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-   -   I'm sorta stumped..... (http://ratrodsrule.com/forum/showthread.php?t=37864)

Bamamav 10-01-2019 08:35 PM

Well Dr C, ground cable goes directly to alternator bracket, also have a braided wire ground from an intake bolt to the firewall, distributor is clean aluminum, bolt and clamp are paint free.
I even tried a hot wire direct from battery to coil, no difference.

I'm wondering about that module. It isn't flat like a GM module with the 4 wires, 2 on each end, it has all 4 wires on one side, but probably works the same. I don't know about the advance, it's down under the pickup wheel, can't really see it.

It has started when it shuts off to spit fuel back out of the carb, that makes me think ignition is giving up, if it was working that should be a fireball, not raw gas.

My chinese distributor may just be junk. I should've just went ahead and bought a 85 Mustang GT carbed distributor and ran it off a GM module, but I got in a hurry trying to make a self imposed deadline. Live and learn....:rolleyes:

Burgerman 10-02-2019 12:10 AM

Think you're on to something with the consistent drop off at 2000 rpm and the fuel spit up as the engine dies. I've replaced stock ignition parts to "upgrade" and ended up going back to them. Hang in there Bama. This is gonna get figured out.

Old Iron 10-02-2019 08:25 AM

Go by Occam's Razor
"The simplest solution is most likely the right one."

Dr Crankenstein 10-02-2019 06:35 PM

I would still verify voltage... measured at the ignition, car running.

I'm simply suggesting, your alternator/regulator may be providing too much voltage, or none at all.

A GM HEI will run on low input voltage, but it's hard on components... too much input voltage will kill the module in short order. Your present ignition may be more sensitive, or not... regardless, I'd want to know what the ignition is seeing for actual input voltage, both static and running, if you can keep it running long enough to measure!

Kindly disregard this message if you've done all that already...

P.S.: What coil are you using and what's your spark plug gap?


Bamamav 10-02-2019 09:35 PM

To answer best as I can Dr C:
New fully charged battery
Alternator is same Delco 35 amp I had on other engine, putting out about 13.6 volts
Read 13.6V at coil static, haven't checked while it's running
Put a jumper from battery direct to coil 13.6V
Coil is used 12 volt taken off a 8N Ford tractor, I had thought it was getting hot causing problem on tractor so replaced it, turned out not to be the cause.
Plug gap is about .035, I had set them to that for the points and haven't reset them yet.

Didn't get a chance to work on it today, maybe tomorrow I'm going to put the points dizzy back in and try it again. If that works, I'm putting my 4bbl back on to try.

I have began to think something is amiss in the HEI, pickup, module, something that works weakly at low RPM's, just enough to fire it off but not enough to keep it going until it spins faster. I mean, when you start letting off the pedal, it gets down to around 2000 rpm, it just shuts off like you turn off the key, and with it spitting gas out as it spins down, the fire has to be out because it doesn't even pop out the carb or exhaust, it just quits and spit gas back out. If there was fire there, it should spit a fireball. It's a magnetic pickup, maybe the magnet is too weak?

phil cottingham 10-03-2019 08:34 PM

Bama, I had something similar years ago with a points distributor and it was the weights or springs in the distributor.

Bamamav 10-03-2019 10:38 PM

Too busy today to try anything. Tomorrow looks busy, too, got 20 ton of gravel coming for the drive and carport. I see a lot of tractor and box blade time for a couple of days...

Dr Crankenstein 10-05-2019 09:58 PM

Your dilemma has been burning a hole in my head, so I did some research...

As you might expect, real technical information for knock-off ignitions is virtually non-existent, so I read up on GM's HEI, which might shed some light on the subject...

A GM HEI control module increases dwell as RPM increases. (I'd expect aftermarket/copycat modules do the same.) The increased dwell ensures adequate time for the coil to fully saturate and deliver the appropriate amperage. (We're talking more camshaft degrees and milliseconds here.)

Here's my theory... good, bad or shotgun fodder...

Your coil's resistance is probably too high. If that's the case, it's too slow to saturate and therefore, can't reach the demand at low RPM. If your module acts like a GM module, more RPM brings more dwell, which could (potentially) allow your slow coil to "soak" long enough to fire above 2000 RPM. [S

Am I nuts? Probably, but one thing is for sure... an electronic ignition requires a low resistance coil to accomplish "high energy". I'm guessing, your points type 8N coil measures something like 2.5 ohms resistance, which severely handicaps an electronic ignition designed for a "fast" coil measuring anything between .3 and .7 ohms resistance.

Sorry for the long-winded post, Bama... just sharing what I believe is the root cause of your failing ignition. I'll bet you a dollar, a proper coil will cure your issue...




26Troadster 10-06-2019 08:46 AM

doc may be on to something there.

Old Iron 10-06-2019 09:54 AM


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