m70 rear engine temp sensors question

[Johanswe]

Hello

Does anyone know what resistance the 3 temp sensor in the rear of the engine of a m70/s70 should have? And what do they control?

http://bmwfans.info/parts-catalog/E3...g_system_pipe/

If i stand infront of the engine the black left sensor with 2 pins only have 600ohms at room temp, the middle one that is white with 2 pins got 2.2k ohms, the black one with 3 pins to the right i havent measure yet.


regards Johan

[shogun]

# 5 is mentioned, should be 13 62 1 707 366 3-POL-2500-OHM
#7 12621288158 M14x1.5 ,20 deg. C, 2500 Ohm, white top
#8 https://www.car-parts24.com/navi.php?a=6320&lang=eng
They measure the coolant temp, details which one for which part I posted here http://www.bimmerboard.com/forums/posts/1212512/

http://www.bimmerboard.com/forums/posts/1213979/

[Johanswe]

Ok thanks, so the black one closest to the fender dont have anything to do with the DME? The sparkplugs is dark and the car jump on low rpm and misfire. Seems like the temp sensor dont give the correct ohm but the temp in the cluster is correct? And can the dark green oxid cause problem on the sensors? Is it worth clearing them and polish? Or just buy new ones?

Regards Johan

[shogun]

The indicator in the cluster is a guessometer, BMW works there with a plateau value, so if it is at 12 o'clock and does not move, it does not mean that the temperature never changes, there are programmed values in the cluster board with limit values, here I posted the info http://www.bimmerboard.com/forums/posts/1245033/
Maybe you can try cleaning the contacts, if it does not work, change them. I would change them, these are important data for DME and EML

[Johanswe]

Ok ty will do.

Btw do you know if the magic reset work? I always remove the negative terminals on both my batteries. Is it true i have to drive the car for a while for it to calibrate?

[shogun]

Removing battery sets the DME's and EML modules to basic values. From the shop manual: Synchronisation of banks of M70 engine cylinders

The following information is important when replacing the Motronic control units or the EML control unit.

Each control unit is programmed with certain basic values, which are only mean values. A control unit receives various input values depending on engine load conditions and compares them with the stored values.
An adaptive system compares the input values with stored curve family values, after which corresponding orders are put out to the concerned control elements.

If, for example, the EML control unit were without current for a long period of time (more than 1 hour), its adaptive system would lose the stored values.

The adaptive system would have to read in and store the input values of a certain engine after restoring operation of an erased control unit or installing a new control unit. This procedure could lead to erratic idling of the engine after starting and disturbances in overrun.
Consequently there must be conformance with the following procedures before an EML control unit is replaced or after restoring operation of a disconnected control unit.

-run engine to operating temperature.
install (new) control unit and drive car. During test drive have the car coast three times from speeds above 5000 RPM to the idling range in transmission range 1 (approx. 10 seconds).

-Have engine run at idle speed in transmission range P or N at least 5 minutes!

These measures serve immediate and precise synchronisation of both banks of cylinders in all operating conditions.

[Johanswe]

Ok thanks! Do you know if the black temp sensor with 2 pins is bad if it can cause the car to pump in to much fuel in the engine?

[shogun]

once more:
1. most towards fender/outside of engine center: temperature gauge sender sensor
2. middle: engine coolant temperature (ECT) sensor DME
3. most towards center of engine: EML coolant temperature sender

1 is only for the gauge indication, 2 and 3 have effect on the engine management

[rjjablo]

Are 2 and 3 the only Coolant Temperature sensors that have an effect on the engine management?

Are there any other temperature sensors that have an effect on the Engine Management?

Mine is running badly when cold but fine once it warms up and the temperature dropped recently and I am looking for items to test before I have to potentially pull the intakes this winter

[Timm]

Cold weather problems are usually inlet-manifold leaks - they get less flexible as they get colder.....

[rjjablo]

I resealed the intake manifolds with Max Lumens gaskets, not discounting that might be the problem

[shogun]

besides coolant temp sensors there are the air temp sensors
#8 at the back of the intakes https://www.realoem.com/bmw/enUS/sho...diagId=11_0949
inside the MAF http://bmwe32.masscom.net/sean750/MA...leshooting.htm

[rjjablo]

What Should #8 Read? I should be able to get them out/test it without pulling the Manifolds

#8 at the back of the intakes https://www.realoem.com/bmw/enUS/sho...diagId=11_0949

[shogun]

use a multimeter, no need to remove, it is a Bosch 0 280 130 060 , google for one of these numbers to find the spec. https://automotivesuperstore.com.au/bosch-0-280-130-060
most probably the usual NTC 2,5 kOhm-Sensor, here the test data http://www.e32-schrauber.de/bmw/date...u-2_5-kohm.png

[clockwork]

thanks for all your help/suggestions Shogun as this is reminding me to check this stuff out too with my similar issue, Ive replaced these parts, but no guarantee a new part works either...

[rjjablo]

They both measured Drivers side measured 3800 and passenger side 3750 at approx 45-50 degree F. Motor has not run in a couple days so air temp. Well within the spec. Thanks. Time to look elsewere

[rjjablo]

Cold weather problems are usually inlet-manifold leaks - they get less flexible as they get colder.....

I went it and loosened the fuel rail and gave every nut I could get to on the intake manifolds a quarter turn while the motor was 40 degree F. Discovered that two of the nuts were missing from the time I resealed the manifolds.

Fired it and and it ran like crap for a bit but quickly smoothed out. I was still getting the same symptoms just not as bad. I was also getting surging after a test drive. Check Engine light is back on which it has not been since I replaced the MAF's and a lot of other items. I am going to do the magic reset tomorrow and see. If that does not work I will pull the intakes this winter and reseal with Reinzoil