Engine management relay module

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Reckless Rat
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Engine management relay module

Postby Reckless Rat » Tue Aug 08, 2017 9:58 am

I believe the EM relay module (YWB 100970) has failed on my Mk1 Mems 1.9 MGF - The car will start and then after it has run for a short while it just conks out. I presume it's the fuel pump relay part of it that's duff.

This is quite an expensive part to replace new according to the Rimmer Bros website so before going down the road of spending lots of my precious beer tokens is there any way of testing the said item to determine whether it's actually faulty?

Electronictrickery isn't my strong point. I'm better with a big hammer.

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Tipper
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Re: Engine management relay module

Postby Tipper » Tue Aug 08, 2017 3:44 pm

How long does it run for?

If only a few seconds then it could be the immobiliser playing games.

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Re: Engine management relay module

Postby Geoff.F » Tue Aug 08, 2017 4:05 pm

Amazingly -Snap.
After a Heavy Maintenance programme, I was taking the car for the MOT this morning and soon the engine slowly cut out. It would start but only run at idle for a short time. The giveaway was there was no pump sound when the ignition was turned on.
I have the wiring diagram to check the relay however at £10 on the Bay of Evil, I will try a replacement first. We have AC so it has a YWB100800 which is No Stock with Rimmers at £113.
Both Part Numbers are common on Rover Models. Your number is also available on B of E
Geoff F.

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Wed Aug 09, 2017 1:15 pm

I've ordered a second hand one from MGFnTFbitz in Glossop. £20 including postage. Turns out its a YWB 100710 which is a Mk1 doofer.

To Tipper, it doesn't run at all now, although the breakdown chappie who brought it back home did say it started but conked out before he could get it onto the wrecker. I don't think it's the immobiliser. It was running fine up and until it died. I'm more or less sure it's the EM control module that controls the fuel pump. No pump. No fuel. No go.

We shall see. I'll update when the part arrives.
The inertia switch has been replaced so it's not that.

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Re: Engine management relay module

Postby Geoff.F » Wed Aug 09, 2017 3:53 pm

My replacement is on the way. I am hopeful that it works OK.
I have looked at the Wiring diagrams and connector Pin Idents to fault find if not. Hopefully neither of us will need them.
Geoff.F

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Roverlike
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Re: Engine management relay module

Postby Roverlike » Wed Aug 09, 2017 6:11 pm

YWB100970 main relay module consist of four relays: main relay, fuel pump relay, starter relay and oxygen sensor relay. So if you suspect to fuel pump relay, it is inside of main relay module.
You said that you are not into electrical things. However, if you want to inspect relay module it can be done but you would need 12V power source (like car battery) and multimeter. If you want I can provide you pinout you need to test. On the other hand you said that you have wiring diagram, so maybe you have all you need.

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Thu Aug 10, 2017 8:13 pm

Part number is actually YWB 100710 which I believe is an earlier version. I have got 12v source and a multimeter so if you can tell me what to check at least I'll be able to verify that the part I've taken off is faulty. You can e-mail me details if you like. bjl2634@orange.fr By the way it was Geoff not me that mentioned wiring diagrams. :) Is there any point in trying to open the box?

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Re: Engine management relay module

Postby Geoff.F » Thu Aug 10, 2017 8:45 pm

The Relay Module is the most likely cause. If this does not fix either yours or mine then I will prepare a diagnostic check. To get to the pump, I have to remove the HardTop and engine cover to run a direct wire to check that it functions.
Spending £10 is preferable to this effort.
Geoff.F

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Sat Aug 12, 2017 2:25 pm

Postie arrived this morning with the replacement module. Fitted in seconds. Tried starting - engine spluttered a few times and died. Bugger. Back to the drawing board. Off with the soft top and engine access panel. Pulled off the centre lead from the dizzy cap & spun the motor - loads of spark. So it's not the coil (Car is a Mk1 1.8 non VVC). Took out one of the plugs and spun the engine over - no spark at the plug. So, unless I'm missing something glaringly obvious it's either the rotor arm or the dizzy cap, both of which are originals (and the car has done 110,000 miles). I've ordered replacements...

The saga continues.

Evening Update

Had another head scratching moment because this is really frustrating. I have a feeling the dizzy cap & rotor thing is a distraction but new ones won't go amiss anyway. I disconnected the delivery fuel pipe between the fuel filter and the fuel rail to see if there was any fuel delivery with ignition on. Nothing. Now am I looking at a failed fuel pump? I can't even here it priming when I switch on. I'm assuming the likelyhood of TWO failed relay units being pretty remote.

Is there any way of testing the fuel pump without removing it from the car?

Tomorrow I'm going to go back into the garage and start again from the word GO, armed with the circuit diagram and check everything from the ground up. It'll be just my luck for it to be a loose fuse or something.

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Sun Aug 13, 2017 9:44 am

There are two fuses which control fuel pump operation on my MEMS 1.9 car. One underbonnet (fuse 2) rated at 30amp, plus two fusible links n°4 (40amp) and n°6 (60amp). They are OK.

Next, there is a 15amp fuse under the dashboard, n°14. That was OK too.

Then I removed the cover to the fuel tank to check the fuel pump.The 12v supply comes in from the relay unit via a white/pink wire. There is a separate wire green/black for the fuel gauge sender, and two black earth wires. Apparently the ECU energises the fuel pump relay momentarily when switching on the ignition, then during cranking and once the engine has started it supplies power continuously (if I've read the manual correctly). The problem is that it's a two person job to see if the "momentary" squirt of electricity to the pump can be monitored when turning on the ignition (I can't be in two places at once!) But to get around that I need to see if I can jury rig a direct 12v supply to the pump to see if it runs independant of the ECU.I will disconnect the fuel line at the fuel filter outlet and run the fuel into a catch tank. If the fuel pump turns out to be OK we have two possibilities that remain:

1. the replacement second hand relay unit is also faulty - possible but statstically unlikely.
2. the problem lies in the ECU failing to talk to the relay unit. More expense.

Watch this space.

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Sun Aug 13, 2017 6:48 pm

EUREKA!

Jury rigged a direct 12 supply to the fuel pump direct from the battery - zilch. As they say round here " La pompe est morte" (ze pump zing eez ded)

Now on the search for a replacement...
Last edited by Reckless Rat on Mon Aug 14, 2017 11:32 am, edited 1 time in total.

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Roverlike
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Re: Engine management relay module

Postby Roverlike » Sun Aug 13, 2017 7:33 pm

Reckless Rat wrote:Part number is actually YWB 100710 which I believe is an earlier version. I have got 12v source and a multimeter so if you can tell me what to check at least I'll be able to verify that the part I've taken off is faulty. You can e-mail me details if you like. bjl2634@orange.fr By the way it was Geoff not me that mentioned wiring diagrams. :) Is there any point in trying to open the box?


I am very sorry that I did not reply earlier, but I had guests last few days which I did not see for a long time and I paid all my attention to them.

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Reckless Rat
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Model of Car: 97 1.8mpi in BRG
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Re: Engine management relay module

Postby Reckless Rat » Mon Aug 14, 2017 11:34 am

After all that I've FINALLY solved the enigma. It's appears to be a faulty earth at the pump/connection interface. I've spliced in a new earth cable using a scotchlok and routed it to one of the bolts holding the pump access cover. Started first time.

This earth failure is probably linked to the boot loom fretting problem I have experienced. Anyway been out for a test drive roof down in 30°C heat and brilliant. Runs just as it should.

This has cost me a rotor arm, a dizzy cap and an ECU relay module which I didn't really need to buy but at least they can sit on the shelf for another day.

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RobboMC
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Re: Engine management relay module

Postby RobboMC » Tue Aug 15, 2017 3:32 am

At 110,000 miles the rotor arm and dissie must have been pretty sorry looking.

Mine had only done 80,000 kilometres and when I looked at them I thought, " No I'm not fitting that back onto a new engine."
The ECU module was 20 pounds worth of fault finding.

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Reckless Rat
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Re: Engine management relay module

Postby Reckless Rat » Tue Aug 15, 2017 5:48 pm

The new Dizzy cap and rotor will sit on the shelf with the spare EM unit - I'm more or less sure I replaced them both a few years ago, because they were both fine. I'm hoping now that I can look forward to several years of trouble free motoring! Although the old girl is 20 years old she's spent most of that in the sunshine and is probably a lot cleaner all round than many UK examples with a lot less mileage. With the re-gassed spheres and everything else I've done she should last a bit longer. Hope so anyway.


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