96 S1 Alarm again :(

timmsky · Post by **timmsky** » Mon May 07, 2007 1:28 pm

Thanks Robin,

I have an account with TNT which is fully insured so when the RLC is ready, shoot me your address and i'll have them call in to collect.

Re: Avon - they are not in today, damned holiday apparently

so will have to wait until tomorrow until I speak to them.

I'll pass on your number and will let them know you are keen to talk to them anyway.

Cheers,
Iain

timmsky · Post by **timmsky** » Tue May 08, 2007 3:58 pm

Okay - small update:

I spoke to Avon today and they have advised me to carry out a simple test as the car is not cranking now, let alone firing. It may be a suspect 5AS unit although these are reported to be bomb-proof in the main.

The test is simply to turn the ignition on and then use the plip to de-activate the system. You should be able to hear a 'click' from the 5AS unit. This is the redundant central locking system circuit activating.
If I hear a click, then the 5AS unit is most likely working. If I don't, then it's potentially gubbed, or there's a fuse out.

I checked the fuses on Sunday under the front inspection panel, and all were fine, including the 10A one for the alarm.

The car stopped cranking after I pressed the button on the fuel cut-off switch in the engine bay. Could this be a potential problem stopping firing??

Tonight i'll try the ignition/click test. If it's clicking then I have to assume that there is something else amiss... wot, I don't know......

Iain

robin · Post by **robin** » Tue May 08, 2007 4:07 pm

Fuel inertia switch is not related to cranking, though the immobiliser at the back is - I would check that the bypass is installed properly (assuming the immobiliser is bypassed!).

Cheers,
Robin

timmsky · Post by **timmsky** » Tue May 08, 2007 4:11 pm

robin wrote:Fuel inertia switch is not related to cranking, though the immobiliser at the back is - I would check that the bypass is installed properly (assuming the immobiliser is bypassed!).

Cheers,
Robin

I haven't installed a bypass for the immobiliser - what would it look like?

I was wondering whether the fuel inertia switch was linked to a problem with non-fuelling when she was cranking? It may be that there were sparks, but no fuel if the inertia switch was gubbed?

Are there any more fuses other than the ones under the front inspection hatch that could affect cranking?

robin · Post by **robin** » Tue May 08, 2007 4:37 pm

There aren't any fuses for the starter motor itself. I would bypass the immobiliser - it sits directly in the path of the cranking and fuelling.

Remove boot bag, locate black riveted cover next to ECU, drill out rivets. Pop out the connector at the bottom of the device inside - connector is white and something like 14 pins in two rows - looking into the end that was connected to the immob:

AXXXXXB
AXXXXXB

Connect A-A and B-B with two short lengths of reasonably heavy duty wire and see what happens next. You can shove it into the female spade terminals in the connector for now. If you have access to split pins, a split pin serves as good bridging wire too - remember A-A and B-B but no connections from either A to either B.

Cheers,
Robin

timmsky · Post by **timmsky** » Tue May 08, 2007 4:41 pm

robin wrote:There aren't any fuses for the starter motor itself. I would bypass the immobiliser - it sits directly in the path of the cranking and fuelling.

Remove boot bag, locate black riveted cover next to ECU, drill out rivets. Pop out the connector at the bottom of the device inside - connector is white and something like 14 pins in two rows - looking into the end that was connected to the immob:

AXXXXXB
AXXXXXB

Connect A-A and B-B with two short lengths of reasonably heavy duty wire and see what happens next. You can shove it into the female spade terminals in the connector for now. If you have access to split pins, a split pin serves as good bridging wire too - remember A-A and B-B but no connections from either A to either B.

Cheers,
Robin

Thanks Robin - isn't this what tut was eluding to on SE Dinosaurs? I thought we concluded this wouldn't work for a non-Emerald car?

robin · Post by **robin** » Tue May 08, 2007 7:37 pm

It's actually a quite complicated circuit.

What I meant by cannot be done is that you cannot completely eliminate the 5AS if you have a MEMS because the MEMS needs to see the code from the 5AS to allow the engine to run.

The fuel pump is controlled by 7 inputs:

(1) the ECU must enable the fuel pump relay (one of the relays in the MFRU) by supplying an earth on one side of it.
(2) the cobra immob (this is the AA-BB thing) must be engaged or bypassed.
(3) the inertia switch must be conducting (i.e. not popped).
(4) the 10A (often uprated to 20A, it seems) fuel pump fuse must be OK and connected to battery live.
(5) the chassis earth system must be conducting back to the battery.
(6) the ignition switch must be in the on position and feeding current to the MFRU.
(7) the 40A fuse must be supplying the main relay in the MFRU (otherwise you won't get the ECU to do anything).

The starter is controlled by 7 inputs:

(1) The 50A maxi fuse must be feeding current to the ignition switch, and the ignition switch must be in the crank position.
(2) the cobra immob (this is the AA-BB thing) must be engaged or bypassed.
(3) the 40A fuse must be feeding the main relay in the MFRU (otherwise the start relay hasn't got a supply to feed the starter solenoid).
(4) the 5AS must be providing an earth to the other side of the start relay in the MFRU.
(6) the starter motor must have good earth through the earth system.
(7) the starter motor main live feed must be connected to the battery.

So both the 5AS and the cobra can in theory disrupt the operation of both circuits.

If you bypass the cobra immob as described above, you can eliminate the cobra from the equation. If the fuel pump runs and the engine cranks then you know the 5AS is happy (remember it's condition 4 in the starter circuit).

If the engine still doesn't run, then you could have engine problems or ECU problems or 5AS->ECU connectivity problems, and short of using a scope or an emerald there is no easy way of telling which fault you have.

I hope that makes some sense now! Tow the car down here and we'll fix it

Cheers,
Robin

timmsky · Post by **timmsky** » Wed May 16, 2007 12:59 pm

Thanks Robin,

Sorry for the quietness of late - been in die Vaterland a lot lately....

Did you get the Emerald out of the RLC?

I spoke to Avon after conducting the 'click' test above, as there was no click, hinting that the 5AS unit is ok.

Now it seems as though the fule pump sometimes primes, and sometimes doesn't. When it does, the car will crank over, but no spark.
When it doesn't prime, then the engine won't turn.. just silence...

Could this be a dodgy earth?

Cheers,
Iain

hiscot · Post by **hiscot** » Wed May 16, 2007 3:36 pm

mfu ?

timmsky · Post by **timmsky** » Wed May 16, 2007 3:53 pm

hiscot wrote:mfu ?

You know, in Alness that's considered swearing

WTF is MFU?

Post by **Shug** » Wed May 16, 2007 4:01 pm

prolly the MFRU

hiscot · Post by **hiscot** » Wed May 16, 2007 4:15 pm

Shug wrote:prolly the MFRU

yep thats the one MFRU

timmsky · Post by **timmsky** » Wed May 16, 2007 4:16 pm

Shug wrote:prolly the MFRU

The language on here is terrible....

timmsky · Post by **timmsky** » Wed May 16, 2007 4:21 pm

Can the relays in the MFRU be replaced individually or is it better to swap with a donor unit?

If so, where would one purchase such a unit?

Post by **Shug** » Wed May 16, 2007 4:34 pm

Need to swap the whole thing.

Scrappys, Rover parts place or I've got a spare kicking about if you want it. Think it came off Mac's car at one stage when he was trying to trace a fault.