Rough Tickover
Turbo Mini Forums

The tickover on the road 998T is rough. A quick play around yesterday shows that cylinders 3 and 4 are missing at tickover i.e. pull the lead off and it makes little differance. Otherwise the car runs fine, smooth and no oil burning etc.

I have change plugs and leads and tried swoping coil supplies (as in swop 2 & 3 and 1 & 4 on the coil pack). Made no differance.

I checked the compression and it was the sam on all 4.

Any thoughts. I'm going to reset the tappets tonight.

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

I would start by checking the pulley to sensor clearance.

Mine was doing similar yesterday. The laptop showed that it was missing teeth occaisionally.

I've not tried the fix yet though.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

here's a test for it, add 180 degrees onto all the points, swap the leads and try that if you can? would prove that theory?

Tried swapping plugs from 1+2 to 3+4?

tappets wil ?

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

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

wil, do a compression check with all the plugs in only removing the one at a time to be tested and then note the results

then do a compression check with all the plugs out note thes two reading
it will show up any head gasket issues

Good tip, Steve.

The problem is, I have to use my wife to the the compression tests as my tester needs to be held in by hand.

I asked he to turn the engine over with her foot on the throttle, don't worry it won't start. She put her foot on the clutch and just sat there. I had to point out which was the throttle and explain that even though I said it won't start, it will still turn over.

She has a full driving licence and drives daily!

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

how old is your kid these days? ready to take over from the missus in the garage? lol

Editied, because i forgot to write about the problem: are you actaully gettin a spark to the leads?

Edited by Mini_Andy on 2nd Jun, 2008.

Girls don't know what a throttle is, at least they don't relate it to the accelerator.

have you got enough rotational angle between the sensor and notch?

just remember, mine didnt like compensating too much for some reason.

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

Well I tried everything tonight, and no change. All compression reading are good, I don't understand it.

Anyway, I'll change the gasket and see.

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

could it be something as simple as a manifold gasket leak?

try spraying some carb cleaner round it first dude.

sounds like something silly. Changed all your plugs & leads etc?

are you sure she is not running lean as this will have the same effect mate

always looking for them bigger bunches of bannanas

Not a bas idea Budd, I'll give it a go. But I noticed a bit of emulsion in the rocker box, so I'll probably change the gasket anyway.

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

Well i lifted the head last night and the gasket looks fin as do all the valve seats. Hummm.

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

I had a similar problem when I changed to a different inlet manifold wil.

Anything under 2 grand and it was only firing on 1 and 2.

Changed back to my old manifold and was fine. Maybe you have a gasket leak on that port?

Mine did exactly this 2 weeks ago (although i have not got MJ) only running on 3 cylinders (ish) and pulling 3 or 4 made no difference

Did exactly the same as you, changed plugs, checked clearances, did a compression test. All was normal apart from sooty plugs.

Started it again last week and it was back to normal, running on all 4 etc. The only things to be disturbed were:

dump valve vac and take off blocked up (due to swelling seals)
FPR outlet removed and a gauge t'd in
Carb balance pipe slightly disturbed.

I have no idea what the issue is, but i'd like to find out before it comes back again!

Doubt that's any help at all, but the symptoms were too similar to not bother mentioning.

i recently fitted a (modified with a vac take off, but only a 3mm spacer due to bulkhead) minispares intake instead of a MG metro with a 0.5inch spacer and that does affect idle quite a bit as well.


rpm readings fluctuate a bit /as they did with the othe manifld tbh), sensor is at 1.0mm dead, non resistive plugs..

can't quite figure that out either..

Edited by Sir Yun on 5th Jun, 2008.

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

Heeeey, that's interesting. I have never been able to get a decent idle out of any engine that I have had in the mini. The only common part (and I have changed everything) is my MS manifold. Hmmm.

I had both the widebands working on my 998 last weekend. Measuring AFRs on inner and outer cylinders.

With the MG Metro manifold and an HIF44 that I just threw on to bed in the cam.

The AFRs were about 13:1 on the inner cylinders and 16:1 on the outers. The narrowband sensor on the LCB Y piece was sitting happy at stoich.

The point is that although you may think that you have perfect mixture on each cylinder the reality is far from it.

Hence a slight weakness on ignition may cause a misfire at idle.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

id be really interested in the mixture variance on the turbo manifold with a hif paul ,

specially at 4k and up ,

it may explain the piston and head gaskets blowing ,if no4 and 1 are running a few afr points lean ?

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

Edited by Paul S on 5th Jun, 2008.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."