schwank

Image borrowed from clark's...

What is the sensor below and left of the speed and reference sensors, just left of the locking bolt? Mine was actually out of the hole when I first started working on the car after the shop did a clutch job. I bolted it back in but am trying to figure out why the car runs rough. What is it, and what does it do? Thx.

sck25jr

the two on top are speed sensors and the bottom one is the reference sensor

schwank

Um, no. That's not true. I won't steal more of their bandwidth but the article on clark's has another image showing the reference sensor and speed sensor mounted into the adjustable bracket on top of the housing. The third one is my quarry....

Clark's Speed & Reference sensor page

ilikemy944

The third one is a sensor used by the factory for some test purpose, and it is disconnected on the other end - it goes nowhere. Its not causing your rough running.

zoltan944

all the pictures look the same to me with differnt writing on them.

xsboost90

i thought the third one was to show TDC by the factory? something like that. I dont believe you really need it. Search DanP's thread about his clutch job in his newly accuired n/a.

Techno Duck

You dont need it, you can take it out if you want.

Lanny Curlett

It is the timing reference sensor used in diagnostics. I broke mine recently and went hunting to find out what it was and what it does. dc Automotive has it listed as named above and charges 24.00 for a replacement IIRC. You can see it clearly in one of the exploded diagrams on their site. Your car will run fine without it unless, of course, it needs timing diagnosis. ;>)

Lanny

sck25jr

My bad, apparently the haynes manual is wrong, it says the top two are the speed sensors. I was under that impression. Explains the difference in flywheel and clutch plate monitoring sensors. (crap I should know this...yeah I did know the difference between BG and DG.)

BlueDog944

Which is exactly why I stopped buy Haynes manuals. :P

sck25jr

Should I burn the book now and listen to my friends here? I got it free with my car so I'm not at a loss.....unless I bought the book and got a free car.

AR10

Is that cable unhooked for the pics? If not that will cause running problems.

FRporscheman

You mean the ground cable? I think that picture is from clark's garage, taken while doing work.

schwank

Yes the pic is from clark's, not mine. Makes sense that the car ran fine before I plugged it back in, but not now (well I did replace like half the crap in the engine bay... well i put back at least half of what i took out anyway )

BlueDog944

Although not as bad as Chilton's, both seems to take some "generalizations" in writing their books. Having tried their manuals for 1st gen RX7s, MGBs, Saturns and 944s, I've found errors in all of them. So I've found in the long run, shop manuals are worth their weight, as well as group knowledge of forums such as this, since people are usually open to sharing their experience and typically document with photos.