Check panel...oil level light..

[daimlerman]

Just swapped an M40 into my ex 2.7 moor door.
No real problems,discovered that power steering pumps differ between 4 and 6 pots....
Now of course I have no sensors on the M40 for oil level/coolant level,any suggestions for kidding the overhead panel,please?
Longer term,I shall need to know how to wire up the same sensors in the 2.7's new home!

[tomson]

Coolant level sensor is in the header tank so no issues there. Oil level sensor is in the sump so I would think some kind of aftermarket sensor retrofitted would be easiest, or possibly see if the E30 M3's sensor is suitable.....

As for retrofitting it back into the cab, this is where you will come unstuck, I'm afraid. Easiest way IMO would be a complete body loom from a 325i cab (cab loom is different to saloon/touring) and swap the lot. Or try choppping the check control loom out and resplicing it back in but this way will be more boring than swapping a complete loom IMO. The check control loom runs the length of the car as the bulb check module is in the boot... Either way it's an interior out job, but I know you already know Malc

[Brianmoooore]

Retrofitting a check system into a car that didn't have one, can only be practically done by swapping over the complete body loom and fusebox!
M40 radiator can be fitted with a coolant temp sensor (drill out the blank UNDER the coolant tank) but it's a different sensor to the 6 pot one. Probably the same as a M50 one.
Oil level sensor should have three wire. one wire needs to be shorted to the earth wire, and the other left disconnected, to put the light out.

[tomson]

Of course, I'd forgotton that 4cyl turds have the expansion tank in the rad !

[Brianmoooore]

IMHO, the coolant level light is well worth connecting up - it's the one warning in the car that tells you that you are ABOUT to do very serious damage, before it actually occurs!

[daimlerman]

All I need to do is stop the two lights on the ex 6 pot from coming on....
Then arrange two fresh lights for the ex 4 pot....for this one I would like to arrange for the lights to be in the lower l/h side of the cluster,and preferably work in the same way as the other lights,ie,come on with ignition as a 'bulb check' and go out when the engine is running.
Is this possible to arrange?
I have no intention of attempting to fit the complete check panel into the cabbie,fed up of false signals from the rear lights!
So to sum up,I need to trace the correct wires at C101 to bridge to put out the lights on the check panel,please,and I assume pick up the same wires to install the two lights on the non check panel equipped car?

[daimlerman]

Sorted the water light out,pin 2 at C101 is blue/yellow,erm,er,what do I do with it?Tried cutting it,tried earthing it and the bloody light still comes on!

[suzie650]

it's because this is the static switch only. You have to ground it, and at the same time cut the wire to the dynamic switch, pin 10 on a '88 C101 (violet/green car side, blue engine side)
HTH

[suzie650]

and I don't suggest that you have to do it simultaneously, before somebody has a laugh about the bad explanation
Just that both wires have to be "doctored".

[daimlerman]

So I earth the blue/yellow and cut the violent/green?(on the car side)

[Brianmoooore]

The dynamic sensor doesn't actually go open circuit in the 'full' position. It has a 1000 ohm resistor shunted across it, but I've no idea if this affects the action of the 'check' panel or not.

[Bob_S]

just unplug the thing they are a pain anyway

[daimlerman]

The dynamic sensor doesn't actually go open circuit in the 'full' position. It has a 1000 ohm resistor shunted across it, but I've no idea if this affects the action of the 'check' panel or not.

Wow,Brian,that's way over my head!
What is the simple version,please?

[daimlerman]

just unplug the thing they are a pain anyway

Erm,yes,it is 'unplugged',but the light still comes up and it upsets 'er indoors as it makes the orange check flash,despite several instruction lessons she still has not plucked up enough corouge to press the 'cancel' button...
which of course still leaves the LeD lit....

[Brianmoooore]

What is the simple version,please?

Connect a 1000 ohm resistor between the purple/green and earth (brown).

[suzie650]

From what I read in my diagrams, the dynamic sensor sets the fault and the static on clears it. (never opened a check control unit to see inside myself, so Brian is certainly more knowledgeable there.)

So I earth the blue/yellow and cut the violent/green?(on the car side)

Yes, I think this would do the trick, although as mentionned by Brian, the violet green isn't normally just "cut" but goes to earth through a 1000 ohm resistor. (i.e. ~12mA current still flows through - but would a CC unit sense 12mA?)

[suzie650]

What is the simple version,please?

Connect a 1000 ohm resistor between the purple/green and earth (brown).

And like that it will work for sure

[daimlerman]

Now I have tried cutting the purple/green and connecting the blue/yellow to earth and tried cutting the blue/yellow and connecting the purple /green to earth,both with and without a 1000ohm resistor.Still have the damn oil level light lit...what am I missing,please?

[suzie650]

On a working unit with original engine fitted, I always found that I had to drive for a while and only then would it go out on the next start. - Don't know whether that was a strange behaviour on my car or if it is a planned one on all cars.

Blue yellow directly to earth and purple green to earth through a resistor definitely replicates a working sensor with full level. - And when Brian says it's a 1000 ohm resistor, I trust him

[daimlerman]

Blue yellow directly to earth and purple green to earth through a resistor definitely replicates a working sensor with full level. - And when Brian says it's a 1000 ohm resistor, I trust him

Still no joy....just out of interest,the 10p resistor that I bought this morning will not pass a continuity test,is that significant?

[suzie650]

It means it is broken. However, it depends a bit on your meter - 1000ohm is a fair resistance, and a cheap one might sense it as open circuit.
But if there is no continuity at all, no current is flowing, which would point towards answering this

[...] It has a 1000 ohm resistor shunted across it, but I've no idea if this affects the action of the 'check' panel or not.

by yes and explaining why it still doesn't work.

[daimlerman]

It means it is broken. However, it depends a bit on your meter - 1000ohm is a fair resistance, and a cheap one might sense it as open circuit.
But if there is no continuity at all, no current is flowing, which would point towards answering this

[...] It has a 1000 ohm resistor shunted across it, but I've no idea if this affects the action of the 'check' panel or not.

by yes and explaining why it still doesn't work.

Thanks for your help so far,I will try another source for a resistor tommorrow!

[Brianmoooore]

I've seen many E30s with working oil level sensors; I've seen some with non working sensors, and repaired these; I've connected M50 sensors to E30s but what I've never done, is try to simulate a sensor!
According to my wiring diagrams, what has been said above should simulate a sensor. My wiring diagrams have all sorts of hand written notes all over them, and the one for the the oil level sensor has 1000 ohms written in beside the resistor.
Presumably, at some time in the past, Ive measured this resistor with a meter.
If you have the engine with the sensor, take the sensor out and put your meter on its pins. Holding it upright will give the "oil low" readings and turning it upside down will give "full" readings.

[daimlerman]

I've seen many E30s with working oil level sensors; I've seen some with non working sensors, and repaired these; I've connected M50 sensors to E30s but what I've never done, is try to simulate a sensor!
According to my wiring diagrams, what has been said above should simulate a sensor. My wiring diagrams have all sorts of hand written notes all over them, and the one for the the oil level sensor has 1000 ohms written in beside the resistor.
Presumably, at some time in the past, Ive measured this resistor with a meter.
If you have the engine with the sensor, take the sensor out and put your meter on its pins. Holding it upright will give the "oil low" readings and turning it upside down will give "full" readings.

I've got the M20 sat in the garage awaiting a few bits from Cotswold,removing the sensor is no problem,will it need power to get a reading?
I'll try it,anyway...

[Brianmoooore]

The sensor is sealed by an O ring, so is removable and replaceable without problems, and where it fits into the sump is just above the max oil level.
It is an alloy canister, with just a small hole top and bottom, so it will take some time for all the oil to drip out of it, especially cold oil.
Measure the resistance between the three pins with it the right way up and upside down.
Before you refit it to the M20, fill a baked bean can with petrol and stick the sensor in it for a while. Lift it up, let it drain, then put it back in again. Repeat a few times - you'll be surprised at the black sludge that will flush out.

[daimlerman]

The sensor is sealed by an O ring, so is removable and replaceable without problems, and where it fits into the sump is just above the max oil level.
It is an alloy canister, with just a small hole top and bottom, so it will take some time for all the oil to drip out of it, especially cold oil.
Measure the resistance between the three pins with it the right way up and upside down.
Before you refit it to the M20, fill a baked bean can with petrol and stick the sensor in it for a while. Lift it up, let it drain, then put it back in again. Repeat a few times - you'll be surprised at the black sludge that will flush out.

Thank you Brian,that's tomorrow morning's little job!
Be almost a rest to go back to work on Sunday!

[daimlerman]

Another option is to wire the sensor back in upside down by itself, that should shut the light up..

Only be a temporary 'fix',as the M20 is going into the project cabbie soon,and I want to arrange a coolant level and oil level light for it!

[Brianmoooore]

Might be the way to go as a temporary measure, though!
Once you've proved that you can get the light to go out, a few measurements with a meter should enable you to simulate the sensor.