Miata Mailing List: April 1998, Message #218

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I have a problem with the J&S timing retard unit on my 97 supercharged
Miata. Basically under full throttle the thing works well and prevents
excessive knocking. 
However under partial throttle it starts excessively retarding the engine
for no good reason. The effect is a large and irritating dip in power as
you moderately accelerate through the gears. It gets so bad it feels like
the engine is running out of fuel. For some reason it happens a lot just
after I down shift under moderate throttle. 
Has anyone else experienced this?
:
I have played a lot with the sensitivity control with unsatisfactory results:
If you back off the sensitivity control enough to prevent the problem then
it is not sensitive enough at full throttle to prevent excessive knocking
(by excessive I mean continued pinging beyond the first loud knock). I
almost wonder if it would be worth bypassing the J&S at partial throttle. 
THoughts?
:
I thought this was just my car until I started asking around at Thunderhill
and found out this is not an uncommon problem.
I spoke with a technical guy at J&S (perhaps the engineer himself) and he
was aware of the problem. He said some electronic signal noise was creeping
into the system but he disn't know where from. He was very nice actually
and he said he might be able to send me some different software for the unit. 
Has anyone else tried this new software?
:
Anyway I feel this email group is the perfect forum to pool our collective
consumer rights. If enough of you have noticed this problem then perhaps we
can pressure J&S into doing enough research on Miata's to "properly fix"
this problem i.e. find out exactly what is causing this and offer a
tailored solution.
Since I only get the weekly version of this email you can get prompt
response from me by emailing me at dakeen@cybermedia.com.