fuel starvation?
Turbo Mini Forums

Hi, last year i was getting a lean spot in 4th when accelerating hard and running through the gears, for example on the ¼ mile.

It was fine on the rollers and on the road.. im guessing that this was fuel starvation due to the increase in demand.

Last year I was using a heavy weight dashpot oil (motor bike gear box oil) – could this be contributing?

Pump not up to the job? (a new Bosch metro turbo item) or do I need a swirl pot??

Any help / ideas appreciated.

Cheers, Mark

doesnt a heavier spring/oil make the car richer, by restricting the air flow?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I can't see the dashpot oil being a problem maybe some 20/50? What sort of condition is the fpr in? I had this problem with mine, fine on the road but the 1/4 was always running lean on a long pull. Maybe check fuel Filters and pressure up the rev range?

sounds like the fuel float bowl is being emptied faster than it can be filled, you can get higher flowing valves,( i cant remember their proper name) its like a sprung loaded pin inside a tube that sits in the bottom of the carb.. yeah that thing

Edited by Brett on 11th Feb, 2010.

Yes i moved to the darkside

Instagram @jdm_brett

i got the avonbar jet ,it leaked , sent it back and got another one ...it leaked ..sent it back and got an su rebuild kit ,in the box ,and it had as big a jet ,and it didnt leak .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I agree that it sounds like the float bowl is being emptied. Check the pump flow rate in situ.

could be the pump or a blocked filter or a crushed pipe.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Mark, what pump pre filter do you have?

thanks for the link - that looks a more substantial, definitely worth a try

also just a thought the plumbing should go

tank (obviously) - pump - filter - fpr

right?

Edited by MarkGTT on 11th Feb, 2010.

If you are using a metro turbo type pump I would personally go Tank-Filter-Pump-FPR.

If something is worth doing, it's worth doing half of.

The roller vane type fuel pump needs to have a good prefilter, without it is a sure fire way to damage it. The damage might not be noticable on say a standard Metro Turbo, where even at full throttle alot of the fuel will be returned to the tank, from the FPR. We are not running standard engines and at full throttle the engine is consuming a large amount of fuel. If the pump's internals are worn from contamination then the flow rate will drop off. I think you maybe looking at a pump replacement to solve your problem, but then I'm usually wrong

umm.. something else to think about then - Thanks.

I haven't done many miles on the new pump so i hope its not damaged.. will get a new filter and re-plumb it in the right place - see how i get on.

simple test is to turn up the fuel pressure till it just affects the tickover ,then try it .if its better ,then its a float needle problem not a pump problem.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

have you got the T peice trick installed ?

Hey Mark,

Tee piece trick is covered in the lower half of this post - see link (in 3). :)



its also worth blocking off the part throttle lean off pipe if you haven't already

I also seem to be suffering a similar problem in top gear after being flat out for a while.

First thing I'm gonna do is fit a higher flow filter, then look at the pump, then needle valve etc.

My pump has a very slight leak on the body so I need to replace it anyway...

Also float extension piece is useless you extend the jet intake down also.

Let us know how you get on.

You can bore the valve out to 2.9 mm and then relap the seat, there has been another post on this fairly recently.

This is another one I found



Also (obviously) make sure you have a good feed from the tank?

I took out the orignal pick up pipe and fitted a 10mm pipe so it matched the inlet size on the pump and ran nice fat 10mm fuel line between tank to filter and pump. Make sure filter has 10mm tails.

Cheers

Brocky

Edited by Brocky on 12th Feb, 2010.

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

Hi Brocky, yeah part throttle lean off pipe is blocked off.. unfortantley it looks like there is a stud in the carb were i need to 't' into (anti run on valve) .. so it going to be a pain to remove.

will check the carb to plenum gasket, change the filter first.. and cross my fingers!

If you're wantintg to try the bigger needle valve, you can drill it out yourself and just lap the needle into the seat with some fine paste. I did this about 4 years ago & have had no issues.

WWW.TURBO-MINI.COM

Mark,

My current carb looks like it never had the run on port even drilled... but my spare carb has both.

Just occured to me, would the tank breather size have any effect if it was too small ?

As I'm sure at full tilt the fuel is leaving the tank pretty quickly?

Phil,

Did you figure out what was causing your problem in the old post above ?

Cheers

Brocky

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

hello.
Fuel starvation are problems that can affect internal combustion engines fuel led by either diesel, kerosene, petroleum or any other combustible liquid or gas.If no fuel is available for an engine to burn, it cannot function. Fuel starvation is slightly different from fuel exhaustion, in that fuel is in the tank but there is a supply problem which either fully or partially prevents the fuel from reaching the engine.

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