Fuel lines and fittings

Fuel lines and fittings

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Discussion

Skyedriver

Original Poster:

17,861 posts

282 months

Monday 10th April 2023
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stevieturbo said:
Really wouldn't worry about the length of the trumpets.

I'd rather a neat fit and finish, easy to work on, than a few mm difference in runner length which in reality will make negligible difference.
If it looks right it is right, aesthetics matter. So does access to the plugs and dip stick
The drain plug was leaking, I literally touched it and it fell on the floor followed by the contents of the tank. Tank removed yesterday, cleaned up today, refitted with a loose plug which I'm going to refix with Loctite 243. Hopefully that shall be it but I'm only putting half a gallon in at first....
Oh and it's not the original tank by the looks of it.

Skyedriver

Original Poster:

17,861 posts

282 months

Monday 8th May 2023
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Just to conclude:


Got there in the end, having considered top filter in a custom box, custom box with side entry, pannier filters (K&N SU-1200) I ended up tidying Tony's original set up. Which ever way I went the bulkhead, bonnet clearance, oil filler, alternator, bonnet catch caused a problem. I still have trouble accessing the dip stick, If anyone can suggest a longer, more flexible one for an Essex V6 please shout up.

Thanks again to everyone who offered suggestions along with Demon Tweeks for the fuel fittings and Stoney Racing for the silicone pipe and advice.

Skyedriver

Original Poster:

17,861 posts

282 months

Tuesday 19th March
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Sorry, thread resurrection and update.

Ever since setting the system back up I've had problems with the car seeming to run rich and fouling one or more plugs.
Never quite got to the bottom of it but think I may have finally found something.
The whole installation was installed before I bought the car.

The set up:
Twin fuel tanks, interlinked.

Facet LP pump under one tank (filter between tank & pump) feeds a OBP swirl tank. A HP fuel pump draws from the swirl tank and feeds one side of the three TBs and a return pipe goes back to the swirl tank.

A run out today (to arrange an MoT on another car) . Car started OK, I usually then flick the switch on the dash which until today I thought was the HP pump but today forgot. Six mile up the road, the car went like a dream. Reached over to flick the "fuel pump" switch and immediately there was a difference so flicked it back off. Three mile return the same then it started to shudder. Broke down 3 times in the last three miles. When I got home, plugs out, for the first time they were a nice golden brown colour rather than gooey black.

What I've found out today is the "fuel pump" switch on the dash is for the LP pump, the HP pump is switched on from the ignition key.

The connections to the swirl tank are not totally correct. Should be:- top= overflow back to tank, 2nd= Fuel rail return, 3rd = inlet from tank, bottom = feed to fuel rail. The middle two, fuel return and feed from tank are swopped so that the fuel rail return is below the inlet from the tank.

I have a pressure gauge on order, the regulator hasn't got one, but it would seem that the first 9 miles was run on the contents of the swirl tank which eventually emptied. I can but assume that the LP pump is somehow overloading the system or the swirl tank connections are causing an overload.

The pressure regulator is located after the TBs/injectors.

AS an aside, I had considered going back to a 38DGAS and removing the Jenvey TBs as the TBs exclude the car from the "Classics" class in Hillclimbs but that's all for the future if I don't sell the old girl first.


GreenV8S

30,205 posts

284 months

Tuesday 19th March
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Not convinced that having the middle connections swapped will matter, apart from slightly affecting the amount of recirculation between the swirl tank and fuel rail.

The other symptoms suggest the LP pump may be raising the pressure in the swirl tank, which might point to a restriction in the return to the main tank, and also suggest that the engine runs better when the pressure is reduced.

Checking the actual fuel pressure seems like an essential first step.

Wouldn't it make more sense to have both pumps activated with the ignition?

Skyedriver

Original Poster:

17,861 posts

282 months

Tuesday 19th March
quotequote all
GreenV8S said:
Checking the actual fuel pressure seems like an essential first step.

Wouldn't it make more sense to have both pumps activated with the ignition?
Would seem obvious, no idea why it's been done like this, not an anti theft thing if I can drive for about 9 mile.

stevieturbo

17,267 posts

247 months

Wednesday 20th March
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Skyedriver said:
Would seem obvious, no idea why it's been done like this, not an anti theft thing if I can drive for about 9 mile.
Some people do really really really strange things when working on cars.

Skyedriver

Original Poster:

17,861 posts

282 months

Thursday 21st March
quotequote all
Fuel pressure is 42lb/ft with the engine off, drops a little at start up. No discernible difference switching on the LP pump.
Next up switch over the two connections on the swirl pot.

Edit: OBP say the two connections (feed from tank & return from engine) being incorrect shouldn't be causing a problem.

Edited by Skyedriver on Friday 22 March 07:58