[holtsaber]

Help!

My 1992 3.6 M5 is very unhappy.

I have today gone through the rigourous task of replacing the fan on the front of the engine after losing a blade last week. The radiator was nicked, but repaired with little difficulty.
On completing the fan replacement, I turned the key and, as usual, it fired first turn. I let the engine run to make sure the rad was holding, and all was well. The idle was however, a little lumpy, but having been parked up for over a week I thought that was fair enough.

Now the disastor. Having turned the engine off and come in to wash etc, I returned to the car after about 10 minutes. Jumped in, turned the key....... turning...... turning...... fired.... spluttered..... stopped.

I thought I'd better see what was going on, so I lifted the bonnet. Tried again. Turned, fired a little spluttered and stopped.
Tried again and after 2 or 3 turns, the engine kicked back abruptly, and the fan started to turn in the wrong direction amid a sort of 'pre-ignition' type noise.

At this point I thought I'd better stop and get some advice!

Anybody got any ideas? My engine knowledge of the M5 is limited, and there is no independant specialist that I know of in Mid Wales .

 

[Stevie]

Help!

My 1992 3.6 M5 is very unhappy.

I have today gone through the rigourous task of replacing the fan on the front of the engine after losing a blade last week. The radiator was nicked, but repaired with little difficulty.
On completing the fan replacement, I turned the key and, as usual, it fired first turn. I let the engine run to make sure the rad was holding, and all was well. The idle was however, a little lumpy, but having been parked up for over a week I thought that was fair enough.

Now the disastor. Having turned the engine off and come in to wash etc, I returned to the car after about 10 minutes. Jumped in, turned the key....... turning...... turning...... fired.... spluttered..... stopped.

I thought I'd better see what was going on, so I lifted the bonnet. Tried again. Turned, fired a little spluttered and stopped.
Tried again and after 2 or 3 turns, the engine kicked back abruptly, and the fan started to turn in the wrong direction amid a sort of 'pre-ignition' type noise.

At this point I thought I'd better stop and get some advice!

Anybody got any ideas? My engine knowledge of the M5 is limited, and there is no independant specialist that I know of in Mid Wales .

Ehhh, the fan usually doesn't lose blades without reason. Either a motormount is shot and the engine is sitting too low, or the little plastic cups that hold the rad in place are split/gone, causing the rad to come backwards at speed. I replaced my fan & rad & shroud only to have them contact eachother AGAIN the same day for this exact reason!!!! So another NEW radiator,fan and shroud were bought, but this time I replaced the missing cup on the chassisrail as well......

http://www.realoem.com/bmw/showparts.do?model=HD91&mospid=47385&btnr=17_0000&hg=17&fg=05
Part 6 and 7


The bad running: Is the TDC sensor still in place?

 

[holtsaber]

Ehhh, the fan usually doesn't lose blades withuout reason. Either a motormount is shot and the enfgine is sitting too low, or the little plastic cups that hold the rad in place are ****, causing the rad to come backwards at speed. I replaced my fan & rad only to have them contact eachother the same day for this exact reason!!!! So another rad and fan were bought, but this time I replaced the missing cup on the chassisrail as well......

Is the TDC sensor still in place?

The fan actually had a crack at the bottom of one of the blades. When I removed the old fan, there was a rusty patch on the steel ring where it had broken off.

Interestingly, just before leaving work this afternoon, I tried the engine again, and it fired straight away! Running very unevenly though.
When I turned the engine off, I realsied that the funny little servo/motor noise that normally comes from the drivers side of the bulkhead didn't happen.

I don't know what it does, but could this be a contributory factor perhaps?

With regard to the TDC sensor, excuse my lack of knowledge on the S38, but where is it and what does it look like!

If anyone knows owhere I can obtain a decent technical manual for the E34 M5, please let me know!

Thanks

 

[Stevie]

When I turned the engine off, I realsied that the funny little servo/motor noise that normally comes from the drivers side of the bulkhead didn't happen.
Thanks

There are only electric motors there, 1 being the variable-wiper-pressure motor, the other the electric waterpump. Both are expendable.

TDC sensor should be on the front of your engine counting the teeth on the harmonic balancer.

 

[holtsaber]

There are only electric motors there, 1 being the variable-wiper-pressure motor, the other the electric waterpump. Both are expendable.

TDC sensor should be on the front of your engine counting the teeth on the harmonic balancer.

Could it be that I've disturbed something on the front of the engine while reassembling the radiator?
I had quite a job getting it all back together, I must admit. Not much room at the front, is there!

 

[Stevie]

Could it be that I've disturbed something on the front of the engine while reassembling the radiator?

Yes, you could have knocked your TDC-sensor about. It's a sensor on the front of the engine pointed towards the harmonic balancer on the crankshaft.

 

[holtsaber]

Yes, you could have knocked your TDC-sensor about. It's a sensor on the front of the engine pointed towards the harmonic balancer on the crankshaft.

That would make sense I suppose. If the engine doesn't know when it's at top dead centre, the timing is going to be all over the place!

It's also possible perhaps that it has been struck by the old fan breaking up? It lost 6 of its' blades in all!

Do you know of a schematic diagram that shows the exact location of the TDC sensor, and how it should be aligned / setup?

I hope to garage the M5 for the winter and do a bit of an overhaul under the bonnet. Perhaps I can even get the air pump to stop growling! I need to get a good workshop manual. I've seen some on ebay. Anybody tried one?

Thanks for all your assistance here everyone. Very much appreciated!

 

[unesential]

Chilton book 8427 covers the 3.6. The crank sensor is located behind the fan on passengr side front of motor. it mounts from the top and is royal pain to get at. The wiring runs behind the hose casting. It is possible that you disturbed the connection cuaseing it to misfire. The connection is top front of motor next to the distributor. The electrical wiring diagrams are available online from manualsunlimited.com. hope some of this helps.