Misfires and backfires
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Misfires and backfires
Hi peeps! New here, I’m a mechanic myself but have run into a roadblock. I bought this 04 f150 with broken timing chain guides, replaced the cam phasers, guides, chains and sprockets. Then it was misfiring so bad it wouldn’t hold idle. Hooked the scanner up and found cylinder 4 misfiring at -34, so I replaced the plugs and cops which were real bad, but I still have a cylinder 4 misfire, swapped cop with cylinder 1 and the misfire stayed at 4. Swapped the plug with cylinder 1 and yet again the misfire stays at 4. And also swapped the fuel injector with cylinder 1 with no change!!! What am I missing????
Oh ya, keeps throwing a bank1 lean code, doesn’t idle worth a crap but has no misfires under a load, in fact drives perfect down the road, however it has recently started backfiring when I push it hard (like when trying to pass someone)
Oh ya, keeps throwing a bank1 lean code, doesn’t idle worth a crap but has no misfires under a load, in fact drives perfect down the road, however it has recently started backfiring when I push it hard (like when trying to pass someone)
Last edited by Bwulff; Dec 6, 2021 at 10:24 PM.
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Hooked the scanner up and found cylinder 4 misfiring at -34, so I replaced the plugs and cops which were real bad, but I still have a cylinder 4 misfire, swapped cop with cylinder 1 and the misfire stayed at 4. Swapped the plug with cylinder 1 and yet again the misfire stays at 4. And also swapped the fuel injector with cylinder 1 with no change!!! What am I missing????
Most likely a burnt or bent valve in #4.
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At the same time take a look at the rollers/lashs on that bank. They are bad about being thrown to the side when roller gives out , mine did . Lost one on number 8 ,missed cam . replaced them all during timing job , newer design points oil towards roller and smaller orifice.That helps oil pressure also.
I would not do a timing job without doing rollers. plus better oil pump mine was m360 but now the hv melling is better.
I would not do a timing job without doing rollers. plus better oil pump mine was m360 but now the hv melling is better.
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