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weird spark ?

Posted By: flyman

weird spark ? - 09/21/14 02:22 PM

I was helping a buddy work on his 1975 ram charger. It only was spark when you turn the ign on and then again when you turn it off. It has no spark when turning the engine with the starter. I swapped the ign box with a known good one, and bypassed the ballist resistor. On change on either one. Pickup coil on the dist? Thanks for your help
Posted By: Crazy68Dart

Re: weird spark ? - 09/21/14 02:53 PM

This a new build or was it working/starting fine and he started having issues?

The ignition switches typically have an ign1 and ign2, one is for "run" and one is for "crank".
Posted By: flyman

Re: weird spark ? - 09/21/14 03:07 PM

It was running driving good. Then it started to quit when hot but always restart when cooled off. Now no start at all.
Posted By: RapidRobert

Re: weird spark ? - 09/21/14 03:35 PM

Quote:

It only was spark when you turn the ign on and then again when you turn it off. It has no spark when turning the engine with the starter.


First check reluctor gap. Make sure the box is grounded (it should be since you changed it). Might be the coil or yes the pickup. Pull the yellow "ign" wire off of the starter relay to disable the starter (you know the starter cranks & no need to run the batt down & have the noise distraction) & have a helper work the key & you under the hood with your VOM & see if the coil positive primary terminal and the ECU power in terminal (2 of em if 5 pin ECU/4 terminal "dual" ballast system) have fire in ign2 (crank) and in ign1 (run). Seperate the zigzag pull apart dist pickup connector & drag the male end of the body half across the intake (ground) to make/break ground with the coil secondary wire (dist end) held 1/4" from ground while helper tries the key in both positions & see if you get sparks. (if so, bad pickup/reluctor gap). If not sparking then then remove all wire(s) from dist neg terminal & with a jumper make/break the neg terminal (not the wire(s) you remove from the terminal) to ground same as before like Morse Code & if it sparks then bad ECU (or not grounded well). Holler back
Posted By: buildanother

Re: weird spark ? - 09/21/14 03:42 PM

You did verify that the distrib is turning, right?
Posted By: flyman

Re: weird spark ? - 09/21/14 04:10 PM

Thanks for your help. I have not checked for dist turning yet. Last it was driven was to the auto parts store, when he tried to leave no start?
Posted By: RapidRobert

Re: weird spark ? - 09/21/14 04:24 PM

Quote:

It was running driving good. Then it started to quit when hot but always restart when cooled off. Now no start at all.


I missed this post which tells me that the dist is turning and the reluctor gap is likely good and the wiring/ground is OK. Hard component failure: ballast (you replaced it), ECU (You replaced with a known good one) or bad coil or bad pickup. I'm gonna go out on a limb & say pickup, coil second choice EDIT With the pickup being such a pain to change I would get it good and hot to where is wont (re) start & seperate the zigzag pull apart connector & do that test ASAP while it is still real hot to confirm (or deny) that it is the pickup. Wouldn't hurt to have a helper to try the key in both positions unless you have already confirmed that everything is recieving fire in both positions & if so turn the key to ign1 "on" & you quickly under the hood pulling the coil wire and seperating the zigzag connector & drag the male end of body half across the rough surface of the intake which will make/break continuity & check coil wire for fire.
Posted By: Red 79

Re: weird spark ? - 09/21/14 04:47 PM

For what it's worth, I had the same problem with my 79 D-100 years ago. It was in fact the dist. pick-up. I did a resistance test with an ohm meter at the dist pig tail that confirmed it was dead. The readings when checking at the pig tail should be between 150 - 900 ohm or another way is connect one meter lead to the pigtail and ground the other, if the meter shows any reading the pickup is bad.
Posted By: flyman

Re: weird spark ? - 09/24/14 12:36 AM

Well I did a little more diggen and found the dist does not turn. Neither does the cam gear when looking thru the fuel pump hole. So it looks like on to the timing gear!! Any one seen a failure like that before?
Posted By: stumpy

Re: weird spark ? - 09/24/14 04:41 AM

Might have the plastic coated timing gear and they strip quite often. If that is what it is then you need to flush all the plastic pieces out of the oil pan or they will clog the pump pick up and you get no oil pressure.
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