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Hot start issue

Posted: Sat May 30, 15 1:28 pm
by MilesnMiles
Last week I was plagued by non starting at Shakey and on the journey up and down when the engine is hot.

So far I have changed
The coil
The starter
The carburettor

I then checked the ohms resistance on the 4 pin ballast resistor
Got 1.8 and 5.8

Running out of idea. Have moved timing back and forward a touch, but no change.
Starts cold every time

Posted: Sat May 30, 15 1:33 pm
by Johnny Dart
Could it be fuel vaporizing in the feed line ?
Does the line run where it's getting hot ?

Posted: Sat May 30, 15 1:38 pm
by MilesnMiles
Fuel line has routing has been changed for the 2 different carbs but the problem persist.
The car almost and sometimes catches as I let the key off. Too much resistance in the ballast resistor?

Posted: Sat May 30, 15 1:56 pm
by Johnny Dart
Along the fuel vaporizing route,is the heat transferring to the carb though the manifold ? Do you have a heat stopping spacer under the carb ?
Could you wire up a conventional 12v coil,do away with the ballas,t to test if its the ballast coil/resistor pack faulty ?

Posted: Sat May 30, 15 2:03 pm
by Johnny Dart
On old British cars with a ballast coil and resistor, if I remember correctly , you had a 6v coil, that had 12v fed to it on cranking , and then on running , had a 6v feed coming from the resistor pack.
I'm not a Mopar guru :lol: just guessing its the same or similar opperation

Try a 12v feed,from an ign switched 12v live, to a known good 12v coil.

Posted: Sat May 30, 15 3:42 pm
by Carl
Ignition box these can play up on a hot engine.

As for it only firing when the key goes back to run but not in start that sounds as though you have an open circuit and your not getting 12v to the coil, (ignition box) or possibly the switch or the dodgy bulkhead connector.

4 prong Ballast resister going down. One side gives 12v to the coil on start and the other gives a lower voltage during run. If there is an open circuit in the 12v side it will not start, but will fire when switch returns to run and voltage is going through the lower side of the ballast.

Ignition switch, run a test wire from the poss side of the battery to + side of coil, if engine starts normal then you have a problem with the ignition switch, take test wire off straight away.

Posted: Sat May 30, 15 4:12 pm
by MilesnMiles
Thanks Carl! that's all good info mate. I'll give it a test tomorrow. I'm knackered from fitting a new headliner :lol:

Posted: Sat May 30, 15 4:26 pm
by Carl
Good luck mate.

Your a braver man than me putting in a head liner, they aint easy, think I would rather be mucking about with the electrics.

Sorry ment to say, Check your ignition 2 circuit as that's the circuit that has the bypass circuit that sends full voltage to the coil.

Posted: Sat May 30, 15 5:09 pm
by Dave81
Have you done the ammeter bypass Miles?

Maybe worth upgrading to and going HEI/true 12V. No more ballast issues! :thumbright:

Posted: Sat May 30, 15 5:20 pm
by MilesnMiles
Dave, bypassed ammeter. Might go the FBO route presuming their ECUs have stopped burning out.

Posted: Sun May 31, 15 10:18 pm
by Steve
Have you tried a hot wire from the plus on battery to plus on coil just to get her started Miles? If it works, you will know you are not getting 12v in the start position on the key. If it starts, take it off straight away as you will burn out the coil unless its designed for constant 12v running.

I would definately consider HEI and blaster coil conversion, it transformed my starting on the Polara.

The carb spacer is a good shout aswell. My Polara has one and the fuel still percolates after a run. I imagine it would be terrible without one!!

Good luck matey :thumbright:

Posted: Mon Jun 01, 15 7:44 am
by MilesnMiles
Steve, problem went away but not sure why although I checked and tightend all connections and changed the coil out for a spare one I had. I could also change to a 2 pin ballast as I have a spare one.
I've looked at the HEI options and read a bunch of stuff yesterday. Did you do a thread on it and if so, any idea what page it's on :lol:

Posted: Mon Jun 01, 15 9:50 am
by Mick
Did you raise the floats Miles ?

Posted: Mon Jun 01, 15 10:11 am
by MilesnMiles
Mick, we dropped the float levels which gave a much better and leaner idle.

Since I got home I've put the Street Demon 750 back on as the car pulls much harder with it.
I changed out the coil for my spare (not yours!) and ran it hard yesterday and it started without fault.
As Carl pointed out, it may yet be the ignition switch and I can test that by hot wiring as the guys above suggest.