I used to be a ‘splainer on a few of the popular online vehicle forums, but my desire to do it wore out, for many reasons but one above all others: It’s nearly impossible to pry an erroneous notion out of a grasshopper’s mind, when said notion seems to the grasshopper to be a plausible explanation for the problem, whether he cooked it up himself or is just parroting someone else, which is usually the case. Anyway, the only way the critter can understand what you’re telling him is to first abandon what he believes, open his eyes and ears, and actually take in what you’re saying without running it thru his preconception filter.

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So ‘splaining is hardest when a person who hasn’t got enough working knowledge to think about the question, thinks about the question. Or has let someone else do it for him.

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Put in one of the rare, actually knowledgable forum participant’s framing, it’s trying to cram the square peg of reasoned deduction into an ovalled-out hole of ignorant preconception.

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Couldn’t have said it better myself.

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It usually sounds something like this: “The engine idles OK but really hesitates on take-off. It feels like it’s not getting enough gas “

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For grasshoppers, it’s always not getting enough gas.

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“I think I need a new fuel pump.”

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Then you ask if it has trouble under high load at speed, and he says no, it runs great once it gets underway, runs nice all day on the highway, climbs hills with decent power, and how he and his wife bought the bus and the kids named it Sophie and love to camp in the backyard and and it gets good mileage and and and his Mom had one kinda like it but not really because that was back in the 60’s but people come up everywhere they go to tell stories of camping in their Dad’s old bus, yadda yadda fucking yadda.

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“Just has trouble getting off the line.”

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So you explain how the electric pump just circulates fuel at a constant rate regardless of what the engine’s doing, so if the engine runs well under the condition where it uses fuel at the highest rate then the pump is able to deliver sufficient volume, so you can definitely rule out a failing pump. Then you describe the usual causes of transitional hesitation and suggest a basic fuel pressure test ‘cuz the pump can be fine but the regulator controls pressure and has to respond to load changes, and the ECU has no way of knowing the fuel pressure to correct for a problem there, and point him to the page in the manual where the test procedure is already laboriously spelled out. And tell him to check vacuum lines to the distributor and fuel pressure regulator and EEC valve, and to inspect the cap and rotor for cross-firing and if there’s any carbon tracking to ring out the plug wires, maybe even pull the plugs to check the gaps, and if we still used scopes a quick hookup would show us any ignition glitches but those are all gathering dust since OBD bred a new generation of morons spoon-fed codes without regard to what they mean, so no one knows how to read the scope traces anymore anyway, so we are back to the old pick-your-way-thru-the-problem methods with pre-OBD cars.

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He replies that he doesn’t want to open any fuel lines cuz it’s dangerous (sources of ignition always seem about to pounce on the unsuspecting, I guess, or else gasoline spontaneously explodes on contact with air where he lives, or something). So he went and bought a new fuel pump and installed it (which requires getting considerably more intimate with gasoline than a fuel pressure test). And it still hesitates.

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He’s pretty sure it’s not getting enough gas.