Pinto Misfire and Starting Problems

[mike.flarry]

Can anyone help? its driving me mad. Had a misfire and coughing on 2 litre Pinto, swapped points for Lumenition Magnetronic electronic ignition,added new 12 volt coil and bypassed ballast resistor as per the fitting instructions with a new 12v feed to distributor and coil. Runs beautifully, best its ever done, but after about 15 miles starts cough for a short while and comes to a stop at a junction and wont start again.Or if I switch off and park for a few mins wont start again. No spark at plugs. Tiny spark from HT lead at coil. put leads back on and usually after about 5 mins or so starts again and runs fine for another 15 miles. Any bright ideas? Was thinking of trying new set of leads.Any help would be appreciated am tearing what little hair I have out as mechanic friends have run out of ideas too. I have just noticed that my battery says 2004 and is for a Fiesta would a bigger one help maybe?

[greyV8pete]

Re: Pinto Misfire and Starting Problems

Hi Mike. I would go straigh to the coil as your problem. I don't understand the instruction to bypass the ballast resistor. If you have one of these the coil will be designed to run on a lower voltage i.e. 12v battery LESS the voltage drop of the resistor. The only time these resistors are normally bypassed are for a short time via the starter solenoid (extra wire / contact) so the coil gets a decent voltage even with the volt drop due to the starter motor cranking the engine. To run with a ballast coil permanently at 12 volts will likely cook it! Peter.

[pdm_engineer]

Re: Pinto Misfire and Starting Problems

Hi Mike
I don't see anything wrong with your wired out ballast resistor. This is perfectly normal when using a 12V coil. A ballast resister is only needed in conjunction with a 9V coil. I would forget the battery, its not the problem.
Check to see if your new wire is heating up with the engine running. If it is then it's too thin, fit a heavier gauge wire.
Other possible reasons for this maybe that your new coil is breaking down with heat. You could check its resistance of the HT and LT sides hot and cold to prove this. (would need to isolate coil from the car wiring)
Or your new Lumenition has a fault when hot - take it back.

[lizbillings]

Re: Pinto Misfire and Starting Problems

Hi Mike. I had a lumenition fail once so it can happen. Regards Liz

[James]

Re: Pinto Misfire and Starting Problems

Hi Mike,
My devise is go for the easy things first. Check especially your rotor but even your distributor cap for hairline cracks. Sounds silly but takes a couple of minutes and can be the cause.

[chris_cussen]

Re: Pinto Misfire and Starting Problems

Is there a condenser/capacitor in the system? If there is it could be that failing when hot. I had that fault several decades ago on a Mini.

[danny_nelson]

Re: Pinto Misfire and Starting Problems

Hi Mike, I have read the above, and I agree with Peter Morris in regard to your new system. However you say that this was happening with the old system? As Chris asks has the condensor been retained in the system? I would go back to the old system and sort the problem before fitting the electronic system. I would look at spark and fuel, air etc.
and test each, and only when I had it sorted would I fit the electronic set up. I would carry points etc in my tool kit so that if the electronic set up failed I could refit the standard set up and get me home.

[mike.flarry]

Re: Pinto Misfire and Starting Problems

Thanks for all the advice,have gone back to basics, put new points in. Once rain stops will drive 20 odd miles or more and hope it starts again. I spoke to Lumenition they say that if the gap between the spinning disc and the base unit is too big it can cause too big a spark which would cause the coil to over heat. Once I know it is running ok with the points may try refitting them. Dont get much mileage out of the old girl so the electronic ignition was bought last August dont think they will look too kindly on replacing them this late on, although have only done about 100 miles since then.

[csjcarolyn]

Re: Pinto Misfire and Starting Problems

Is it possibly fuel starvation? Is any fuel line too close to a heat source? Roger

[philws]

Re: Pinto Misfire and Starting Problems

You may be sorted by now but I had a similar problem with my Berlinetta some years ago. I thought it was fuel I kept cleaning the carb, it would run just to stop again a couple of miles up the road. I turned out to be a cracked coil. A new coil sorted the problem. Phil

[keith_h]

Re: Pinto Misfire and Starting Problems

Mike

Have you by any chance recently fitted a new fuel filler cap? If you have and it is not vented and the tank is not vented elsewhere these are exactly the symptoms you describe. The engine will run as long as it takes to build up a vacuum in the tank then you have had it - no fuel being pumped to the carb. If air can seep in then you will eventually be able to start the car and run for as long as it takes the vacuum to build up in the tank again.