Hot_Dog

My 90 GXL has been running very badly for the past couple months. Firstly, the car was running overly rich. So rich that the stench from unburned gas became overwelming at times. Needless to say, the car was burning gas like there was no tomorrow. The car also seemed to be lacking that instantaneous acceleration that I've experienced with the rotary. Normally, when I'd give it gas, it would go effortlessly and without hesitation. In addition, it just didn't sound right -- it didn't have that distinctive rotary humming sound. I'd also like to add that my engine is relatively new, with only about 40k miles, so I knew it most likely wasn't the engine. Well, last week I was rummaging through some boxes with used car parts that I bought a while back, and I came across a warning light unit. I bought the warning ligth unit because I've been having problems with my clock. Sometimes it would work, and other times it would not work but it would always display the correct time. Well, I decided to install the used warning light unit last weekend. I put it in and the clock now works great, but it turns out that most the the warning lights didn't work. Afterwords, I take the car out for a drive, and notice that it is now running perfectly. Not only does it have that characterist rotary sound, but no more hesitation, no more overly rich gas stench, and a great improvement in gas mileage. My thoughts on thia are that the wire that runs from the ECU to the CEL must have been shorting out within the warning light unit. There are diodes in that warning light unit and the CEL diode must have failed and shorted out the ECU. I was always under the impression that diodes failed open circuit, but after some research on the web found that diodes could fail either open (29%) or short (51%) circuit. Well, apparently it was a stroke of pure luck that lead me to find and fix this peculiar problem. BTW, I orded the last new remaining warning light unit that was in Mazda USA inventory. The unit is for a convertible with air bag, so it will probably have an air bag light. I'm curious, is there anyone on the list that had a similar experience with this warning light unit?

Hot_Dog
90 RX7 GXL
02 Acura RSX-S

Icemark

I have rebuilt versions of that available on my website (your model FC66 only $55 USD) at http://www.mazdamark.com/Clockwarningpanel.htm.

And no; I have never heard of that particular problem and based on the design of the ECU, I would rule out the clock/warning panel having anything to do with the ECU operation.

Hot_Dog

Believe me or not...the idiot light cluster was definitely affecting my engine performance. I have no explaniation for this...it definitely has me baffled. After I changed out that idiot light cluster, the difference was like night and day.

My model (90 GXL coupe) uses warning unit p/n FC02-55-710, but Mazda USA has sold out and doesn't make them anymore. Same applies to the TII version...no longer available. I bought the last remaining unit available in US inventory, which is for a convertible (i.e., FC66-55-710). I'll have to make the necessary modifications, which will probably be slight. Moreover, I tried like hell to find a used unit for an S5 cpe, but nobody had one that they were willing to part with so I bought a new one. Thanks, and I'll keep you in mind as a source for parts.

Hot_Dog
90 RX7 GXL
02 Acura RSX-S

Icemark

I have a ton of the FC02 models in stock, and probably about half dozen of the FC66 models.

You relize that the FC66 has alarm and other functions in it, and really shouldn't be used in a coupe.