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Throttle Jack, EGBP and Charcoal Canister - Engine/Ancilliaries - The Lotus Forums Jump to content
Chillidoggy

Throttle Jack, EGBP and Charcoal Canister

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Whilst doing the engine/gearbox job, I'm keen to tidy up redundant pipework. It looked like a snake's wedding in the engine bay when I took the covers off, and I detest seeing loose pipework hanging around. The solenoids in question, along with the boost solenoid, were waving around in the breeze, supported only by their vacuum pipes.

 

I have a question: Can I simply omit the throttle-jack and EGBP valve solenoids, bag-up the electrical plugs, and tie them up out of the way? Will it result in an ECU warning? If not I can ditch all the associated vacuum lines and plug them where necessary.

 

As for the evaporative charcoal canister, I've read the posts from various members on the subject (my thanks to all those who posted them). I'm unconvinced that it's deletion is likely to end in tears. I am therefore minded to pipe up the tank breathers and vent them to atmosphere somewhere, probably down low in the engine bay. If I later find that this was the wrong decision to take, then I can at least revert back to the original set-up. The next question is the same as before: can I remove the plug, bag it, and secure it without affecting the ECU?

 

Obviously I won't know if it works for some time, so bear with me on this last one!

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You must leave the relays in place for throttle jack and ebpv - or it flags up on cel - at least on mine!!!! Everything else can be disconnected can block up that vacuum pipe - or remove the tee and add in a joiner - one less future leak!!'

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The relay has to be there, but the connections into the solenoid can be unplugged our used to power a chargecooler pump for instance. The EBPV connector works for that purpose.

I would not remove the charcoal canister and vent the tanks to air, unless you really like the smell of fuel and a possibly lean engine. The pressurized tanks help the fuel pump provide enough pressure, and also help the engine start faster. Restarting the engine after system is de-pressurized takes longer. If you have a garage, it'll really smell of fuel with the tanks vented. Gas mileage suffers as well, fuel has a low vapor pressure and will constantly boil off while sitting...

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So by inference, you're saying that the stock Lotus fuel pump is not man enough for the job, and thus the evaporative system was put in to compensate? Or was it to meet emissions regulations? Or was it for both, effectively killing two birds with one stone? I'm struggling to understand why Lotus would fit a sub-standard pump, even if I've been disappointed by some of the things I've uncovered from the factory build!

I've had quite a few cars with open breathers, and never noticed any problems with fuel smells in the garage, so I'm curious to learn how the Esprit system differs from any other. I know the fuel will expand and contract with temperature, but one thing I don't know is whether the removable filler caps themselves have a breather hole in them, I will have to look at them tonight to see if they do. If so, I would certainly expect to smell fuel from that area, and there must surely be some vent in the system. What happens when temperature rises significantly if the system is sealed?

I do have the electic chargecooler pump, but I don't know where it gets its power from yet, I will have to check that too. It is ignition fed, because I can hear it start to run once the key is turned to the on position.

I'm at the stage of finally getting the new fuel tanks in, and will soon look to piping up the fillers and breather system.

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no, you're putting words in my mouth.

 

I said the vapor pressure in the tanks helps develop fuel pressure.  I also did not say that Lotus tacked on a vapor recovery system to enable the pump to do it's job. In fact Lotus designed specified the fuel system together in it's entirety, as it is designed as a system by GM (including vapor recovery)...  Take away part of the system and you may not get the expected results.

 

I do know, from experience, that any slight reduction in fuel pressure (in the system) can easily result in a loss of proper fueling with boost, resulting in a LEAN condition.  The ECU will not necessarily throw a check engine light, and you may not necessarily know that damage is being done!  I had a slight pressure loss above the pump from a very slightly loose rubber seal in the pulsation damper, this was enough to cause a lean condition and engine damage (eroded head gasket).

 

The fuel system is similar to one used in the Corvette, Camaro, Quad 4 cars, and other GM cars.  However the Corvette, for instance, does not use a rising rate fuel pressure regulator that increases fuel pressure with boost, as the Esprit does.  The Esprit actually runs much higher fuel pressure above idle than the GM cars! 

 

If you remove the charcoal canister, then you will have a permanent check engine light.

 

If you vent fuel vapor (and sometimes liquid fuel, depending on circumstances), down low, then you risk spraying the exhaust with fuel...  And a fire.

 

Do this experiment, take a jar 1/2 full of fuel and place it on your porch with the lid off on a warm day.  See how long it takes for the fuel to evaporate due to it's low vapor pressure.  No do it again with the lid on.  The pressure helps keep most of the fuel in a liquid form...

 

 

BTW, I have my tanks vented in my garage right now, if I open the inner door to the house for even a minute, then the lower level of my house reeks of gasoline for the rest of the day!!

 

BTW, by law fuel filler caps on modern cars, including the Lotus, have a pressure valve.  Designed to hold fumes in the tank unless the pressure goes above some fairly high limit.

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Much obliged for that comprehensive reply, Travis. Your use of the word "system" makes sense. It's unfortunate that the charcoal canister is no longer available, and I had a price quoted on an import from the U.S. of $327. I therefore intend to pick one up when I'm in Florida later this year instead.

I won't be trying the fuel in a jar experiment, not where I live. Someone will either steal it, or just set fire to it.

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Margate ??? - Ian I reckon it would get drunk......

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