M20 Power hits a wall at 4k rpm exactly

[nerdydorkus]

Hi guys,

I tried searching but couldn't find an answer. I have a M20 swapped 2002 and it drive around great. But anywhere above 1/4 throttle going up the rpm the range the car just hits a wall at 4k and doesn't accelerate past that. If it is less than 1/4 throttle, it goes all the way to redline cleanly.

CPS? AFM? My AFM is mounted sideways, hopefully that doesn't affect anything.

[ak-]

See if the CPS is loose where it bolts onto its little bracket. Happened to me.

[ForcedFirebird]

Yup, first check the gap on the sensor to crank wheel. Loosen the 13mm bolts on the bracket and adjust it a little.

Next thing I would check is the AFM. They tend to get dead spots on the wiper track and when you open throttle slowly, it may not be "snapping" open that far.

[LJ851]

CPS, and don't put a cheap ass aftermarket one on there either. BMW or OEM only.

[nerdydorkus]

Thanks, nice to see you're all at the same consensus. What is the gap on the CPS? or is it even adjustable?

[ForcedFirebird]

Yup, first check the gap on the sensor to crank wheel. Loosen the 13mm bolts on the bracket and adjust it a little.

Thanks, nice to see you're all at the same consensus. What is the gap on the CPS? or is it even adjustable?

Yes. The bracket has wiggle room where it's bolted to the block.

[packratbimmer]

Had a similar problem and it ended up being fuel delivery. A new fuel pump solved it.