Testing distributor

[RatLabGuy]

'73 Bronco, original 302.
Ran (rough) last fall. Benn parked for 6+ months, no hood.
Can't get it started now, no combustion even pouring gas right into carb.
Best I can tell, does not seem to be a spark... if I pull a plug wire and hold it to the block, no spark arc (even if I put a jumper wire up into the plug cover)
If I put a meter on the output from the ignition coil that goes into the distributor, it reads 12v constant while the key is ON, while I try to start it (via bypassing the ignition switch and jumping the starter solenoid) it drops to ~10.5 or so.

So to me this means there is juice going into the distributor
Now, if I pull a plug wire off the distributor end and put the the meter on one of the "out" plugs of the distributor... nothing, ever, while starting. Shouldn't it spike while the rotor passes?
Does this mean there is something funky w/ the cap? The buttons didn't look too bad, I cleaned them really well, as well as the rotor leads...

I'm baffled as to what could have "gone bad" on a distributor while just sitting.

On a completely different note - when checking the wire routing, I realized that the plug firing order is set for a 351, instead of what it should be for a 302. After scratching my head awhile (since this DID work), I'm wondering if this means there is some kind of funky cam in in it... anybody heard of that? I'm having a hard time understanding how you could ever change the plug order so dramatically and it still works.

 

[Infamous1]

I have seen guys switch up the firing order before and no issues some guys think one runs better than the other idk about that but lt ran like that so no worries. I think your points are probly stuck, pull the cap off and then the rotor and the points cover and run a piece of sandpaper between the points contacts. Some of the more "seasoned" guys on here probly be alot more help but that is my thoughts on it. Good luck!!

 

[Tim C]

Yep if it has points they're probably corroded. Sand or use a nail file on them and I'd bet it'll start. If not points and condenser is cheap. An ohmmeter won't check the cap and rotor cause there's a small air gap between them they don't touch. If someone swapped in a newer model 302 it'll have the 351 firing order if its a high output or 5.0ho. All the injected mustangs use that order and quite a few aftermarket cams too so someone may have just picked a can with that order during a build.

 

[RatLabGuy]

The points on the underside of the cap don't look too bad. I cleaned 'em w/ a brush.. .as well as the rotor (it ws fairly corroded) but still no change.

Even w/ the small air gap, when the rotor passes by the point and arcs, once (if) an arc is made shouldn't you be able to read voltage on the other side?
E.g. what I would expect is a flat nothing then a quick temp spike of 12v then back to nothing until that point fired again... I'm getting nothing at all.

Fun part of this is - I have no idea what the ignition/cap is. Its definitely not a "normal" one, instead of the cap being tall and skinny, its wide and short, the buttons ae not very tall and have an expose tip on them. Does not match the generic replacements for a 73 302.
All I can find is a logo for Standard on the button... but no idea what the distributor is to buy a replacement

 

[Tim C]

Check out a post 1976 302 cap. It sounds like it has the duraspark ii electronic ignition cap. That'll have a plastic cap adapter shaped like a funnel going to the wider cap. The points I was referring to were breaker points which electronic ignition won't have. Is there a silver box somewhere with two wiring connectors coming out of a blue grommet? That's the ignition module. Its about 5"x5" or so.

The cap won't spike 12v when the rotor passes it. If the coil actually fires it'll be in the 20-30000 volt range. But it the module or distributor pick up is bad it won't fire.

Can you post a pic of the cap and also of the distributors guts. That'll help a bunch with diagnosis. It's possible to put the wider electronic ign cap rotor and adapter on an older distributor.

 

[Blkvoodoo]

Dave, it sounds like there may be some terminology confusion ( air gap, contact points, terminals ) which could lead to some confusion in trying to help your problem.



get us a picture of what you have, will help in figuring out what needs to happen next

 

[Ron]

You dizzy should be putting out 10,000+ volts. Your meter probably cant read that high. It also puts it out for a very short duration only a quality meter with a high point memory Latch" to ever see it.

This isnt the raffle bronco is it?

 

[Blkvoodoo]

This isnt the raffle bronco is it?

No, the was won by Brandon @ Rides of Conover, never to be seen again ( the Bronco ) Can you believe that was five years ago ?

 

[broncosbybart]

Never to be seen again?? It went back to TN. Then Ben @paradisePWoffrd had it for a while. After that, it went back to TN, where it probably still is.

Based on the discussion, can't tell if you have a points type dist or not. 73 was the last year for points in a Bronco. Post up some pics of what you are working with. It is possible that it was replaced with an electronic dist when the engine or cam was swapped. It may have a HO engine in it. Very common swap. If it does, the dist gear will need to be a steel gear. A cast dist gear on a steel cam will cause BIG problems. The original dist would have had a cast gear on it.

If it has been sitting for 6 months with no hood, I'm sure no spark is your issue.

 

[paradisePWoffrd]

Never to be seen again?? It went back to TN. Then Ben @paradisePWoffrd had it for a while. After that, it went back to TN, where it probably still is.

Based on the discussion, can't tell if you have a points type dist or not. 73 was the last year for points in a Bronco. Post up some pics of what you are working with. It is possible that it was replaced with an electronic dist when the engine or cam was swapped. It may have a HO engine in it. Very common swap. If it does, the dist gear will need to be a steel gear. A cast dist gear on a steel cam will cause BIG problems. The original dist would have had a cast gear on it.

If it has been sitting for 6 months with no hood, I'm sure no spark is your issue.

Raffle Bronco was in nc until 2 yrs ago when it went to TN & is now in KY.

I'm with Charles, likely it's corroded electrical pieces

 

[RatLabGuy]

See attached pics. Sorry for dirty cell phone quality.
As far as Iknow the engine is ooriginal...

 

[RatLabGuy]

To me this seems like a typical distributor, but I have limited experience w/ em. No aparent electronic control model etc. The button points under the cap really don't look bad to me, but I'd have no problem just changing it out - if I knew what it was.

 

[Tim C]

That's the duraspark electronic ignition. Not stock on pre75ish fords. You'll need to look up parts for a 76 bronco or pickup. The part with the wires in the distributor is the pickup coil. There should be a module somewhere on a fender or firewall. I'll post some testing info and pics when I get home in an hour or so

 

[Tim C]

Thats what the ford duraspark module looks like. It'll be mounted on a fender or firewall somewhere unless the previous owner is using the ford distributor to trigger an aftermarket box such as MSD6A or something.

If it has the ford box the red wire on the two pin connector is ignition hot (12v+ key in run and start) the white wire is 12V+ key in start only. The black wire in the 4 pin connector is the modules ground, it goes through the distributor. If you check it with an ohmmeter it should be a low resistance 10ohm or less from the module to the engine block/ battery negative. If the distributor is corroded between the block and the dizzy base it can cause a no fire. That black wire runs into the distributor and grounds on a screw head near that pickup coil. The green wire from the module goes to the negative side of the coil. The coil will have two small (primary) wires going to it. One will be hot (12V) in start and run, the other goes to the module green wire. The orange and purple wires on the module goes to the pickup coil (the part inside the distributor with the small wires going to it:

Every time one of the arms on the reluctor wheel or stator (the octopus on the dizzy shaft) passes this pickup it generates an ac voltage pulse. The module uses this pulse to trigger the switching transistors inside itself which opens the ground on the green wire firing the coil. The purple and orange wires coming out of the distributor should be 400-1000 ohms between them with the dizzy unplugged. If you read between them with the dizzy unplugged and have someone crank the engine they should produce a low AC voltage (.7- 2.0 volt). If the pickup produces ac voltage and the ohms are good at the pickup and between the black wire at the module and the battery - post and you have 12volts on the red and white wires at the proper times then the module is bad.

The duraspark modules are notorious for failing to the point that most folks mount a second one beside the original so when one goes out you can swap wires and drive off in seconds. The pickup is the next usual failure point but not as bad as the module. However since yours has sat with the hood off for a while I'd check the grounds and powers too just to be safe.

If you have a different aftermarket or 4 pin GM HEI module then post up what it is and I can help you diagnose that too.

 

[Ron]

Never to be seen again?? It went back to TN. Then Ben @paradisePWoffrd had it for a while. After that, it went back to TN, where it probably still is.

Based on the discussion, can't tell if you have a points type dist or not. 73 was the last year for points in a Bronco. Post up some pics of what you are working with. It is possible that it was replaced with an electronic dist when the engine or cam was swapped. It may have a HO engine in it. Very common swap. If it does, the dist gear will need to be a steel gear. A cast dist gear on a steel cam will cause BIG problems. The original dist would have had a cast gear on it.

If it has been sitting for 6 months with no hood, I'm sure no spark is your issue.

There were 2 raffle broncos werent there?
i thought Dave won the first one and Brandon won the 2nd one?

 

[catfishblues]

There were 2 raffle broncos werent there?
i thought Dave won the first one and Brandon won the 2nd one?

The first one was a Cherokee from Dylan. Yes, Dave won it. I rode bitch in the race. I should have bought it when I had the chance. That thing flat worked.

 

[RatLabGuy]

View attachment 158864
Thats what the ford duraspark module looks like. It'll be mounted on a fender or firewall somewhere unless the previous owner is using the ford distributor to trigger an aftermarket box such as MSD6A or something.

If it has the ford box the red wire on the two pin connector is ignition hot (12v+ key in run and start) the white wire is 12V+ key in start only. The black wire in the 4 pin connector is the modules ground, it goes through the distributor. If you check it with an ohmmeter it should be a low resistance 10ohm or less from the module to the engine block/ battery negative. If the distributor is corroded between the block and the dizzy base it can cause a no fire. That black wire runs into the distributor and grounds on a screw head near that pickup coil. The green wire from the module goes to the negative side of the coil. The coil will have two small (primary) wires going to it. One will be hot (12V) in start and run, the other goes to the module green wire. The orange and purple wires on the module goes to the pickup coil (the part inside the distributor with the small wires going to it:
View attachment 158865

Every time one of the arms on the reluctor wheel or stator (the octopus on the dizzy shaft) passes this pickup it generates an ac voltage pulse. The module uses this pulse to trigger the switching transistors inside itself which opens the ground on the green wire firing the coil. The purple and orange wires coming out of the distributor should be 400-1000 ohms between them with the dizzy unplugged. If you read between them with the dizzy unplugged and have someone crank the engine they should produce a low AC voltage (.7- 2.0 volt). If the pickup produces ac voltage and the ohms are good at the pickup and between the black wire at the module and the battery - post and you have 12volts on the red and white wires at the proper times then the module is bad.

The duraspark modules are notorious for failing to the point that most folks mount a second one beside the original so when one goes out you can swap wires and drive off in seconds. The pickup is the next usual failure point but not as bad as the module. However since yours has sat with the hood off for a while I'd check the grounds and powers too just to be safe.

If you have a different aftermarket or 4 pin GM HEI module then post up what it is and I can help you diagnose that too.

Thank you thi has been very helpful.

Yes, it looks like this is indeed a Duraskpark II, w/ the blue grommet. Soem of the wiring colors are a little different but everything is there.
I have discovered a few things.
First I should say the wiring on thsi truck is a major hack job done by some yahoo (possibly my uncle, lol) and lots of butt connectors and 10 year olf electrical tape mess. So I'm having to trace through things to figure out what I've got.
I did find that once I started pulling apart a giant wad of gooy electrical taped wiring, the white wire coming from the module was broken off just behind a butt connector. Fun part - no corresponding wire in the same bundle of goo . However over in a different bundle that several of those were tied up with on their way to the dizzy, I found a different broken end wire... double fun: it's a 12v when in "run" but not just "start". So I don't know if thatst he one it had been hacked too (seems unlikely b/c the lengths aren't quite right) and it was just previously mis-wired or I have multiple random loose straggler wires (very possible).

All that aside - when I test resistance on the orange/purple lined coming out of the dizzy base pickup, there is nothing. Looking inside, both wires appear connected to the magnetic inductor. It is dusty though, a little rusty but dosn't look aweful. Is there a way to get that thing out to clean it? Does the whole dizzy base have to come out? That certainly seems like it could be my problem.

 

[RatLabGuy]

The first one was a Cherokee from Dylan. Yes, Dave won it. I rode bitch in the race. I should have bought it when I had the chance. That thing flat worked.

yes the infanous "$30 XJ". I have only a handful of regrets in life, one of them is not hanging onto that thing and bringing it up here w/ me.
... but I'd certainly have no room for that and this Bronco so that would have been rough.

This ia '73 that belonged to my uncle for many many years, he used it as a hunting/beater toy for a while before he got older and didn't get out anymore... its been sitting a long time and has had a lot of quick-hack work done to it.
This has been quite an education after being a Toyota guy for so long.

 

[Tim C]

The pickup sounds bad if there's no resistance. It can be replaced separately. Mark the reluctor wheel (8 armed piece) so it can go back on correctly, ie: sharpie marker facing forward. Take two flat screwdrivers and pry it gently up from the base of it. DO NOT pry on the arms themselves. The reluctor and a small roll pin holding it in place should come off the dizzy shaft. Then you can replace the pickup. Rust doesn't matter unless its huge flakes of cancer rust. Surface rust is about normal due to humidity. You can buy a reman dizzy for 40 ish dollars that'll have a new pickup and stuff.

 

[Tim C]

I'm pretty sure the white wire won't affect it cranking or running. It retards the timing while cranking to make it easier to start. That's why a lot of older fords would fire right up if you tapped the key as long as the carb was properly tuned of course.

 

[RatLabGuy]

The pickup sounds bad if there's no resistance. It can be replaced separately. Mark the reluctor wheel (8 armed piece) so it can go back on correctly, ie: sharpie marker facing forward. Take two flat screwdrivers and pry it gently up from the base of it. DO NOT pry on the arms themselves. The reluctor and a small roll pin holding it in place should come off the dizzy shaft. Then you can replace the pickup. Rust doesn't matter unless its huge flakes of cancer rust. Surface rust is about normal due to humidity. You can buy a reman dizzy for 40 ish dollars that'll have a new pickup and stuff.

Yeah I've been reading baout this, having a really hard time getting that reluctor off, it looks like the roll pin is really jambed in there and stuck w/ some rust.
If an aftermarket dizzy comes w/ everything for $40, I'd think that would be just easier in the long run to help eliminate problems anyway?
Now for what seems like a silly question but I can't find details - what vehicles would I use to search for at the auto parts store for this distributor? New body (77+) Bronco or F150? I assume it must match the 302

 

[Tim C]

Yea. It Has to be a 302. Ford came out with duraspark in 74 but not across the whole line. I'd look up parts for a 76-79 pickup f100, small bronco, f150, etc. As long as its a 302.

For 40-50$ you'll get all new everything so there's nothing worn out like the advance mechanism

 

[RatLabGuy]

Yea. It Has to be a 302. Ford came out with duraspark in 74 but not across the whole line. I'd look up parts for a 76-79 pickup f100, small bronco, f150, etc. As long as its a 302.

For 40-50$ you'll get all new everything so there's nothing worn out like the advance mechanism

Roger. I'll probably just go that route, seems more cost effective because then I'll know what I have.
Thank GOD I already checked the plug wiring and realized it's the 351 setup, that would have been a nightmare.

 

[Ron]

I'm a die hard ford guy at heart.
Got 3 Mustangs (1st and 2nd gens) to prove it.

That said I HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE HATE the duraspark box.

If it were mine and I didnt want to run a multispark box, Id run this:
http://www.speedwaymotors.com/351W-...B70Ts8G8B9hyY-XA4gxzWqAn8-Yt7j41M2XuEnobw_wcB

Get rid of the duraspark and get a hotter spark to boot. You can get a cheaper version as well as low as about $70...that gets you a new coil in the process. The duraspark box will fail. Thats why the one car I ahve that has one has a spare in the glove box. And btw when you go that route test that spare and dont trust advance auto to have a good one.

 

[Infamous1]

Don't sugar coat it Ron, how do you really feel about duraspark??