Dc-2Luke

I have a B20 and just recently the rpm gauge on the tach suddenly goes crazy after about 3000 rpms. Also my motor runs like its lacking fuel or putting when I accelerate and when it's idling. Help please.

Bond

Check and replace your ignitor if needed. When an ignitor goes bad it will cause your tach to jump back and forth like crazy while holding rpm steady. Seen this lots and ignitor everytime so thats what i'm putting my money on.

B serious

iTrader: (1)

This happened to my GSR with a bad CYP. Is the car throwing any CELs?

This could also happen because of a bad ground. Check the chassis to trans ground, the valve cover to chassis ground, and the ECU to thermostat housing ground.

Dc-2Luke

I replaced my spark plugs now the motor isnt even turning over. it jus makes a click sound.

Bond

sounds like a dead battery. the clicking is from the starter soleniod not staying engaged because of the lack of voltage. test the battery and jump start the car if needed.

B serious

iTrader: (1)

That sounds more and more like a ground to me. Could be a dead battery as a coincidence...or as a cause of a bad ground.

Check the trans to chassis ground. I'm never wrong about anything.

0S2Carbonworks

Def. an electrical issue.
Check the battery, ground etc. first.
If that's ok, you might check the TPS and or map sensor, make sure those are working.

B serious

iTrader: (1)

TPS or MAP wouldn't make the Tach act crazy and make the car not turn over.

91b17a1DxH/b

"TPS or MAP wouldn't make the Tach act crazy and make the car not turn over."
__________________
No but a bad ground and bad tps will.

Just had the EXACT same problem with a b16 swap I did. Tach jumping around like crazy backfiring all sorts of nonsense. Some IDIOT told him to replace the IGNITER bcuz he was 100% sure thats what it was. Turns out it wasnt. I went back and rechecked all the grounds. TSTAT GROUND WAS LOOSE!!! Tightened it bac up and put some thread lock on it.Car started right up and the tach Stopped jumping as much. HE went and bought another dizzy since thats what everyone said was wrong. Guess what it didnt do? FIX the tach jumping and stuttering. TURNS OUT THE TPS was BAD and was sending a BAD SIGNAL TO THE ECU SENDING IT TO THE DIZZY CAUSING THE TACH TO JUMP. Replaced the tps And all is good. CHECK ALL YOUR GROUNDS FIRST, then move onto things like the tps or igniter....my buddy didnt and it cost him almost 300 bucks to figure out he needed a 35 dollar part.

Bond

Why would you throw $300 at the car without atleast testing the igniter, coil and TPS? Should have checked the TPS sweep for any voltage jumps or dead spots. Seems like common diagnosis is a thing of the past. A good DVOM and a honda manual go a long way.

Good to hear you found your own mistake, but seems like you found it too late.

I only suggest guesses, but in the end it's up to the op to get the proper diag done. can't exactly diag a car on the interwebz, like you would in real life, but i always suggest things and always say "check and replace if needed". i don't think anyone can make a real educated guess without checking the system properly.

Also anyone who does swap igniters from other dizzy's when testing for igniter fualts should always remember that not all igniters are the same. yes they all fit, but dwell will be different. use a spare to test, but don't run it unless it's for your engine. i see it all the time when tuning and dwell can be off 10-20% and the owner has no clue

B serious

iTrader: (1)

yep...that's what I said. Check the grounds. I'm with ya.

DDTECH

ECU Ground on top of the water housing is probably loose..

dc2luver

this is happening to my car right now...check the rotor, cap, and igniter. Also check all your grounds but yeah fix this asap and your not lacking fuel your misfiring. I also thought my car was undergoing lean spike aswell until i was tuned by Derick the guy who posted above me. And the tune was amazing skull dragged a few cars that used to beat me by like 2 cars then next thing you it happened again. Took the cap off the rotor was completely destroyed (been like that ever since i bought the car but i guess the rotor became worse over time) still dont know how my car was even running.

DDTECH

This is what dc2luver's dizzy cap looked like.

dc2luver

i swapped distributors yesterday with a new one...car runs perfect and no more crazy tach needle

Bond

Cough...Ignitor...cough