Hello all, I've been struggling with my obd1 B swap in my 89 sedan, and cannot get it to run right at all. currently I'm on my 4th MAP sensor, and 2nd TPS and it idles at 2k+ rpm and fluctuates occasionally. It has no MIL or codes stored, but as soon as the throttle is cracked the RPM dives. the TPS is calibrated 0.5v closed 4.7ish WOT, and the MAP is a genuine honda part and outputs about 1.4v at atmospheric. IACV is stock and works, verified map wiring/powers/grounds, checked for vacuum leaks. I'm nearing the end of my rope with this, I don't even know what could be wrong anymore.

 

I've been driving the car with the MAP unplugged for a while because I had 3 bad ones, and it would run rich with bad light throttle drivability but it pulled decent

 

Check out your seals and gaskets. If I’m thinking of the right engine, your intake should have both a fast idle valve and the IACV on the back side of the intake. If spraying down the intake doesn’t reveal a vacuum leak, check the o-rings for both of those. A leak between the ports on an IACV will cause a really high idle and could confuse the computer causing it to die out.

refer to a shop manual, a lot of Honda car bibles have symptom->solution charts that are really helpful.

 

it's got an aftermarket throttle body on it so no FITV, Ive sprayed down the manifold with brake clean and got no response. All the intake related gaskets are new, went through them with the engine out

 

Skunk2 tb with stock intake manifold? Ensure they have the same channels. I had an issue similar but inverse. Junk2 manifold with stock tb. Turns out it'll bolt on just fine, but doesn't line up at all.

 

skunk2 rep yeah, I asked a local guy who's worked on a lot and he suspects similar. have a stock throttle coming. also decided to officially rule out the harness by just going with a rywire.

 

I've gotten the idle closer/lower after finding that the IACV and TPS connectors had the pins in the wrong places, but it still feels like it cuts all power the moment the throttle is opened

 

Following up on this, the fix was that I had the signal and ground pins were swapped on the MAP sensor, the diagram haltech has on their website at the moment is wrong. correct pinning is power-ground-signal from the firewall not power-signal-ground. I've emailed them and they should fix it