i have a 93 civic lx sedan and when i start the car the rpm guage sits at zero if i slowly rev the engine it sits at zero untill the car is at about 3000 rpm then the needle will jump to over 8000 and sit there ttill i let off gas then it the needle goes straight to zero. and if the needle is at >8k and i signal the needle jumps everytime the blinker turns on and when i use my wipers. can anyone help me please!

 

If the needle is sitting at "0 Rpm's" then i dont think the engine is actually on..lol
The RPMS reach all the way to 8k rpms?

Does the engine sound like its actually at 8k rpms? or is the needle not reading the actual RPMs correctly..? Cuz a stock p06 ECU rev limiter is around 6.8k i think...
Is your check engine light on?

 

the engine is for sure on because i drive and it reads 0 no the engine sounds like its at like 3k but needle reads over 8k then i let of gas and it goes back to 0.

 

short in the wiring

 

where?

 

Check the G201 and G401 ground wires:

 

where is the g401 i cant tell where that is exactly

 

The picture shows it on the side of the car under the dash. My '95 also had a ground wire right behind (in front of) the cluster. Whenever seemingly unrelated electrical stuff interacts, suspect a bad ground. It could also be that your tachometer unit is just bad. Sometimes they can be fixed by resoldering the circuit board inside, like a main relay.

 

oh and i have a d16y7 in a car that came with a d15b7

 

this is a little vidoe of what happens.

http://www.youtube.com/watch?v=_bKK7YVg6Hs