Engine doesn't run right.

[drummerboy858]

I think I might have a doozy for you techs out there.

1999 Civic DX 5 Speed D16Y7
A6 intake manifold
rewired IACV (from three wires -> 2 wires (rotary -> linear)


the car was running fine for about 4 months after doing this swap.
then all of a sudden it just simply would not start. it would turn over but not start. after months of working on the car myself, I replaced the Distributor, the IACV, TPS, MAP, Spark plugs, spark plug wires, fuel injector main relay.

I finally got the car running, but when i even attempt rev it, it doesn't rev past 2500 rpms most of the time. while holding the accelerator steady the engine it jumps from 2000 rpms to 2500 roms about two times every second.

i have 2 ECUs for the car, both of them make the car run the same. So i haven't counted them being bad. keep in mind that after i do anything with the electronics i reset the ECU by pulling the back up fuse. any suggestions would be very greatly appreciated! feel free to private message me to for long responses!

[drummerboy858]

engine codes are:
1 - primary O2 sensor. I have an aftermarket header, no catalytic converter and the secondary O2 sensor isn't plugged up due to no place for it on the manifold. (a little help on remedying this would be greatly appreciated also!

4 - crankshaft position sensor (i dont know if its talking about the CKP or the CKF (crankshaft fluctuation sensor)

14 - even though i did the 2 wire fix and it idles perfectly, i think it just might have to ride out of the system over time.

[Jo060]

Almost sounds like its in limp mode.

[drummerboy858]

??? what do you mean limp mode?

[cantu_austin]

wow that is almost exactly what is wrong with my d16y7 when i hold the gas pedal steady it bounces like crazy around 2000 through 2500 rpm and to top it off it wont rev higher than 5000 rpm like if it had a rev limiter im stumped

[drummerboy858]

that's exactly what is going on, if you figure it out, please give me some insight!

[drummerboy858]

I have replaced a few more sensors on the car. It still runs like crap. I have talked to a couple people from Honda and they said that the a6 manifold I have could not be ran correctly with my Y7 ECU because of the sensors on that manifold. So as a fix for that I got a y8 IM off of a 2000 EX automatic (IACV is the same as the y7). If anyone else has a recommendation, let me know. cantu_austin i think your TPS is bad, new throttle body would probably help you out. thats what I've been told.

[drummerboy858]

well i put the y8 IM on, i think i've got a vacuum leak somewhere, and it won't rev past 4,000 RPMS. completely different set of sensors and everything except the tps. i just don't see how that could be messed up. does anyone have any suggestions?