Well to start out with, I just got a 1991 mazda rx7 convertible for my wedding present it's the best. but there is one thing. The guy that gave it to me told me that for the time that he was using it ran great had a rebuild engine he gave me all the paper work to prove it. anywho. the one thing that he said started to go wrong was that when he passes 60mph all the gauges started to go out of control and after that. the car would turn off and to his suprise the cpu fried. he took it to a mazda mech and that the mechanic gave up!! he told him that it was costing him too much to find out what was wrong with the car. i talked an semi expert. and he mentioned if i had different exhaust and it does.. so he said it might me that what is causing the car to mess up like that.. if you know anything familiar with this problem Please let me know!! i've been soo anxious to start driving it. !!! i'll post pictures of the car in detail in a couple of days to see maybe just be looking at some of it someone can catch something wrong.

thank you.

 

It's not the exhaust.

Can you be more specific by what you mean when you say the gauges go "out of control"?

 

CPU = Body computer. Controls the brake Lights and the warning buzzers
ECU = Engine computer. Controls the engine spark and fuel injection and emissions equipment.

Neither control the gauges.

Sounds like a voltage issue rather than a speed issue. What was the voltage when this happened?

and the exhaust would have no effect on the electrical either.

 

i mean ECU sorry about that. there was an extra one on the seat when i got it. it's right under the glove compartment.