P38 crankshaft senor enquiry

Question, my p38 2.5d auto started revs up and down erraticly but not all the time.
I been told it could be the crankshaft sensor?
Just to confirm it could be the problem, so I get someone to replace it. Been showen a picture, it is apparently located above the starter motor

Also, always, when this is happen and engine starts rev up to about 2.400 the automatic starts giving problems switching up and too early down using the nengine to slow the vehicle down.
Checking the error codes I only had once a message engine speed senor mailfunction.

Guessing this sensor is also responsible for it?

What ever you do, DO NOT undo the bracket that holds the sensor or you will enter a world of pain, it can be removed with the bracket in place.
It's worth a try changing the sensor.
What year is your car?

Yes I been told to leave the bracket alone.
Some to do with air gap if I understood right?

1996.

I know it needs doing / changing to solve the rev problem, just was wondering if this is also the cause of the gearbox switching different as usual.

The plan is new oilfilter housing and pipe, oilfilter and engine oilchange incl glowplugs and a new rocker cover gasket in one go. And this senor, so it should be good again for a while.

tyke100 said:

Yes I been told to leave the bracket alone.
Some to do with air gap if I understood right?

1996.

I know it needs doing / changing to solve the rev problem, just was wondering if this is also the cause of the gearbox switching different as usual.

The plan is new oilfilter housing and pipe, oilfilter and engine oilchange incl glowplugs and a new rocker cover gasket in one go. And this senor, so it should be good again for a while.

Click to expand...

As gear shifts on the Auto are affected by engine revs, then the sensor could affect shifts.
Yes it's the gap between the sensor and the tangs on the flywheel.
Don't forget to change the oil and filter in the gearbox, needs doing about every 25K miles, worth doing the transfer box and diffs too if not done recently.

Thanks. I give all info to the guy in my garage doing the job.
Guess it's just old semsor out, new one in


Just out of interest is bear march ok for a new sensor or should I use another source ?

tyke100 said:

Thanks. I give all info to the guy in my garage doing the job.
Guess it's just old semsor out, new one in


Just out of interest is bear march ok for a new sensor or should I use another source ?

Click to expand...

Bearmach should be fine, I used them for ABS sensors with no problem.

Cool. Thanks.
Just a question I tried to order this cps but it asked me for the engine type.
M51 and bmw 6cyl.
Know I have a bmw as it is stamped on it and is 6cyl.
What's the difference to the m51 as there are 2 sensors, one for each type? And how do I know I order the right one ?
( sorry, first time I seen this question ordering parts )

tyke100 said:

Cool. Thanks.
Just a question I tried to order this cps but it asked me for the engine type.
M51 and bmw 6cyl.
Know I have a bmw as it is stamped on it and is 6cyl.
What's the difference to the m51 as there are 2 sensors, one for each type? And how do I know I order the right one ?
( sorry, first time I seen this question ordering parts )

Click to expand...

Engine is M51, the early version has no MAF but that is the only difference I know about. Go to a site like Island 4x4 from where you will quite likely be able to find the right part number, then you can order where ever you like.

Right. OK. Thanks for that. I couldn't find any info regarding the difference m51 and bmw 6cyl.
Don't think mine has a maf. At least I can't see any indication of it. Lol.

Yeah I get number of island and maybe is cheaper or same price and order from there.

Guessing the rockercover gasket is the same regardless of bmw 6cyl or m51 type describtion.

tyke100 said:

Right. OK. Thanks for that. I couldn't find any info regarding the difference m51 and bmw 6cyl.
Don't think mine has a maf. At least I can't see any indication of it. Lol.

Yeah I get number of island and maybe is cheaper or same price and order from there.

Guessing the rockercover gasket is the same regardless of bmw 6cyl or m51 type describtion.

Click to expand...

Rocker cover gasket is the same on all M51's as far as I know. Type code for the BMW 6cyl IS M51

Thank you.

I'm now getting confused sorry.
I have the error code I posting the pic below
Enquired, and been told new glowplugs, engine oil and cranck shaft senor solves it
Got everything here,
Symptoms on the car was
- high and low revs intermitted, disregarding speed or outside temperature.
It also tells me on gearbox fault - lost intermittent engine speed, sensor intermittent fault.
While on high revs gearbox changes also intermittent as pleased. Or only get up the next gear by about 3600 revs.
It's a 2997 2.5 bmw 6 cylinder d.
Auto gearbox.

I ordered from bearmarch this cranck shaft position sensor which came up as themperature sensor.
Unknown to myself, ok, must be the one. Which I posting in picture 2

Today I been told it can be a cranck shaft position angle sensor.
Which Is complete something different.

Anyone can share defo inside info on that please.

When the job get done it is a roadside and I can't leave the car there in bits while missing the right part.

Help please.

( I also can't download RAVE to get pictures of the part or where those sensor located neither what to take care of by putting new ones in )

And that is what I been told today what I need apparently, which I didn't know it exist or where I can get it from.

From memory the crank sensor fits in a bracket above the starter motor right hand side of the engine looking towards the back. The temperature sensor fits in the cylinder head again right hand side, you didn't say what year,the later engines have three sensors the early have two.You will probably have to take the inlet manifold off to access the sensor,just check you replace the one with the green plug.

The crank sensor is the one you want, it's where Allan said it is. DO NOT undo the bracket just undo the sensor bolt to remove it.
The water temperature "invalid reading" may be nothing.

Thanks. It's a 1997.
So it is the black one I need? In the last picture.

tyke100 said:

Thanks. It's a 1997.
So it is the black one I need? In the last picture.

Click to expand...

Yes.

tomcat59alan said:

Yes.

Click to expand...

And yes again

tomcat59alan said:

Yes.

Click to expand...

I've just seen your replacing the glow plugs so you will have the inlet manifold off to do them so temp sensor at the same time.you may need inlet manifold gaskets if you have the aluminium manifold.