4.3 issue
Thanks in advance for the help.
Recently bought a vehicle with a 4.3 tbi in it. Has mild cam. Starts and idled well but hesitant and poor power under load. Previous owner stated : ran excellenf until out mudding and blasted through a mud hole. Ever since then ran crappy Took it home checked a bunch of things Good compression Good fuel pressure Good map Nonsign of spark arcing Fuel spray pattern looks good Pull plug wires one by one while running, same rpm drop for all. Seem equal, no dead cylinder. Ok now the weird part Checked timing (yes properly disconnecting timing wire) and found it to be a bit retarded. Advanced to correct spec run a bit better but still poor. Continued advancing time until it runs nearly normal. Approximately 20° initial now. Starts and runs and accelerates good now. Though 20° initial seems very excessive. My thought is that he over revved it playing in the mud and skipped a toogh on the cam timing. Likely to have crappy nylon timing gear Racap Only runs decent with way advanced intilal timing. Ran fine until playing running it hard. Thanks for the ideas |
it does sound like something has slipped. but what year 4.3 are you working on?
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TBI 4.3
88-91ish |
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