M20 Coolant Temp Sensor TOO SMALL WTF

[hi its me alec]

So I used to have my old brown temp sensor from my 325e in the M50, assuming it would work, but it didn't. I assumed that didn't work because I now have a 325i gauge cluster. The old 325e sensor screwed right into the head.

So I got a new sensor to match my new cluster, supposedly from a 325i, but the PNs are the same anyway between i and e. PN# 13 62 1 357 414

This new one is waaaaaaay smaller, only thing the same is the plug/pins. The color is white/clear (instead of brown.) The new sensor will drop straight into the head without threading, way too small.

Has anyone else encountered this problem? I don't F'ing get it!! This is an OBD1 M50 BTW, no OBD2 machining necessary. I'm thinking I have the ECU coolant sensor for the M20 and threads into the block or something? I don't have an M20 to look around, but I think I'll have to bring the part back to the dealership on monday and bring my old sensor with.

[samiam3356]

You figure this out?

[hi its me alec]

Looks like my local parts department got me the wrong sensor.. the correct part number is 12-62-1-710-512

[10Toes]

The white sensor is the temp sensor for the ECU.

So I used to have my old brown temp sensor from my 325e in the M50, assuming it would work, but it didn't. I assumed that didn't work because I now have a 325i gauge cluster. The old 325e sensor screwed right into the head.

All the clusters use the same sensor.

[hi its me alec]

Now I'm having another related problem..

So I got the correct brown temp sensor, and that fits fine (I put it in the head's second hole.) Unfortunately the coolant gauge still doesn't work.

If the car originally came with an eta Motometer cluster, can I just swap a b25 VDO tach onto the motometer cluster? Or is there a better option? Right now the whole cluster works except for the coolant temp gauge..



The first hole in the head can only fit the blue coolant temp sensor, which I know is for the e36 cluster.

I have a new black sensor and tried to put that in today, but what the hell, it won't thread into the head. The blue one has a copper washer and that doesn't quite fit over the black one's threads. So it appears they're a different size.

Has anyone else run across this problem?

Again it's a '93 M50 Vanos

[MattM]

if you just put a brand new sensor in its not the sensor, follow the wire back and make sure its hooked up correctly

the first hole and blue sensor are for the DME, and it still needs it, so dont touch that one.

[10Toes]

Tap on the cluster, some times they stick in the cold position.

[hi its me alec]

if you just put a brand new sensor in its not the sensor, follow the wire back and make sure its hooked up correctly

the first hole and blue sensor are for the DME, and it still needs it, so dont touch that one.

OK wait, I just read last night that the black sensor was for the DME and the blue one is for the cluster. That's why I tried replacing the blue one with black and found out that it didn't thread in. So right now I have a new blue sensor in the left, and new brown in the right.

Also the car runs like SHIT when the engine is cold. Starts and dies a few times before it finally warms up a bit. Once I leave it running for a while, it idles a lot better but still doesn't run very well. That's why I figured I might have the wrong DME coolant temp sensor plugged in there, or something.

Tap on the cluster, some times they stick in the cold position.

The needle moves, but never goes past the far left white line. It moves from the 'dead cold' position just fine when I turn the key though. I took the cluster out before I left the shop yesterday, I'm going to clean all the grounds on the back, and also the main cluster ground down by the pedals.

[MattM]

to test the connection, turn the ignition to run, and ground the wire on the sensor, this should peg the needle in the red zone. If it doesnt then its a connection problem

[Reckless_Havoc]

Also the car runs like SHIT when the engine is cold. Starts and dies a few times before it finally warms up a bit. Once I leave it running for a while, it idles a lot better but still doesn't run very well. That's why I figured I might have the wrong DME coolant temp sensor plugged in there, or something.

Check your ICV. Mine did something similar to this, and it turned out it was stuck. I cleaned it up and the car idles nicely both cold and warm.

Also if the car is throwing any CEL's follow up on those.

[Mr.SWISS]

to test the connection, turn the ignition to run, and ground the wire on the sensor, this should peg the needle in the red zone. If it doesnt then its a connection problem

Exactly no need to rip the cluster out again.