engine missfire
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Freshman User
Joined: May 2005
Posts: 34
Likes: 0
From: long island
engine missfire
i have a 1990 bronco with a 302. for the 2 years i had the truck the exhaust always makes a popping sound if you rev it. i just hooked up tru duals with my side pipes, and the popping is coming out of the passenger side of the motor. what is causing this, how can i find out what is wrong, and how can i fix it? thanks
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
Could be something as simple as crossed plug wires. Double check the firing order and make certain none of the wires are swapped. If that isn't the problem check for a fouled (dead) plug. Anything worse than that would have shown up with far worse symptoms by now.
Senior User
Joined: Mar 2005
Posts: 256
Likes: 0
From: B.F.E.
Popping?Are you sure it sounds like a pop ? you may have a hole in the exhaust system somewhere,also if you still think its electrical go out when its dark and look at the wires ,sometimes if you have a split in the wire you'll see it "crossfire"a small blue spark as the current jumps to something.As far as a the exhaust it may be a manifold gaskett or I ended up with a leak at the heat riser inside the exhaust manifold where it meets the pipe.
Freshman User
Joined: Sep 2004
Posts: 37
Likes: 0
From: DC
check the exhaust by plugging up the one end and have someone rev it while you listen for a leak i would also pull the plugs check firing orders and pull the cap off the distributor and make sure everything is ok
Posting Guru
Joined: Nov 2004
Posts: 1,467
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From: N. Gwinnett Co. Georgia
When you rev the engine, does the popping sound occur when you take your foot off the gas? Is it popping all through the cycle of acceleration/deceleration? I'd think valve train if you eliminate the plug wire issues. How many miles on the truck? Hot carbon buildup can post iginte fuel when the valve is opened, especially during decleration. If this is the occurance and you've determined that it's not the plug wires or an exhaust leak, try running a can of Seafoam through the engine and 1/2 a can through the vacuum system to cut some of the carbon buildup. After using Seafoam during the last 6 months, I'm amazed at the condition of my cylinders inspected using a fiber optic scope. They are almost perfectly clean and I have 251,700 miles on the truck.
