Carb, Ignition, Timing Issue?

[brbuilder]

'69 302, Holley TA 470, Performer intake, Cardone Electronic Dist & 4-Pin Module

After sitting for several months started it up and had issues, flooding. Cleaning the secondary bowl needle and seat cleared that up. Got it running but had to advance distributor to 30 - 35 or it just cranks but won't fire. Once started I could dial the timing back to about 10 but if I shut it off it will not restart unless I advance the timing to 30 - 35. Idles about 900-1000. Accelerator screw is all the way in. Idle mixture screws are about 1/2 to 1 turn out. Vacuum around 19 - 20 at that 900 - 1000rpm. In the garage, engine would rev good without the vac advance but would backfire through the exhaust if the vac advance was connected. Runs rich, new Autolite AP45's. Pulled the plugs and 1 was clean, 2 were light grey and the other 5 were black.

I've been adjusting timing, mixture screws, new gas. I tried a Motorcraft Duraspark ICM (Amazon) but the wires powering it and to the e-core coil got really hot. Does this ICM need to be attached to the body (grounded) to work properly?

Any ideas/help would be appreciated. Thanks

 

[DirtDonk]

I don’t think it needs to be grounded to the body, but it wouldn’t hurt.
However, it is grounded to the distributor through one of the wires I think, so that’s possibly a future issue. Something to check out anyway with the wiring diagrams.
The reason I don’t think they need to be grounded is that many of them were bolted to plastic body parts on some vehicles.
So I’m guessing the answer is no.

However, they were not designed to power your e-core coils, and so you may simply be running too much current through the ICM.
And are you still running it through the original resistor wire? I doubt it, since that type of coil does not usually need that. But that could affect how hot the module gets.
What about the color? Is it a blue grommet model?

You may need to go back to zero though, and start by checking your timing marks with the actual top dead center point.
Then move on from there.

It kind of sounds like you have more than one issue, but that would be a reasonable first step.

 

[brbuilder]

Thanks for your reply.

It is a blue grommet module. I thought that the module could take full voltage but the factory coil that was originally used required the reduced voltage. Power is coming from the green with red stripe wire from the ignition switch. I am spliced into that wire after the connection through the firewall at the driver side back of the engine. Previous owner had a wire spliced in at this location. The fusible link wire is cut about 3” from the ignition switch. I originally connected here at the 3” section of fusible link wire but it got hot quickly and started to smoke while just testing for voltage at the ICM and coil. Connected at the splice in the engine bay and no smoke but the green with red wire at the switch was getting hot and the + wires to the e-coil were getting hot. This doesn’t happen with the 4-pin module.

I’ve checked for TDC and pretty sure I’m good but may get a TDC checking tool or piston stop tool to get more accurate. The piece of nylon fuel line in the #1 spark plug hole might not have been the most accurate means of testing.

 

[DirtDonk]

It is a blue grommet module. I thought that the module could take full voltage but the factory coil that was originally used required the reduced voltage.

Correct. Blue modules use 12v but the coils on Broncos always got their 6-9v or so through the resistor wire.

Power is coming from the green with red stripe wire from the ignition switch. I am spliced into that wire after the connection through the firewall at the driver side back of the engine.

Do you mean Red w/green stripe? If it's actually the Green w/red, then it's got 12v because it was originally for the external voltage regulator. If not being used for other things, it's a good source of 12v in START and RUN for the ignition.
If it's the Red w/green though, this is your resistor wire. Or at least it's the visible part.

Previous owner had a wire spliced in at this location.

At that connector (is it a red colored flat-3 connector?) there is a factory splice with a Brown wire on the body side of the connector. It's the Brown "I" wire from the starter relay on the fender so that the resistor wire is temporarily supplemented with a full 12v for starting.

The fusible link wire is cut about 3” from the ignition switch. I originally connected here at the 3” section of fusible link wire but it got hot quickly and started to smoke while just testing for voltage at the ICM and coil.

That's not a fusible link. It's actually a resistor and is designed to get hot. Heat actually builds the resistance to flow even further during use.
However, you were correct to stop the test when smoke started! That short section at the switch was not able to safely handle the current of the new ignition components it sounds like. It's also hard to splice on to reliably, which is why through it's entire length it's printed with the words "Resistor Wire Do Not Cut or Splice" or words to that effect.

Connected at the splice in the engine bay and no smoke but the green with red wire at the switch was getting hot and the + wires to the e-coil were getting hot. This doesn’t happen with the 4-pin module.

Yeah, it was probably not meant to be I suppose. You say 4-pin module, so are you running some kind of GM HEI conversion? Maybe the small cap style since you have a separate coil? This is not the coil-on-cap style with the big monster distributor cap then? Are they even compatible with a Ford ICM? I guess the "trigger signal" isn't so far off.
How many wires coming out of the distributor? Got a pic of this setup?

I’ve checked for TDC and pretty sure I’m good but may get a TDC checking tool or piston stop tool to get more accurate.

More accurate is always good. But if the marks are somewhat close when you're at the point you think is TDC then it's probably good.
But check for damper ring slip too. If this is an older damper, the elestomeric material (or whatever it is) may have deteriorated. Or is this all new stuff?

The piece of nylon fuel line in the #1 spark plug hole might not have been the most accurate means of testing.

I dunno, but hey, if it works!
I think nylon line (if you mean tubing) is a good way to do it. But if you meant nylon as in fishing line, then nope, probably not the best. At that point, it's probably better to just use your finger over the hole and feel for when pressure builds, then stops.
Tubing however, might be just the ticket.

Sounds like you have a timing light, so that's half the battler here. While it was running, did you happen to check the action of the two advance mechanisms? Mechanical and vacuum should be very consistent and give a good amount of change.
Oh, and the idle being high was a result of your advancing the ignition timing so far. More advance means a higher idle usually. Which means when you adjust the timing you almost always have to re-adjust the idle.
But in this case, adjusting it for 30 degrees at idle doesn't seem to be the best way to go. Getting the timing figured out first, then set the idle. But you can certainly play with 10 to 18 degrees while you're messing with this.
With my '71 I found that 10 to 14 pretty much covered all the bases under different conditions, but at 18 it was just struggling too much. Never really had a pinging problem, which was weird(!) but did notice a point of diminishing returns at about 15 degrees BTDC when experimenting.

Paul

 

[DirtDonk]

By the way... How's the TA carb set up? Right out of the box? Or did the installer (you?) make any changes?
Is the choke working as expected? Did you check that with the air cleaner off, or has the air cleaner been on all this time?

Unfortunately, unless something has changed in the last few years, Holley used to not recommend the 470 for the V8 engines in a truck. Go figure!
For 70 years or more they've been telling us that too big was wrong and smaller was better (to a point) with carburetor ratings. So 600 was borderline for a stock 302 and so something below 500 would be better. But then along comes the Truck Avenger series and the whole thing goes out the window.
So they do (or used to) recommend the larger TA carbs for even a stock 289/302 in a Bronco.
Has anyone here heard anything different from the previous years?
Personally I would have thought a 470 would be the perfect size for us. But maybe it ain't so...

Good luck.

Paul

 

[brbuilder]

I am getting power from the green with red stripe wire. It comes from one of the two larger 8 pin connectors at the firewall. It’s not coming from the flat red 3 pin connector.

Brain block, should have said resistor wire. Larger outside diameter, dirty pinkish color.

It is the GM 4 pin module mounted remote. The distributor is a Cardone duraspark distribution with the large cap. 3 wires out of distributor-orange, black and second black for the ground.

It is a Summit brand balancer replaced a year or so ago along with timing chain and gears.

Nylon tubing fuel line. Replaced the old lines.

I have a timing light. Mechanical advance is working. Vacuum advance is working also but causes backfiring through the exhaust when hooked up.

TA has 55 primary jets vs the stock 57. I thought the 470 would be a good size for a basically stock 302. Just carb, intake and long tube headers.

 

[DirtDonk]

I am getting power from the green with red stripe wire. It comes from one of the two larger 8 pin connectors at the firewall. It’s not coming from the flat red 3 pin connector.

That’s right. I forgot this was a 69 with the two firewall connectors.

Brain block, should have said resistor wire. Larger outside diameter, dirty pinkish color.

Yep. Puke brown/pink

It is the GM 4 pin module mounted remote. The distributor is a Cardone duraspark distribution with the large cap. 3 wires out of distributor-orange, black and second black for the ground.

OK great! Should be a good setup.
Nothing wrong with keeping the GM module. Inexpensive and easy to find replacements just about anywhere.
Generally considered more reliable than the Dura spark, as long as they are of high the quality variety.

I have a timing light. Mechanical advance is working. Vacuum advance is working also but causes backfiring through the exhaust when hooked up.

Backfiring at all times? Or just under some conditions?
Are you using ported vacuum, or full manifold vacuum connections?

TA has 55 primary jets vs the stock 57. I thought the 470 would be a good size for a basically stock 302. Just carb, intake and long tube headers.

It’s possible you might be running lean.
The headers usually dictate slightly richer carburetor jetting.
And maybe the 470 requires a little more fuel?
Not really sure here, since I’ve never run one.

I believe they still use a power valve, but it should theoretically be of the blow proof variety. Correct?
So in theory a blown power valve should not be causing your current running issue.

 

[gr8scott]

It is the GM 4 pin module mounted remote. The distributor is a Cardone duraspark distribution with the large cap. 3 wires out of distributor-orange, black and second black for the ground.

One of those black wires should have a lavender stripe. I have one mounted as a backup ignition in
case My Spark Disappears, lol

 

[DirtDonk]

Speaking of remotely mounted brb… Is your GM module mounted to metal at least? Or better yet, a heat sink?
Either way, with the use of thermal transfer compound?

 

[brbuilder]

The module is mounted on an aluminum heat sink that came out of an old speaker or computer. Also used thermal transfer compound between the module and heat sink. Similar to gr8scott setup. I need to clean up and color code my wiring once I get things figured out.

Revs good without the vacuum advance connected. When connected to ported vacuum I can open the throttle very slowly and it will not backfire but if I open the throttle more quickly it will backfire. I’ll pull the plug’s again and check them. Pulled them earlier and 5 of the 8 were sooty black.

 

[Soylent]

Do you mean Red w/green stripe? If it's actually the Green w/red, then it's got 12v because it was originally for the external voltage regulator. If not being used for other things, it's a good source of 12v in START and RUN for the ignition.
If it's the Red w/green though, this is your resistor wire. Or at least it's the visible

Paul, whenever I read these discussions I wonder if there is a chart or list by year what the various color combos for wires mean. Does this exist? Interesting that I can’t even find it in the original shop manuals.

 

[Oldtimer]

The maximum amount of vacuum advance can be adjusted.

FORDMUSCLE webmagazine: Timing is Everything - Distributor Curving for Maximum Power

 

[gr8scott]

I wonder if there is a chart or list by year what the various color combos for wires mean. Does this exist?

SeaBiscuit68

 

[DirtDonk]

Paul, whenever I read these discussions I wonder if there is a chart or list by year what the various color combos for wires mean. Does this exist?

Thanks again to Oldtimer for providing some well proven and much appreciated wiring diagrams.
In our case, Ford kept 99% of the same wire colors and functions the same for all years of early bronco. Other than some potential differences in the early 66 models, most everything was the same for all other years.

Interesting that I can’t even find it in the original shop manuals.

You can find them in the aftermarket manuals from Haynes and Chiltons. And not always Haynes! :-(
To get them from the factory manual, you have to have the very specific electrical schematic books. Separate volumes in many cases.
Most shop manuals are advertised as being “the full manual, including wiring diagrams“ but that’s misleading because it has diagrams showing where electrical components and the wiring harness are located, but not the actual schematics.
Sounds like you ran afoul of that.

 

[nvrstuk]

Backfiring thru the exhaust and not being able to give it any real quick throttle w/o backfiring is timing and lean mix. You could be fighting several battles here and not knowing which is the culprit for which symptoms. 35 deg of timing to start is a clue. Are you sure your timing chain hasn't jumped? Check #1 valve timing with TDC.

Do you have a buddy that can slap his carb on so you can eliminate that issue and then dive back into the ignition?

Heck, slap an old points dist in with a coil and lay wires all over the engine but then you'd know where to isolate the issue and go from there

 

[brbuilder]

My plugs, 5 of the 8 are black. #1 reddish,brown, #4 and #7 are clean. These are new Autolite AP45’s. It’s a new timing chain and damper. I’ve checked TDC again and it’s right on zero.

 

[nvrstuk]

Those are the same plugs that were in the engine when it was flooded really bad, correct? If so, that's why those 6 are still black. the other 2 might not be firing at all. Gas and air doesn't discolor plugs black firing them with fuel does (more tan), and oil does. So you have no way of knowing if they are that way because of what's going on now or when the carb was flooding the engine.

Best best, find somebody's running carb and with only 4 bolts, 1 wire and 1 throttle clip to disconnect and you can then isolate it to only ignition...

OR

Slap in a points distributor ignition and then see if your carb is creating most of these symptoms (except the 30deg to start symptom)

Are you willing to put $1,000 up for the timing gears and chain being aligned perfectly? 30-35deg to start is obviously about 22-25 too much. Remember, just because you can rotate the distributor to align #1 on the rotor with #1 on the cap and have TDC doesn't mean the cam timing is correct-hence the 30deg to get the mixture to fire when the valves and pistons are where they should be.

 

[Broncobowsher]

The HEI module needs to be grounded by one of the mounting bolts.
The HEI module should fire the E-core just fine. And bypass the ballast resistor. HEI takes a full 12V. Don't forget to keep the ignition bypass off the starter solenoid.
You stated the damper is new, but did you confirm it has the right timing parks to match the pointer? Small block Ford can have the timing marks in 3 different locations. Two of which are fairly close to each other.
Ohm out the plug wires, mostly the coil to distributor wire. I've fought hard start a few times just to find it is a bad coil wire.
You might be getting it to start with excessive advance simply because the cylinder pressure is still low enough to toss a spark by igniting before the cylider pressure builds too much to prevent the spark from jumping.

 

[nvrstuk]

I forgot that the HB was new
Definitely check the timing marks, HB placement/ alignment.

 

[gr8scott]

Thanks again to Oldtimer for providing some well proven and much appreciated wiring diagrams.

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