Pertronix and fuel pump issues - carb'd 347

[Gumball]

I mentioned a couple weeks ago in the Open House thread that I was planning on going, but was sidelined by an ignition and fuel issue. Some may remember my plug wire thread from last summer where I discovered, after experiencing a miss that got worse over time, that the old-school OEM appearing plug wires I used were getting cooked under the heat sleeves down between the headers. But, due to those sleeves, I didn't see the issue until it was too late and the wires were literally falling apart due to heat damage. The solution was to install some sort-of old-school looking heavy duty silicone wires - problem solved, or so I thought.

Shortly after that, I started to deal with a hot start issue. If the car was warm, it needed some throttle to keep running for the first couple of minutes. Also, if it didn't catch right away, chances were it was going to need to sit for a while and cool off - this only happened twice. But, the last straw was when it was running a bit rough and then died on me as I was pulling away from a stop doing a left turn in the middle of a huge and busy intersection.

I eventually got it running, but noticed that it had a weak spark and that the fuel pressure was around 1.5 psi.

It has a Pertronix Ignitor II module in the OEM Ford dual point distributor, a Pertronix coil, and a mechanical fuel pump with a replaceable fuel filter right at the carb feed line.

After putting a meter on the coil, I realized that for the past four years that the engine has been in and running - two of those years licensed and on the street having covered around 7,500 miles, I've had the wrong coil. Turns out I had the Pertronix FlameThrower I coil, which has 1.5 ohms resistance, when I was supposed to be using the FlameThrower II coil with 0.6 ohms resistance to match the Ignitor II module. That was resulting in a weak spark situation to the distributor and those new sewer pipe type plug wires were throwing a horribly weak spark at the plugs.

The fuel pump issue is, I'm guessing, related to ethanol gas, but can't be sure. A new Carter mechanical pump and a new filter resulted in a solid 5-6 psi again just off idle.

So, with solid fuel pressure and a hot spark, my car is running better than ever. Too bad I couldn't get this done in time to load it up and head out to Wareham for the open house.... sigh..... maybe next year.

[CraigS]

Wow, this has been a frustrating couple of months. I am glad you got it all sorted out. Don't feel bad about the coil. I have an old school type coil and replaced it maybe 6 years ago. Then 3 years ago I removed it to do some other work and realized the bottom, which should be flat, was bulged out. Started researching and realized this coil should have been using a resistor all this time. Don't know how I missed that on initial install but I did. I was lucky that it never failed but I ordered and installed a new coil and resistor.

[GoDadGo]

Chris,

Thanks For Posting Your Issue Because It Is Things Like Your Mis-Hap & The Posting Resolution Of It That Helps Us All!
Even if some of have Chevy's sitting between the frame rails, the basics are the same.
Congratulations On Resolving The Issues!

Steve