[96greengt]

Yeah, the pic is for illustration (snagged from the F-150 forums).

The 4.6 and 5.4 are close in design. I also looked at the schematic for this truck, the PCM does not apply a ground to open the EGR, it rather applies voltage, from a signal of the DPFE to the EVR through the PCM to open the EGR.

[lazer96gt]

Originally Posted by 96greengt

Yeah, the pic is for illustration (snagged from the F-150 forums).

The 4.6 and 5.4 are close in design. I also looked at the schematic for this truck, the PCM does not apply a ground to open the EGR, it rather applies voltage, from a signal of the DPFE to the EVR through the PCM to open the EGR.

WOW! Ok then. Well I was mistakenly under the impression that the pcm would send a ground because when I checked the vehicle at idle there was a constant + signal. Well now here is another issue. KOER the EVR is constantly hot. There is no ground then. I have not checked the EVR KOEO to see if the signal was still hot. Regardeless the EVR has no ground. I really need more time with this truck. The intake will come off and be cleaned. Now I need to figure out this electrical shizzle. I wish this truck had balls so that I could kick them bitches

[96greengt]

You are actually over thinking the situation. The #1 failure from the P0401 code is normally the DPFE sensor, once 50+k miles happens, then the carbon becomes a factor, unless the owner really used shitty gas from mom and pop gas stations or ran fuel conditioners of all brands in the gas.

[lazer96gt]

Originally Posted by 96greengt

You are actually over thinking the situation. The #1 failure from the P0401 code is normally the DPFE sensor, once 50+k miles happens, then the carbon becomes a factor, unless the owner really used shitty gas from mom and pop gas stations or ran fuel conditioners of all brands in the gas.

Well, I won't argue any of that. Everything that I found (internet) on this issue said DPFE. Regardless of the clog though, shouldn't the EVR get the signal to open if the PCM is reading the DPFE as it should? Why do I not see any vacuum from the EVR during test drives when the EGR curve rises? I may be over thinking as you said, but shouldn't the EVR at least open?

[96greengt]

Originally Posted by lazer96gt

Well, I won't argue any of that. Everything that I found (internet) on this issue said DPFE. Regardless of the clog though, shouldn't the EVR get the signal to open if the PCM is reading the DPFE as it should? Why do I not see any vacuum from the EVR during test drives when the EGR curve rises? I may be over thinking as you said, but shouldn't the EVR at least open?

Unless there is a break in the vacuum line, only way to test is to apply either voltage at the EVR (running) or manual vacuum from the EVR to the EGR.
Since 96, Ford finally fixed the EGR problems, now they all had problematic DPFE sensors and carbon problems.

[lazer96gt]

I'm not seeing a ground at the EVR though? Should I try grounding it? At idle the + is constant at the EVR. When I raise the rpm (in park) there is no fluctuation of the voltage. This is why I made the assumption that the way the PCM engaged the EVR was through a ground. Vacuum at the EVR is solid. EGR side of EVR no vacuum. Vacuum lines all good as well.

[96greengt]

The schematic shows no ground from what I see. And raising the idle does not really mean it will activate EVR to command EGR. You'd have to do a WOT to get any signal out of the EVR.
The EVR has 2 vacuum lines, one that has constant vacuum, the other supplies vacuum to the EGR through the EVR.

Generally, over 3500 rpm, the EVR will open slightly (but in neutral) the open rate is little compared to cruise.

[96greengt]

And the PCM internally grounds the DPFE, there is no ground on the hard part side...

[96greengt]

[lazer96gt]

Originally Posted by 96greengt

The schematic shows no ground from what I see.

^ this I did not know

Originally Posted by 96greengt

And raising the idle does not really mean it will activate EVR to command EGR.

^ this I did know which is why I did driving cycle with a manual vacuum gauge on the EVR, and the scanner connected to watch the EGR curve.

Originally Posted by 96greengt

The EVR has 2 vacuum lines, one that has constant vacuum, the other supplies vacuum to the EGR through the EVR.

^ I've checked all of the vacuum lines and they are good. Vacuum to the EVR is good. There is no vacuum coming from the EVR. I would like to know how to manually activate the EVR. If I'm seeing a constant power KOER then what is the other wire? The EVR has nowhere to ground out to complete a circuit. This is not a ground wire?

I'm just gonna have to just get the truck back. I can only get it on Thursdays though. That's why this is such a bitch. I don't have any time with it.

[lazer96gt]

PSHHH! I missed the schematics before I posted.

[96greengt]

The EVR is just a solenoid, unplug the connector and apply power and ground to JUST the sensor (leave the vacuum lines connected and engine running) that will not only verify the EVR is working on its own, but will verify no vacuum leaks to the EGR via the vacuum line from EVR to EGR.


The PCM internally grounds the EVR. If you apply ground with KOEO and probe the "signal" line, you may fry the PCM, the VREF line, if applied ground, will just pop a fuse or burn your wire.

[lazer96gt]

Originally Posted by 96greengt

The EVR is just a solenoid, unplug the connector and apply power and ground to JUST the sensor (leave the vacuum lines connected and engine running) that will not only verify the EVR is working on its own, but will verify no vacuum leaks to the EGR via the vacuum line from EVR to EGR.

^ that is what I wanted to know. I'll do that.

Originally Posted by 96greengt

The PCM internally grounds the EVR.

^so I was right about that. I'm not crazy

Originally Posted by 96greengt

If you apply ground with KOEO and probe the "signal" line, you may fry the PCM, the VREF line, if applied ground, will just pop a fuse or burn your wire.

^ I needed to know that. Cool. I didn't want to take that risk which is why I was asking about manual EVR actuation.

1st off the intake will get pulled off and thoroughly cleaned. If by chance that doesn't fix it then I'll verify the solenoid actuation to try to rule it out. If the solenoid is good, then I will have to check the grounding of the EVR during a driving cycle. I'll let this one rest for now until I can get the truck. I'll be owe'n you some lunch dinner and a 12 pack after this.
Thanks Jody. I'll be letting you know.

[96greengt]

Do the easy stuff first, test the EVR before you yank the upper plenum. Just by chance, what color is the DPFE?

[lazer96gt]

It is black. It's NOT the one that mounts to the intake. It's the one that mounts to the evasporator tube via the two rubber hoses. Part # is 4U7E-9J460-AA which is the updated unit. Also the one that came off was the same updated DPFE.

[96greengt]

So it is the tiny DPFE style then?

[lazer96gt]

Originally Posted by 96greengt

So it is the tiny DPFE style then?

yes sir. ^ I didn't see this post till today I just got the truck for a few minutes. When I put a volt meter on the EVR, the constant + is good. When leaving the volt meter tapped into both EVR wires, I see only a 1.2 and lower voltage. I'm assuming that the PCM is not fully grounding the EVR. What voltage should the EVR see? The solenoid functions properly with manual power & ground applied. If the EVR voltage is within spec what's the next step? If it is not........... PCM??????

[96greengt]

The DPFE should see between .9 and 1.3 volts. Anything greater than +- .4 is a bad DPFE.

I am still leaning on the passages plugged up.

[lazer96gt]

Originally Posted by 96greengt

The DPFE should see between .9 and 1.3 volts. Anything greater than +- .4 is a bad DPFE.

I am still leaning on the passages plugged up.

not the DPFE voltage. The EVR voltage. The solenoid/regulator is at 1.2v and less. The DPFE checked out. The PCM I'm still questioning because the ground that the PCM completes is only allowing for .1v - 1.2v. If I ground the volt meter to the chassis and positive on the EVR hot wire I see 12v. If I ground the volt meter to the PCM (ground) wire it's not completing the ground. Again I only see between .1v at tip in and 1.2v at cruising speeds with partial throttle above 2k. Basically the EVR is not seeing a 12v circuit completed at the harness. To eliminate the wire as a possibility, I'd like to check the EVR signal (ground) at the pcm.