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Fuel leak. Please help.


kwandokun
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Hi guys,

Tried starting the car today after a long while sitting. 

The car cranked fine, but it wouldn't start. I then started to smell fuel, which I then saw leaking out of the bottom of the car from under the RH fuel tank. 

I think I found the culprit - the line from this (I think secondary fuel pump) was disconnected and fuel was linking onto the tank and then underneath. 

Can someone please confirm what this is and where it should connect? I can't find where it connects anywhere. 

TIA!

20221008_161923.jpg

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1 hour ago, kwandokun said:

the line from this (I think secondary fuel pump)

The parts manual shows only one fuel pump, that looks more like a filter :thumbup:

Cheers,

John W

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Yeah I'm a bit confused about it myself. 

It looks like it's powered though, which is why I thought it was a pump of some kind?

Could it be a fuel accumulator?

The thick fuel line goes into the engine. 

Trying to figure out where the nipple is meant to connect with.

 

Edited by kwandokun
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7 minutes ago, EXCEL V8 said:

It looks similar to the vacuum pump (purge pump) that connects to the air box on the Excel to aid hot starting.

Pete

Pete! Yes, you're right, it's a purge pump.

Is the nipple meant to connect to the airbox? It's meant to send fuel to the airbox?

It leaked a bunch of fuel out when the hose broke off.

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6 minutes ago, EXCEL V8 said:

If it is a purge pump there should be no fuel!  The idea is that it pulls hot air from the airbox to aid hot starting.  

Pete

I've done some more reading and picture matching and its definitely the purge pump. Excels had them and late model carb Esprit's.

Weird thing is that it was definitely leaking fuel....

Any ideas why/how that would happen?

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Presumably the carbs flooded for some reason and the overflow fuel found it way there.  Does the pump still pump?  They are notoriously poor on the Excel - there are threads (on The Lotus Grand Tourers forum) about it and how to refurbish/replace them.

Pete

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7 minutes ago, EXCEL V8 said:

Presumably the carbs flooded for some reason and the overflow fuel found it way there.  Does the pump still pump?  They are notoriously poor on the Excel - there are threads (on The Lotus Grand Tourers forum) about it and how to refurbish/replace them.

Pete

I think you're right again Pete.

I tried starting the engine a few times and may have flooded the carbs...

I'm actually not sure if the pump still works for not. 

Should I just block it off? 

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1 hour ago, kwandokun said:

Any ideas why/how that would happen?

After many years of sucking from the air box full of fuel laden air the fuel has condensed in it, nothing to worry about. It's there to aid starting the engine which can be difficult when hot. 😃

The original Elans had vacuum operated pop up lights with a reservoir built into the chassis  which could rust through & people would then try & repair by welding. Result, one less Lotus on the road. :thumbdown:

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Cheers,

John W

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1 minute ago, jonwat said:

After many years of sucking from the air box full of fuel laden air the fuel has condensed in it, nothing to worry about. It's there to aid starting the engine which can be difficult when hot. 😃

The original Elans had vacuum operated pop up lights with a reservoir built into the chassis  which could rust through & people would then try & repair by welding. Result, one less Lotus on the road. :thumbdown:

That's good to know.

Now I just need to figure out how I flooded the engine and to get it started properly.

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11 minutes ago, kwandokun said:

Now I just need to figure out how I flooded the engine and to get it started properly.

Take out the spark plugs, clean, dry them of any oil/fuel & check the gaps while they're out then put them back in & spin her over with half open throttle & no pumping :thumbup:

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Cheers,

John W

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10 minutes ago, jonwat said:

Take out the spark plugs, clean, dry them of any oil/fuel & check the gaps while they're out then put them back in & spin her over with half open throttle & no pumping :thumbup:

Yes haha that was my problem I think - too much pumping.

Another issue I had was that as soon as I turn the key to ignition, the battery cuts off. Power comes back with strong voltage as soon as key goes back to position 2. 

 

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  • Solution

If the float valves in the carbs don't seal, the electrical fuel pump will overfill the bowls and fuel can make it's way to the plenum. The purge pump in turn will draw in the fuel. Not sure your '89 Turbo Esprit but on the Excel you hear the fuel pump tick ever slower until it stops when the float valves seal. My guess is your pump keeps ticking/pumping and is flooding everything. It's easy enough to take off the fuel lines and carb covers, to clean and check the valves. 

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I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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  • Gold FFM

Twice now, I have seen pressure regulators fail dangerously.  When this happens, way too much pressure is pumped into the system and the plenum will end up filling with fuel which then drips toward the distributor.  On each occasion I've even heard the tanks flex.  FPR is well worth checking.

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3 hours ago, Escape said:

the Excel you hear the fuel pump tick ever slower until it stops when the float valves seal.

The Turbo doesn't have a SU pump so there's no ticking, just a whirring 😀

Cheers,

John W

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11 minutes ago, jonwat said:

The Turbo doesn't have a SU pump so there's no ticking, just a whirring 😀

Thanks for educating me. 😉

I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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21 hours ago, Escape said:

If the float valves in the carbs don't seal, the electrical fuel pump will overfill the bowls and fuel can make it's way to the plenum. The purge pump in turn will draw in the fuel. Not sure your '89 Turbo Esprit but on the Excel you hear the fuel pump tick ever slower until it stops when the float valves seal. My guess is your pump keeps ticking/pumping and is flooding everything. It's easy enough to take off the fuel lines and carb covers, to clean and check the valves. 

Cheers Filip. This is very handy to know.

I definitely hear the fuel pump and it keeps going until fuel starts coming out of the plenum.

Guess I'll be checking the float valves. 

Any issues with me plugging the line from the plenum to the purge pump at least to stop the leak? I've heard many remove the purge pump altogether.

 

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The issue with plugging the line to the purge pump is the fuel will go elsewhere (if the problem is indeed the float valves not closing), like the cylinders which will lead to flooding for sure and possibly even bore wash if left too long. You want to make sure the fuel supply stops and if not, that it at least has somewhere to go instead of flooding the engine. I would disconnect the pump, but keep the line open, maybe with an empty bottle or such under it to catch any spilled fuel.

Just to get the bigger picture, the fuel leak is on the same car as the starting problems in the other thread? So first it turned over but wouldn't fire, you've noticed the fuel spill, and afterwards just a click from the starter? If so, I don't think the leak could have caused the starting problems, but prolonged turning over could affect the battery. At least you can rule out a seized engine, but I would take out the plugs to make sure there is no fuel left in the cylinders. The plugs probably need cleaning anyway.

As an aside, a few weeks ago I had a similar flooding problem with an old military Land Rover on an off road site. On a severe side slope the engine cut out and wouldn't restart. After doing some checks we noticed the carb was flooding. A mate gave us a pull backwards to more level ground, we took out the plugs to clean, turned over the engine without plugs to clear the fuel in the cylinders, refit and he started no problem.

wrenching.thumb.jpg.d23c83fcf247d10ca3ab98e4a786f40c.jpg

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I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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1 hour ago, Escape said:

The issue with plugging the line to the purge pump is the fuel will go elsewhere (if the problem is indeed the float valves not closing), like the cylinders which will lead to flooding for sure and possibly even bore wash if left too long. You want to make sure the fuel supply stops and if not, that it at least has somewhere to go instead of flooding the engine. I would disconnect the pump, but keep the line open, maybe with an empty bottle or such under it to catch any spilled fuel.

Just to get the bigger picture, the fuel leak is on the same car as the starting problems in the other thread? So first it turned over but wouldn't fire, you've noticed the fuel spill, and afterwards just a click from the starter? If so, I don't think the leak could have caused the starting problems, but prolonged turning over could affect the battery. At least you can rule out a seized engine, but I would take out the plugs to make sure there is no fuel left in the cylinders. The plugs probably need cleaning anyway.

As an aside, a few weeks ago I had a similar flooding problem with an old military Land Rover on an off road site. On a severe side slope the engine cut out and wouldn't restart. After doing some checks we noticed the carb was flooding. A mate gave us a pull backwards to more level ground, we took out the plugs to clean, turned over the engine without plugs to clear the fuel in the cylinders, refit and he started no problem.

wrenching.thumb.jpg.d23c83fcf247d10ca3ab98e4a786f40c.jpg

Filip you're a deadset legend. Thanks so much for your responses.

And yes - same car. What you described is spot on.

I must have flooded the engine trying to get it started, drained the battery in the process.

Currently researching how to check/service the carbs and the floats in particular. If you have any good references would appreciate a pointer in the right direction.

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I do not have direct experience with the carb turbo (as pointed out above), but have done similar on a Twin Cam so here goes.  The tops of the carbs come off easily with just 4 screws (after removing the fuel lines and choke linkage), that reveals the twin floats operating the valve. First check for obvious dirt or such. If you blow through the fuel lines, you can check if the valves open and clear correctly. Often they don't open because of dirt from sitting for a long time (like on that Twin Cam). But it is also possible they're not closing properly so the fuel pump keeps delivering fuel and the bowls overflow.
I've even heard of a leaking float, that obviously didn't really float anymore so would never close the valve.

I've not had to reset float heights, so let someone else explain about that (eager to pick up a few pointers myself!).

Filip

PS: I assume you've hooked up the Ctek again to charge the battery for future tests.

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I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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6 minutes ago, Escape said:

I do not have direct experience with the carb turbo (as pointed out above), but have done similar on a Twin Cam so here goes.  The tops of the carbs come off easily with just 4 screws (after removing the fuel lines and choke linkage), that reveals the twin floats operating the valve. First check for obvious dirt or such. If you blow through the fuel lines, you can check if the valves open and clear correctly. Often they don't open because of dirt from sitting for a long time (like on that Twin Cam). But it is also possible they're not closing properly so the fuel pump keeps delivering fuel and the bowls overflow.
I've even heard of a leaking float, that obviously didn't really float anymore so would never close the valve.

I've not had to reset float heights, so let someone else explain about that (eager to pick up a few pointers myself!).

Filip

PS: I assume you've hooked up the Ctek again to charge the battery for future tests.

Thanks mate. Very helpful. 

I do have the CTEK back on, but I think the battery is on the way out. Although it gets up to voltage, the CCA is probably much lower than rated. I don't have a battery monitor tool to check.

 

 

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