electrical or carb issue mmm

[cudaboy 67]

hello, odd one here, had for last couple months now, car starts a1 then great until i give it a little beans, goes fluffy, no idle then dies, tonite was last straw as had to get tow home, in past i left car for half hour but tonite worst ever, car a 68 barracuda,ive rewired so know electric good, ign a msd 6a run off points dizzy <msd will trigger from these fine> mech fuel pump, holly 750 vac sec 4 speed manual.msd blaster coil, now im getting tiny bubbles in clear filter, never given much concern as had these before,pump the gas pedal and you can see fuel squirt in primarys.car still real fluffy and not reacting to fuel input,coil does seem quite warm as mounted on carb inlet yet facing upright,changed condenser still same,put my multimeter on wires from msd to coil and no 12v yes does start and kinda run. bet you $20 ill go out there in mourning and she fire up run sweet...........till goes wobbly. ps the msd settup been on car last 12 months and not missed a beat.,,,.............just went on msd website quote"One common question in regards to MSD Ignition controls is &#8220;Why isn&#8217;t 12V power on the orange (COIL +) wire?&#8221;
The main reason 12V won&#8217;t be present at coil + is because your MSD ignition is a Capacitive Discharge Ignition... so aint that lol

 

[Mopar2]

timming?

 

[67Dart273]

I don't know. Since you are running a points ignition I would be VERY tempted to yank the MSD out of there at least temporarily. High on my list of suspects is the coil itself. Have you checked starting spark to get a feel for this?

(On that note, it is IMPORTANT, if you still have a ballast resistor in circuit, to check cranking spark BY USING THE KEY to crank the engine, and NOT jumpering the start relay. This is because you won't have the resistor bypass circuit in affect.)

I don't believe you WANT the radio suppression cap (condenser) on the positive side of the coil with an MSD, so if you have one, I'd remove it.

(So far as the condenser in the distributor, I don't believe it's needed for MSD, but probably won't hurt. It certainly is needed for a stock points/ coil)

Check your original "dark blue" "ignition run" wire supplying the ignition system. This is the wire coming from the key/ switch, out of the bulkhead, which originally supplied the "key" side of the ballast, and also the ignition terminal on the ballast.

Check this key in "run" engine OFF. Stick one meter probe on that wire, the other probe on the battery positive. This will show voltage drop through that circuit, and you should read LESS than .5 (1/2) volt. The less the better, and even 1/2 is generous

That much or more indicates a drop somewhere, most likely bulkhead connector, the ignition switch connector or the switch itself.

Any thoughts on condition of fuel, tank, fuel line? Have you had the carb apart to inspect for dirt/ rust? How does the filter look in this regard?

 

[cudaboy 67]

thankyou for reply, i rewired car and wiring to and from new keyswitch coil and msd,no ballasts there anymoreso i know the wiring ok,i cannot see any crap coming through inline filter so im miffed. im going to drop the tank and clean out as a matter of doing anyway, maybe there be poo or even water in there,cheers for reply, nathan.

 

[67Dart273]

Regardless of rewiring, you need to check the ignition voltage. You could have a poor ignition switch, or bad connection at the switch or through the bulkhead.

 

[cudaboy 67]

hello, cheers for the help. i did away with the bulkhead connectors when i rewired the car,im going to clean my tank out as a precautionary as twice sine ive owned car in 6 years its been parked up for long period and outside here in wet wales :sad7: then im going to take for a spin but remembering my toolbox in back!