I noticed the car's (1993 mazda rx-7 manual) spedometer stopped working - it works occaisionally... (thank god it worked during inspections)

I was driving it today , was in 3rd gear and brought it from 2000rpms to about 4000 and saw it boost about 11psi on my gauge. right after that the Malfunction Indicator Light went on.

Now the manual says 'this light shows a problem in the engine electrical system)

Can anyone discern my problem from this info? I don't really want to take it to the mazda dealer if this is something I can fix myself and/or dont have to worry about.

any advice would be appreciated- thanks

-nill

 

So the problem is with the speedo, or check engine light?

 

in wondering if the light came on because the spedometer wasnt working - or if thats possible

can anyone describe the method for finding the diagnostic # of the problem?? i read somewhere how to do it but it was pretty vague

 

Do a Soy'ch under ECU Codes and you will find what you need.

 

I will mention that I was having a check engine light when I would boost. I read the code and it was the speedometer sensing signal going to the ECU. The ECU checks vehicle speed during boost, though it doesn't effect the boost, probably just uses it to make sure the RPM's don't skyrocket while not actually going anywhere, or something. Anyway, I'm betting if/when you pull the code (do WITH the check engine light lighted at idle), you'll see speedo sensor. Fix the speedo, the light for this failure will stop coming. Other lights are a different story, of course...

 

the tie in with the ecu is probably for the steering. steering is speed sensitive.

 

alright -- the damn problem is the light doesnt come on until ive been driving for about 10 minutes or when i engage turbos to with a near-full boost

 

im going to try fixing the speedometer and see if it doesn't fix the lttle warning light problem. thanks for the advice guys

 

The code is stored in memory so the light does not have to be on to read the code.

 

http://www.scuderiaciriani.com/rx7/engine_codes.html

 

lol, you said soy'ch. Thats funny cus it has soy in it.


Anyways. If after you check the codes it turns out that the speedo needs to be replaced, it's really rather easy to replace. Just thought I'd give you some hope.

 

Indeed!!!

A power-drill with a phillips screw bit and a flat head screwdriver are all you'll need to remove the gauge cluster.

 

Minus the power drill. Just a regular screwdriver will do fine.

 

Wha??? That would take forevar!!!

 

To take the speedo out? It's like 7 screws. 4 that hold the gauge cluster to the hood, and 3 that hold the speedo to the cluster. What other part of your car are you meanlessly dissassembling to get the speedo out?