The Impossible 2001 Ford Taurus Problem!!!
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Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
A distorted signal might not throw a code, and scoping the signals might not be a bad idea.
I haven't dealt with the protection system on Fords -per se- but have dealt with it and similar protection systems on Jaguars. Basically, the computer sees a change in rpm every time a cylinder fires, and when it doesn't see an expected change in rpm, it declares a misfire. This was a big problem on GM trucks years back- Going down a rough road would cause a similar fluctuation, and trip the check engine light. On newer vehicles, the emissions need to be kept in check, so they stop dumping fuel in on that cylinder.
FWIW, it's not the excess fuel that makes the cat run hot, it's the extremely lean condition caused by the slug of unburned air being dumped in.
I haven't dealt with the protection system on Fords -per se- but have dealt with it and similar protection systems on Jaguars. Basically, the computer sees a change in rpm every time a cylinder fires, and when it doesn't see an expected change in rpm, it declares a misfire. This was a big problem on GM trucks years back- Going down a rough road would cause a similar fluctuation, and trip the check engine light. On newer vehicles, the emissions need to be kept in check, so they stop dumping fuel in on that cylinder.
FWIW, it's not the excess fuel that makes the cat run hot, it's the extremely lean condition caused by the slug of unburned air being dumped in.
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danmm7
2.6, 2.8, 2.9, 4.0 & SOHC 4.0 V6
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May 28, 2018 12:53 AM
