Backues

i have a 97 honda prelude with an h22a1 and every time i drive it the tach jumps and i have no idea how to fix it.

pamamayaian

Check engine grounds, Battery and alternator tested, and distributor connections first. Does it occur more when headlights and radio on?

nordic97mist

i had something similar to this. i would look straight into the distributor and ignition coil

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red92si

Check the ICM inside the distributor.

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Tyler

Backues

on or off it does it

pamamayaian

Like many electrical problems are its a process of elimination. Start with easiest first; battery, alternator testing, check grounds,connections to alternator, distributor connections. Then move on to checking ICM. I dont think the tach reads off the crank position sensor but rather from the distributor, but I could be wrong. My advice is do all the testing you can that is free that you can do, follow advice from others suggestions, and last resort is if you have to take it to a professional you can tell them your list of problems you eliminated so hopefully they won't waste time and labor cost rechecking the easy stuff.

nordic97mist

yeah it reads of the distributor, or more technically the icm inside it. theres a couple wires on the icm. if i remember right the blue wire is the one that sends the rpm reading to your tach

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