Still got really annoying fuel problems, seriously need help!!! :(
Turbo Mini Forums

First things first: now that you don?t have a gauze in the outlet you will need a filter between then tank and the pump. Roller vane pumps do not like grit and dirt. Get a big efi filter with 10 mm inlet/outlet.

Next, now that you have the tank sorted check the fuel pressure. Switch the ignition on so that the pump runs (don?t start the engine) and check the pressure. Set it to 3 psi.

That sorted, try start the engine. If it does not start and overfuels, you most likely have a stuck needle valve in the carb. In most cases you?ll see it when you remove the dashpot/piston and look at the jet. With stuck needle valve you will see fuel coming out of the jet. My mate had fuel spraying at the windshield... Remove the carb and clean the needle valve.

I don?t run any filter between the carb and regulator. The big one prior to the pump is all that?s needed.

One thing though, when the fuel pressure dropped, did the pump sound different ? There may sometimes be problem with pump starving and you will hear this with abnormally running pump. Don?t know how to describe the sound, gurgle perhaps ?

another to watch out for when overfuelling is the choke catching on the heatsheild, or hard o-ring seals in the choke mechanism.

carb rebuild is the answer to those.

Hi,

Not overly keen on doing any brazing on my tank so my chemist colleague pointed me towards this super duper epoxy called scotch-weld which I am assured is unbeleivably strong and fuel resistant.
So any way made my new fuel pick up and epoxied it in place fitted the tank back in and now just waiting for it to set fully before adding my fuel. I have fitted a golf GTI mk1 metal fuel filter in between tank and pump. Which I think is probably going to be a good fuel reserve tank lol. I have also made a restrictor as I have equal sized fuel supply and return lines. Once the epoxy has set I will do the tests above again and check the results then will fit the restrictor and try again.
Should be all ok then though!
I will also attempt to get another fuel tank to upgrade the supply by brazing for the sake of it maybe.

I hope I don?t sound too impolite but you gotta be kidding ! I don?t give rat?s a** whether it is strong or fuel resistant. What you are doing is sealing the lowest point of tank with epoxy. Now think about the smooth suspension in Mini and all the non existent vibration. Add the fuel feed pipe and hose and you will get all kind of twisting against that super dooper epoxy. Sooner or later it will leak all what?s in the tank to the boot. Shit, go ahead, it?s only a small boot to worry about and what else is there but a battery. Fumes and arcing create explosion.

Sorry for the opinion but GET IT DONE PROPERLY.

As Jukka says, why are you afraid of brazing a tank?
I Don't have any quarms about welding a tank after flushing it out with water a few times.

I do not have the money at the moment to get kitted out with blow torches and brazing wire after buying new filters and fuel pumps etc ( I have spent over a hundred quid replacing things I am not sure were even broken).

The biggest problem is that I have not brazed in over 10yrs and dont have the facilities to do it.

I have every confidence that my fuel supply line will hold for long enough for me to test the theory of the supply line being the problem. Epoxy creates a chemical bond and I have checked the datasheets that suggests its pretty damn strong even under the infulence of petrol. I have no intentions of driving it for miles or even at all. I just need to do the tests that Turbo dave gave me, otherwise if I wreck the tank ill have to wait until I get enough money to buy another tank before i can even see if this is the problem. If this is the problem then there is nothing stopping me taking out the tank and re-doing the supply with a brazing joint.

Jukka, I am not stupid just an electronic engineer/scientist not a welder so wanted to test the theory before letting myself loose on the tank with a blow torch.
So, no need to be quite so sarcastic. OK.

aaaaah - a temporary job to do some tests...
I see, I see !!!

Jukka wasn't being funny- I believe like me, he didn't twig that this was a temporary 'suck it and see' exercise.

I am honestly sorry if I got you upset. (Well, you got me). Main thing in my way of doing things is safety. Period. Fuel and electrics do not match that well, especially in confined space.

Take the tank to any shop that does plumbing, you should get it brazed for a price of pint or two. No need to buy the equipment.

BTW; where is your pump located ? You may have mentioned it elsewhere but it needs to be at tank bottom lever or lower. These pumps don´t suck well, they need good supply of fuel by gravity.

Making the fuel outlet bigger is wise move, I have std sized outlets but with two tanks feeding the pump it´s not a big deal. Also my return line runs to the inlet of the pump, not to the tank.

I will attempt to get my fuel tank brazed one way or another as soon as possible.

I have the pump laying flat on the floor of the boot the input is just lower than the output of the tank. (found this out the hard way). lol

I have been floundering a lot during the build of my turbo. There is no hard and fast quick start guide to help when making one. I have had my car on and of the road, but what I thought was finished for about 16 months now. However, I am still finding things out, like the restrictor thing only last week.

I was an apprentice where I did sheet metal work and welding courses I am also pretty good with a lathe and mill. Still with little money and no electricity in the garage which is a few hundred metres from my parents house it has been a long haul.
I have had a pretty steep learning curve too, before starting to build my mini I knew nothing about cars really. lol.
Still, now that I know about the restrictor and fuel tank outlets etc should have my car back on the road soon and hopefully will actually be quite fast and reliable and a lot better than it was 16 months ago. lol

I pressure tested the new petrol pump and the psi went of the guage. Decided to refit old/orginal pump and fix flat to the floor. When testing this pump the pressure showed a steady 3 psi. Took it out last night for an impressive 40min drive with no problems.

The only trouble now is the local garage Tesco where I buy my 4* from no longer do it. So I now have to go on a mission to find some where. After talking to the women in Sainsburys said they will no longer be doing it either. Beware!!!

Will try it again tonight to see if problem is finally sorted. Will let you know.

Keep us posted Neil,

Hopefully we'll be seeing something published at some point in the near future re turbocharger conversions.

Edited by turbodave16v on 12th Apr, 2005.

I did my conversion in 1995/96 and had exactly the same learning curve. I got great advice and help from Stuart Gurr by fax. Rest had to be figured out the hard way. No one knew about them locally, sure there were "experienced" people with great advice like: blow thru SU ? Are you serious ? Go get yourself a carb !

Most of the info is here but it takes a lot of time to get everything you need. Maybe Dave will have some spare time to get everthing edited in a good package, keeps him away from burger joints...

One another thing, talked to my mate who also has a turbo Mini. He used to have same fuel pressure problems, especially with fuel level below 1/4 mark. (It was annoying because I had sold him my old fuel pump.) With full tank the car behaved. He had the fuel return to the tank. He copied my setup with the return line feeding the inlet side of the pump via a tee-piece and no problem ever since. If everthing else fails, try that. I believe the pics of my saetup are somewhere in the forums ???

I see everyone has beated me to replys on this one, I had the same problem with my mini a couple of years ago when i first did the conversion - it turned out to be the outlet on the tank - as soon as this was replaced my problems went away.

Obviously set up your fuel pressure again once you have the new pipe etc.

Hi OK I tested the new outlet and fuel filter and I got good steady results on the fuel pressure guage. So I think all is working OKish. So I brazed a permenant steel pickup pipe into the tank.
However, when I added the restrictor I found that I could wind down the pressure to only about 2 psi not as low as 1 psi like you guys had previously suggested. Not sure if this is such a problem or not.
I also had issues with the car idling it was really reluctant to do so. I am unsure if this is to do with the fact that the I may now be over fuelling or the fact that it has been sat off the road for months now and not been started for at least 2/3 weeks.

Any more advice would be great!

Also got a great tip for de-fuming your fuel tank before brazing. Take out the sender unit and stick the filler neck over the exhaust of a running car for a few moments. So then the tank is flushed with carbon monoxide :) Ta da thought this was genious!

Idling will be general carb/ign setup, not the fuel pressure.

2psi as a minimum is a good start. Wind it up to 3.5 or therabouts.

So basically, the pulsing you experienced is no longer there? That is good news!

Incidentally, did the gauze in the old pickup pipe appear to be slightly blocked? I recall mine didn't look to be that bad when I removed it...

So, next step.

Well, you have the fuel lines sorted now by the sound of it, so next thing is to take it for a run?

Check there is oil in the dashpot - if low/empty the idle will suffer.

The gauze looked pretty rubbish actually it had alot of brown stuff on it and I think that and the narrow outlet must have been the main problem.

I took it for a run after I got the tank in and was definately better when revving hard but it needed a bit of effort to keep it going. It is a good sign that even after the short journey that I took it on it the pressure did not die away or pulse like it had done before on the same journey.

By the time I got the tank in last night it was starting to get a bit dark and couldn't really see what was going on in the dash pot. I will hopefully spend Saturday getting it all running smoothly.

This hopefully, is the beginning of a much happier turboing experience.
I have also got an intercooler to chuck in when I am satisfied that it is running correctly.

After I get it set up I'll try and get some photos to post on the forum too!

Thanks all, for your help!

I know how you feel about having no electricity in your garage, everything takes twice as long!

My mate Wes was having loads of problems with his cutting out on boost, we managed to narrow it down to fueling problems.

To find out excactly where the loss in pressure was we ran a clear bit of tubing between different points ie. fuel pump to regulator, regulator to filter, filter to carb etc.

if you poke the clear tubing out of the bonnet (or somewhereyou can see it) you can see air bubbles in the line when you lose pressure.

Not the safest method i know n not exactly the same problem but it worked to find out exactly where the pressure was being lost!!

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1/4mile in 13.2sec @ 111 terminal on 15psi

OK drove the car for about 20 odd miles the other night and all seemed fine. However, plucked up the courage to use it for work this morning and I found on the dual carriage way that my fuel pressure is still pulsing.

It is strange as I feel that it is being much better behaved, pulling nicely and quite a bit faster. When it does start pulsing It doesn't feel like it causes a reduction in power either.

I am unsure what is going on. I think that there may be a small leak in my air system as you can hear it suddenly make a lot of noise late on in the boost. But, I dont think this is the problem.

Is the noise you can hear the poppet valve in the plemun opening and dumping boost as it has climbed above the pressure the valve will blow off at? If so then this could also cause your fuel pressure to pulsate, as the boost pressure will be changing as the poppet valve opens and closes, hence your fuel pressure reg will be matching the boost........

Have you fitted a stronger spring? Or blocked it off altogether?

No I havent, and if i do have a leak it is very likely that I will be causing it to blow off (ooh err!). Any suggestions as how to do that?

One thing I have just noticed is that the turbo boost guage does not wobble like the fuel guage. I dont know if that leads you away from this being the problem!

Mark, have I got a poppet valve in the plenum??

Also, Jukka. When you return the "used" fuel back to the pump, won't the fuel get hot? I always thought that one should pump it back to the tank to cool it so to speak.
Isn't this something to worry about?

After all. (PV)/T= constant, and the fuel is sort of under pressure all the time.

vegard, marks pc has died, but I don't think you have a poppet valve with the boost he was running

Team Racing

What boost pressure are you running? Anything over approx 8psi will cause the "over pressure relief" poppet valve in the plenum to lift off. This is an "intentional" leak, e.g. it happens on purpose to prevent the engine "overboosting". If you are running more than standard maximum Metro boost pressure (7psi) then there is a good chance that the valve will be lifting.

However, as for fuel pressure "pulses" have you got the float level in the carb set correctly? As if it is to low it could be opening and shutting rapidly, causing the fluctations as the pressure backs up in the feed line (where I assume you have your pressure gauge fitted?)

When i did my conversion i used a late injection tank, it has the pump inside and a feed and return already on the top. I used 8mm pipe for the feed and return and have never had any problems.

Hope this helps