| 72VWSB |
Tue Feb 18, 2020 7:35 am |
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| Been working on my 72 VW SB, new inside carpet, upholstery, padded dash. No seats but have a milk crate, took car for a spin and noticed it backfiring...I've done no changes to the engine but of course I have wires all over the place in the dash because I'm waiting for vents for my new dash pad. Can't see this causing backfiring but perhaps I'll take a drive again when I get the dash back in and wires connected...jeesh! |
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| vwoldbug |
Tue Feb 18, 2020 12:43 pm |
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| If it backfires on deceleration it's probably an exhaust leak. |
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| 72VWSB |
Tue Feb 18, 2020 12:54 pm |
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| Idles fine, doesn't backfire on deceleration...only on acceleration... I did find some loose wires to the distributor...we'll see if that fixes it. |
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| Airstream65 |
Tue Feb 18, 2020 2:42 pm |
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| Check the points! |
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| green1303 |
Tue Feb 18, 2020 2:57 pm |
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| X2, check the point gap and then the timing. I have seen points slip out of adjustment, causing those symptoms. There is supposed to be a 4 mm inner diameter flat washer and toothed washer (toothed one on top) under the screw that holds down the points. |
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| Tim Donahoe |
Tue Feb 18, 2020 3:35 pm |
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I’ve also found a bum condenser can cause backfiring.
Tim |
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| 72VWSB |
Tue Feb 18, 2020 6:29 pm |
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Ok, discovered my problem or not...lol. I called my son, he built my motor...I'm running a Delorto 40 single carb. Sorry I didn't add that when posting! I also have the petronix flame thrower distributor. Seeing as the backfire was below about 3000 rpm, he suggested I take out the idle jets, blow them out which I did. Car ran fine after that! Delortos run on idle circuit till about 3000 rpm.
Must have been a little dirt in there, have a good gas filter on the bug... |
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