well i have gotten everything pretty much lined out now (for those who read my other post i am talking about the idle issues). so now i have put 100 miles on the car and i have not ran the car over 3k rpms...well maybe i hit 3500 once but all was off boost. so today i decided to see what it would do under a little boost . but as i got on the gas i noticed when my boost came around to 0 and startd to about 1psi the car started missing and it felt like the car pulled back and didn't want to go. so i let off the gas and the needle droped back below 0 and the car picked up and went. so i tried it a couple of more times with the same results. has anyone else had this problem? so to sum it up pretty much the car will not run under boost...could this be a bad mass air problem?

mod list:
cp pistons (8:5:1)
eagle rods
crower stg2 cams
crower springs and retainers
850cc inj (fuel pump is stock until my new one comes next week)
3" perrin intake
fp red turbo
utec (running stg 4 until tuned)
tgv delete
txs turbo back
p&p

Sounds like it's leaning out. I'm not really sure what exactly could be causing it though. Not knowing what your mods are isn't helping either. Do you have an A/F gauge or an EGT gauge you can monitor when this happens?

edit, just read your other post with your mods. Are you sure all of your lines are hooked up correctly and no leaks are present? For some reason, it seems like you're starving for fuel with boost. Those two things seem contradictory, but could be two separate issues.

Sounds like it's leaning out. I'm not really sure what exactly could be causing it though. Not knowing what your mods are isn't helping either. Do you have an A/F gauge or an EGT gauge you can monitor when this happens?

edit, just read your other post with your mods. Are you sure all of your lines are hooked up correctly and no leaks are present? For some reason, it seems like you're starving for fuel with boost. Those two things seem contradictory, but could be two separate issues.

yeah all the lines are hooked up i have went over everything several times to make sure. no i don't have a a/f gauge yet, just haven't had enough time to insall one, but i will soon. yeah i thought it was needing more fuel as well, however i noticed that on my back bumpter where the exhaust is it is black (i know that this is no real indication) and i thought it
may be running more rich than lean.... anyone else have this issure before?

Sorry if this is irrelevant, i didn't read your other posts, but hope it helps.


it is probably a tuning issue. I'm not sure what the utec stage 4 map is, but i assume the tune isn't specifically for your car. That would be my best bet. I just finished building my hybrid with a 35r and it was just on a base map from my tuner but it didn't drive really nice all the time, and it's amazing what just a little adjustment to the fueling did for me. I never ran my car under boost until the actually tune, but i would assume that if my car sometimes hiccuped under daily driving without boost, it would happen under load conditions with boost and not a specific tune.

I had the same problem right after I put the gt35r + pe850's + bigmaf on my STI. It was a combination of boost leaks and tuning issues (injector scaler/latency and maf calibration).

Get the wideband + fuel pump installed, test for boost leaks, then work out the tune. Whatever is happening when you give it boost, you probably don't want to be doing that a lot during engine break-in. If you just threw all those parts on and are trying to run an off-the-shelf utec map, you can't honestly expect it to run good.

You are going lean. You need a better base map to break it in. I'd start by going into your UTEC, select the Fuel Map, select all the columns from 10%-100% and add what would average to about 20% more fuel. Look at the numbers. I'd also go to the Timing Map and subtract 3-4 degrees from all the load sites in the 10%-100% columns.

This is not a built motor issue. Go to the UTEC section.

thanks for all the replies guys. yeah i know that it is in serious need of a good tune. i called turboxs and asked them what i could do for breakin until i had them tune it. they told me to run the stg4 map until then and it would be fine. also i scaled my inj to 730. thanks bboy i will try that also and see.

This is not a built motor issue. Go to the UTEC section.

d00d chill. He obviously had no idea it might be a tuning issue until he started asking questions. He has a built block, so his question was welcomed openly here.