Non starter - baffling S1 fuel pump or electrical issue...

[Scottd]

I'm kinda out of ideas on this one so any thoughts would be much appreciated!

So the car turns over fine, but it's not starting and I don't hear the fuel pump. But it was intermittent for a while, sometimes I'd hear the pump and it would start... but then when I was driving, it would cut out. Then either struggle to start or just not start. The battery also seems to drain power (I've tried a new one).


I'm sure it's not getting fuel, so first thought was that the fuel pump's broken, but from what I gather that's rarely what's wrong. Plus I really don’t want it to be that as it's a fuel tank out job. So I want check every other option first

This happened not long after I changed the Head Gasket and did the fuel filter at the same time. So it could be related to that?

I put on a new alternator (which it was needing anyway) but that didn't make a difference.

I've pressed the reset button on the inertia switch.

I can't find the fuel pump fuse, manual shows it near the ECU on older S1's. I've checked the front fuse box and all are good.

I've tried a few other things but am about to start going through everything again methodically, but any suggestions would be great!

Cheers
Scott

[robin]

It will be the fuel pump wiring or the immobiliser relay.

You need to trace the fuel pump wires and look at each connector for corrosion and burning.

If you cannot find any issues then it will be internal to immob relay and bypassing it is best solution.

Post year of build and I can write up the locations of wires and connectors.

Cheers,
Robin

[hiscot]

your fuse is on its own single fuse holder right at the back
you should also look at swopping the mfru to rule that out ?

[tut]

As the fuel pump fuse is the easiest to check try that first as I had exactly the same problem. It can get corroded so be intermittent as opposed to a complete failure.

As Bob says it is located at the left rear near the ECU. I think that it is in a holder and a fairly big fuse, could be 40 amp, so look until you find it. I had to fit a new holder. It actually saved me from being caught in our 15 car convoy that was stopped by the police at Crathes Bridge, as it cut out two miles short.

tut

[les]

I had a similar issue back in 2013 on my '96 vintage elise, which Robin did a fantastic job of identifying the circuits over the phone To cut a long story short, my 5as immobiliser unit had indeed failed. MEMS ecu and the loom itself were all fine. The 5as unit was not switching the on the earth to the fuel pump after sending back the correct code to the ecu. Double Whammy for me

The comms link from the 5as unit (behind the stack) goes on Pin 13 on the loom plug at the MFRU in the engine bay. After a few hours of testing points with a multimeter and reading over the wiring diagrams for the car (the Robin on the phone), it was a case emulating the immobiliser signal and then cutting the black earth wire into the MFRU and the engine roared back into life. I still have details on who to contact for the 5as repeater if you require it

[les]

Or indeed have a MEM's 1.9 and matched bypass that I no longer use if you want to try that out

[Scottd]

Thanks for the replies!
Robin it's January 1999.
Tut / Bob, yea in the manual it pictures the fuse next to the ECU but I can't see it on any of the boxes, mines kinda look different to those illustrated too!? I'll have another look around tonight.

The comms link from the 5as unit (behind the stack) goes on Pin 13 on the loom plug at the MFRU in the engine bay. After a few hours of testing points with a multimeter and reading over the wiring diagrams for the car (the Robin on the phone), it was a case emulating the immobiliser signal and then cutting the black earth wire into the MFRU and the engine roared back into life. I still have details on who to contact for the 5as repeater if you require it

Yea could well be that 5as thing, I'll pick up a MFRU tomorrow from the motor factor, think they're fairly cheap.

Cheers!
Scott

[robin]

It will probably not be the MFRU itself unless it's been smashed about the engine bay ...

The fuel pump fuse is accessible through a circular hole cut in the boot on the passenger side up towards the wheel arch - the fuse itself is in the engine bay, but access is supposed to be from the boot (that's from memory - might be wrong).

I'll take a look at the wiring diagram later and write up the circuit ... could be worth searching on here for fuel pump circuit as I reckon I've done it before!

Cheers,
Robin

[robin]

http://www.scottishelises.com/phpbb/vie ... it#p439950

It's possibly a bit terse - let me know if you need more details ...

[Scottd]

Sweet! Thanks Robin, will let you know how I get on!

[robin]

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

Also possibly helpful thread.

[Scottd]

It looks like it might just be the fuse!
But ffs, it took me over an hour to realise I'd even found it (assuming I have), through what Lotus call an 'access' hole. As the fuse appears to be melted / rusted / dissolved away to almost nothing!
The thing the fuse goes into hasn't faired well either so I need a new one of those. I'm not too sure where to start looking for that but Elise Parts / eBay might do the job.
It would be great if that’s all that needs fixed!

Should I disconnect the battery for doing this kind of thing? The answers going to be yes isn't it lol.

Cheers
Scott

[Scottd]

As the fuel pump fuse is the easiest to check try that first as I had exactly the same problem. It can get corroded so be intermittent as opposed to a complete failure.

As Bob says it is located at the left rear near the ECU. I think that it is in a holder and a fairly big fuse, could be 40 amp, so look until you find it. I had to fit a new holder. It actually saved me from being caught in our 15 car convoy that was stopped by the police at Crathes Bridge, as it cut out two miles short.

tut

Fingers crossed it's same issue you had Tut, any idea what the holder is called or where to find one?

Cheers
Scott

[Dominic]

As the fuel pump fuse is the easiest to check try that first as I had exactly the same problem. It can get corroded so be intermittent as opposed to a complete failure.

As Bob says it is located at the left rear near the ECU. I think that it is in a holder and a fairly big fuse, could be 40 amp, so look until you find it. I had to fit a new holder. It actually saved me from being caught in our 15 car convoy that was stopped by the police at Crathes Bridge, as it cut out two miles short.

tut

Fingers crossed it's same issue you had Tut, any idea what the holder is called or where to find one?

Cheers
Scott

I would call Elise Parts, and failing that, call Craig at Murrays.

[robin]

You can buy in-line fuse holders of this type:

http://www.halfords.com/sat-nav-audio/c ... lder-20amp

Just make sure you get something that will take 20A and do a good job of splicing it in - I suggest you cut the original wiring at least 1 inch back from the fuse holder and then use a butt splice of this type to connect in the new wires:

http://www.halfords.com/motoring/garage ... 111-35-amp

Note these are heat shrink type to use post crimping - the heat shrink keeps moisture out of the joint.

Cheers,
Robin