Bang Bang; new tach speed?

[FoX]

Everytime I manage to bottow my car out my tach reads wierd. Last week I was coming out a parking lot and bottomed it on the front, now instead of being at like 3000rpm when i shift it is like at 2000rpm. Anyone know what gives? I have checked the sensors in the distributer and they are fine. This is really wierd.

[A20A1]

Bottomed? you mean slammed on the gas? or Redlined?

Auto? 5-Speed?

['89AccordLX(Rus)]

I think he means that he slammed the suspension down all the way. Check for a loose contact somewhere in the gauge cluster or at the coil. The sudden stress that the car experiences when the suspension bottoms out may cause a loose wire to be dislodged and give a false reading because of a bad contact. Just an idea.

P.S.: The obvious solution may be to drive more carefully. :D

[FoX]

I've checked everything i can think of. It is still reading lower than normal, even witha tester attached to the coil. I have a blaster 2 coil so it is pretty easy to check, all connections good there, but why would they change at the coil if the sensors are not damaged?

['89AccordLX(Rus)]

It may also be the tach unit itself. Since it basically analyses the impulses from the coil, it may have a profound impact on the reading. Try swapping the tach from another gauge cluster and see if the problem disappears. That is the last link in the chain and it is a very precise instrument that may be affected by stress.

[A20A1]

Maybe you jerked a wire loose... I'm thinking ground wire to transmission or grond wire to valve cover...

[FoX]

somehow I am going to say no. My car is manual. I have a hyper ground system that gives my 3 grounds to the tranny and about 6 to the motor. I am wondering if a short between the coil and the tach would cause the whole system to read wrong. I had someone break into my car last night and try to hot wire it. They stole a whole bunch of stuff and generally this sucks. The tach seems to be reading lower today then ever. at 50mph in 4th gear i am at 3000rpm usually in 4th gear at 50mph I am at 4000rpm. I have a shop manual so i fixed all the wiring the thieves messed up. Tomorrow i am putting in an alarm and some fog lights since i will be in there looking at wiring anyway. I kind of wonder if the computer might be sending the wrong signal to the tach. this might all be an ECU problem. Its just wierd to me it is the same with an external test unit .