holdmypocket
nil
Getting a popping/backfiring sound through the carb around light-moderate throttle at light load (like a small incline) or accelerating to 40-50 MPH. Seems to be around 2500-ish RPM.
Since I got the Bronco running I've been cruising around the neighborhood up to about 50mph and never had a problem, even ripping around and flooring it. A few days ago I finally took it on the freeway, accelerated fine up to 70, cruised there for about two miles and then got a pop/backfire through the carb as I steadily but lightly accelerated to get past someone. Once I exited, I went from a stop and accelerated to 50mph when it popped again.
Other than this the Bronco runs great.
Details:
1. Rebuilt 302 maybe 2000 miles ago.
2. Holley 4160 completely original. Bought this new in 2019, ran it on my truck for a couple of years, then it sat in a box for a year or so before I ran it on this Bronco a few months ago.
3. Pertronix ignition module and coil. The coil is brand new, the Pertronix came with the engine.
4. Timing was 10, increased it to 12 which made no difference.
5. Found that I had vacuum advanced hooked up to manifold, moved it to ported, made no difference.
6. Put a vacuum pump on the vacuum advance with the cap off and confirmed stuff is moving around under there as vacuum is applied and then removed.
7. Revving the engine in idle with the advance hooked up, it hits 30 degrees at about 2500 RPM, and then continues to increase.
8. The gas in the tank has been in there for over month, I suppose it could be bad gas but I've never experienced this in the past with other Broncos/Trucks that I've had sit for much longer.
Here's a video of it happening (sorry about the orientation, trying to drive ). You after the second pop I let off the gas.
I don't know if this would be bad enough to cause this but this is what the cap and rotor look like, I'll be replacing these:
Since I got the Bronco running I've been cruising around the neighborhood up to about 50mph and never had a problem, even ripping around and flooring it. A few days ago I finally took it on the freeway, accelerated fine up to 70, cruised there for about two miles and then got a pop/backfire through the carb as I steadily but lightly accelerated to get past someone. Once I exited, I went from a stop and accelerated to 50mph when it popped again.
Other than this the Bronco runs great.
Details:
1. Rebuilt 302 maybe 2000 miles ago.
2. Holley 4160 completely original. Bought this new in 2019, ran it on my truck for a couple of years, then it sat in a box for a year or so before I ran it on this Bronco a few months ago.
3. Pertronix ignition module and coil. The coil is brand new, the Pertronix came with the engine.
4. Timing was 10, increased it to 12 which made no difference.
5. Found that I had vacuum advanced hooked up to manifold, moved it to ported, made no difference.
6. Put a vacuum pump on the vacuum advance with the cap off and confirmed stuff is moving around under there as vacuum is applied and then removed.
7. Revving the engine in idle with the advance hooked up, it hits 30 degrees at about 2500 RPM, and then continues to increase.
8. The gas in the tank has been in there for over month, I suppose it could be bad gas but I've never experienced this in the past with other Broncos/Trucks that I've had sit for much longer.
Here's a video of it happening (sorry about the orientation, trying to drive ). You after the second pop I let off the gas.
New video by Charles Howard
photos.app.goo.gl
I don't know if this would be bad enough to cause this but this is what the cap and rotor look like, I'll be replacing these: