cobra621

I have had a ton of trouble with my 90 RX7... I never drive it hardly because it gives me headaches

Anyway, my tach has been acting strange for awhile. It will work for a little while, maybe 25 seconds, and then quits. Today when it quit, the check engine light came on and the car started running a little rough. I drove it out of the garage to wash it and it didn't act any less powerful. If I turn the car off and then back on, the tach works the same. Just a little bit and dies. My brother had this car for awhile and he had trouble with the trailing coil, so he replaced leading and trailing with some he bought off this board.

It has also suddendly quit revving to 3k for 17 seconds when I start it.

Where can I start? I checked engine codes. It flashes once every 5 seconds, so I am assuming this would be code 01, trailing coils. Has anyone else had this same trouble?

Yes, I did do an extensive search, and it made me even more lost, lol.

HeffBoost

Since you've been through trailing coils once already, I would be looking at the connectors and wiring closely. Make sure it's grounded good also.

Hmm, although with it consistantly working fine for a while after restarting, makes me wonder if you didn't get another bad one.

cobra621

I remember helping my brother test the coils back when we installed them, and they were good. Maybe something is making them go out?

He had tried to run MSD coils for awhile, I don't think he had them hooked up properly.

MasteRX

When my car was having trouble with the tach, it turned out that the engine block to firewall ground wire was fried out. This happened after I installed an aftermarket exhaust, since my stock exhaust had a ground strap on it that I didnt replace. So the firewall groundwire was being overloaded. I replaced it with a heavier wire and all problems dissapeared.

cobra621

I will definitely check that. There is a header on this car and I already located a ground that was not hooked up awhile back and fixed that.

modimport

I don't know if your problem ever got figured out but if the problem isn't the ground wire then more than likely its the alternator. Low voltage could cause your ecu to throw the engine code and the tach to go crazy.

fc3salb

I thought if the voltage was low, it just made all the idiot lights come on.. I'm pretty sure about this because all the lights came on once for me. I looked under the hood, and sure enough, the belt snapped.

totallimmortal

A little off topic but once my alt belt snapped and all my idiot lights came on and stayed on but the car still ran fine and even started and ran for a few days with no alt. really wierd but the battery died for good about a month later not sure if that was related but i wouldn't be suprised

silvbullit

My tach is doing exactly the same thing, check engine light also...but mine is a 1990 GTU with a JDM TII motor...any answers for this?