brian, a little help? oil level sensor

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slideways
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Location: Sligo, EIRE

Post Sat Jul 09, 2005 8:10 pm

first thanks for the advice i have given me so far regarding this problem
I was told i needed 1kohm resistance in the oil level sensor to put out the light. with the level ok in the sump i checked the sender unit. middle contact was good to earth but every other combination of reistance check came up open circuit. on a tight budget so to be sure that was the preoblem before i bought the sender i got a crank sensor off a crashed vito (merc) in work. resistance in this was 1070 ohms. thought it would be close enough. then checked the loom where it plugs into the sender. 12v in one pin. got a spare plug off another 325 and plugged it into the loom (the lead that goes around spark plug lead no. 6) attached the 2 outside wires to the sender and the middle to earth but still no joy. could it be the signal wire back to the roof cloth thats broken or does it even go ther. i know its unlikely for both the wire and sender to be gone but want to be sure. all help and advice greatly appreciated
A1BMW325iSport
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Post Sat Jul 09, 2005 8:14 pm

i have an oil level sensor if you need 1
slideways
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Post Sat Jul 09, 2005 8:16 pm

is it the 3 wire one? have one on a preface lift 325i but it only has 2 wires. am in ireland tho...
A1BMW325iSport
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Post Sat Jul 09, 2005 8:17 pm

i`ll check now, 2 secs
A1BMW325iSport
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Post Sat Jul 09, 2005 8:33 pm

Hi mate, its the 2 wire one....

Image
slideways
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Post Sat Jul 09, 2005 8:35 pm

Thanks anyway. was just reading the post about the h27 engine
sounds unbelievable
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Brianmoooore
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Post Sat Jul 09, 2005 11:28 pm

The memory isn't quite like it used to be, but I'm fairly sure a car I bought last year had the oil levlel light permanently on for no good reason. I had a spare roof panel around, and fitting that was the cure.
Never did get around to repairing the original panel at component level, but there are several small signal diodes (1N4148s probably) and some BCXXX transistors inside. I would expect one of these to be either open circuit or short circuit.
Regarding the internal circuitry of the E30 3 wire oil sensor and the 1000 ohm resistor. These are figures I measured off a M20 325 oil sensor with a meter when I was doing my M50 conversion, to work out if the E30 check system would work with the E34 M50 engine.
I've no idea whether the 1000 ohm resstor is neccessary or not, although it is shown on one of the E30 wiring diagrams I have.
slideways
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Post Sun Jul 10, 2005 4:12 pm

thanks.
have a spare one too will try that
cheers again :beer: