mx5cartalk.com

hey all i just bought my mx5 yesterday, what happened was the night that i bought it on the way back i heard something wierd in the engine bay and kept on driving for about 10km on they way the car was losing power all electronics were failing, the tacho acted crazy going to about 14k revs way past the limit.

I found out it was the altenator belt was very old and needed replacing asap. I got it fixed but the revs are not working at all, staying below 0, the car had a very hard time driving home it was stuttering alot rocking back and forth. The cars running fine now besides that.

Anyone know what it could be? thanks!

Check earths:
search.php?keywords=earth&terms=all&author=russellb&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Weird. As Mr Clubman suggested check out the earth points. I would also check your battery and ensure that the leads are not loose on the batter terminals.

One other suggestion that comes from my own experience. Check that the wiring loom plugs into the ECU are seated nice and tight. Ensure you disconnect the battery before do this.....if you don't nasty things will happen (Please don't ask me how I know this) One of those nasty things was that I zapped/blew the ignition ignitor. This caused the tacho to stop working, and the car ran on two cylinders. The fact that you are saying your car is running OK except for the tacho may (or may not) indicate that your ignitor is OK. If you can I would suggest seeing if someone will allow you to try their ignitor....it takes two seconds to swap the parts. A replacement aftermarket ignitor can be had from SuperCheap for around $130.


J.

aka_juffa wrote:Check that the wiring loom plugs into the ECU are seated nice and tight.

Which reminds me, the earthing post inside the ECU has also been an issue in the past.

OP, have to say was surprised that alt belt alone fixed your original problem - sounded like it might have also involved a bad plug lead or two.