bent sensor

[honerboys]

so I was checking the crank end play measurement on the 84s - wanted to make sure the engine wasn't trash before continuing to work on this car - while I was under there I noticed one of the sensors that are pressed into the flywheel is bent - you can clearly see in the pics that it's bent to the right - so my question is would this bend have an effect on the running of the engine - also i'm assuming they are a press fit and can't be easily removed but could I tap it with a hammer to straighten it out or would this most likely snap it off - I started this car yesterday for the first time in a year and it runs but badly -like it did a year ago - now I know it needs tuning and adjusting but would the slight bend in the sensor have an additional effect - there are two of these sensors - is one for crank position and the other for rpm's - thanks in advance

[JhwShark]

Something is not right. I observe in your pic, cutting into the housing in three places from that sensor?

[honerboys]

wow really I thought those cuts were from the factory - i'll get back under there tomorrow and see if they continue all the way around - so I seems like they sensor was bent at some point and cut the casing? - do you think I can just bend it back? - or is it worth it as it doesn't seem to touch the case now - maybe the sensor came loose ,hit the casing, got bent and gradually wore the casing away

[Mrmerlin]

those pins are for the rear CPS sensor,
its not used except by the dealer.


What I would do is spin the flywheel around so the pins are at the bottom,
get a mapp gas torch and heat the pins,
then tap them back to original position with a small hammer.
NOTE heating the pins will make them easier to move back to position.

Also it would be a good idea to check the crank end play

[honerboys]

went back under the car today - loosened the clamping bolt and disconnected the flex plate from the flywheel so there could be no possible interference while measuring the crank end play - measured it 5 times - 4 of those times it came up --- .065 mm - the fifth time it was .060 mm - so i'm assuming since the wear limit is .4 mm i'm good there - now as for the sensor..it bent back easily with very little heat and a soft tap of the hammer - they both seem to be pressed in tight so I don't think they can move on their own - might have been bent by PO using it to move flywheel? - so can anyone tell me for sure if those cuts on the bell housing were factory made? - they look as dull as the surrounding area so they haven't been getting shaved lately - there is plenty of clearance between the sensors and the cuts in bellhousing - also take a look at the sensor pickup on the top of housing - is that what it's supposed to look like? - i'm coming over here from the 944 side - on those cars the end of the sensor pickup is closed and you can't see the insides of the pickup - for my trouble while torqueing down the clamping bolt it snapped off - oddly enough it spun right back out easily unlike most things I encounter on these cars..or life in general for that matter - anyway on the 944's those clamping bolts are hex socket heads while this one was a standard bolt - is that the right bolt or should it be a socket head like one in picture - does anyone know if the 944 and 928 bolts the same? - thanks

[Mrmerlin]

the hex head bolt is the wrong bolt.
It was twisted till it failed

Please get 3 new bolts from one of our vendors,
they are special 12.9 strength., torque them to 66 ft lbs .

the sensor your looking at is the dealer RPM sensor its normal and it is not used

[Landseer]

The cutouts are factory.
84 USA, Right?
If so, the pins are unused. Don't waste time with them. The bend will not affect running.

84 USA has only one sensor as you show in the picture, and its only for factory read of timing as I recall.

The crank position is read indirectly inside the distributor, where a location sensor reads essentially the rotor shaft position and infers piston position from it. The green wire connects that sensor with the brain on the inner pass fender.

Euro 84 has a CPS like the later cars. But yours is not Euro, right?

The 944 has speed and cps sensor pair, both critical to runnability, but 928 doesn't. On 84 USA 928, no sensor at bell housing area matters. Hope that helps. I have both 84 USA and Euros in driveway if you need other information.

Running rough, then start old fashioned way, ensure distrib cap is clean inside. You time the 84 by turning the distributor. Simple.
If it sat a while, good chance you need to have injectors degummed. 84 is unlikely to have crank endplay issue, as you rightly confirmed.

Are the threads messed up inside that sleeve? If not, get the bolts mentioned. If so, you need to get the sleeve from somebody who has one lying around.

[honerboys]

ok - thanks - that makes me feel better - I've already put in a lot of hours redoing the entire interior of this car - I know what you're thinking.. why do the interior before you have a running car - it went against my better thinking also - thing is I had two interiors sitting here - those parts (seats,rear side panels, door panels, dashboards) are large and I was running out of room - too many 944 and 928 parts around here - also it was winter and the cutting vinyl and carpet, gluing, and sewing seemed more like winter sports - anyway the interior is just about done and so is winter (but it's rained here in Denver about 40 of the last 45 days) - now it's time for engine and tranny stuff - the car starts right up and will idle roughly - the tranny is slipping badly - could be fluid as a I just cleaned up the puddle it left on the floor - thanks for your responses - one question ..why 3 bolts? - are you saying they can't be re-used or are you assuming the wrong ones are also on the rear coupler - I haven't looked back there yet - landseer..yes it's a U.S. model and yes it needs tuning and probably injector work and the threads in the front clamp seem ok - was kind if strange I loosened that bolt on Friday to check end play and torqued it back to 65lbs. with no problem then yesterday it snapped when I did it again - thanks again

[JK McDonald]

Hey Honer, You mentioned an idle and/or running rough issue with your 84 928 - like Landseer suggested, a good tune-up will resolve most of these types of problems. There are also several good write-ups discussing 928 running quirks - involving injector cleaning, vacuum leaks, green wire etc.... but don't forget to also check the two thumb sized voltage dropping resistors that provide power to the ignition coil. The .4 ohm (cut out of the circuit during start) and the .6 ohm resistor (both in series during run) are located just forward of the power steering reservoir mounted on the drivers fender wall. Initially my 84 had a similar rough idle and erratic miss that had chased both the previous owner and me around for quite a while until finally discovering these corroded resistors. Mine originally were not only in poor condition and covered in rust but all the wiring terminals were badly corroded. Once I had cleaned up the connections, she would start up much easier and ran pert-near better than new.

If you have the resistors dismounted or the wiring disconnected - make sure to reconnect them in the correct relationship.

Good Luck, Michael

[honerboys]

thanks mike - i'll give them a look - spent today installing back seats and cleaning all my tools out of it - this week I start looking at engine and tranny stuff - see if i can get it to do more than stagger out on to the driveway and back into the garage

[Sapientoni]

you can make your own sensor, just cut a square keystock to round the size of the hole and tap it in with some loctite retainer compound.