Fuel Pump not working (I think) - help!

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rogbmw
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Fuel Pump not working (I think) - help!

Post by rogbmw »

I went out to start the Excel last weekend and I could not get it to start. The last time I started it I had to tap on the fuel pump. Now, I do not hear anything from the pump - no ticking or anything. Sounds to me like the fuel pump may be gone. Does that sound correct? If it is gone, what is the general feeling on a rebuild vs a new pump? All help from the west side of the pond is much appreciated.

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rbgosling
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Re: Fuel Pump not working (I think) - help!

Post by rbgosling »

Well, first job is to confirm diagnosis. Unscrew the fuel pipe at the carbs and aim it into a jar, and try the ignition - do you get fuel coming through enthusiastically? If not, try disconnecting just before the fuel filter in the boot - if you get flow there, most likely the filter is blocked, or there's a problem in the pipework between the boot and the carbs.

If there's still no flow, then it's worth checking out the pump. It may well just respond to a strip down and clean up. If more is required, I'd say the "best" option is the points-less solid-state upgrade to the electrical bits on the top of the pump. Seach out "Burlen Fuel Systems", they are the holders of the torch for all things SU these days, but their kit is no doubt stocked by dealers on both sides of the ponds, since their equipment is so ubiquitous in British cars for several decades. I went with a much cheaper option - an imitation Facet-style fuel pump off eBay. A minor faff, as I had to track down some adaptors to connect the hoses as the pump didn't have the same threads, and I also needed an AV mount so the ticking didn't reverberate around the entire car. But it's been reliable and leak-free for 6 years so far.
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

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rbgosling
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Re: Fuel Pump not working (I think) - help!

Post by rbgosling »

Here is the SU electronic points conversion kit.
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

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rbgosling
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Re: Fuel Pump not working (I think) - help!

Post by rbgosling »

This is similar to the pump I got, and at about the same price.
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

rogbmw
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Re: Fuel Pump not working (I think) - help!

Post by rogbmw »

Thanks Richard. I will be replacing the fuel hose from the pump to the carbs anyway, and will check everything out. I have also found those replacement pumps over here on ebaymotors, so it may be good insurance just to purchase one as well. When I check the filters, is it a mesh where I can clean it, or do I have to replace the filters?

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rbgosling
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Re: Fuel Pump not working (I think) - help!

Post by rbgosling »

The main filter is in the boot (trunk) just after the pump, it uses a paper filter element so needs to be replaced (at regular service intervals). There should also be a mesh filter where the fuel goes in to each carburettor, but these are less likely to be blocked since nothing should get past the paper filter in the boot.

Image
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

rogbmw
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Re: Fuel Pump not working (I think) - help!

Post by rogbmw »

Thanks Richard. I noted the filter, to the right of the tank, which I believe is a prefilter. Then there is the fuel pump, then what looks to be an electric cut off switch to the left of the fuel pump. Is this correct? Sorry for what may seem to be dumb questions. I know BMW's like the back of my hand - especially E30 3 series, and E31 8 Series, but the Lotus is new to me, even though I had one in the late 80's when I was on exchange with the Royal Navy on the exchange program with the US Navy. I knew several of the Lotus higher ups then, and purchased a factory EXCEL demo at that time. I believe it was the actual car Lotus sent to the US for evaluation as to the possibility of importing them to the US. It was white/Blue half leather. Hence, the purchase of my current car. It has a lot of little things to bring it back up to my standard. Thanks again for all your help.

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Hawaiis0
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Re: Fuel Pump not working (I think) - help!

Post by Hawaiis0 »

Yes there is a flow lock as you mentioned
Nothing is fool proof. Fools are clever!

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rbgosling
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Re: Fuel Pump not working (I think) - help!

Post by rbgosling »

The filter in the boot is the main fuel filter, the only other filter is the gauze where the fuel enters each carb. Fuel should go from the tank, to the pump, then to the filter, then to the flowlock valve - all in the boot - then forward to the engine bay.

Picture below from the SJ Sports Cars site, copied from Lotus' original parts manual:

Image
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

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Excel SA
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Re: Fuel Pump not working (I think) - help!

Post by Excel SA »

Item 3 in the drawing above is also a gauze filter which is in the tank, on the output line banjo fitting.

Neil.

rogbmw
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Re: Fuel Pump not working (I think) - help!

Post by rogbmw »

I have replaced the fuel pump, filter, and hoses in the trunk. I have also added a manual shut-off valve. I have posted pictures in this thread: https://forums.thelotusforums.com/topic ... nt-1055513

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