I just completed the MPFI swap on a 91 CRX DX w/ automatic transmission. Here are the parts i used:

- 91 si intake manifold, throttle body, fuel rail/injectors, etc.
- 90 si distributor
- 88-89 integra LS automatic transmission ECU
- 91 si injector resistor box

I double checked all the wiring, it started up first try without any codes. HOWEVER:

Once i start the engine, it starts accelerating as if the gas pedal was fully depressed. I tried slackening the throttle cable, adjusting the idle screw, i even removed the throttle cable, and it still accelerated. I just shut the engine off once it hit 6-7000 to prevent any problems. Also, I cannot shift out of park (i dont kno whether its because of the acceleration problem, or because i did not disengage the shift lock solenoid at the ECU).

All vaccuum connections were done with reference to a chilton's manual diagram and were double checked. Almost all hoses were clamped. I'm guessing one of the valves is broken (fast idle control valve maybe?), but i'm not sure what controls that acceleration when i start up the engine.

Any help is appreciated. The car scene isnt big around my area, so i dont have a local mechanic or anyone knowledgeable to help me. Its only me and my suburban garage w/ minimal tools. I really need to get my car back up and running, because school starts in a week and it'd be sad being the only senior riding the bus to school :P

Again, ANY HELP IS VERY MUCH APPRECIATED!!!

 

Is it throwing any codes? Do you make sure to swap out the wires on the TPS so that it doesn't go to redline when it thinks its at idle.

 

It's probably a vacuum leak.

Did you use new intake manifold gaskets? Did you leave any of the vacuum barbs on the intake manifold disconnected? Is the IACV connected and working properly? If the engine will run up to redline with a closed throttle you have one serious leak between the throttle body and cylinder head.

 

It is probably the TPS. When you do the MPFI swap you have to switch 2 wires in the TPS Or it will give gas when Idleing or Idel when you give gas. Check your TPS

 

why in the hell would you use an 88-89 integra ECU??? thats probably it

 

Two things will support massive revving like that: Air and Fuel.

There is one hell of a leak around the throttle body somewhere, plain and simple. A mis-wired TPS will make it run rich, but not make it go into run-away. The wrong ECU will make it run rich, but not make it go into run-away.

Was the TB modified in ANY way? If the throttle plate was removed for any reason, chances are it was put in backwards, or off-center. It's got a beveled edge so the plate can close without catching the bore of the TB. Otherwise, the IAC valve could be stuck wide open. Throttle body gasket? Broken vacuum port? Hole in the intake manifold, leaky IM to head gasket. All those things will cause your problem, so check carefully.