having just done a good bit of work on my '97 tour, i figured i'd do something about the inspection that's going on close to 2 years expired. cel p0401. pretty common to all fords from what i'm seeing. i read through the forums and archives on this site, checked the pinpoint tests on the ford cd, but mostly followed the info from autozone's repair guide: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800a8aa6
egr valve tested a la 'suck test'. it's fine. valve opens and closes and the car stumbles when vacuum's applied at idle.
now onto the evr solenoid and dpfe sensor. and this is where i get thrown off.
to start with, definite typo in the az guide:
so then, i have two evr solenoids in hand, one old and one new. they both seem to behave the same. very little air can pass through regardless of whether they're getting no power or 12 volts and a ground. to begin with, no air should pass through when not powered, so that's one problem. and the solenoid should energize and open up if fed 12v and a ground, right? both the old and new one are no good maybe?
now the dpfe. the ford cd and az guide's diagram shows the dpfe's sig rtn connection to be the middle pin. when i backprobe that connector, i get nothing: 0v with or without vacuum. checking out the other two pins, i see that the bottom one is at a constant 5v while the top one is at ~0.95v. now with the top pin backprobed and vacuum applied, the top pin's voltage goes up to 5v as it should. so, is the autozone guide off or is there something funky with my wiring?
egr valve tested a la 'suck test'. it's fine. valve opens and closes and the car stumbles when vacuum's applied at idle.
now onto the evr solenoid and dpfe sensor. and this is where i get thrown off.
to start with, definite typo in the az guide:
i'm guessing that 'b' should read 'if air does flow through.Apply battery voltage (approximately 12 volts) and a ground to the EVR solenoid electrical terminals. Attempt to lightly blow air, once again, through the solenoid.
- If air does not pass through the solenoid, replace the solenoid with a new one.
- If air does not flow through the solenoid, the solenoid is OK.
so then, i have two evr solenoids in hand, one old and one new. they both seem to behave the same. very little air can pass through regardless of whether they're getting no power or 12 volts and a ground. to begin with, no air should pass through when not powered, so that's one problem. and the solenoid should energize and open up if fed 12v and a ground, right? both the old and new one are no good maybe?
now the dpfe. the ford cd and az guide's diagram shows the dpfe's sig rtn connection to be the middle pin. when i backprobe that connector, i get nothing: 0v with or without vacuum. checking out the other two pins, i see that the bottom one is at a constant 5v while the top one is at ~0.95v. now with the top pin backprobed and vacuum applied, the top pin's voltage goes up to 5v as it should. so, is the autozone guide off or is there something funky with my wiring?