throttle position sensor
 

Took my 91 to the dealer to see why the check engine light was coming on, he plugged it in to the obd system and told me I need an eccentric shaft sensor and a throttle position sensor. Both very expensive , anybody know what those are for. My dealer doesn't seen very competent with older rotories.

Doesn't surprise me. Find a competent mechanic in your area who specializes in rotary engines.

"The Throttle Position Sensor (TPS) is part of the Fuel and Emission Control System. It has two major functions: turns injectors off on deceleration to prevent fuel loading which will cause the engine to buck around during deceleration, and to tell the ECU the position of the throttle opening. This allows the ECU to make adjustments to the air/fuel mix at different throttle positions."

You might want to check your mechanic's work and take a look at the engine codes yourself. Follow this procedure next time you see the CHECK ENGINE light come on.
http://howto.globalvicinity.com/gv_w...i=50&co=1&vi=1

Not sure what you mean by eccentric shaft sensor.

a piston engine guys guess at a crankshaft sensor?

The TPS may just be out of adjustment, espicially if people were messing around with the TB trying to improve the idle.

The eccentric shaft sensor is probably what is more commonly called the crank angle sensor (CAS). It sends a signal to the ECU to control injector and spark timing. If it is throwing a code for that chances are it's bad.

I would still take the car somewhere else where they know what they're doing.

If the sensors are bad then they are bad. Look in the for sale section. Those things are a dime a dozen and both cheap parts(used) to fix.
Something else to think about though, with the TPS at least, if it's not adjusted right it might throw out a code and still be good.


Sidenote: I think it's funny how Rotary people are so strange about what to call the CAS. Mazda calls it a Crank angle sensor but, we don't have a "crankshaft". It's "eccentric"....

the throttle position sensor commonly goes bad. Don't expect a used one to last too long. The crank angle sensor rarely goes bad and you'd be safe with a used one. But you need to find someone who can change your CAS because you can mess up your ignition timing if you're not careful.

Thanks guys, I think I'll take it in to someone else. I also saw some of the other threads, and I wonder if it could have got out of adjustment when I had a compression check done, I believe it has to be disconnected?