348 Crank Sensors

I agree and here is a huge list of parts and sensors like that that can be replaced pro-actively.

Here is a tip the top sensor bolt you can get to with a 1/4 drove socket, a swivel elbow and a long extension. You can get to it from the passenger wheel well. Otherwise the AC belts are in the way and it takes forever from the bottom.

 

just to note, some crank sensors may have tiny shims that fall off when removed. Having said that I'm too lazy to look up the exact clearance required. Murphy's law steps in and is a pita to find. Magnet is your friend.....

 

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A few have done this to their regret ) Too many shims (perhaps) = poor/intermittent signal. Too few (perhaps) = tooth contact for some kinds of sensors.

0.35~0.90mm ... I'm not sure what kind of instrument you would use to measure this. A micrometer depth gauge can be quite bulky.

 

Feeler gauges. I replaced mine with OEM sensors and mine are at .35 with 1 shim.

 

oops.. of course. I was thinking of cam sensors and the like (in holes).

 

I know every one call them shims but I've never seen a car, any car, that had none or more than 1. The tolerance is pretty wide and the "shims" are really pretty thin. Note that these "shims" would only be useful if the gap is too small. What if the gap is too wide? Do you throw away the sensor and try a new one hoping it will be ok? I'm of the belief that the gap variation is to allow for manufacturing tolerances, which at 0.35~0.90mm, or 0.014to 0.035 inches, is pretty rough. The "shim" IMO, is not a shim buy an aluminum gasket placed to ensure the sensor does not adhere to the engine block. I could be 100% wrong on this but I just get the feeling... I replaced one of these on my car and in doing so noticed bout had only one spacer and the gaps were considerable different for both. There was no record of them being changed so I would assume if they are installed at the factory they either didn't care that much about the gap or it's just a gasket as I surmise.

Oh, and after all the pain and suffering replacing the side mounded sensor on my problem turned out to be a broken lead in the connector to the sensor, wiring harness side. Neither sensor was bad or cracked. They should measure about 900 ohms between signal and ground. The 3rd pin is a shield and open to the other two pins.

So to the OP, check the impedance of the old sensors and tug of the harness a little. If a wire is broken internally at the connector, the insulation will stretch like spaghetti.

 

On my 348, there were 4 shims on one sensor and none on the other from the factory so they are obviously not gaskets. I think the reason for using the shims is to achieve equal gaps for the banks and not to achieve any particular gap (as long as it is between 0.35 and 0.90 mm). How it is probably done is attach both sensors, measure the gaps and verify they are both between 0.35 and 0.90 mm, then bring the smaller of the two up to the gap of the other (bigger gap) sensor with the shims.

When I installed new KIA sensors, they both happened to have the same gap of 0.65 mm so I did not use any shims. To measure the gap, it is better to get a set of non-magnetic feeler gauges. I got a good one on Ebay in 0.05 mm increments - https://www.ebay.com/itm/FACOM-804-AM-ANTI-MAGNETIC-FEELER-GAUGE-SET-10-00-100-100mm-THICKNESS-GAUGES/360858085107?hash=item5404d166f3:g:UkAAAOxyRhBS-k5p

 

I spoke wrong my OEM ones with 1 shim was at .813mm on both.

 

Off my own car. 2 shims on one. 1 shim on the other. I refitted them to the position they came from with new sensors and the gaps were both within tolerance. I checked before and after fitting. They were the original sensors as far as I can tell. Just what I found but Im not sure if there was a thickness difference in the individual shims.


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Good info. I still wonder how you are supposed to correct a gap that is too wide. But those don't look like Bosch sensors. Of course, if they are form 91 they might have changed from a metal to plastic case later on.

 

My original 1990 ones were metal cased as well as those are, my new OEM ones are plastic bodied. New ones are plastic, if they are too far out they can be easily sanded. Its what I would do.

 

Nice job Haole.

 

They are defo Bosch sensors I removed. Ive got no record of them being replaced previously though so I presume they are the originals. My new ones are plastic bodied.

 

But not those older metal can ones.