B

B16FUN

Active Member
Evening all,
Does anyone know the correct air gap that the crank position sensor (CKP) should be set to on the BMW Diesel engine (mine is a 1996 P38 2.5 dse)? I need to fit a new one including mounting bracket so need to set the airgap, however, I don;t have the correct tool (LRT-12-122) for the job and as I only hope to be doing it once I don't want to have to buy one!
I've been searching google all evening and I've searched my copy of RAVE but to no avail!
If anyone can help I'd really appreciate it!
Thanks,
Andy.
 
The gap should be 0.060" between sensor and nib on crank.

Sorry, I'm no genius, I just put 'crank sensor air gap' into the search function for posts in this forum. I even found a link to a Utube video on it but don't ask an old duffer like me to transfer that onto here, I can just about find the keys on the keyboard.
 
Hi mate,
Yeah, I'd seen that but that post relates to a petrol V8 whilst this is a BMW 2.5 diesel so I'm assuming there is a difference in the air gaps between the two engines as they are different sensors, can anyone confirm that? Cheers for trying though.
Andy.
 
If you are fitting a new crank sensor just unbolt it from the bracket and fit new one. It should be in correct place. DO NOT unbolt or disturb bracket on Cylinder block. If you do you will need special tool LRT-12-122 to reset it with. This means setting TDC pin on flywheel into centre of sensor hole, then setting set back of bracket using special tool.
 
Hi Wammers, cheers for your advice but I'm already aware of this. I need to reset the bracket as the sensor has come into contact with one of the pins on the flywheel, smashing the sensor apart and shearing the one pin that it hit. I have spare pins to replace the damaged one and a spare sensor and bracket but while the engine is out and I'm doing this I'll need to set the bracket/sensor to the correct air gap so if I know the measurement then I'll set it with feeler gauges.
I have found somewhere I can buy the tool from but as I only intend on doing it once I don't really want to go to the expense of buying such a specialist tool to only use it once.
Cheers,
Andy.
 
Cheers Wammers. I'm going to have a quick word with the local Land Ranger Services tomorrow and just see if they either have the tool or if they know the correct gap, failing that I will use the 0.060" gap.
Cheers,
Andy.
 
B16FUN said:
Cheers Wammers. I'm going to have a quick word with the local Land Ranger Services tomorrow and just see if they either have the tool or if they know the correct gap, failing that I will use the 0.060" gap.
Cheers,
Andy.
Click to expand...

If you can get them to measure from where it bolts to bracket to end. The difference in length between that and sensor length from bracket boss to tip is the air gap.
 
Well, just to update people, pulled the engine out, stripped the flywheel off, replaced the one pickup pin that had been sheared off, fitted the new crank position sensor using the 0.060" measurement (checking each pin against the face of the sensor with the feeler guages to ensure they were all fine), refitted the engine, plumbed it all back in and....
...it fired up and settled into a perfect idle. So, if you have to change the crank position sensor AND bracket AND can remove the engine then it seems that 0.060" is an acceptable gap for it. HOWEVER, if you do need to change the sensor simply because it had failed but the bracket is ok then remove the sensor, leaving the bracket attached to the block.
Hope this is of help to someone if they end up in the same position as I did!
Cheers to those who helped with suggestions.
Andy.
 
B16FUN said:
Well, just to update people, pulled the engine out, stripped the flywheel off, replaced the one pickup pin that had been sheared off, fitted the new crank position sensor using the 0.060" measurement (checking each pin against the face of the sensor with the feeler guages to ensure they were all fine), refitted the engine, plumbed it all back in and....
...it fired up and settled into a perfect idle. So, if you have to change the crank position sensor AND bracket AND can remove the engine then it seems that 0.060" is an acceptable gap for it. HOWEVER, if you do need to change the sensor simply because it had failed but the bracket is ok then remove the sensor, leaving the bracket attached to the block.
Hope this is of help to someone if they end up in the same position as I did!
Cheers to those who helped with suggestions.
Andy.
Click to expand...

You could always make a shouldered setting pin in the lathe, 0.060" longer than the sensor. That way you won't knock the position pin out by getting the bracket in the wrong place. :):):)
 
Glad to have found this thread, I have a suspect sensor. Story goes, at the MOT Diesel after passing emissions starts to misfire, generally bad throttle response on the way home. No overheating, felt like it was out of fuel. Plugged in the nanocom and found low fuel flow. Hence changed the tank pump u/s, fuel now to the injection pump, but not coming through to injectors when cracked. Is there a bleed screw on the inj pump ? Fault has now gone off the nanocom, replaced with immobiliser. Yet engine is cranking. Noted rpm signal to be 193rpm at crank. What is going on ?
Resistance of ckp is 1100 ohms.
 
Last edited:
tnseal said:
Glad to have found this thread, I have a suspect sensor. Story goes, at the MOT Diesel after passing emissions starts to misfire, generally bad throttle response on the way home. No overheating, felt like it was out of fuel. Plugged in the nanocom and found low fuel flow. Hence changed the tank pump u/s, fuel now to the injection pump, but not coming through to injectors when cracked. Is there a bleed screw on the inj pump ? Fault has now gone off the nanocom, replaced with immobiliser. Yet engine is cranking. Noted rpm signal to be 193rpm at crank. What is going on ?
Resistance of ckp is 1100 ohms.
Click to expand...

Did you disconnect the battery when you did the in tank pump?
Sounds like the immobiliser is triggered or loss of sync, both can be checked with Nanocom I believe.
How many RPM do you expect off a starter motor?
 
Thanks for the suggestions. open to any future ones, but the story so far.....In a galaxy not so far away...
sorry for the delay, fip is at fault. For the future the air gap as per BMW is 1mm. I remembered I had got the BMW CD's a while ago and looked up the engine as a M50 which was as close as I could get, the M51 has a EGR valve. The codes were all clear on the ecu and therefore after finding an excellent guy at King's Lynn a few pointers have been made. We both looked at all the diagnosis to come to the most logical, the FIP as a fault. fuel is now clear of air, yet still the pump will not push it to the injectors, the cut off valve has power and the engine cranks. no new faults are on the system.
 
tnseal said:
Thanks for the suggestions. open to any future ones, but the story so far.....In a galaxy not so far away...
sorry for the delay, fip is at fault. For the future the air gap as per BMW is 1mm. I remembered I had got the BMW CD's a while ago and looked up the engine as a M50 which was as close as I could get, the M51 has a EGR valve. The codes were all clear on the ecu and therefore after finding an excellent guy at King's Lynn a few pointers have been made. We both looked at all the diagnosis to come to the most logical, the FIP as a fault. fuel is now clear of air, yet still the pump will not push it to the injectors, the cut off valve has power and the engine cranks. no new faults are on the system.
Click to expand...
Power to the cut off valve does not mean it is going to operate.
 
tnseal said:
Thanks for the suggestions. open to any future ones, but the story so far.....In a galaxy not so far away...
sorry for the delay, fip is at fault. For the future the air gap as per BMW is 1mm. I remembered I had got the BMW CD's a while ago and looked up the engine as a M50 which was as close as I could get, the M51 has a EGR valve. The codes were all clear on the ecu and therefore after finding an excellent guy at King's Lynn a few pointers have been made. We both looked at all the diagnosis to come to the most logical, the FIP as a fault. fuel is now clear of air, yet still the pump will not push it to the injectors, the cut off valve has power and the engine cranks. no new faults are on the system.
Click to expand...

It sounds like the EMS security code is out of sync Engine ECU to BECM. The cut off solenoid does not stop the engine. The fuel quantity solenoid going to zero does that. If the EMS is out of sync the ECU will not move the control collar via the quantity servo to give start fuel. The fuel cutoff solenoid is only a back up if the quantity control circuit fails to prevent a runaway. If the security code is out of sync you can turn the engine for the rest of the year and it won't start.
 
wammers said:
It sounds like the EMS security code is out of sync Engine ECU to BECM. The cut off solenoid does not stop the engine. The fuel quantity solenoid going to zero does that. If the EMS is out of sync the ECU will not move the control collar via the quantity servo to give start fuel. The fuel cutoff solenoid is only a back up if the quantity control circuit fails to prevent a runaway. If the security code is out of sync you can turn the engine for the rest of the year and it won't start.
Click to expand...

In the How To sections there's a guide to checking and synching the diesel using a Nanocom.
 
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