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Author: Subject: A+ series engine wont run when warm
MK9R

posted on 13/9/10 at 12:06 PM Reply With Quote
A+ series engine wont run when warm

Got an A+ series engine from a 1993 mini cooper running on a single carb, car use dto run fine then suddenly cut out. It now starts and runs fine when cold for a couple of minutes, then once its warm its starts spluttering and missing and cuts out. Where do you think i should start, new fuel pump has been fitted already, although i reckon it maybe too higher pressure, but seeing that problem is the same with the new pump can't see it being related.





Cheers Austen

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madrallysport

posted on 13/9/10 at 12:10 PM Reply With Quote
the coil may be breaking down, when it heats up thus you get a weak spark or loose ot completely





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MK9R

posted on 13/9/10 at 12:13 PM Reply With Quote
quote:
Originally posted by madrallysport
the coil may be breaking down, when it heats up thus you get a weak spark or loose ot completely


if thats the cause, i'll be happier than a happy man on happy pills

Not had a mess yet, i have some of those spark plug things that show you have a spark so very easy to check

[Edited on 13/9/10 by MK9R]





Cheers Austen

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t.j.

posted on 13/9/10 at 12:29 PM Reply With Quote
let it suck your hand!

- take airfilter hose off the carburetor
- rev the engine up
- lay you hand on intake, full trottle (engine will try to cut out, due mixture too high)

If you're lucky, it will running fine
if not, clean carburetor

Other checks:
- Is the fueltank getting air back for the missing fuel.... (return open?, or tank breather open?)
- it the fuelline not coming to close to the engine (air-lock)

BTW: if it's really old and having this, check it, the ignition-timing can be wrong (worn out)
http://minigarage.nl/osCommerce/images/Contactpunten%20bruin.JPG

[Edited on 13/9/10 by t.j.]





Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)

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snapper

posted on 13/9/10 at 12:33 PM Reply With Quote
Check the dash pot has.....
1.the correct level of oil
2. The correct viscosity of oil





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NigeEss

posted on 13/9/10 at 12:34 PM Reply With Quote
Second vote for coil.





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avagolen

posted on 13/9/10 at 02:48 PM Reply With Quote
I have a previous experience with the mini and running rich/cutout.

Is the carb an SU? if so, check that the jet has not been worn by the needle.

The 'self centering' needles can rub the side of the jet causing it to become oval in shape.

HTH.

Len.





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MK9R

posted on 13/9/10 at 02:50 PM Reply With Quote
quote:
Originally posted by avagolen
I have a previous experience with the mini and running rich/cutout.

Is the carb an SU? if so, check that the jet has not been worn by the needle.

The 'self centering' needles can rub the side of the jet causing it to become oval in shape.

HTH.

Len.


cool will check, its an SU





Cheers Austen

RGB car number 9
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rallyingden

posted on 13/9/10 at 03:50 PM Reply With Quote
Another vote for coil or ballast resistor if one is fitted.

RD

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jonno

posted on 13/9/10 at 04:25 PM Reply With Quote
Probley coil, but did have a dizzy cap cause simular problems many years ago !!





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MikeRJ

posted on 13/9/10 at 04:50 PM Reply With Quote
Another vote for coil, had the exact same symptoms on one of my mini's
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iank

posted on 13/9/10 at 05:07 PM Reply With Quote
I already voted coil in the thread when you bought it





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adithorp

posted on 13/9/10 at 07:04 PM Reply With Quote
Also check The valve clearence. Too tight would give simlar symptoms.

adrian





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britishtrident

posted on 13/9/10 at 07:13 PM Reply With Quote
Spluttering is a big clue start by cleaning out the carb and fuel lines and checking for water or floating debris in the tank.

If it were the coil it usually would cut dead, and it is unlikely to be the valve clearnces.

If the car has the electronic distributer then it might could be the bolt on amplifier module

[Edited on 13/9/10 by britishtrident]





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MK9R

posted on 13/9/10 at 07:16 PM Reply With Quote
Tank, pipes etc all been cleaned or replaced, new fuel pump fitted, still the same. Started it tonight after unloading from bus and it just about ran to get it in the garage, but very badly





Cheers Austen

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www.automatedtechnologygroup.co.uk
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avagolen

posted on 15/9/10 at 03:18 PM Reply With Quote
Keep us posted, would like to hear the outcome of this one....

Len.





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MK9R

posted on 15/9/10 at 03:22 PM Reply With Quote
Last night it would tick over, but as soon as you gave any throttle it cut out. Have got a new coil to put on then i know all electrics have been replaced (coil, dizzy, leads, pump). Checked needle and all moved nice and free and as should. Will fit coil tomorrow and give it a go, if no better the carbs are coming off. Its the newer type of SU with the vacume advance from the carb to dizzy and the diaphram type of float chamber (i think)





Cheers Austen

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www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
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MK9R

posted on 16/9/10 at 08:56 PM Reply With Quote
right ok, coil replaced, no better. checked compression all ok, fuel is coming from pump ok, plugs are sparking and checked they are all connected to correct cyclinders, played with timing, no better, took carbs to bits and seem ok (needle is slightly off to one side, is that correct?)

Just to clarify what is happening now, engine will just about start and just about idle, very roughly, as soon as you give it any revs it dies. The carb is a single HIF44, the vacuum advance is connected from carb to dizzy as expected, and there is no leak if you suck the pipe from the carb end.

plugs are sooty when you take them out.

Any more thoughts???

[Edited on 16/9/10 by MK9R]





Cheers Austen

RGB car number 9
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www.automatedtechnologygroup.co.uk
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t.j.

posted on 16/9/10 at 09:28 PM Reply With Quote
So the plugs are wet?

Sounds like to much fuel.
- Look if the choke is not on
- the carb is not flooding
- oil in dashpot.
- right needle

http://www.autowiki.org.uk/wiki/Tuning_SU_Carburettors

found this:
http://www.minimania.com/web/SCatagory/FUEL%20SYSTEMS/DisplayType/Technical%20Information/DisplayID/87/ArticleV.cfm

[Edited on 16/9/10 by t.j.]





Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)

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ShaunB

posted on 16/9/10 at 09:33 PM Reply With Quote
If the plugs are coming out sooty then for some reason it's running very rich. When first started it'll cope with it as it's like having a bit of choke on, but it'll hate it when hot.

Electric fuel pump? If so is the pressure too high and its forcing petrol past the float valve? Does the float valve actually stop fuel flow? Any fuel coming out of the overflow? Any chance fuel is being forced up the jet, rather than being sucked up by the vacuum?

Can you wind the jet up to weaken off the mixture?

Check the ignition timing - has it slipped? Does it actually advance with the vacuum?

Shaun.

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MK9R

posted on 16/9/10 at 09:34 PM Reply With Quote
quote:
Originally posted by t.j.
So the plugs are wet?

Sounds like to much fuel.
- Look if the choke is not on
- the carb is not flooding
- oil in dashpot.
- right needle

http://www.autowiki.org.uk/wiki/Tuning_SU_Carburettors

found this:
http://www.minimania.com/web/SCatagory/FUEL%20SYSTEMS/DisplayType/Technical%20Information/DisplayID/87/ArticleV.cfm

[Edited on 16/9/10 by t.j.]


plugs are black but not wet





Cheers Austen

RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk

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MK9R

posted on 16/9/10 at 09:37 PM Reply With Quote
quote:
Originally posted by ShaunB
If the plugs are coming out sooty then for some reason it's running very rich. When first started it'll cope with it as it's like having a bit of choke on, but it'll hate it when hot.

Electric fuel pump? If so is the pressure too high and its forcing petrol past the float valve? Does the float valve actually stop fuel flow? Any fuel coming out of the overflow? Any chance fuel is being forced up the jet, rather than being sucked up by the vacuum?

Can you wind the jet up to weaken off the mixture?

Check the ignition timing - has it slipped? Does it actually advance with the vacuum?

Shaun.


plugs may be sooty due to having to get the car to tick over it needs a little bit of choke.

What i did notice is that the pipe connected the crank breathers has a leak in it, it could be sucking air in there??

Yes it has an electric fuel pump, but we let it run and could see no fuel coming through float chamber overflow or jet

[Edited on 16/9/10 by MK9R]





Cheers Austen

RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk

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ShaunB

posted on 19/9/10 at 04:35 PM Reply With Quote
quote:
What i did notice is that the pipe connected the crank breathers has a leak in it, it could be sucking air in there??


If that pipe connects back into the carb, then yes it might well be having an effect.

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prawnabie

posted on 19/9/10 at 04:46 PM Reply With Quote
If you have taken the grill off and put it back on recently, make sure you haven't put a screw through the loom. I did this a while back and shorted the wire from the coil to the dizzy lol.
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MK9R

posted on 20/9/10 at 07:09 AM Reply With Quote
The bastard won't even start now!! it won't even fire with Cold start, plugs must be fouled up too badly.





Cheers Austen

RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk

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