I've had 2gdfis installed on my car for 3 years now. Every now and then it sputters on a cold start. Just recently it started sputtering worse on cold starts and when it idles it randomly dips 200RPM and sputters for a second then returns to solid idle for 10-11 seconds. Could I have it wired incorrectly, but yet it worked for 8000 miles and 3 years? I inspected my jets, bleeds, fuel lines, swapped 3 other j-109s around, played with my Sterling Nikki mixture and accelerator pump screws, and checked timing.

The car still pulls pretty hard at WOT and chirps 2nd and 3rd gear, but it bogs a lot more lately than usual and of course the bad idle.

I attached a modified version of Jeffs picture to illustrated my setup. Except I currently have the resistor on the + battery side rather than the + ignitor side. Is this my problem? Should I switch the resistor to run inline to the ignitor like the illustration I made? The 2+ and 2- wires should be connected together on the FC coil terminals respectively right? I have 2 wires via ring terminal on the + and - FC coil.

BTW if Ive been limiting my coils input power all this time with the resistor I'm going to feel pretty stupid...

 

You sure its just not the colder weather messing with you on this?
Sounds like a cold startup behavior to me.

Does it do this when its hot. Ignition failures of coils and ignitors usually manifest
when they get hot, not when they are cold.

I would still look at your carb and fuel delivery as well. Have you changed the
fuel filter lately?

 

I replaced the filter this summer. It's never acted like this in the winter before though. The idle still bogs and sputters when hot. What I'm really concerned with is that I fried my FC coil by possibly having it wired incorrectly. It's always been a little sputtery on a cold start, but it's worse all of a sudden. Plus I worked on it yesterday and it was 50 degrees.

 

Well when I ran the 2G coil, my ignition went out after about 3 years but I then
gutted it all and fabbed up a new ignition setup using GM HEIs and Ford TFI coils.
In my case I think the ignitors or the ignitor box failed (this was a stock 80 electronic
ignition at the time). So I can't positively say the 2G coil went bad for sure. I do
know of others that have lost 2G coils but I also know of others that have been
running them for years. So its hard to say in your case.

You could try swapping in some known good coils to test with. Seems like if its the
coils you should notice a difference right away.

You can test the ignitors to make sure they are good. Its described in the FSM.

Check the adjustments on the air space for the dizzy pickups to make sure they
are correct.

Put a timing light on it and see if the spark acts erractic when the idle goes lumpy.

You've got multiple unknowns here, so you need to carefully plan a strategy to
verify each part of the ignition to narrow it down to the failing piece. Its tedious
and labor intensive but it will yield a result eventually. Make sure to only change
or modify one thing at a time and make notes of what you did.

 

Dumb question here, but are you still using the same plugs & wires from 3yrs/8k mikes ago?

 

I'm using NGK wires that are at least 2.5 years old. They are perfectly fine and should last a couple more years. The plugs have maybe 3000 miles on them. I don't replace plugs every oil change. I just clean and wire brush them a bit. Plugs and wires don't seem like they'd cause an erratic problem.

Seems like ...

...coil
...ignitor
...internal passages in the Nikki clogging?

The cap and rotor look clean.

 

Definitely as suggested put a timing light on both sides and see if the spark goes inconsistant during your issue. If not, I'd go straight to fuel delivery. And take a look at your cap/rotor too. They wear out fast.

 

Cap and rotor look good and have maybe 1000 miles. By fuel bowl also stays right above the half point in the sight glass too so it's not floats.

 

Well it always turns out to be the easiest fix the gets overlooked. I swapped the spark plugs with known good ones and it runs like it should. Maybe there's a hairline crack in one of the plugs causing low output or something. that's happened to me before.

 

Most of the time secondary ignition catches you consistantly or under a load.

Good find!

 

Glad it was a simple fix. One of the plugs may have been leaking to ground via
a fault of some kind and it caused the miss fires.