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fuel pump pressure regulator

Posted: 16 Mar 2011, 12:31
by avant-garde
Hello, I have a 2ltr CU 1981 T25 and a couple of weeks ago I had to fit a new electric fuel pump as my old mechanical one died. I took the advice of JK and fitted a fuel pressure regulator - set it at 2.5 on the dial. No idea if that setting is right or not - some say set it to 1 some say set it to 3!!!

When I stop I can smell petrol from the air intake side vents on my bus and everytime I look inside the engine compartment and touch the pressure regulator it is wet with petrol!
I also have a fuel filter fitted just before the the T pipe that goes to the carbs...when I stop and look at the fuel filter there are air bubbles inside the fuel filter. The petrol inside the filter goes down untill the level of petrol is below the outlet of the filter. Where is the air coming from? I realise that there has to be some sort of air vent to allow the pressure/vacume created inside the fuel system to equallize. Just wanted to know where the air vent is? Do you think it may be the fuel pressure regulator?

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 13:06
by kevtherev
I think you need to change your fuel lines before you drive that van anywhere else. Use proper fuel hose clips not jubilee type
there should only be one external fuel filter... next to the tank.. not in the engine bay.

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 13:41
by avant-garde
All fuel lines have been replaced and I havn't used jubilee clips. The pressure regulator states that there has to be a filter next to the fuel pump. I'm still driving it - I have no choice!
I'm waiting for JK to send me the replcement part.

As for the fuel air intake vent - do you know where that is?

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 13:49
by R0B
Never mind what it states.kev is right.The one after the tank is the only one you need.What is one next to the regulator going to do.When the one after the tank has already done it?


The pressure regulator states that there has to be a filter next to the fuel pump

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 14:01
by kevtherev
avant-garde wrote: I realise that there has to be some sort of air vent to allow the pressure/vacume created inside the fuel system to equallize. Just wanted to know where the air vent is? Do you think it may be the fuel pressure regulator?

You have an electric fuel pump to replace the mechanical pump...
OK so it must deliver at least what the mechanical one did... (about 0.2 to 0.3 bar)

isn't a regulator for fuel injected engines that need constant supply, please enlighten me on it's necessity for a carburated engine.

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 14:10
by avant-garde
Hey I'm just going by what is recommended...details from JK below.

Fuel Pressure Regulator Kit (Adjusts Fuel Pressure To Prevent Carb Needle & Seat Damage) Part Number: J13370

It fits the following:

T2 Bay Window
Petrol, 1967 - 1979, 1600 cc, 1700 cc, 1800 cc, 2000 cc
T2 Split Screen
Petrol, 1950 - 1967, 1200 cc, 1500 cc
T25
Petrol, 1979 - 1992, 1600 cc, 2000 cc, 1900 cc
Beetle
Petrol, 1946 - 1998, 1200 cc, 1300 cc, 1500 cc, 1600 cc

Adjust fuel pressure to your carb, to prevent needle and seat damage and over fuelling. We recommend these are fitted while installing the Electric fuel pump.

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 14:12
by avant-garde
Basically the fuel filter in the engine compartment connects 8mm fuel pipe to 6mm fuel pipe due to the fact that the filter has both 6mm & 8mm inlet/outlet.

The garage which fitted the fuel pump had squeezed the ends of the fuel pump which were 8mm o/d into a 6mm fuel pipe and the pipe was splitting. They has done this all over the place. I thought it best to replace all the fuel pipe - some were 8mm and some 6mm. The only way I could connect two ends of pipe toghether that were different sizes was to use the filter. Luckily there was only one join like this that had to be made.

Is having two filters going to do any harm?

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 14:17
by kevtherev
yes it will as it creates drag in the delivery.
I've just searched on here regarding these regulators and of the three posters I found, they all moan about leaking fuel.
One of these regulators is not for road use (empi).

I would turn it down to 1 or less and see what happens

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 14:52
by avant-garde
Yet more confusion - like I said before some (and you) say turn it down to 1 and others like bigherb for example, say set it to 3. There is no indication if the settings are BAR or PSI! JK don't know either.

Postby bigherb ยป 23 Feb 2011, 17:52
The regulator is marked in PSI and should be set to 3 PSI.

So I will indeed turn it down to 1 and see what happens. What is the worst that can happen?

Empi mark these units (and others) with the note saying not suitable for road use, this is for California... more (where Empi are based) and some other states in America where a manufacturer can be held accountable in the event of a vehicle modified with their equipment having an accident, as there is a culture for sueing anyone and everyone, they put this on to cover their backs.

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 15:37
by kevtherev
Big herb is not wrong
If you convert the bar figures for the mechanical pump it turns out to be 2.9 to 4.3 psi

if they leak petrol I think they are not suitable for road use here either

there are no regulators with mechanical pumps are there?

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 16:43
by Mocki
yes, but mechanical pumps only pump when engine running, and taking fuel, electric pumps run upto pressure as soon as power applied to them, so will either show leaks or indeed make them.......

the fact remains they are too powerfull for the use on these engines, and a correct electrical pump needs no toy regulator.......

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 16:45
by kevtherev
Which is why I was questioning the relevance of it Steve.

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 18:30
by avant-garde
correct electrical pump needs no toy regulator

So am I right in saying that the pump that JK sells is not correct. The details for the pump they sell are:

Flow rate for the electric pump is 114 Ltr/Ph, 0.42 Bar (so that would make 6 PSI)

I've done a quick search and I have found this electric fuel pump below with 3 psi

Image

12 volt Negative earth, Pressure 3.0 - 4.0 psi, Flows 1.6 Ltr/Min, Dry prime height 0.3 metres, Thread size 1/8th nptf.

So would this be more suitable as a fuel pump for my T25? If that was mounted in the engine compartment would it be able to draw the petrol from the front of the bus all the way back to the engine? And I wouldn't need a pressure regulator - right?

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 19:51
by Mocki
if the psi info correct....... but it should be near the tank i think, as its better to push than pull with electric pumps, as they cut out when up to pressure, and it may not if its only pushing a few inches???

not sure about the flow rate...... seems high enough.... its almost double the tank capacity per hour

check its ok for petrol though, eh?

have a search for peirburgh, they used to do the correct ones....

Re: fuel pump pressure regulator

Posted: 16 Mar 2011, 20:53
by bigherb
The standard mechanical pump delivers 0.2-0.3 bar (2.9-4.3 psi) ideally the electric pump should deliver the same pressure, hence the use of a regulator if the pump has more pressure to stop the float valves being overcome.
This tread gives some more ideas of fitting.
viewtopic.php?f=37&t=48046&p=7331271&hilit=posiflow#p7331271