Another non starting 325i

[Farbbm]

My 87 325i Sport is now not starting, it cranks over but doesn't fire. I've done the usual checks and there isn't any spark so I'm thinking it's the CPS, but I'm not exactly sure where it is. The Youtube videos I've viewed all suggest it's at the front of the engine, but as mine is a pre factlift Tech1 (May 1987 build) I presume it runs the earlier ignition system and has two sensors on the bell housing. if that is the case where is best to try and located them, and if I do need a new one, where best to source it from.

Thanks

[Speedtouch]

Which ECU do you have? If it is a Motronic 1.1 version rather than the earlier 1.0, apparently they only use the one CPS - see the Zone Wiki guide here, which includes how to test it at the ECU socket:

https://www.e30zone.net/e30wiki/index.p ... ion_Sensor

You can identify your ECU from this list:

https://www.e30zone.net/e30wiki/index.p ... st_of_ECUs

[Farbbm]

Going by the build date of May 1987 and the fact that I can't find the single sensor at the front of the engine would mean the two are on the bell housing.

Thanks

[Speedtouch]

In which case, you can check the pair of CPS at the ECU socket here:
https://www.e30zone.net/e30wiki/index.p ... tronic_1.0

AFAIR, at least one is fitted inside the bellhousing, necessitating removal of the gearbox to replace it!

[minesapint]

Going by the build date of May 1987 and the fact that I can't find the single sensor at the front of the engine would mean the two are on the bell housing.

Thanks

I’d be very surprised if yours was not the single cps mounted at the front.
My 325i build date was Jly 86 & is single cps at front, as yours is 12 months younger I’d expect it the same.
Are you sure, they’re not easy to see.
Photo of mine with stuff removed when replacing timing belt, showing sensor.

IMG_3549.jpeg

[minesapint]

PS. Only buy genuine CPS from BMW

[Farbbm]

Going by the build date of May 1987 and the fact that I can't find the single sensor at the front of the engine would mean the two are on the bell housing.

Thanks

I’d be very surprised if yours was not the single cps mounted at the front.
My 325i build date was Jly 86 & is single cps at front, as yours is 12 months younger I’d expect it the same.
Are you sure, they’re not easy to see.
Photo of mine with stuff removed when replacing timing belt, showing sensor.
IMG_3549.jpeg

It does indeed have the CPS at the front on the engine, however that wasn't the one which failed.
Managed to tow the car to the garage, and they've confirmed it's the Reference Sensor at the back of the engine, which has now been replaced with a Bosch item and the car is running again.

Thanks for you replies.

[Speedtouch]

Glad to hear it. Did they have to remove the engine/gearbox to replace it?

[minesapint]

Going by the build date of May 1987 and the fact that I can't find the single sensor at the front of the engine would mean the two are on the bell housing.

Thanks

I’d be very surprised if yours was not the single cps mounted at the front.
My 325i build date was Jly 86 & is single cps at front, as yours is 12 months younger I’d expect it the same.
Are you sure, they’re not easy to see.
Photo of mine with stuff removed when replacing timing belt, showing sensor.
IMG_3549.jpeg

It does indeed have the CPS at the front on the engine, however that wasn't the one which failed.
Managed to tow the car to the garage, and they've confirmed it's the Reference Sensor at the back of the engine, which has now been replaced with a Bosch item and the car is running again.

Thanks for you replies.

This is not making sense to me.
You’ve said your CPS is mounted at the front of the engine, therefore the previously used two sensors system mounted onto the bell housing will not be on your car, as the front CPS replaced those.
So what have the garage replaced?
The only other sensor at the rear of engine I know of is CID sensor, (cylinder identification) or pulse sensor, which informs DME exactly when cylinder number 1 fires, it’s a small sensor attached to number 6 spark plug lead. But I’m unsure if your car has this & the symptoms for this failing don’t fit with your symptoms.
So I’m confused.
Your car is fixed & working so you’re happy, I’m just intrigued, were there any part numbers on your bill?
Glad you’ve got it sorted.
Cheers

[Andyboy]

The front mounted crank sensor arrived 9/87 with the facelift and Motronic 1.3.

The front sensor on the pulley on pre 9/87 is the position transmitter for diagnostics. These older cars have two sensors on the bellhousing, one for TDC and another for flywheel speed to calculate ignition advance. The flywheel has a trigger pin to activate them.

[minesapint]

The front mounted crank sensor arrived 9/87 with the facelift and Motronic 1.3.

The front sensor on the pulley on pre 9/87 is the position transmitter for diagnostics. These older cars have two sensors on the bellhousing, one for TDC and another for flywheel speed to calculate ignition advance. The flywheel has a trigger pin to activate them.

Thank you for this info, I never knew this, always assuming the front sensor was the CPS on mine.
No wonder I was confused in this post. We live & learn.
Thanks & cheers.

[minesapint]

The front mounted crank sensor arrived 9/87 with the facelift and Motronic 1.3.

The front sensor on the pulley on pre 9/87 is the position transmitter for diagnostics. These older cars have two sensors on the bellhousing, one for TDC and another for flywheel speed to calculate ignition advance. The flywheel has a trigger pin to activate them.

Again thanks Andyboy, it’s encouraged me to find out more about these sensors.
As you say the one in my photo above is only for diagnostics going to the diagnostic plug in the engine bay, in fact I’m told the car will run without this in place.
To answer Speedtouch’s question, the two on the bellhousing are replaceable without removing the engine or gearbox so AI tells me, I’ve priced them, both sensors are the same, Bosch part number 0261210002 @ £38 each, others cheaper.
Cheers