Fuel pump circuit on s1

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les
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Fuel pump circuit on s1

Post by les » Mon May 21, 2018 12:42 pm

Does anyone have details on the fuel pump pin outs from the MFRU to the pump itself? To cut a long story short, I was out driving a few weeks ago and the car cut out (mid EK whirlies roundabout). Fuel pump didn't prime and then realised that I had a blown fuel pump fuse. Replaced the fuse but on crank, fuse blows again. MRFU does appear to still trigger. As the car was driving my thoughts are that its the pump itself thats gone but I would like to check wiring etc before spending £300 on a new pump and removal of fuel tank etc.

Robin had previously written this:

http://www.scottishelises.com/phpbb/vie ... 15#p236482

but car wiring isn't my strongest point. I have no immobliser (5as or cobra) in the S1 and ECU currently is an Emerald K3.

Thoughts/advice/help greatly appreciated

Cheers

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campbell
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Re: Fuel pump circuit on s1

Post by campbell » Thu May 24, 2018 12:52 am

I have an S1 workshop manual. Maybe they're in there?

I should check!!
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Mikie711
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Re: Fuel pump circuit on s1

Post by Mikie711 » Thu May 24, 2018 9:32 pm

I would pull the inspection cover behind the passenger seat and disconnect the plug for the fuel pump. Re-istall an new fuse and switch the car on. If the fuse goes again then the fault is in the wiring or the MRFU, if it doesn't then the fault is most likely with the pump.
The fuel pump relay in the MRFU has pins 1-1,1-2,2-1 & 2-4. The wire to the fuel pump is colour code NS from memory it is brown/slate (grey)
Do a google search and you will find loads of S1 wiring diagrams and full service manuals.
I found a copy here
Don't buy a new pump, I have a couple of them lying around in the garage that I am sure I can get the misses to dig out and send you if your stuck.
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les
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Re: Fuel pump circuit on s1

Post by les » Fri May 25, 2018 8:21 am

Thanks guys

>>I would pull the inspection cover behind the passenger seat and disconnect the plug for the fuel pump. Re-install an new fuse and switch the car on. If the fuse goes again then the fault is in the wiring or the MRFU

Did this on Tuesday night, and thought the MFRU migh have been playing up so ordered s 2nd hard one off fleabay for the huge total of £16 from a 1999 elise apparently :) Pulled the pump plug and the fuse survives, but more confused at the moment as I foolishly decided to check the continuity of the wiring, although nothing appears to be shorting, I don't get a complete circuit but perhaps I'm looking at the wrong wires. Away this weekend with the kids but will check on Monday when I'm back in the house.

Mike, can I take you up on the fuel pump offer please?

Cheers

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Mikie711
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Re: Fuel pump circuit on s1

Post by Mikie711 » Fri May 25, 2018 8:31 pm

no worries, drop me your address and I'll see what I can do.
Golf R (daily spec)
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Mk1 Escort (Still a bare shell spec)
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les
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Re: Fuel pump circuit on s1

Post by les » Sun Jun 10, 2018 12:28 pm

Quick update: With Mike's help and a new(er) fuel pump, it looks like not only has my the pump failed I have burnt out wiring at or near the ECU plug itself :( . Currently at work but will check on the car what else (if anything) doesn't appear to be working and then compare with the emerald pin outs to see what circuits in the loom are effected. Hopeless with a soldering iron but repair where appropriate although looking some threads from seloc, the MG-F engine loom (pre-2000) is a direct swap for a S1 which I guess might be an option even as a template to see what wires go where

Spitfire
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Re: Fuel pump circuit on s1

Post by Spitfire » Thu Jul 26, 2018 9:06 pm

It's pretty standard for a failing pump to draw more power and burn out the fuse so it should be a warning sign.

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