3rd gen ecm compatability
#2
Honda-Tech Member
Re: 3rd gen ecm compatability
you can use an auto or manual ecu in a manual 3g prelude, and both will operate exactly the same. but if the car is auto, the ecu has to be auto.
TPS has no effect on rpms.
high idle, whether it's while rolling or sitting still, is usually due to a vacuum leak, ignition too advanced, or a bad FIV (fast idle valve).
3g preludes are notorious for the fiv failing or coming loose internally, causing high idles or bouncy idles. the fiv is located on the rear of the intake manifold on pk3 (b21) engines. take it the cover off it, I forget if its the top or bottom cover you need to remove. but you're looking for a white/yellow/brown plastic circle thing that can be screwed down. screw it ALL the way down, then put the cover back on it. if that doesnt fix it, start looking for a vacuum leak, and/or check ignition timing (distributor adjustment) with a timing light
TPS has no effect on rpms.
high idle, whether it's while rolling or sitting still, is usually due to a vacuum leak, ignition too advanced, or a bad FIV (fast idle valve).
3g preludes are notorious for the fiv failing or coming loose internally, causing high idles or bouncy idles. the fiv is located on the rear of the intake manifold on pk3 (b21) engines. take it the cover off it, I forget if its the top or bottom cover you need to remove. but you're looking for a white/yellow/brown plastic circle thing that can be screwed down. screw it ALL the way down, then put the cover back on it. if that doesnt fix it, start looking for a vacuum leak, and/or check ignition timing (distributor adjustment) with a timing light
#4
Honda-Tech Member
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