3.2 speed sensor question

[75Carrera]

I'm looking for a speed sensor for my 86 3.2 motor. I'm unsure exactly what it does and haven't found any parts in the Preformance catalog named "speed sensor." Are they called something else?

[JeremyD]

Impulse sensor?

Pelican Parts as follows

[75Carrera]

Thanks Jeremy,

Is this timing mark sender the same as or commonly called a speed sensor?

[J Smith]

No such luck. You need the expensive one ($128.55). That's the speed sensor.

[Early_S_Man]

Do you have a Bentley manual???

Speed and reference sensors are identical, so one spare can be used for either application.

What makes you think you need one? I know many on this board recommend replacement based on symptoms alone, but if you haven't looked at [tested] the signal with an oscilloscope while cranking ... you can't be really sure! There is a clearance adjustment that is quite critical ... and should be done or verified before declaring the sensor bad.

[75Carrera]

Thanks Warren,

I bought this '86 3.2 motor as a complete upgrade package. It was missing a few small parts. The "speed sensor" wasn't included.

[ChrisBennet]

There are 3 sensors that might be confused. The two you need are the "speed" and "reference" sensors. That are held in the same bracket at around 1 o'clock as you look at the flywheel. There is a 3rd sensor at 12 o'clock which you don't and never will need. It's only purpose is to plug a gap in the engine tin though you could conceivably use it for diagnostic purposes.
If the insulation on the speed or reference sensor is cracked (twist the wire a little and look closely) replace both sensors. They can scope out fine today and leave you stranded in tomorrow's rain or bucking on your next hot track day. They lead a tough life right over the hot exhaust and the original sensors are read to retire IMO.

Save the old sensor Find a 0.8mm thick washer (easier said than done) and glue it to the end of the old sensor to make a tool for setting the sensor gap. The tool is only necessary if you need to set the gap with the engine in the car.

Speaking of sensors, if the head temp sensor (on #3 head) is the old single wire kind, replace that now. Check the (white) plug for the head temp sensor, if it's got only one pin, it's the old single wire style.

BTW: Performance Products is a (higher priced) competitor to the Pelican Parts - the sponsor of this BBS so it's kinda uncool to talk about them in any way that would be detrimental to our host.

-Chris

[JeremyD]

Good recomendation on using the old sensor Chris!

Thanks - I would have tossed mine

[JeremyD]

and just for the record - this is where the ref sensor sits...

[paulgtr]

is there a procedure for changing the sensors without dropping the engine?
I've been searching and getting a ton of links for 944's but nothing about 911

[cgarr]

I have done it, the hardest part was getting the wire and grommet back in. Just get a lot of room under the car

[paulgtr]

is that both sensors in that one spot?

[cgarr]

Yes, and you need to keep the proper gap setting so you don't want to remove the bracket, just the sensor.

[paulgtr]

cool. I am just looking it over in the bentley manual now.
I want to be careful removing the sensors, use something to loosen up the bolts before I try to get them out.

[burgermeister]

schnellman posted a BMW part number early this year (or late last) that is the identical sensor (3" more wire) for $99 from our host. I installed one, works dandy.

I believe this is the part number:

12-14-1-708-618-M14

[buttjoint]

I also replaced mine with the bmw replacements. They are identical and arn't that hard to replace while the engine is in the car.

[88911coupe]

By chance do you have the BMW part #?

[KTL]

Here's more discussiion on the BMW reference sensor in case anybody's skeptical.

BMW Motronic Reference Sensor Same as Porsche Part

You have no reason to be skeptical. Think about it BMW, Porsche, it doesn't really matter because they're both using BOSCH Motronic engine management systems of the same vintage & design. So that's why there's interchangeability with the sensors.