21 replies to this topic

[Nielsj1996]

Hello,

My 1991 Mini cooper 1275 hif44 has the following problem:
Sometimes the engine needs 5 or 6 turns before it catches on. Other times it will start after only one turn. The car is completely standard.

What already has been replaced during the restoration:
Ignition
Coil with gcl143
Spark plugs and wires
Fuel pump
Carb has been rebuild

Compression is exactly what it should be, the engine starts fine when warm.

Did I miss something, or what else could it be?

[cal844]

Does it play up cold or hot? Edit my memory is that of a goldfish!

Remember if it's from a totally cold start that the fuel pump will need time to lift fuel from the tank (assuming mechanical pump)

Another possibility is the choke cable isn't set quite how it was before the rebuild.

Regards
Cal

Edited by cal844, 06 May 2021 - 07:06 PM.

[Ethel]

What plug gap are you running? You could try increasing it a little.

[Nielsj1996]

It only happens on a cold start. 

I know the pump has to lift fuel first. The strange thing is it does not always happen, I cold started the Mini 5 times last week 3 times it started first try but 2 times it took some cranking. 

 

 

The spark plug gap is 0.85 mm (33 Thou). Should it be bigger?

[cal844]

33 thou sounds about right

[roblightbody]

I think my similar mini takes maybe 5 or 6 turns from a cold start, and I consider that normal, and that it's one difference between a carb and injection car? Once warm it starts within 1 turn or so.

[slidehammer]

Things I would consider are as follows-

Is the fuel fresh?, I have just had another tank go off whilst the Mini was being used infrequently.

The bad fuel meant it was hard to start from cold, but did run once warmed up.

Is the battery in good health and the starter motor?, sometimes you can find the starter is taking too much power to crank and the ignition system is left under powered.

You can sometimes tell this if the engine catches when you release the key from the cranking position and the engine fires whilst still spinning over from the starter

[richmondclassicsnorthwales]

What fuel are you on over there in the Netherlands ?

 

By this I mean are you on E10 yet which is added in the fuel (Ethanol) ? (Awful gear)

 

It is due to hit the forecourts soon at Petrol stations, but wondered if you are already using it in your fuels. I seem to think I read that  your Government were keen to roll it out quite quickly there and be using it by now.

 

One thing you could also look at is your timing, see if it is a little retarded, just ideas for the pot.

[bpirie1000]

Fuel draining back to the tank and pump not up to par maybe?

Check the flow and amount to the carb?

[Nielsj1996]

Hello,

It's been a year but the Mini still has the same problem. And I would like to solve it. It takes a while for it to start. And the idle fluctuates. New things I have tested:

Disconnected fuel pump and tried to start with exactly the same result the car starts after 5/6 turns and runs fine on the contents of carb. Which rules out the fuel pump.
New Plugs
Checked the ignition timing
Used high octane fuel
After a long drive the idle fluctuation becomes less. When driving It runs perfect.

What else can I try?

[Timmyquick]

When my mini was having idle fluctuations including long crank, same carb as yours. It was a combination of fuel mixture been lean and ignition timing needed advancing a few degrees.

[Nielsj1996]

When I adjust the carburator to be richer the idle gets better. 
But it becomes to rich at higher RPM when driving. It also makes no difference for starting.

Edited by Nielsj1996, 09 August 2022 - 09:49 AM.

[Timmyquick]

Would assume you need a better su needle profile if too rich at top end (check for vacuum leaks), would it not be worth trying to advance the ignition timing a little bit as an experiment? Just mark its current position. Haynes Says my carb cooper should be at something like 5 BTDC but it more like 10 now obviously it no longer a standard cooper anymore.

Always worth looking for vacuum leaks when messing about, believe they can play havoc with idle.

Temp disconnect vac from carb to dizzy (block carb end) quick and easy to try.

[Nielsj1996]

It could indeed be a vacuum leak somewhere. What are the common places where the leak could be and what is the easiest way to find it?

 

Should I test cold starting with the vacuum advance disconnected? 

Edited by Nielsj1996, 09 August 2022 - 01:42 PM.

[sonscar]

Valves not sealing would be my guess.Steve..