Ignition Electrical Troubles

C

cbmind

Member
So in an effort to tune the carb, I've developed a no start condition. See thread here https://u2964092.ct.sendgrid.net/wf/click?upn=oqq1wamxfxfdvhttozscnvqj9hbpou6ogisiiyl1hbgd2kdqauygftr-2fl1hkzwnw1kbaj-2f1xstuqd7zp2zzhi3qupv0shn2qrklk0pk5uea-3d_c7rd0pcoydg4ypggenzsdyyztvierxjnlryioo8kyv-2ffvoemqy9-2bix9rfzyec-2bo-2bauuoaezrjm8q6mujzm3-2f-2fr-2bxtxgmoafj43c67zcojkg14ykqepeqyffdeq0le650tqywpc3xgqzwi2-2fglp-2fray-2fc8i1yt6bwvgpys7uyalfmbew3n1zchc538d2lunuvckwdpzp5fqmlh2-2fkk79tpffohox7cfx4zxpxd3bbdeo-3d

Truck specs- 1980 traveler with recently installed kwikwire harness. Ih345 v8, Holley points distributor converted to duraspark with GM 4 pin module. Msd blaster 2 coil, new olugs, newish wires. Was starting and running reliably.
In diagnosing a flatspot in fueling, a cable to the bat pole on starter sparjed on the firewhile with key on, engine not running. Since then, won'the start. Turns over, but no spark.

Tested good GM 4 pin module, msd blaster 2 coil tested .8 ohm on low end, 5.245 on high end.
With key forward in run position, have 13.2v to coil positive. Have 13.2v to b terminal on GM 4 pin module.

Pulled off distributor end of coiled wire, inserted old spark plug, grounded threads of spark plug, connected connected crank switch, key in run, bump motor, no spark at plug. Coil wire ohms measure 3.077k. Fuses look good. I have 10v to coil positive terminal during crank.

What's wrong? Where do I go from here? I fixed the wire that was grounding out on firewall. Bad shrink wrap job.

Thanks
 

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I'm not familiar with the duraspark conversion, but there has to be something inside the distributor that functions as a sensor or pickup. What about that component? With the 4 pin checking out good and volts at the coil, I'd be looking inside the distributor.
 
Was the 4 pin module verified good before or after the arc welding at the firewall? Also kind confused about the spark plug test. I usually just pull a plug wire off a plug, insert a spare spark plug in the end of the wire, ground the plug someplace and crank the engine.
 
Yeah I know. Researching how to do that now. It's essentially the reluctor wheel and hall effect sensor from a late 70s to early 90s Ford v8.
 
hondo said:
was the 4 pin module verified good before or after the arc welding at the firewall? Also kind confused about the spark plug test. I usually just pull a plug wire off a plug, insert a spare spark plug in the end of the wire, ground the plug someplace and crank the engine.
Click to expand...

That's what I did. Just used a bump switch at starter to roll the motor with the key in run position.

As far as the 4 pin module, the truck was running prior to issue.

Series of events- diagnosing fuel issue> did vacuum check> did compression check> reinstalled fresh spark plugs > reinstalled spark plug wires> no start. At that point checked fuses> looked at wires, that's when I found the wire down to bat terminal grounding/ arcing on firewall at a soldered splice joint I had made and done a bad shrink wrap job on.

The wire above has a fusible link at the bat connection at starter, just soldered in a new one for good measure.

Still no spark.

Researching how to test hall effect sensor for duraspark now.
 
I worked on this ignition conversion but it was on a mallory distributor, so not exactly the same. But the parts were. What I found was that the air gap is important. Too wide, no spark. There really isn't a "too close". If your reluctor touches the pickup, its too close.
The other thing is the module itself. I went through three different "cheap" brands of modules before I bought a standard or delco one (can't recall which). The others would crap out and leave me stranded. This one didn't. In fact, bill (of hamilton injection) says to have your "suspect" unit tested at the parts store three times before you decide its actually good. If it fails during one of these tests, its ng.
And if all that fails, drag the parts out onto the bench and test them as a unit. Meaning the distributor and module, the coil, and either a 12v batt charger for power, or the battery itself. A pain in the butt, however now you can spin the distributor and view the spark quality. This will also verify your coil and the airgap placement, as well as the condition of your cap-rotor-wires.
Not sure how sparking the wire against the firewall would cause the issues you're having. You have tested voltage upstream, and it all looks good. Nothing really fragile about the pickup coil in the distributor. Ohm-ing it our will show if it still has continuity (if it reads zero ohms its bad). My efforts would be proving the module is ok.
 

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When you say air gap, do you mean the gap between the reluctor wheel fin and face of the pick up sensor magnet or some sort of relationship of the plate to something else?
 
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As the current pickup coil is installed, it ohms out at 433.8 new one measures .618 both gotten from a radioshack digital multimeter.

Readings aren't making sense to me. Is the first number good or bad? Second number is from new unit, not installed literally our of the box. Am I supposed to ground it or something?
 
The two pickups I have read .600 ohms (Ford) and 320 ohms (mopar). I ran the mopar one in the original buildup. The Ford one is new in the box. Kind of a head scratcher...

According to bill:

to test the stator (also known as the magnetic pickup assembly), you will need an ohmmeter. Run the engine until it reaches operating temperature, then turn the ignition switch to the off position. Disconnect the wire harness from the distributor. Connect the ohmmeter between the orange and purple wires. Resistance should be 400-800-. Next, connect the ohmmeter between the black wire and a good ground on the engine. Operate the vacuum advance either by hand or with an external vacuum source. Resistance should be 0-. Finally, connect the ohmmeter between the orange wire and ground, and then purple wire and ground. Resistance should be over 70,000- in both cases. If any of your ohmmeter readings differ from the above specifications, then the stator is defective and must be replaced as a unit.

Based on this, I'd go with the higher reading one.
 
dealbreaker74 said:
hmmm, standby. Those numbers should be closer. I think I have one in the shop I can ring out.
Meantime, did you look at one of bill's links to mod your distributor? Like this one?

http://www.binderplanet.com/forums/...rk-distr-conversion-carb-efi-save-500.125949/

I figure its ok to post it since he sells his stuff here...?

Be back with an update in a few...
Click to expand...

I bought the used distributor already modified for the FI conversion to control both fuel and spark using the GM 8 pin module years ago and used with success for 5 years. The tuck sat idle due to engine swap. Had issues with TBI, threw the carb back on it in an effort to get it running and tagged. During that time I swapped to a GM 4 pin module following that link. It was running until last week, although with a rough spot.

So I suppose the answer is yes..
 
dealbreaker74 said:
the two pickups I have read .600 ohms (Ford) and 320 ohms (mopar). I ran the mopar one in the original buildup. The Ford one is new in the box. Kind of a head scratcher...

According to bill:

to test the stator (also known as the magnetic pickup assembly), you will need an ohmmeter. Run the engine until it reaches operating temperature, then turn the ignition switch to the off position. Disconnect the wire harness from the distributor. Connect the ohmmeter between the orange and purple wires. Resistance should be 400-800-. Next, connect the ohmmeter between the black wire and a good ground on the engine. Operate the vacuum advance either by hand or with an external vacuum source. Resistance should be 0-. Finally, connect the ohmmeter between the orange wire and ground, and then purple wire and ground. Resistance should be over 70,000- in both cases. If any of your ohmmeter readings differ from the above specifications, then the stator is defective and must be replaced as a unit.

Based on this, I'd go with the higher reading one.
Click to expand...

Good info! I'm at an impasse.. Looking at bill's video in the link and your pictures, it looks totally doable to test the entire circuit outside of the vehicle. I need to get at the pickup coil, so I guess my next move is to pull the coil canister , distributor, module and jury rig it using as much installed wiring as possible and see if I get a spark, then go from there.
 
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dealbreaker74 said:
I worked on this ignition conversion but it was on a mallory distributor, so not exactly the same. But the parts were. What I found was that the air gap is important. Too wide, no spark. There really isn't a "too close". If your reluctor touches the pickup, its too close
Click to expand...

Confirming your talking about the 8 spoked wheel as the relucror and the pickup as the pickup coil/ duraspark part? Air gap= relationship of the magnet face to the edge of one spoke as it turns?
 
Yes, correct. If you get everything on the bench, you can spin the distributor by hand and with a vom hooked up, you'll see the voltage jump as each of the metal "flags" passes by the pickup. Your radioshack vom with the needle is perfect for this. Just set it to the lowest dc volt setting.
If the needle is bouncing, then hooking the rest of the stuff up should let you see a spark jump off the coil. Like I said, an external 12 v power supply is best, but a battery charger works too. You'll need about 5 amps for the coil to spark. And obviously use caution. This will snap the crap out of you if you're holding onto anything metal!
Plenty of wiring examples are available on bill's forum over on IH Parts America site.
 
Reading through the distributor thread, I finally noticed what May be part of the problem. The distributor I have was set up to use full FI, hence the weights and springs are gone. I hate to throw parts at a problem, but figure I'm better off locating another Holley distributor to convert. The fellow who suggested this problem earlier (about being disabled) is probably spot on. So I'm in search of a good used Holley distributor, I've already got the Ford parts. Will follow up with result, hopefully closing out this problem.
 
That is a decent idea if you're going back to a carb. The distributor in its current state will not be suitable.
That being said, no spark is still no spark. If your current setup doesn't work, you'll need to get that issue solved no matter what you drop in. If the problem persists with the next distributor, you'll have to start looking at why.
 
Good point!

I wanted to say thank you for all the help! I managed to locate a Holley gold box distributor and did the GM 4 pin kids w/ duraspark per bill's instructions. Fired right up! I will say that I'm certain it was a faulty module, everything else checked out. That should close out this thread.

Thanks again! Now, back to the fuel issue...
 
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