me and my friend have recently turboed his civic (d16z6) and it seems like when he hits somwhere around 4000rpms(which we think is maximum boost, 9psi) it wont let it go any higher like its holding him back and the check engine light usually comes on. he has a missing link. seeing how its at max boost we think maybe it has somthing to do the wastegate maybe. wondering if anyone knew what it might be.

 

wrong forum

 

i know!!!

its a D series!!!

 

When you say it holds him back, do you mean the car won't rise above 4000 rpm, or the power just drops off?

If it won't rise above 4000 rpm, I don't know what your problem is. The ecu is probably still detecting boost somehow and putting you into some weirdass form of limp mode. I honestly have no idea.

If the power just drops off, I doubt it has to do with the wastegate, unless you think its opening too early. Tell him to buy a boost guage, it would make it much easier to assess the problem.

Please explain his setup and explain the problem in detail, I'm sure theres someone who can help you, even if this isn't the correct forum.