silviadad
03-19-2014, 10:49 AM
My sons car.
S14 swap in a 92 Hatch. Engine was rebuilt last year, .020 over stock compression everything else is stock except FMIC. Engine has run great up till now.
He was driving it and had it under boost in 3rd gear about 6500 rpm, shifted to 4th and it fell on its face and wouldn't make boost. Engine is running rough, bucks and chugs at lower RPM's and will only make about 5lb boost when we do get it wound out in 3rd but it is very slow to get there. At idle it surges (hunts) between 700-1000 rpm. Vacuum is 16 to 18 depending what the idle is doing.
What we have checked.
I suspected a blown coupling. We checked them all and they are fine.
Did a smoke test for a vacuum leak and all is good.
Pulled the plugs and they are fine.
Compression test on the engine cold was 130-135 on all four. That seems a little low but I thought it may be the cold engine.
Replaced fuel filter, I did not check fuel pressure though.
Cleaned the MAF.
I had him pull the hot side piping off and there is oil in the piping, not a lot but it is there. The turbo still spins free and does not have any excessive end play or run out. So I do know the turbo needs a rebuild kit and we will be doing that soon.
So now here is where I'm getting confused, when I unplug the MAF at idle the engine will sometimes continue to idle and other times it will die out in 10-15 seconds. It always dies if I plug the MAF back in.
The other item that has me puzzled is if I unplug the O2 sensor nothing changes. The check engine light does not come on, we checked the ECU for codes with the write up that is posted here. No codes, LED does not flash at all.
I have a wide band O2 sensor in my race car and can pull it out and hook it up in the 240 but it would be a big PITA at this time. If someone thinks we need to do it I will.
Any suggestions? Thank you.
Lee
S14 swap in a 92 Hatch. Engine was rebuilt last year, .020 over stock compression everything else is stock except FMIC. Engine has run great up till now.
He was driving it and had it under boost in 3rd gear about 6500 rpm, shifted to 4th and it fell on its face and wouldn't make boost. Engine is running rough, bucks and chugs at lower RPM's and will only make about 5lb boost when we do get it wound out in 3rd but it is very slow to get there. At idle it surges (hunts) between 700-1000 rpm. Vacuum is 16 to 18 depending what the idle is doing.
What we have checked.
I suspected a blown coupling. We checked them all and they are fine.
Did a smoke test for a vacuum leak and all is good.
Pulled the plugs and they are fine.
Compression test on the engine cold was 130-135 on all four. That seems a little low but I thought it may be the cold engine.
Replaced fuel filter, I did not check fuel pressure though.
Cleaned the MAF.
I had him pull the hot side piping off and there is oil in the piping, not a lot but it is there. The turbo still spins free and does not have any excessive end play or run out. So I do know the turbo needs a rebuild kit and we will be doing that soon.
So now here is where I'm getting confused, when I unplug the MAF at idle the engine will sometimes continue to idle and other times it will die out in 10-15 seconds. It always dies if I plug the MAF back in.
The other item that has me puzzled is if I unplug the O2 sensor nothing changes. The check engine light does not come on, we checked the ECU for codes with the write up that is posted here. No codes, LED does not flash at all.
I have a wide band O2 sensor in my race car and can pull it out and hook it up in the 240 but it would be a big PITA at this time. If someone thinks we need to do it I will.
Any suggestions? Thank you.
Lee