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No volts at coil? 
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Joined: Fri Apr 15, 2011 6:04 pm
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Post No volts at coil?
On trying to start my car the other morning the car would not start, turning over but no spark. ( GTM Libra fitted with 1.8 k with rover MEMS unit).

On investigation there is no supply to the coil hence no spark! I have now found a tech help circuit showing various wiring options used on the MEMS/K-series.

I will not have another chance to investigate until the weekend so any have been there tips are welcome. It looks on first view of the circuit that the coil supply is fed from terminals 28+ and 25- on the MEMS unit. What are the pre requisites for the outputs from these terminals to feed the coil?


Wed Feb 22, 2012 9:00 pm
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Location: Sheffield
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Post Re: No volts at coil?
Do you have a 5AS unit? Mine once armed itself and I had to have someone bring me the fob (i leave it unarmed so didn't carry the fob) to disarm it.

SAS

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2000 GTM Libra 1.8VVC 145BHP


Thu Feb 23, 2012 11:51 am
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Post Re: No volts at coil?
I have the fob and I can hear it arming/disarming so think not but will keep in mind.


Thu Feb 23, 2012 7:01 pm
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Post Re: No volts at coil?
Possibly crank speed sensor had one go on a 1.4mpi k series.On mems 2j.
Matty


Thu Feb 23, 2012 8:32 pm
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Post Re: No volts at coil?
Matty H wrote:
Possibly crank speed sensor had one go on a 1.4mpi k series.On mems 2j.
Matty

I was thinking it could be the crank sensor from the circuit diagram and the information I have read today so will keep in mind when I have a look tomorrow.


Thu Feb 23, 2012 9:44 pm
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Post Re: No volts at coil?
Ok had a poke round but eventually called on the good old AA. They came with all the mod cons in the big yellow van. The fault would appear to be the fuel pump relay and this was reinforced by squirting the super rich fuel spray in via the air filter where the engine sparked into life for a few split seconds. Now where is the said relay hidden in the Libra? Once found I will replace and see if they were right!!


Its ok I remember the location under the dash drivers side!

Steve


Sat Feb 25, 2012 6:52 pm
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Post Re: No volts at coil?
Is the fuel pump relay not in the multi function unit.Black box with two multi plugs connected to it near the ecu.
Matty


Sat Feb 25, 2012 8:22 pm
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Post Re: No volts at coil?
There seems to be two options the one as you describe part number YWB100970 black in colour or part number YWB100790 which seems to be red in colour and of 4 pin type. I will carry on tomorrow looking for either of them!!

Using this link for most of my direction

http://www.gaima.co.uk/peter/RoverMEMS.pdf


Sat Feb 25, 2012 8:46 pm
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Post Re: No volts at coil?
The relay is the MG Rover. Engine management Main relay.(YWB 100710). I was unable to locate the inertia switch which may be either require re-setting. I don't see why it should but it would have been nice to find and see if so, or it may be u/s. I had a look through threads and although I know what it looks like I cannot see it in any of the likely places may be it was never fitted?

So I will buy part YWB100710 and see what will be. Has anyone one stashed away waiting for a buyer?


Sun Feb 26, 2012 6:20 pm
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Post Re: No volts at coil?
I'd have a serious search for the ineria switch first if I were you -- the relay box is very expensive!


Mon Feb 27, 2012 3:05 pm
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Post Re: No volts at coil?
Steve Shield wrote:
I'd have a serious search for the ineria switch first if I were you -- the relay box is very expensive!


The only place I have not looked is within the dash and the underside close to the fuel tank.The second site is more likely but I would have to say its more likely to be faulty or a loose connection than for it to have been activated.

I have sourced a used but working relay for £30 delivered so I have it on order. This is due this wednesday thursday.

I will get the car up the first dry day I can to have a look for the inertia switch which may or mat not be fitted


Mon Feb 27, 2012 6:54 pm
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Post Re: No volts at coil?
Had today off so had a good go. Went through from scratch. Fuses first all ok. Unplugged the master relay and checked for voltage where it was to be expected ok

Checked both the new master relay and the old relay checking for circuit on the individuals coils (4 in each all good). Then started checking the condition of connectors associated with the fuel pump circuit found one core badly affected by water, reconnected this and voltage found on the core going towards pump.

Still no fuel in the fuel line to engine. I then chased the core through a number of connections confirming voltage and eventually stripped a piece of insulation of the final core that exited towards fuel tank area behind the engine. Voltage found so I now need to get the car up and drop the tank as the cable loom disappears over the top of the tank and out of view.

Progress all the same. Still never found the inertia switch or in-line fuse as shown on circuit schematics found on metro/rover sites. However they are shown after the core with the 12v identified!!


Fri Mar 02, 2012 5:51 pm
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Post Re: No volts at coil?
Just an update for info. The problem was a combination of a loose connection and the alternator looked like frost had got to it as the casing was swollen and cracked although still producing voltage. The alternator has been replaced and the connector made secure.


Sat Apr 07, 2012 4:35 am
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