Thread: Fresh turbo build hesitates at 12.5% throttle....

what should they be gapped to?

just keep gapping them until you get a hestation.

couple other issues aswell. tried to get my car in timing mode and when i unplug the tps the car shuts off immediately. keep in mind i have the brown plug of my idle controls unplugged, it will make the car idle at 2k and wont come down. so what i did was plug it up rev 3k 3 times and unplugged tps and idle control and timed the car that way. crappy way of doing it i know, but is my tps bad or idle control stuck/not working?

With your setup, I'd gap them around .038 to .036"

ok will try that, i have them at .033 now. Also i made a boost leak tester and checked for leaks. i had a couple very very small leaks. but something is telling me i should have the calum ecu checked out to see if the tune is correct. The more i think about how lean it goes above 3k the more i want to think the tune isnt right... it should be a stock DET program which should be fine with a VE head corret? i know it bumps the CR up a little. so i backed my base timing down to 16/17 deg just to be safe.....

UGHH I think I have this same issue (again). It's not a boost leak, I already verified that part. According to my SAFC II it's around 12% throttle also. If I slowly depress the gas pedal it will buck at around 12% throttle or around 3000 rpm (it's random).

In first gear I can redline the hell out of the car, even at WOT. In every gear besides first the car is bucking at around 4,000 RPM and hitting the wall around 4,500. At 4,500 the car basically falls flat on it's face at WOT. I haven't been able to try it with a gradual press of the gas pedal because I run into the issue in the first paragraph.

I running #7 plugs gapped to .30 I believe and my timing is set to 17*. Could the knock sensor have anything to do with hitting the wall like this? I think I have a ghost code for the knock sensor because it was present a few weeks ago and then disappeared.

Have that wideband yet? engine could be seeing light knocking at partial throttle and may be pulling timing?


btw you're playing with fire if you don't know your AFRs and you are continuing to drive it like this

fullah you got a wideband?

Have you tried adjusting the fuel with the afc and see what happens?
check settings for maf, and etc on the afc

I dont think its knock sensor...

Yea I have a wideband. At idle the car is at 14.8-15.1 afr and about 11.3-10.9 at full boost. I have my safc II at 6 and 6 in and out and 20% and 40% as my cross over points. I've messed with the afr at the rpm where it's bucking but it doesn't seem to help anything at all.

What is confusing me is why it's allowing me to beat the hell out of it in first gear but acts up in other gears. Could it be because I still have my timing set to 17* and using the colder plugs?

i promise u its a bad boost leak or bad wastegate acutator. i had the exact same prob on exact same setup