Ford F150 - 93 I-6 failed emissions test

larry499 · **Posted:** Mon Sep 25, 2006 6:50 am

Hello all from new member. My 1993 f150 I-6 with 280,000 miles failed emissions test due to high nox. Can anyone clue me on some things to do to remedy the problem? Thanks,Larry

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cleat · **Posted:** Mon Sep 25, 2006 7:27 am

High nox usually is caused by a bad or plugged EGR valve.

larry499 · **Posted:** Mon Sep 25, 2006 7:42 am

cleat, Thanks. I'll get the Haynes book out and hope it has a test procedure. If you think of anything else I would certainly appreciate knowing. Thanks Again, Larry

Steve83 · **Posted:** Mon Sep 25, 2006 3:45 pm

'93 EGRs don't get plugged - they're plumbed differently from the later ones. But they do sometimes break the valve off the pintle, and (MUCH more often) their vacuum supply develops a leak, preventing them from opening. Check the sticker under your hood for your vacuum map & follow the lines from the tree on the intake plenum (red line) to the EVR & then (green line) to the EGR. haynes gives several tests for the EVR, EVP, & EGR.

larry499 · **Posted:** Tue Sep 26, 2006 5:07 am

Steve, Thank you for the help, Larry

Ford F150 - 93 I-6 failed emissions test

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