So I’ve got this that lawn ornament of a 99 Honda Accord 4cyl (190k miles or so) in my yard. I’d had a problem with thick carbon build-up on the spark plugs electrodes, which was blamed on poor timing. So at the recommendation of the dealer mechanic, I did an ECU swap. Put the new computer in and started the car, seemed fine! Let it idle awhile then drove it in a big circle. Did OK for maybe a minute or two, then stopped and has never started again.
The immediate cause seems easy to diagnose: oil on the spark plug electrodes. It’s easy to check: pull the spark plugs out, clean them off, put them back in, crank it for a bit (it may catch a little) then pull them back out and they are covered in oil again.
Since two compression tests have come back roses, I’d suspect the problem is up top. But here’s my question: why all 4 cylinders? If leaky valve gaskets were the problem, for instance, how likely is it that they’d go bad in all 4 cylinders? Is there something else that could cause an oil leak in all 4 cylinders that’s a more likely explanation?
EDIT: Where I had previously written “terminals” has been corrected to “electrodes”.