Archive for 1987 to 1991 Honda Civic Sedan Owners Club
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Mpfi swap problems

I just did a mpfi swap this past weekend and now my rpms keep rising and falling all by itself and the car idles high now. all the wiring was done right i just cleaned out my iavc. could this be my dizzy doing this or could i have bad timing? or even a vaccum leak? im desperate need of help this is my only car and need it for work.

any help is greatly appreciated

also when the idle bounces it goes up to about 2500 rpm and falls pretty fast to 1000k

did you do a engine swap?

is it throwing any codes?

could be map sensor or idle control solenoid

Sorry I forgot to include that no its not throwing any codes at all and no I didn't do an engine swap either

if its a D series motor try unpluging the green plug on the idle control valve, see what it does, it will throw a CEL. if no change i would look at map sensor.

why did you go to multi point?

i went to multi point cause its better for performance cause i want to start building my engine. ill go try unplugging that sensor and see what happens

thank you man

i dont know how to post a video on here caise i have one of what it did when i took it off.

But when i took it off it idled like it normally does when its cold but the rpms were still bouincing but not as bad.

what does this mean is the iacv bad? or the wiring messed up?[/img]

ohh and it did throw a code when i disconnected it

when u disconnected that you loose your high idle for when the motor is cold. and it sounds like its doing its job. You might need to do a idle adjustment since its mpfi now.

let your car warm up then, while the engine is running, disconnect the IACV electrical plug behind the intake manifold, and adjust the idle screw to 800rpm. After doing that turn your car off, reconnect the IACV plug, then disconnect the battery for a couple of minutes to reset the ECU because you will have a CEL, doing this will get rid of that CEL. Connect the battery and your Idle should be at its normal range - 800 +/- 50 rpm"

this is what happens when i disconnect it

this is what happens when its connected.

i tried to disconnect it and play with the idle screw but the idle speed wouldnt budge?

I've never done this swap, but it does look like the same as a vacuum leak.  Maybe one of the lines is unplugged, or plugged in the wrong spot., or got a split as you were swapping everything. Forum Index -> Drivetrain
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