9 replies to this topic

[GreenMini17]

Still trying to start this damn car and i think i may have found the problem.

I have fuel at the carb, i have spark on all 4 plugs, i have compression and i have oil pressure. From the little bit of testing i did, the engine earth strap is fine too.

The engine fires and attempts to run for about 5 secs then dies immediately. I have noticed that when ive been cranking the engine over, the ignition cuts out and cuts back in again?! Its bloosy weird. I assume its cutting out as my tacho power goes off along with my electric fuel pump then they both power up again.

Anyone got any ideas what it is?

[KernowCooper]

You need to check with a volt meter you have a constant feed on the coil + and then do the normal terminal checks is where I'd start

 

Is all your ignition components up to scratch ? check you have a feed to the coil when cranking and when you let the key off

[M J W J]

My mini did this and it turned out to be the coil. As above, that's where I'd start.

[dklawson]

Does the engine run at all when you release the key or does it only fire when the key is held in the start position?

 

What year is your Mini?  Is it outfitted with a factory electric fuel pump or is it an aftermarket change?  

[GreenMini17]

Aplogies, i forgot to mention, im using omex 200 series ignition so no coil or distributor. Due to the engine having the old style intertia starter motor, as soon as the engine fires, it stops cranking (which is bloody annoying)! Its an aftermarket fuel pump.

[Dan]

Possibly with the inertia starter your battery just isn't up to it. So when the voltage gets low enough the pump stops. With a conventional ignition, especially if ballasted, there may just be enough juice there for it to fire in these circumstances but when the ignition is run by a computer it will just shut down. Measure the battery voltage during cranking, preferably with an old fashioned moving coil meter rather than a digital one.

Edited by Dan, 12 January 2014 - 08:24 PM.

[GreenMini17]

The battery is fine. The lowest it gets is about 12.08 volts when cranking and this is after some abuse too. That said, it maybe worth looking at what voltage the pump is receiving when cranking. Hmmm interesting.....

[GreenMini17]

Just put 12v across the fuel pump directly from the battery and the pump now runs constantly. The ignition still cuts out when trying to fire up. Its almost like the starter hasnt got enough ummmfff to turn the engine over when its on a compression stroke. It sounds weird but the engine cranks over fine, then all of a sudden, like if it was on a compression stroke, the starter wont turn it over, the dash goes off and then it all comes back on again. Its very bizarre?

[dklawson]

Everything you describe above is consistent with Dan's earlier suggestion that perhaps the battery is not up to snuff.  If you have another car you can use as a donor, I would remove your Mini's battery and try the donor one.  (Not a jump start... a battery swap).  If that is impractical, I suggest disconnecting your battery in the boot and connecting another car via jumper cables (not booster cables, jumper cables which are heavier duty) to your car.  Remove your battery completely from the equation, use power from a known good battery and see what happens.

[GreenMini17]

Everything you describe above is consistent with Dan's earlier suggestion that perhaps the battery is not up to snuff.  If you have another car you can use as a donor, I would remove your Mini's battery and try the donor one.  (Not a jump start... a battery swap).  If that is impractical, I suggest disconnecting your battery in the boot and connecting another car via jumper cables (not booster cables, jumper cables which are heavier duty) to your car.  Remove your battery completely from the equation, use power from a known good battery and see what happens.

The more and more i delve into this, the more i agree with you. I will do as suggested and remove my battery altogether and jump my battery from my everyday car across to it. Thanks guys. Lets hope this is the issue!