Im having some issue with getting my car to run right when in boost. While logging the car around 4500-5000 rpms and it starts to break up. my load when logging is only at 150% when it should be up close to 300%.

I just installed the turbo, manifold, 02 housing, cams, springs, injectors and fuel pump this week. boost is at 25lbs.

some history of the build
I had to replaced my oem 02 sensor with a bosch universal since the oem wouldnt come out of the old 02 housing no matter what i did.

I did a boost leak test and found no leaks.

After the install car started and idled fine. But once we took it out on the road it began to stall when coming to a stop and then continue to stall and not wanna start unless i gave it gas to keep it running. So first thought was timing but i checked and its all lined up and good. So then we thought maybe boost leak but couldnt find any at all.

Today after some reading on the forum we got the car to idle on startup and not stall when coming to a stop. I did turn the biss screw out a few turns and my tuner made some adjustments to the idle in the software.

I dont know if its my universal 02 thats messing things up, maybe the cas? or could timing possibly be off even thou all marks are lined up. The car runs and drives under normal conditions as long as I dont boost and the a/f's are bouncing between 14-16 like normal. Before the install i had no issues and car ran great with previous tune. i'm so lost and never had this issue before even with the dsm's i have built in the previous years. My tuner has scaled my injectors and everything. It seems like an issue with the car itself and not the tuning. Any insight would be great. If you need more info let me know.

Thanks ahead of time!!!


EDIT: as of 9-2-10 i lowered boost to 20psi, i have replaced the spark plugs, put a new wastegate on (had stock 8 put on forge that i had), did boost leak check and still nothing..... please please give me some ideas!!

 

Just out of curiosity...who is your tuner?

 

my tuner is a friend, he has done my previous tunes and other and have no issues and is pretty good

 

bump anyone have any ideas???

 

Does the boost maintain where you set it (i.e., 20psi) while load reads just 150%? Whats the AFR while this is happening?

 

whens last time you cleaned your throttle body? it doesnt explain breaking up while driving but it does explain why your idling so bad. maybe your idle control vavle is totally gunked up?

 

Boost maintains boost and doesnt jump around at all

when i had it off i wiped off the inside, didnt clean it 100% with any solutions cause i didnt want to mess it up so i just wipe it got some stuff off

 

What year is your car? Do you have any data logs of this happening?

 

I have an 04. My friend has the logs ill see if i can get them from him

 

i would assume you are on mbc or an ebc. looks like one of your sensors is bad causing your load readings to be off. i'd check the maf and all the wirings make sure everything is connected properly.

 

need log