Hi,
I have a 440 in a Dodge Travco motorhome.106k miles. It has an Edelbrock aluminum intake and a Holley Spreadbore vac secondary.
Stock Dodge Electronic ignition.
As I was driving along last night, it started bucking and backfiring through the carb a little. Then it would stop.
If I pulled over and put it in neutral and dry revved it , it would break up bad and backfire mildly through the carb.
I thought for sure it was the coil.
Nope.
So far I replaced the ign wires with MSD 8mm
Cap, rotor, coil and spark plugs
Replaced all 3 fuel filters. I have 4 psi at WOT and about 6psi at idle of fuel pressure.
The Holly was rebuilt about 2 years ago and gas is fresh.
I drove it around for about 2 hrs and did not have any drivablity issues like last night. It pulled a couple steep hills fine. But if I dry revv in neutral, still get that backfiring missing and that tells me there is still a problem. It sounds exactly like a bad rev limiter on an ATV.
Oh, I changed the Elec ign Module and cleaned the terminals on the Resistor.
I have no idea what is wrong with it. Do these things have a rev limiter stock ? I'm running NGK UR5 pugs. The auto parts store showed gasketed spark plugs for all 440's but this engine came to me with peanut plugs and the heads are bevels for the UR5 peanut plugs.
I really have no idea what's wrong with it. Our vacation was ruined and I was supposed to go away with it in two weeks but now I am afraid to go anywhere with it.
I'd be grateful for any help at all. I am a diesel guy and really have no clue with old carbed engines. The carb like I said was rebuilt 2 yrs ago but I don't wanna blow 300$ on a new one unless I know that is the problem.
Also put a miti vac on the Distributor advance. It moved and appears to hold vacuum.