW, that major bucking can also be timing or rich AFR conditions, not just lean.

Maybe 2-3 inches closer to the turbo. It seems like it gets loaded up and wont rev and just bucks and sputters. Would a WB 02 read lean if the mixture is way too rich? And what kind of timing would do this? too much? too little? thanks

Maybe 2-3 inches closer to the turbo. It seems like it gets loaded up and wont rev and just bucks and sputters. Would a WB 02 read lean if the mixture is way too rich? And what kind of timing would do this? too much? too little? thanks

Too much timing will jerk. A WB that isn't calibrated will be off. 2-3 inches closer isn't too bad though. Check your calibration to the WB and make sure your ingnition advance is acceptable as well that's it's not too rich.

Also, can you post a map?

Also, can you post a map?

I wish I had one to post but I havent even begun to build a decent map since no matter what we do the car wont run correctly.

You might want to try looking up the FP Red that PDX posted data on in the PPB forum area. If you can find it, try reverse engineering the map ;) What I mean is pull the info from the pump gas map looking at the load columns by RPMs. That'll give you a good indication if you're in the ballpark. That won't help you with scaling the map though.

You might want to try looking up the FP Red that PDX posted data on in the PPB forum area. If you can find it, try reverse engineering the map ;) What I mean is pull the info from the pump gas map looking at the load columns by RPMs. That'll give you a good indication if you're in the ballpark. That won't help you with scaling the map though.

We scaled the injectors at 550-650 and went 0 in the 0% load collums, we watched the Fuel trims as we reved to 6000rpms in nuetral and LT went from 0 at idle to 3 at 6000rpms and ST went from 25 at idle and 11 at 6000 rpms...

bump. anybody?

anybody got some experience with fuel trims???

Bump. cause my buddy is about to launch his car off a cliff.

Almost feels like the car is in a Limp mode. when we make fuel adjustments it seems to run good for about 20 seconds and then runs like crap again. We go the fuel trims pretty steady but we are still adding way too much fuel and im positive we have the injectors scaled just fine. the only true thing that I think could be causeing this would be the TGV delete, but them he bought the APS things and got the bar set right but that changed nothing. We have also reset the ecu and left the battery unplugged overnight. After every change we made we have reset the ecu. No codes now execept a low votage in the rear 02 sensor. Anybody think it could be a bad 02 sensor???? PLEASE HELP!!!