Backfire! - Fuel Economy, Hypermiling, EcoModding News and Forum

elhigh · 05-21-2010, 09:07 PM

The old pickup and I get along pretty well. We're both getting old so sometimes we make a little extra noise in the joints, slow to get going in the morning, etc. But I never had any parts fall off, and Josie did. $100 later and I have a new el cheapo exhaust system from the cat back.

Josie's carbureted. Fuel cutoff isn't 100% when you turn off the engine; a little gets pulled through as the engine winds down. Here's what happens when you go to turn the engine back on, but don't have enough speed/distance to coast the engine with the ignition off to purge the exhaust pipes.

From the rear, looking forward.

The sound it made when it went was huge. I've had backfires before, but dang.

I think I can squeeze it together and clamp the edges shut with a couple of hose clamps. I'm not especially keen to take it back to the original vendor since really it's my fault this happened, no error on his part.

elhigh · 05-21-2010, 09:24 PM

Okay, I clearly suck at posting photos.

Christ · 05-22-2010, 12:29 AM

:Rolleyes:

Can you post a link of where they're located in the internets? I'll edit this post to show them for you.

Gasoline Fumes · 05-22-2010, 07:26 AM

I have never seen that happen before! My old '84 Civic used to spit fire when you lifted off the throttle and nothing like that ever happened.

chuckm · 05-22-2010, 09:37 AM

I've never had this happen to me, but I've seen a backfire big enough to do it. A buddy of mine used to have an old car he could make backfire pretty much on command. We were driving under an overpass and I was in the rather, umm, exciting position of being the car behind him when he did his thing. In a quick sequence, he went from ~30% throttle to idle, which let it lug for a second, punched it to the floor, then back to idle. Unburned fuel made it through into a exhaust system that was a bit rusty (read: there was at least one hole eaten through), where it didn't remain unburned for long. Let me tell you, this underpass made a VERY impressive echo chamber and it was dark enough to clearly see the fireball erupting from the rear of the car. It sounded like being next to a double barrel 12 gauge shotgun.

If you know anybody with a welding rig, clamp it closed and weld it shut. TIG is best here, MIG second, and stick is just a maybe (and only if you have the right type of rod).