Changing the RPM sensor on 240 with B230K engine

Hi

Does anyone know how to change the RPM sensor which is mounted above the flywheel on a B230K engine. The sensor is definately faulty, fails when hot, but I can't access it because the back of the engine is so close to the bulkhead and I can't get a spanner onto the 2 bolts. It looks like it is going to be a real pig, might have to drop the engine or move the engine forward, am I missing something?

The other option I am considering is to fit a distributor with the hall effect pick up in it to drive the ignition, has any one tried this or know of any problems.

Any help will be gratefully received.

Cheers

http://pic7.picturetrail.com/VOL188/...8/23744414.jpg
I`m pretty sure that your ignition computer (ECU) will not work with a Hall Effect sensor.
Although they do the same job, they give out a different type of signal.
The Hall effect modifies a current fed to it by the ECU., and the inductive sensor on the flywheel generates its own signal pulses.
I`ve never heard of dropping the engine to do this job but generally, if you can see the bolts you can undo them with a suitable assortment of sockets, extension and universal joints (preferably 3/8" drive).
Colin.

I can confirm that changing the flywheel sensor is a pig of a job but it can be done without dropping the engine.
As Colin says above, use a 3/8" drive (or even 1/4" drive) socket set.

Best of British, Beardy Rich.

Update!

Thanks for the help. I have managed to change the impulse sensor without having to drop the engine (thank god).

For info the impulse sensor on the 1987 240 is not the normal type. It is mounted using 2 bolts which are screwed horizontally into the flywheel housing and they cannot be accesed with a socket set. The only way to move them is with a 10mm ring spanner and a lot of patience! You need to remove the 2 heater hoses first to improve access. I used a telescopic magnet to lift the screws out 'cos you can't actually get your fingers onto the bolts.

I asked at the local Volvo garage before I attempted it and they said the only way to change the sensor was by removing the gearbox! Also the sensor appears to be only available from Volvo dealers. Nordic were not able to supply the correct part for my particular 240.

Cheers

[Peter Milnes]

In the Green Book for the engine they list the alternative Bosch part number as well as the Volvo number. If you buy from the dealer it will have a Bosch number on it (Volvo number on the packaging). If you went to a motor factor they would be able to get you the correct Bosch part numbered item for around ½ to ¾ of the Volvo price.

All the best, Peter

The sensor on my 240 is not Bosch but Renix hence the problem with getting a suitable part from a motor factor. The Volvo part number is 1389357 it would be worth knowing, for future reference, if there is a non Volvo replacement.

Cheers

[Soumroro]

Hi,

I have exactly the same problem with my volvo 240 and exactly the same sensor.

I would be really grateful if I could have a chat with you about the way you fixed it.

Thanks a Lot

Romain

[aljopad]

Hi

I had this very same problem when it packed up on me leaving me stranded at my uncles in Manchester.

I was also told that you had to drop the box to change it so I opted for another solution which my local Volvo Independent specialist suggested, which was to fit a distributor from a low mileage donor car which had old fashioned CB points. It was interchangeable with the existing distributor (apart from different rotor arm) but requires a standard coil pus rewiring of the LT circuit. Fitted with new points, condenser, coil HT lead and timing adjusted, the car starts first time every time and runs fine.

I am looking at reverting back to the Bendix Rex system to keep the car original, and having examined the CPS sensor with an endoscope, it does seem possible without dropping the gearbox as has been stated in the earlier posting. If I go this route i will post again but if you need a cheap fix which won't fail again then go for one of the earlier distributors with CB points.

[CaptainAhab]

Side view of sensor. There is a vertical bolt on mine which might let you withdraw the sensor out of the mounting plate with the aid of some Plus gas or something.

Can't speak to removal technique in situ as I had the gearbox off the remove mine.

Cheers.

[aljopad]

I wish mine was like that. My car is automatic and the CPS is attached to a metal bracket and retained to the rear of the block by two horizontal bolts. There is a cut-out in the gearbox housing around the CPS which will allow a spanner on the bolts, and a small gap between the bolt head and edge of cut-out. If the bolts are not too long there may be enough space to undo and withdraw them with the aid of an extending magnet or very long thin nosed pliers. The only way to get at them without removing the engine or box is to remove the heater hoses, the CPS is directly below them and not visible from above without their removal.

It looks a very fiddly job which will require time and patience, and the removal of any nearby swearboxes otherwise it could be expensive.

If I can get hold of a new CPS I will probably attempt the job and post a few shots of the job as I go along to help. It may be a few weeks yet though.