Backfiring through carb

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Jul 6, 2003 | 10:10 AM

Chuck Batt

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Backfiring through carb

77 Ford van 351W

Starts fine, idles fine, drives fine for 30 to 45 minutes. Then, when stopped, begins to idle rough. Taking off produces popping through the carb. Then as car is driven popping continues intermittently.

Have replaced plugs, ditributer and rotor, fule filter, PCV valve, fuel pump. Car passed emmission test when taken in before the 30 to 45 minutes went by.

Jul 6, 2003 | 12:13 PM

Colossus

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From: Oak Harbor WA

Backfiring through carb

My truck does this every now and then, used to do it all the time.
Check timing and the choke. That's all I can think of at the moment.

Jul 6, 2003 | 01:16 PM

Chuck Batt

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Backfiring through carb

Thanks. We'll give it a try. If anyone else has any ideas, please let me know.

Jul 6, 2003 | 01:21 PM

Ds7776

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Backfiring through carb

When my F100 did this it did it more than your van does, what I did was replace the power valve on the bottom side of the carb and it fixed that.

Jul 6, 2003 | 05:02 PM

Torque1st

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Backfiring through carb

Check your ignition module, heat can make them intermittent. Parts stores will test them for free. If in doubt replace it with a Motorcraft module only. Mount it with 1/4" spacers so that air will circulate under it.

Also check your engine with a vacuum gage to see if you have a leaking valve.

Jul 6, 2003 | 08:49 PM

jar06896

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Backfiring through carb

I'm curious. I just changed out a leaky intake/valley pan gasket, and I kave a similar problem. Truck runs great at idle, but at about 2200-3000 rpm, it gets rough, and lacks power. I changed the fuel filter, checked the plugs, checked all the gaskets and played with the timing. popping through the carb...timing too advanced? Advice?

78 F250 351M 4spd,np205.

Jul 6, 2003 | 08:56 PM

Colossus

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From: Oak Harbor WA

Backfiring through carb

Was the gasket properly installed? I did read that air leaks in any of the engine or carb gaskets can cause problems.

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Jul 6, 2003 | 09:56 PM

Colossus

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From: Oak Harbor WA

Backfiring through carb

Cleaning the carb can help, you might want to check if your carb is calibrated properly, and make sure the choke is working - that's what was wrong with mine.