77 Spider Backfire / Misfire at high sustained speed/rpm

JB · Post by JB » Thu Sep 07, 2006 3:47 pm

I have a 77 Spider with points and 32 ADFA carb. This care is still pretty new to me. I've replaced timing belt, wires, plugs, points, 1 condenser, cap, button, fuel air and oil filters. First of all if someone has any procedures and diagram for tuning the carb I would be grateful if you could send my way. My book (Haynes) does not show the 32 ADFA at all???

OK heres the deal. After I do my tinkering I take her on our usual route. 45 -60 mph for a couple miles and then onto the interstate where I open it up. When I'm around 70ish and over 4,000 RPM's and starting to put some strain on her she starts backfiring / misfiring some kind of bad. I let off and we continue OK until I start to accelerate again and backfiring / misfiring starts again. Off the interstate and on regular roads at lower speeds, lower strain, lower sustained RPM's I'm good.

Where should I start? Thanks!

racydave · Post by **racydave** » Thu Sep 07, 2006 5:42 pm

Best wild guess, sounds like Dist could be worn,your dwell should not vary. Dave

So Cal Mark · Post by **So Cal Mark** » Thu Sep 07, 2006 11:00 pm

check the fuel pressure, and also look at the fuel hoses between the tank and pump. If the inlet side hoses have cracks, the pump can suck air.

bandit · Post by **bandit** » Fri Sep 08, 2006 2:58 am

Could also be a Fuel Filter to add to what Mark said , sounds
more like a Fuel feeding issue then Ign.

Daniel

JB · Post by JB » Tue Mar 27, 2007 10:36 pm

Just to close the loop it was bad line fittings on the fuel pump.

So Cal Mark · Post by **So Cal Mark** » Tue Mar 27, 2007 10:39 pm

thanks for the update!