11 replies to this topic

[ghostleader101]

i have my 1991 mini neon, 1.0, had a stage 1 kit put on a while ago and now theres a big lag in acceleration:
1st gear its only like 0.5 - 1 secs
2nd 1 - 2 secs
3rd 2 - 4 secs
4th is about 3 - 4 seconds lag.

Its quite bad especially when its first fired up and trying to pull away quickly.

I think its the needle and spring thats been changed thats causing it but im not too sure. the dash pot is filled and everything is fine (apart from the temp sensor not working :L)

is there anything i can do to sort this problem out? oly been driving a week :L

still makes me laugh everytime you drive past another mini and they flash and wave n that love it

Thanks
Rob Cool

[lrostoke]

Have a look which needle is fitted. You do need to take the top section of the carb off to get to it.

Most likely if a standard stage 1 kit its an AAU needle. If so try an AAA or AAM needle. Had same problem when I fitted my stage 1 AAA needle cured it.

[TopCatCustom]

Spring isn't too hard?

[liirge]

I've had similar issues, it can be various factors, including a clogged air filter. The mixture may be out, the way I usually sort this out, is if the mixture is ok, I put in thicker dashpot oil, something like 20w50, this will make the mixture a bit richer upon acceleration.

[ghostleader101]

yeah i was thinking about getting a new needle, the air filters a new minisport one so i wouldnt have thought that would get blocked. im using 20w50 oil in their atm, when you accelerate it happens really quick because you can hear the air i think, sounds a bit like a turbo? The mixtures been tweaked to get throguh the m.o.t. i think its a blue spring?
I bought a half stage 1 kit from mini sport which came with everything apart from the exhaust and the got a sportex twinbox, twin centre exit pipe (very loud) when i got it fitted first the mechanic didnt change the gasket so air was coming in through there and made driving impossible but got it all sorted apart from this problem.

whats the difference between AAA and AAM needles?

thanks for the help
Rob

[maggies_minder]

this was happening to mine up until yesterday when it went on the rollers, it was running very lean.
correct fueling and timing sorted it perfectly.

[JakeJakeJake]

Dashpot oil could be too thick, the thinner it is the quicker the mixture will ritchen.

[liirge]

Dashpot oil could be too thick, the thinner it is the quicker the mixture will ritchen.

Incorrect I'm afraid! the thinner it is the leaner the mixture will be.

[ghostleader101]

yeah i think its too weak still, it was really weak before due to the old gasket sucking in air and it was doing the same where there was throttle lag but its still there, do you think its a case of the needle and the mixtures still not right?

buying quite alot of stuff soon so if i need a new needle il buy the one people recomend and fit it on

thanks
Rob

[ghostleader101]

im going to buy alot of stuff today, mostly seals :L and going to buy a new needle too

shall i buy just one, probably the AAA needle or shall i get 2, AAA and AAM?

ive weakened the mixture slightly and its got a bit better, i made it richer the other day and used up half a tank in just over a day not good but its all better now
ive also been told that the needle could be going up too slow due to having engine oil in so was told to put automatic transmission fluid in insted?

i think its due to my driving at the moment, having to put my foot right down to pull away or when im on a motorway etc but im only getting about 100 - 150 miles out of a tank, is this alright?
because of this lag i only get power for about 1.5 inches on the pedal after that it goes all sppluttery and nothings there and if its right down after a few seconds it starts kicking in and pulls away. its really annoying :L

thanks
Rob

[MiniLandy]

Dashpot oil could be too thick, the thinner it is the quicker the mixture will ritchen.

Incorrect I'm afraid! the thinner it is the leaner the mixture will be.

Nope. Thicker dashpot oil causes the dashpot to rise more slowly when the butterfly's open. Since dashpot rising = mixture richening, the thinner the oil, the richer the mixture, upon full throttle.

Since your mixture was tweaked to get through an MOT, this means they leaned it right out. Richen the mixture a bit, twist the dizzy left or right to find the sweet spot, and test drive till you're happy.

If you haven't already got one, get one of these: Linky

[liirge]

Dashpot oil could be too thick, the thinner it is the quicker the mixture will ritchen.

Incorrect I'm afraid! the thinner it is the leaner the mixture will be.

Nope. Thicker dashpot oil causes the dashpot to rise more slowly when the butterfly's open. Since dashpot rising = mixture richening, the thinner the oil, the richer the mixture, upon full throttle.

Since your mixture was tweaked to get through an MOT, this means they leaned it right out. Richen the mixture a bit, twist the dizzy left or right to find the sweet spot, and test drive till you're happy.

If you haven't already got one, get one of these: Linky

Nope sorry you're still wrong, think carefully on where the venturi is and and the butterfly, if the piston rises slower it increases the vacuum, but still limits air flow due to the varying nature of the venturi, with an increase in vacuum you physically suck more fuel through the jet in comparison to the air flow through the carb.! If the piston rises quickly there would be a lower vacuum and alot of air flow - thus weakening the mixture...

http://www.autowiki....SU_Carburettors
http://www.chicagola...eneral/549.html

Edited by liirge, 10 March 2011 - 12:57 AM.