Author Topic: Temp gauge not accurate (Read 4054 times)

thebutcher37 · « **on:** November 02, 2011, 11:57:30 PM »

My temp gauge is not working correctly, it worked fine before my motor went kaput.
I turn on the car but don't start the motor and it goes directly to hot.....
Start the motor and the temp goes back down to cold...
after driving for a while it still stays cold while driving and doesn't warm up.
Until I stop, shut car off and it shoots to red hot and stays there.
it will stay for a while unless you tap on the gauge it goes back down.

Here's a video link..
http://youtu.be/bDulLD5neBA

The car isn't overheating... I took out my cluster and replaced it with another known good working cluster and everything works fine, except the temp gauge, same problem persists so i know its not the gauge itself...

What should i do? what could it be?
I added the video, its not the nuts on the back... I checked em and I also tried out another known good working cluster and same problem.

*also oil light stays on aswell... note: Car runs fine.....

Geoff · « **Reply #1 on:** November 03, 2011, 05:36:56 AM »

you say motor went kaput-different motor with different temp sender? different motor with your old temp sender? if its a different sender, I'd suspect that. if its the same one, maybe the wiring is loose, corroded, or otherwise somehow compromised?
also, the 2 senders on the head under the intake-they are kinda close together, and it is possible to put the wiring reversed on these two-and then you will have problems Geoff

91 e30m42 · « **Reply #2 on:** November 03, 2011, 04:35:23 PM »

also i see your rpm gauge kinda looks faulty its should be right under the 1k when the car is on may want to check into that..

thebutcher37 · « **Reply #3 on:** January 16, 2012, 02:06:36 AM »

Update...

So just to clear things up, I found out why my oil light was on and my temp gauge wasn't working... the two sensor plugs were switched.... (meaning the rear plug on the block was switched with the oil plug... weird, I know)
I swapped em back and boom.. temp gauge works.. oil light off...

Geoff · « **Reply #4 on:** January 16, 2012, 06:18:15 AM »

sweet, you can buy me a beer later on:D
fixed is good!
Geoff

asmir · « **Reply #5 on:** February 11, 2012, 09:10:11 PM »

i have same problem switched but noting changed.si battery good

thebutcher37 · « **Reply #6 on:** February 12, 2012, 07:21:05 PM »

Quote from: asmir;110195

i have same problem switched but noting changed.si battery good

You might need to replace your sensors...

I have my old ones up for sale, both working, I replaced them with new ones when I didn't know what my problems were. Turned out the sensors weren't my problem.
Link to For Sale Thread: http://www.m42club.com/forums/showthread.php?t=14505

M42 coolant sensors
----Coolant sensor $10 (p/n: 12621710512) [used -tested working]
----Coolant sensor $10 (p/n: 13621709966) [used -tested working]

http://img684.imageshack.us/img684/3176/img6701t.jpg<-(link to higher res photo)

http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_4373&hg=11&fg=15
Sensors #6 and #8 in the diagram, on this website.^^^