Having problems with duraspark 2

[Anonymous]

HI ALL

I just swapped out my old points for a duraspark 2 setup. I have a 67 mustang 200, 3spd auto. I bought a new distributor for a 79 fairmont and pulled the rest of the parts from a 79 granada with a 250. The cap and rotor look new, but the control box and the coil look original. Now, at low RPMs (idle to around 2500) it is much slower and seems like it could be pushing a lot harder. When I get up above 2.5, it pulls really well. I regapped my plugs and nothing changed. Also, with my old distributor, the car started really well and never died when it was cold, but now, it dies and sometimes doesn't want to start when it is cold. It almost makes me want to switch back to the old distributor, but I think this can be fixed.

thanks for your help,
Steve

 

[pedal2themetal45]

HI
Sounds like the timming is off. Whats it set at?
Tim

 

[Anonymous]

The timing is set to where I had it before the upgrade. I was wondering about that, whether I need to change it to accomodate the upgrade.

Steve

 

[CobraSix]

tisk tisk...

you are using a junkyard control box and coil?

shame shame

Seriously, the control box is like $10 from Autozone. Get a new one. Eliminate that as the possbility. If that doesn't do the trick, look for a new coil, or get some new wires and cut one to work with your old coil.

Slade

 

[Anonymous]

I know, but I was actually that short on cash that saving $7 was necessary. I did buy new wires and they came with an extra coil wire for another type of coil, my old one. But I heard the coil had to be DS2 compatible. Should I try it anyway?

 

[Anonymous]

Could an upgraded alternator increase the spark power, if a new control box and coil don't fix the problem?

 

[Anonymous]

i would think you would need a hotter coil tooo

 

[CobraSix]

No...alternator and hotter coil are not the issue.

Yes you can use an older style coil with DS2. I'm running my DS2 with my old Flamethrower that I used for my pertronix ignition.

I would shoot for replacing that and the control box. Old electronics are not trustworthy, especially after sitting in a junkyard.

Slade

 

[MustangSix]

Are you feeding 12V to the control box or is the stock resistance wire still in place? That could make a diffeence.

 

[Lazy JW]

Are you feeding 12V to the control box or is the stock resistance wire still in place? That could make a diffeence.

I dunno about Granada's but the wiring schematic in my shop manual for my truck (1979 schematic) shows a ballast resistor in the "run" circuit but not in the "start" circuit (I am running without the resistor, however). It would be easy to jumper 12 volts to it as a test. The mechanical advance unit in my DS2 fell apart into a rusty heap (literally ) Gave me fits until I quit being so lazy and opened it up for a look-see. A rebuilt distributor solved that problem.
Joe

 

[mustang6]

I believe you are suffering from slow distributor timing advance, which was designed into these late model distributors and DS2 control modules. Your advance is coming in much slower than your old distributor did it. The cheapest route to fixing this is to buy one of those cheap distributor recurve spring sets and put some lighter springs in the mechanical advance unit in the distributor. This will wake up your engine at lower RPMs.

If you want to increase the total amount of mechanical advance available you can also remove the advance assembly and rotate it to the longer advance slot on the other side from the one being used (the later model distributors always use the smaller slot in stock form).

 

[Anonymous]

Thanks for all the help, guys. When Tim mentioned that the timing may be off, I figured that with the bigger spark plug gap, the spark would be slightly retarded. I changed my timing to 12-13 degrees btdc and everything works great. In fact, my car is a LOT faster at all RPMs. It responds well to any amount of gas I give it. I haven't noticed ANY problems since I changed the timing. Thank you all again for all the info. Odds are I will need quite a bit of it in the future.

Steve

 

[Anonymous]

what WAS your timing? higehr or lower?

 

[Anonymous]

My timing WAS at around 6 degrees. Why does it need to be so much higher with the upgrade?

 

[Anonymous]

maybe it should have been at that all the time...but you couldnt tell any improvement