I am new to honda. I just rebuilt my d15b7 in a 94 civic lx. before when I was driving it I would crank it up and it would rev from idle to 2k up and down and up and down almost always hot or cold. and had no power ever due to no compression. then the crankshaft broke at the harmonic balancer.

so after total rebuild....

runs great with high compression

however if I give it part throttle it will go wild between 1300 and 2000 rpms.
any ideas on why this is? I have cleaned the map sensor and throttle body. Is there a replacement for the tps seeing as how it is riveted in?

thanks

 

Is there a fluctuating or high idle problem? Are you saying that when you barely touch the throttle pedal, the engine rpms fluctuate?

Any CEL codes?

Is the throttle cable adjusted with about 1/2" of slack?

Have you checked the ignition timing with a timing gun? Is the mechanical timing off by one tooth on the timing belt?

 

timing is set and idle is perfect. when i barely touch the throttle i.e. cruising in a parking lot at 10 mph. I either have to get it going fast and let it slow itself down or stop moving there is no in between. I have driven it 500 miles since the rebuilt and this part is totally throwing me for a loop.

 

Any CEL codes?

Have you checked the timing with a timing gun?

Sticky or misadjusted throttle cable?

 

timimg was set with a light .
no codes whatsoever
sprayed throttle with wd-40
even when I raise throttle by hand when it hits that rpm range it goes wild.
I deal in ls1 engines and I keep thinking this is a throttle position sensor issue but the massive jump in power at anything above 4k rpms is confusing me. or maybe I just answered my own question? bad tps signal = low power? why are they riveted to the throttle body? do I have to do any computer work or learn how to rivet to replace the tps sensor?

 

Measure voltage between the TPS ground wire and the TPS output wire to the ECU with the key in ON(II). It should be about 0.5V at closed throttle and about 4.5V wide open. Voltage also should smoothly increase from closed to open.

 

thanks i will do that