I finished the engine swap on my '90 CRX and I'm having problems. The car is the standard model (DX), as is the engine. However, since the engine has the Si intake manifold, I had to use a conversion wiring harness for the Multi-point injection. This conversion wiring harness didn't work perfectly though, as the cam position sensor wires didn't have anywhere to plug into, etc. That area was re-wired though, and doesn't seem to be a problem anymore.

When I start the car, it idles very high, around 1750 RPMs, and it isn't very smooth. After a few minutes the RPMs drop a bit to about 1500 RPMs, and it smooths out a little. It will idle indefinately like that with no problem. However, if I go to rev the engine, it takes the throttle imput VERY poorly. The RPMs do go up with the rev, but then they just crash right down and the car stalls out. After it stalls, I can start it right back up without a problem, and it goes back to the smooth idle at 1500RPMs. The ECU flashes error code 1, but the car has a hollow cat, and it flashed that error code with the stock engine. The ECU doesn't flash any other error codes.

One other item of interest. On the front side (engine side) of the throttle body is a little box with vacuum lines coming out of it. I can't remember the name of it, and I don't have my manual with me at the moment. The problem is, the manual shows that it should only have one vacuum line coming out of it, but mine has two. We tried doing some re-routing of the vacuum lines, but it didn't help the problem.

So, if anybody has any ideas on what the problem might be or suggestions on where to start looking, please let me know. Thanks.

Matt
'90 CRX #33 PS3; NASA Pro-Atlantic
(hoping to make it to VIR this weekend)

 

It's your map sensor. Happened to a friend. Go to Honda or a junkyard.