Coil.?..

[redroadster68]

Hi all
Last month I had an issue with 2000 solex sputtering and crapping out under load. Did the usual troubleshooting and in the end I replaced coil and all was great, car ran so strong. I parked the car for 3 weeks waiting for one nice day to add fuel stabilizer and park it for the winter. Problem back. Can barely make it around the block under load. Exact same symptoms as before . Any reason why coil would crap out ? Spark plugs gap at .37. When car sat for the 3 weeks I didn’t touch it. It has fresh Shell Vmax 91 in it

[Datsun.David]

Hmmmm... Sure you don't have crap in your fuel tank? I chased intermittent problems for a year and a half. Finally pulled the tank and cleaned out about 2 pounds of rust. Sealed tank, reamed out pick up, and hasn't had a problem since... I replaced coil, plugs, dizzy... if I would have just removed the inspection plate in the trunk and pulled the sending unit, it would have saved a tonne of heartache - with a flashlight it looked like bowl of cornflakes in my tank.

[C.Costine]

What test indicated a bad coil?

[rwmann]

Fuel pump diaphragm? Inline fuel filter? Banjo bolt filters? Corn flakes?

[redroadster68]

shot in the dark last time to replace coil. immediate solution. car ran perfect as soon as I installed it. car has electric fuel pump and pertronix iggy. inline filter les than one month old, clear.

[rwmann]

If inline filter is downline of electric pump, the pump inlet could be fouled with corn flakes.

If inline filter is upline of electric pump, the tank pickup could be fouled with corn flakes.

[Gregs672000]

Tough One! Is it coughing through the Carbs? Usually a lean mix will result in carb backfiring. Obviously you can check FOR spark, and see if it appears "weak", but another option is that the timing is not advancing as it should. No advance, no power, limp around the block. Buy or borrow a timing light (Harbor freight has a cheap dial back one) and confirm the timing is advancing normally and holding it.
Your electric pump probably has a filter in front of it, try changing that out (or put one in!). A lean running car will literally "feel" and sound like it's starving... a kind of "haaaaaa" sound when you try to accelerate. Snap rev the engine by hand from idle... if its lean it will likely backfire, especially if the fuel level is low in the carb. Rich and it will bog and not accelerate, but I doubt it's rich unless you have a needle and seat issue or your pump is overwhelming it and flooding the carb, and that's usually one carb that will show up on the respective plugs (1 and 2, or 3 and 4)... check your plugs for differences or an out of normal color (white or black). Mikuni like 3-4lbs of fuel pressure.
On the street the engine will bog if the timing is not advancing. I vote that you have a timing advance problem unless you find some bad wiring... could be, since you just messed with them a little replacing the coil. Maybe it temporarily reconnected, but is now again not doing so. I'd start with a timing light.

Also, the only time I've had problems with fuel delivery has been with a leaking stock glass bowl fuel filter. If they don't seal they starve the carbs. I don't recall if this happened before or after I went electric pump, but I think it was before. Left me stranded once until I figured it out and bypassed the filter until I got home.

[notoptoy]

Not because I am a vendor, but Pertronix has been known to be flaky on Roadsters not sure why.

[rwmann]

No experience with Pertronix. Excellent experience with the Gary Boone electronic distributor mod, MSD Blaster 2 coil, Magnecor wires, NGK BP6ES plugs.

[redroadster68]

car has pertronix currently. all plugs are gapped correct and all very black. prior to parking it they were all good. just limping around the block im sure made them black. car ran likea top prior to parking 3 weeks ago

[redroadster68]

does anyone know if I blow back through the gas line to the electric pump if the air will pass backwards through the pump and into the tank? the pump is back near the tank, the fuel filter is in engine compartment apposite from solexes. so in other words, if I disconnect the fuel filter and blow air back through the line towards the tank, will the air go past the fuel pump and into the tank ? thanks everyone

[rwmann]

Depends on the pump type whether it can be back-flowed with air or fluid pressure. Is there a filter between tank and pump? Many pump manufacturers require a filter ahead/upstream of the pump to protect its internals.

[redroadster68]

I will check... installed prior to my ownership so no idea what kind it is.... gotta find it...lol

[redroadster68]

disconnected fuel line at carbs. lots of flow when I turn on the pump.

[redroadster68]

696FEBED-3024-4290-BCB5-73C30AB5A37D.jpeg

Look familiar. I don’t think this is the issue.