10 replies to this topic

[Jimbopoo69]

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Model:850 Saloon
Year:1980 ish

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Hi guys, anyone who can help me sort this problem out will be a life saver!! I am literally pulling my hair out. OK here's the problem:- Engine turns over fine but does not fire, I took the HT lead out of the distributor cap and put it close to the engine block to see if there was a 'bright blue spark' as the engine turned over. Sadly not, only a very weak one which would not even jump a 3/4 mm gap, certainly not enough to generate a spark at the plugs. On my quest to discover the problem I've;

- Checked the supply to the LT terminals on the coil (fine supplying 12V).
- Invested in a new Non- Ballast Coil and condenser.
- Checked the condition of the breaker contacts in the distributor (No pitting or anything).
- Checked the earth return in the distributor.
- Inspected the HT leads no visible damage, also checked the resistance of the ht lead that runs from the coil to the distributor and found it to be 10.7 K Ohms. However I have no idea what the resistance should be.......
- Rotor arm spins fine as engine turns over.
- Breaker contacts open and close as expected.
- Breaker contacts gap set to 0.35mm -0.4mm when fully open, is this correct?

I think that's it.......... Does anyone have anymore suggestions? I'm thinking that I may need to replace the HT leads? *I should also mention that the mini has sat outside under some tarpaulin for about a year ( *


Once again any input would be gratefully appreciated as this problem is really really winding me up!!

Cheers

[taffy1967]

Did you charge the battery?

[taffy1967]

to be honest if it was mine and it had been standing for that long, then I'd consider replacing the Spark Plugs, HT Leads, Dizzy Cap, Rotor Arm, Contact Breaker Points and the Condenser.

I'd also treat it to a full service/oil change and I'd put some fresh engine oil into the carburettor dashpot too.

Edited by taffy1967, 14 September 2008 - 09:35 PM.

[Jimbopoo69]

Cheers. Yep the battery is charged, and I've replaced the oil in the dashpot. I'll probably give it a full service once I've at least got a spark. I think I'll replace the HT leads and Spark plugs next, the Dizzy cap, Rotor Arm and Contact Breaker Points all look fine.

Do you know whether 0.35mm -0.4mm is the correct gap for the breaker points when fully open?

[burnerking]

according to haynes, that is the correct gap for points

[Dan]

Why do you think it's not producing a spark at the plugs? If there's a spark at a lead held to the block there will be a spark at the plug. As for the spark strength, if you only give it a 3/4mm gap to jump you'll get a weaker spark than if you give it the proper 0.025" gap. The spark energy that can be generated in the coil is partly a function of the gap provided, it takes so much energy to spark over a certain distance and once the coil has got that energetic it will spark. Set the gap wider and it will build more energy before sparking. To me it sounds like the ignition is functioning fine. The timing may be out but that's a different problem.

People above suggest the car's been sitting. How long for? If it's on unleaded try new fuel. Unleaded has a useful shelf life of about 6 months, after that it's far less potent (but still highly flammable).

Edited by Dan, 14 September 2008 - 10:39 PM.

[Jimbopoo69]

Right problem solved, thanks guys! I hadn't set the gap for the points very accurately, I now have a spark at the plugs - Success. However the engine still won't start, Dan I'm guessing you're probably right and the fuel has turned to urine as the cars been sitting there for at least a year. There isn't much in the car can I just top it up with fresh fuel or do I need to drain out all the existing fuel?

Cheers!

[taffy1967]

Well I just added fresh fuel to my Mini when I resurrected it after it's 2 year sleep. That was very low in storage too.

But I've since flushed out the tank and I didn't get any problems.

[dklawson]

If the fuel has been sitting for a year... it still might burn but change the fuel anyway. What may also have happened from sitting so long is the fuel in the carb (assuming you didn't run the bowl dry) will have turned to varnish. You may find that the carb needle is encrusted with deposits from the gas as it dried up. The jet tube may also be plugged with these deposits. Lastly, the float valve may be stuck closed from sitting for months. A can of spray carb cleaner and a gentle touch with a pipe cleaner may do more for your car than anything else.

[Jimbopoo69]

My fuel gauge is broken but from rocking the car I can hear some fuel splashing around. I've obviously been trying to start the car with no success, so I removed the carb and disassembled it. The carb needle, jet tube, and float valve are all fine no encrusted or stuck, but the carb is absolutely bone dry....... So obviously no fuel is reaching the carb? Any suggestions?

[dklawson]

At the risk of sounding obvious, check the fuel pump. Mechanical pumps are on the back of the engine block. If you have an electric pump (stock) they mount on the rear subframe. The pump could be dead, you could have a plugged fuel filter, you could have a collapsed rubber fuel line on the suction side of the pump, or the pickup tube in the tank could be plugged. I'm afraid there is no substitute for working your way through the components checking each as you go.