Loss of fuel pressure
Turbo Mini Forums

and fill it with fuel.

Exactly what filter do you have pre-pump....and what screaming noises is the pump making ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Morning,
Took the car out last night after checking all the bits again. Runs fine to 40mph, but when floored, and the boost comes in, it sets off like a scalded cat but after 500 yds, the pressure dissappears and cuts the engine. Stop, and restart straight away no probs.
This morning I am gonna fit a pressure gauge to the incomming fuel line just to see if the pump is doing what it`s suposed to. ie, 3 bar. As to noise from the pump, this varies a bit, so last night I ran a new feed to it from the battery, using a relay powered by the original supply feeding the coil. This should then stop any problems with under voltage and give the pump the full monty.
Will let you know how I get on.
Cheers

The pump wont produce 3 bar when the regulator is set for 0.3 bar. It'll only produce 0.3 bar

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Ok, answers
This is a new build. Have had lots of help from Benross over other matters that he has solved. Bought a bit of a dog to be honest.
Took it to Slarks for a rolling road session last month and this problem never came up due to it only having short bursts on the dyno.
The filter is a clear glass type. Not a cheap item, bought a good one from CBS.
The noise from the pump varies (hence the rewire) can range from loud with girgling to a solid high pitch buzzing. Don`t know the reason for the difference.
Seems that you guys are now aiming your attentions towards the pump.
Sprocket, will test the pump before the regulator and see what it is actually kicking out.
Time to get covered in fuel again

Again, exactly what filter are you using and what screaming noises is the pump making.

The only glass filters I see on CBS are cheap, and in no way suitable for a pre-filter for an injection pump.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Stevieturbo,
Ok, ditch the filter, what alternative do you recommed. Surely a filter should be fitted to keep the crap out of the system? Your advise please.
Bit difficult to describe pump noises as I have nothing to compare them to, only facet types that click a lot. Could phone you when it`s running and let you hear it.

Something like this should be fine:

http://www.ebay.co.uk/itm/321027453184

We ran a similar one on the upside down skip with no issues.

Thanks for that,.
Ordered and on it`s way

I would prefer to see larger diameter fittings on the ends, but yes that would be a suitable filter.
They do them with larger fittings too, or threaded fittings.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Hi,
Well I think I have got this sorted now.
I did all the checks as you people sugested. I stripped the whole fuel system down, blew out all the lines and made sure there were no restrictions. The pump was checked by running off the car in and out of a plastic tub and showed good pressure.
My only place left to go was the tank, so drained and removed. Looking into the tank via the float gauge hole I saw that the filter looked a bit discoloured. I cut open the tank to get it all out and found the filter was semi blocked on the inside.
As the tank was out I though I would weld in a new 10mm supply tube at the base of the tank and weld up the large removale hole. A bit of cleaning and jiggling saw the clean filter refitted to the new supply pipe. Clean up and repaint. Taken me all day and I stink of petrol.
Out on the road it will boost and stay there with no loss of pressure. Nearly bought a new tank sometime ago. Wish I had. All set for the Riv-run I hope.
Thank you all for your help. Nice to know you guys are there to help out us less knowledable folks.
Cheers

Hello again,
Well I thought I had this problem sorted, but no way. The problem is this.
Runs fine up to about 45mph, anything above this and the fuel pressure slowly dissappears to almost nothing. Enough to run at about 45mph. Leave it ticking over for 2 mins and you can watch the pressure slowly creep back up
Things I have done.
1 Fitted a new regulaor
2 fitted a new pump, correctly wired.
3 used 8mm piping all the way through, except the new tank outlet which is now 10mm.
4 run the car with no fuel cap just incase
5 done the tee piece trick on the boost pipe
6 always had nearly a full tank
7 fitted a race type breather to the filler neck.
8 cried a lot, and fended off the wife, who`s birthday it is on Friday and we are booked in for the Riv run for her birthday bash.
Come on clever people show me the way.
Please

this now points to the pressure regs as you know this item controlls the fuel pressure and thats its job

you may have 2 fooked pressure regulators alan .......simple as i know you dont have a third but ......... just give the old one a wirl again to see if its exactley the same fault ? if it is .... then i would place a peice of tubing in the return line near the regulator to make the orafice 6mm id and get back to us soon as or ring me ............

it can only be the reg or 2 wank pumps but my monies on the reg

what do you think chaps alan is now sweating as his trip is near, and without that his wife wont speak to him for the next 2 years

Where is the new outlet from the tank located? Back, front, how far up the tank?

Is the pump higher than the tank?

In the 13's at last!.. Just

The new outlet is at the front centre and bottom of the tank. if i take off the feed pipe to the regulator i get the full 3 bar from the pump. the pump is 18 in from tank and about 2 inches higher than the bottom of the tank.

Come to think of it. If the wife wont talk to me for 2years that could be a bonus!!!!

Is the pump on front of the tank or behind it?

If in front, could it be the pump being starved as you accelerate? This would explain why it was fine on the rollers and not on the road.

I think this is what Rod was getting at.

Edited by theoneeyedlizard on 1st May, 2013.

In the 13's at last!.. Just

Right, we are all trying to help here, but you need to help us to help you. And that means getting out there with a digital camera of some description and getting us photos of everything even vaguely related to the fuel system. 8949 sets of eyes are better than one, but there could well be some good clues for us to help you in some pictures.

Edited by Tom Fenton on 1st May, 2013.

What i cannot understand is if you have disconnected the feed to the fuel regulator how the fuel punp can maintain 3 bar fuel pressure!?......

Sorry for late reply
at work
the pump is desined to run at a steady 3 bar and i pump it into a bucket.
will get home at about 6 and will photo everything
.Have booked it into slarks for first thing tomorrow to watch it happen whilst running.( bet it dont do it, sods law)
cheers gents

The pump cannot make any pressure if it is pumping to an open end, what it does do is produce a flow. The fuel pressure regulator then restricts this flow, it is the restriction that generates the pressure in the line.
Think of a garden hose. Turn on the tap and the water flows out of the open end. It has a flow or speed but no pressure really. Then crimp the hose with your fingers, this causes a pressure in the hose between your crimp and the tap, as you are restricting that flow.

leave the fuel regulator in line as it is intended then Remove the fuel feed fron the carb. Place that into a bucket and then measure the fuel flow.

How is the fuel pump wired?

I have a pressure gauge in linr between the reg and carb. With the pump running it shows 4psi.
While running you can blow hard down the tube to the top of the reg and the pressure will increse.
The pump is wired direct from the battery via a relay that is controlled via the fuse block. pos and neg correct. I understand about the flow .will post pics asap