Possible Coil Problem

[LurkinLimey]

Happy New Year Everybody!
Got a wierd problem - 383 is running fine but on 2 occasions motor has lost fire on hard deceleration / engine braking and wouldn't restart.
(Both times in traffic so pretty embarasssing)
Thought initially it was a dirty fuel problem as I'd just cleaned carb, but on both occasions great fuel pressure and cranking fine but wouldn't fire.
Managed to refire after leaving car sitting for about half an hour and fiddling with coil connections and jiggling coil.
So now thinking I've got a bad coil - Ancient Accel Superstock coil mounted on inner fender (see pic).

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So 2 questions:
1) Am I right in thinking coil problem, or should I be looking elsewhere?
2) If it is the coil, what's a good replacement? Been looking at MSD Blaster 2 coil as a relacement, but says I need a ballast resistor to work with my points ignition.
Will probably be converting to electronic ignition at some point, but looking for a short term fix to get me back up and running.
Any thoughts / advice welcomed.
All the Best,
Limey

[SJH]

The first thing I would check are the LT connections on the coil. Check for a tight connection and check if the spade terminals are green with corrosion. Get it running and then try gently wiggling the connections to see if you can make it stumble or cutout.

cheers
Shayne

[graham fury]

not sure if it would be any use to you but I had probs with my 318 poly in my fury I got a her conversion dizzy from assault racing products via eBay total price including priority shipping came in at 91 quid it took about 10 days to get here and car is running sweet as a nut now

[Dave999]

could be

ignition switch (when it does it just run a wire from battery + to coil plus and see if it starts right up)
ballast resistor (just get a new one cheapest option)
coil (any 12 volt ballast coil will do lucas dlb 102 would do )

or any of the connectors in the wires between the lot...


OR

Standard mopar electronic dizzy
GM HEI module
Lucas DLB 198
bypass ballast

you then have something akin to what was used on a V12 Jag (jaguar just hid the module in a jaguar branded box and charged 10x more for it)

job done

here
http://www.moparuk.com/forums/viewtopic ... hlight=hei

or look up HEI on this board for a range of people who have done it


or go with a pertronix.....

i just don't like paying £60+ for something only slightly better than points. they burn out if you leave the key in the run position when stalled, if the dizzy is in the coil ON position.

but they are fit and forget if you treat them nice.

Dave

[LurkinLimey]

Thanks All, and Thanks Dave for the detailed rely.
Checked all connections and wiring, and all clean and good, so looking to get a replacement coil.
Still a bit baffled why I only seem to lose fire when I come off the throttle.
Car has always taken a lot of cranking to start (esp when cold) and doesn't like to idle, but had always put that down to the big cam.
Also, due to my ignorance still a bit confused about the ballast resistor - checked all my wiring and can't find any additional components in the coil circuit, so do I need one with a replacement coil?
Thanks again,
Limey

[Blue]

It's possible you might be dealing with a carb flooding issue, is it an Edelbrock carb by any chance?

[morgan]

Also, due to my ignorance still a bit confused about the ballast resistor - checked all my wiring and can't find any additional components in the coil circuit, so do I need one with a replacement coil?
Thanks again,
Limey

Stock mopar stuff runs 8v and only supplies 12v at startup.
So on crank you get the full 12v and once running it feeds through the ballast and knocks down to 8v.

Depends on the ignition module you have.
If its points; ballast. If its mopar/orange-box - ballast. If its aftermarket it might be 12v and NO ballast (hei module or MSD all in one).
It looks like a white block and mounted on the bulkhead. There will also likely be a voltage regulator next to it.

The coil may offer a clue - does it have any labels on it ?

There are LOADS of ignition diagrams kicking about - I spent ages going round this loop. You'll chase it out. (but answer blues question on carb first!)

[Blue]

It's an Accell super stock coil, they use the stock ballast I believe. To further clarify, it's the coil that dictates if a ballast is needed or not. Some coils happily run at a constant 12V, others will fry if subjected to more than a constant 7-8V, that's the only reason the ballast resister is there.

[Steve]

I went down the HEI conversion route, Blaster 2 coil, electronic distributor, no ballast resistor. Easy to do and works well.

I thought overfueling when I first read this. Almost like the fuel is still filling the carb when foot comes off the throttle, flooding, then struggling to start until fuel has cleared. I have an Edelbrock 1406. Was a nightmare until I disconnected the electric choke, no problems after that.

If it is an Edlebrock, might be worth checking that the metering rods move freely. May be stuck on WOT (wide open throttle) so fuel will be pouring in when you ease off the pedal. Easy to check. Just pop the aircleaner off and very gently loosen the torx bolts on the metering rod covers. If the covers lift up when you unscrew them a bit then they should be moving ok when the vac passes over them as you accelerate. When you decelerate, they drop back down into their seats under spring pressure and restrict the fuel flow (they are tapered). You can clean them if they don't move freely. VERY GENTLY draw them out being very careful not to bend them then give them a very gentle clean. I use Duraglit wad style polish as its not too abrasive (if you use an aggressive cleaner it can theoretically wear them and increase the fuel flow unintentionally). Carefully put them back in and make sure they bounce up and down on the springs. Reseat the covers and tighten the torx bolts. Simple 30 sec check that may just solve it...

Good luck and keep us posted

[LurkinLimey]

That's great - Thanks all.
Blue / Steve - Initially thought this was a fuel problem as this only started after blasting everything with carb cleaner, so might have disturbed something.
Also, could hear fuel draining away when the car was standing after losing fire, so coil thing might be a red herring.
Carb is a Holley 750cfm 4779-9 with the 4 corner idle adjustment.

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So, symptoms sound like those outlined by Steve for a fuel flooding problem, so is there a similar procedure to that Steve outlines that I can follow for my Holley?
Have pretty much decided to replace the coil anyhow as although all connections are good it looks pretty ancient.
On the subject of the ballast resistor, are you saying it's the ceramic white thingummy on the firewall, and if so do I need to worry about it if I'm replacing the coil one for one?

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Thanks again for your patience,
Limey

[Steve]

Blue/ Pete/ Dave etc are the pros on Holley carbs and Im sure can answer properly as I have very little knowledge of jetting etc in Holleys and will be able to help on that.

I think you would be wise to get an MSD Blaster 2 coil capable of handling 12V constantly as this will work on a standard electronic ignition system and is also suitable for a future HEI upgrade (future proof). I have used the cheaper Lucas ones that Dave suggests but have found in my experience, that they are a little hit and miss in the quality dept. Don't think they are British made anymore (may be wrong) but I fitted one to my old Fury and it failed spectacularly recently. Could just be a rogue one but my Blaster 2 on the Polara has served me well to date.

Its been a while since I fitted my HEI but if you go down that route (GM style HEI conversion), you don't run a ballast resistor. Just join the wires together and take it out of the system. If you retain the Mopar Performance orange box style electronic ignition (standard Mopar after 68 I believe, certainly on C bodies) then you will still need a ballast resistor in the circuit.

Again, its been a while so I would make sure this is confirmed by the experts on here

Cheers Steve

[Steve]

Forgot to say, you could try putting a one way valve (non return) in the fuel system to stop the drain back on the fuel?? Just stabbing in the dark but may be worth a try and is cheap. Put it as near to the tank as you can, not the carb end as I initially did on mine

[morgan]

Yes, the ballast is the white thingy. The blue thingy just in shot is likely the voltage reg.
Dont know why ballast would be intermittent... so if it works if prob works. I'd eliminate other stuff first. They are not expensive.

[Blue]

In my experience coils and ballast resisters either work or they don't I've not come across them playing up intermittently. The fuel level on a holley is set removing the brass sight plugs on the front and rear fuel bowls. Do one at a time with the electric pump on but the engine off. Fuel should just spill out when the car is rocked gently side to side.

[LurkinLimey]

Thanks Steve / Blue,
Going down the new coil route, and will have a go at resetting the float bowls (found a youtube video on this).
Assuming would be a good idea to disconnect the coil while doing so if leaving the battery connected to keep fuel pump running.
Coming round to thinking that it is a fuel flooding problem as only started occurring after (vigorously) cleaning the carb.
Will let you know how I get on, and thanks again for taking the time to help.
Limey