Cam Position Sensor

My cam postion sensor just died on my 94 (~185k mi). My mechanic (Howard at the Sports Car Center for the STL locals) said this is the first he's ever replaced on a Miata (and he works on lots of Miatas). He called me later in the day after I got the car down there (1st tow in 10 years) and said he had an interesting conversation with another mechanic in the area. Apparently this other mechanic said he's replaced a ton of these.. he even keeps a spare in the trunk of his own Miata since they're so prone to failure! Of course, one might ask why he's seen so many while this is the first Howard has seen.. but more importantly, I was wonderring what the experience was here.

Have any/many of you had cam postion sensors fail? It's a pretty expensive little part ($500+ local, $400 at one of the online shops - Rosenthal I think it was). I was able to find a pretty young one (45k mi) at an online boneyard (PartsGroup.com) for $125. Based on Howard's experience and the fact that mine went about 185k mi, the used one looks like a pretty good option.

-Scott

Reply to
Scott Hughes
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called me

years) and

Rosenthal I

My 1990 had 113,000+ miles on her when she died and as far as I know, still had the original sensor. I did replace the o-ring at around

100k but that was it. I can't recall anyone in our local club having the sensor fail either.

Iva & Vixen

2004 Classic Red No more winkin' Miata
Reply to
Iva

My wild guess is that the mechanic who says they keep failing didnt know to replace the O-ring, so when he found problems that said "bad CAS", he took them at face value. I'd replace the O-ring whenever I set the timing. They tend to go, especially if you were silly enough to use a rubber O-ring. ;-) Like me!

Reply to
r0lliSl1fe

The second mechanic must have a curse of some sort, or he is pulling Howard's leg. :-) I have worked on far fewer Miatas than Howard, but I have also never seen the CAS fail, only leak once the seal goes.

If the CAS was that fragile on a car that is otherwise so reliable, we would also see a lot of posts here about "that damned CAS going out once again". Your's may be the second or third post about the CAS failing that I have seen on r.a.m.m. in over 8 years.

There are no parts on a miata that I consider so failure-prone that you need to carry an extra one with you, imo.

Pat

Reply to
pws

I wonder if the second mechanic was referring to the O ring? They do fail fairly often, the clue is an oil leak. They're not too difficult to replace and many here, including me, have done it or had it done.

Reply to
XS11E

pws wrote in news:46fa8c82$0$19608$ snipped-for-privacy@roadrunner.com:

A bad seal wouldn't keep the car from starting would it? Mine died while driving - engine just shut off and wouldn't start again. And the computer claimed the bad CAS.

-Scott

Reply to
Scott Hughes

Nah, it is like a leaking valve cover gasket. It will get worse with time, but as long as there is enough oil in the engine it is fine, just messy.

IIRC, the CAS seal is the one that drips oil onto the heater hoses and weakens them, which are a chore to replace.

That and keeping a clean engine bay are the main reasons to replace a leaking CAS seal right away, but the car will still be fully operational in any case if the seal is the only problem and the engine hasn't been allowed to run dry.

Pat

Reply to
pws

No but bad seals could cause the second mechanic to comment on the frequency of the job.

Reply to
XS11E

My cam position sensor was causing intermittent problems, (car would act like it was running the tank dry, check engine light would come on, then it would run as usual). This happened twice in traffic before I broke down and replaced it (very easy on my 2001). When I scanned the computer, it said it was the cam position sensor. I replaced it ($89 for my 2001) and no problems since. I am considering carrying an extra for my next long trip.

Wm. Morris Red 2001

Reply to
William Morris

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