boosting and going nowhere
Turbo Mini Forums

I think I may have mentioned this b4,

took the mini for a raz today ;

Very strange indeed , it really seems to misbhave even though its been on the rollers ( a bit suspect !! )

It sometimes goes like the clappers ; but other time it can be boosting like a good un but not qactually having the power surges I had it a 9PSI and it was not roaring at all; whereas other times It will be flying

What could cause this ???

TurboLessTosser

running lean? cant imagine the ignition timeing changeing al over the place.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Sounds like you are having similar probs to me!

Does it loose its power after you have been driving with the engine upto temperature for a while?
I bought a fuel pressure gauge to check my idle pressure, then found that after the engine has been hot for a while, the fuel pressure goes completly!
Be carefull if you have got this problem, as it could be goodbye engine!

Could be the Bi-metallic strip in the base of the carb....

Hmmm, but why would that affect the pressure?
Nope, i don't know why. The fuel pressure is governed by two things - the pump and the regulator (and the pressure the regulator recieves from the plenum).

Hmmm, but fuel evaporation can do funny things...

Are you running with carb heat shields? is your bonnet vented?

Try taking the bonnet off then going for a drive and trying to replicate the problem...

Turbodave are you using the cooling pipes on the inlet manifold or have you done what I did and just chopped them off?
My fuel pressure gauge is plumbed into the feed to the carb from the fuel pressure regulator.
Is there anything in the carb that could stick open or allow the petrol to vent out somewhere when it gets hot?
The strange thing is once the pressure has gone you can let the car idle for as long as you like and the pressure never returns but if you turn the engine off for about 5 mins the pressure comes back?

never used the pipes.

I'm just not believing what you're saying - especially that there is zero fuel pressure, but it will idle forever?
Impossible is a word that springs to mind...

There doesn't need to be fuel pressure for the engine to idle, as there is no boost / load on the engine.
I have however had a close look at the filter again and there seems to be a very very slow feed of fuel to the filter but not enough to register on my gauge, hence the 0psi readout before.
Many thanks for the help.

there does need to be fuel pressure for it to idle otherwise it would never get into the carb, the fuel tank level will be lower than the carb...

maybe the gauge is slightly out...

is the filter in the correct way, i.e the flow direction of it is correct?

I dont think my problem is related to fuel pressure ...

AM interested in the Carb Bi Metallic strip though . DAve what is that all about ; I dont understand ?

Funny this problme did not manifest itself on the RR ?

I have one of thje AvonBar needles here; I might put that in; get it to idle nice; then give that a go ....

TurboLessTosser

theres something in the forum somewhere about fabricating a replacemet for the bi-metalic jet holder. have a wee look :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

This is very strange...

I'd be pulling apart the regulator and checking the diaphram is still nice and taut. If rippled / creased, it probably needs replacing. It does seem odd that it only happens occasionally though????

I wouldn't go fooking about changing needles after a RR sesion, or you'll have wasted your money.

Find the cause of the fuel pressure problem first.

Hi all'

Just a quick update on the fuel pressure problem.

Luckily I had a couple of spare carbs, so I swapped my suspected faulty one with a good spare and hay presto problem solved - no loss of fuel pressure after the engine is hot!
Only trouble is my needle was setup for the faulty carb so a rolling road tune is called for now.
Does anyone know a good rolling road up north? I live in North Wales.
On the subject of needles - is anyone running a 1293 8.1cr with a 9psi boost. - If so what needle are you using as I would like to do a comparison. - Cheers!
Still need to install some bonnet vents, but will do that sometime this week.
Oh, you all probably know by now but bmc is selling new clubman shells now, about ?1800 quids - Do you think they will sell many, as its rare to find anyone that likes them other than turbo bods!

if you are not using an intercooler a 'str 1062' needle should do the trick -its metro turbo challenge spec - set ign timing to 28 degrees @5000 rpm