40 replies to this topic

[mike.]

Over the past couple of months my mini seems to have developed this problem - Which seems to b getting worse - Either that or its just getting on my nerves more. The problem is acceleration at low RPM. I notice it most pulling out of junctions/from lights etc. Basically i'll engage the clutch and the car will move foward very slightly, the engine will near enough stall (drops to about 500rpm at a guess) So at this point i sort of panic and put my foot to the floor to keep it going then the revs very very slowly climb (estimate 2-4 seconds just to reach 2500rpm) then when they hit 2500-3000rpm i'll just get a sudden blast of power and the revs will rip round to 6k instantly and i'll need second gear straight away!

This is becoming a real pain getting to college/work because i have to allow for a huge gap in traffic to compensate for this slow acceleration, and i can barely pull out at round abouts - For example i'll make eye contact with another driver, see they're letting me go - Then i'll try and zip out and i'll go so slow that other cars assume i'm not going and all start pulling out and cutting me up

This problem can also be felt through all gears - The car is fine crusing along at say 2krpm then i'll try and accelerate and i'll acctually feel the car go slower then suddenly gets a boost of power as the revs climb. This'll happen in 2nd, 3rd and in 4th the car can barely move for example when i'm accelerating from 30-40 etc until i hit about 50. This also makes climbing motorway sliproads a problem because i just won't have the power to accelerate up the ramp until i actually get to the top.

The best way of describing it is as if its misfiring under 3krpm - However i don't think it is.

What could be causing this? I filled up the dashpot with engine oil about a month ago, the plugs/leads aren't that old. I've not touched the timing or mixture?

I used to just put it down to the engine being cold - ut even when i let it idle for 5 minutes before use i'll get the same problem.

I puzzled...

[JetBLICK]

Check your clutch and your ignition system - theres a trouble shoot to test your ignition system in teh back of a haynes manual. Testing your clutch is a bit harder as you kinda need to know what a slipping clutch feels like. Failing that.. i'd replace the basics, the points and condensor, as they are the cheapest thing to replace first and often play up for no apparent reason.

[Kernal H]

Hmmm mine kinda does this too. Only does it when cold really, but pulling the choke out always helps! I notice with mine there's a nice power band at 3-4000 rpm. Below that is a bit slugish but not as bad as you've described, I've always thought its because its an old small engine!

[lrostoke]

Your profile says you've got a Stage 1 kit..did it start after the kit was fitted ??

I had a similar problem, wasn't quite as bad aas yours but basically it was fuelling, the needle that came with the kit was a bit weak, I've since fitted an AAA needle and it cured the problem.

It could just be the carb wants setting up.

[mike.]

No i bought the car with the stage 1 kit. The problem has started over the past month.

It does feel worse when the engines cold - I don't seem to notice it once i'm nearly at college/work after a 20-25min drive - But surely i shouldn't have to sit there for 10min+ until the engines warm.

I'll have to check the ignition components tommorow but considering the problem only happens at low rpm and is non existant at high rpm then it led me to think fueling.

I might try running with abit of redex in the fuel, see if it helps any.

[mike.]

Ow also what about the fuel filter? Could that be clogged? Also the air filer - I've never cleaned that...

[ourkid]

Ow also what about the fuel filter? Could that be clogged? Also the air filer - I've never cleaned that...

I had the same thing with mine and being an auto it was a real pain - I know exactly what you mean about pulling out at junctions!.Anyway with a nice warm engine a tweaked the timing slightly (advanced it) just until the revs started to rise,and it's now far better.Being new to the scene i may be talking C**p but a guy i know who used to race minis years ago advised that they all like to be advanced until they pink then just back off,giving cooler better running overall.Check your dizzy isn't loose(mine was).Oh,and your brakes aren't sticking (seizing shoe or sticky cylinder)

Ade.

[Aus]

Check pipes on carb and inlet & exhaust manifolds for airleaks

[mike.]

Check pipes on carb and inlet & exhaust manifolds for airleaks

I think the manifold blows abit somewhere near the Y piece but nothing bad enough to cause this.

I'll check the timing when my dad gets round to showing me how to...

[Aus]

No, check where it seals to head, make sure nuts are tight and gasket is not damaged

[luke6040]

Check pipes on carb and inlet & exhaust manifolds for airleaks

I think the manifold blows abit somewhere near the Y piece but nothing bad enough to cause this.

I'll check the timing when my dad gets round to showing me how to...

I get the same problem when the points are on there way out or not set quite rite. so i personally would start with ignition.

Edited by luke6040, 30 April 2008 - 09:11 PM.

[mike.]

I'll check the manifold - Should be fine though - Replace the head gasket recently.

[pyromaniac_yeti]

mine did that, it was timing.

on the dizzy theres a nut - 7/16ths i belive, loosen that off till you can just about turn the dizzy. start the car up and with the engine running turn the dizzy one way and see if the revs rise or fall, if it falls, go the other way. keep turning it till the revs stop rising, then do up the nut. give it a blast down the road and see how it goes after that. after id tweaked mine the flatspot totally dissapeared. although you may need to adjust the idle screw on the carb, its a little stop screw on the side where the throttle cable connects. should be able to adjust with your fingers (mine does anyway, screws about 6mm).

if that doesnt work, id suggest checking the rest of the ignition out, plugs, rotor arm, points, condensor, HT leads & so on. either way, id bet on it being ignition related. if that doesnt solve it id put it down to blocked air filter/carb settings.

good luck

[luke6040]

mine did that, it was timing.

on the dizzy theres a nut - 7/16ths i belive, loosen that off till you can just about turn the dizzy. start the car up and with the engine running turn the dizzy one way and see if the revs rise or fall, if it falls, go the other way. keep turning it till the revs stop rising, then do up the nut. give it a blast down the road and see how it goes after that. after id tweaked mine the flatspot totally dissapeared. although you may need to adjust the idle screw on the carb, its a little stop screw on the side where the throttle cable connects. should be able to adjust with your fingers (mine does anyway, screws about 6mm).

if that doesnt work, id suggest checking the rest of the ignition out, plugs, rotor arm, points, condensor, HT leads & so on. either way, id bet on it being ignition related. if that doesnt solve it id put it down to blocked air filter/carb settings.

good luck

I agree with 'pyromaniac_yeti' and would say he has hit the nail on the head.