DPFE or EVP Codes
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DPFE or EVP Codes
I posted this previously in the Full Size Van section but didnt see any response so I thought I would try this section.
The check engine light has been coming on in my 1992 ford Club Wagon with a 302.
I scanned it and found two codes (334 and 337) in memory.
According to fordfuelinjection.com
code 334 is caused by DPFE or EVP circuit above the closed limit of 0.67 volts.
and code 337 is caused by DPFE or EVP circuit above the maximum limit of 4.81 volts.
Does anyone have an idea what would cause the voltage limits to be exceeded?
What is the difference between the closed limit and the maximum limit?
The check engine light has been coming on in my 1992 ford Club Wagon with a 302.
I scanned it and found two codes (334 and 337) in memory.
According to fordfuelinjection.com
code 334 is caused by DPFE or EVP circuit above the closed limit of 0.67 volts.
and code 337 is caused by DPFE or EVP circuit above the maximum limit of 4.81 volts.
Does anyone have an idea what would cause the voltage limits to be exceeded?
What is the difference between the closed limit and the maximum limit?
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Joined: May 2004
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From: The hills of No. Calif.
Perhaps bumping it up to the top will get it some attention this time around. In the meantime, I'll take a stab at it...
Both of those codes have to do with the EGR. PFE is Pressure Feedback EGR and DPFE is Delta Pressure Feedback EGR. I suspect that you simply have a carbon buildup in the EGR that is holding the pintle open a bit, allowing an amount of exhaust gas into the intake all the time rather then only at part-throttle cruise as is normal. Is the idle the same as always, or is it idling a bit rough? A little loss of power at WOT? (Wide Open Throttle)
If so, pull the EGR off and clean the passages and the pintle valve.
Both of those codes have to do with the EGR. PFE is Pressure Feedback EGR and DPFE is Delta Pressure Feedback EGR. I suspect that you simply have a carbon buildup in the EGR that is holding the pintle open a bit, allowing an amount of exhaust gas into the intake all the time rather then only at part-throttle cruise as is normal. Is the idle the same as always, or is it idling a bit rough? A little loss of power at WOT? (Wide Open Throttle)
If so, pull the EGR off and clean the passages and the pintle valve.
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We havent noticed any rough idle or power loss; however, we have noticed it will occasionally stall. When it stalls it doesnt run roughly, its just stops running.
I replaced the egr valve 10 or 20,000 miles ago along with the sensor on top of the egr.
I did not replace the EGR vacuum solenoid.
I replaced the egr valve 10 or 20,000 miles ago along with the sensor on top of the egr.
I did not replace the EGR vacuum solenoid.
Hotshot
Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
When you replaced it, did you notice a lot of carbon buildup in the EGR ports, and did you clean it out? I've seen a perfectly good EGR not work simply because the ports were totally clogged with carbon.
Vacuum solenoid is another possibilty, or even simply a vacuum hose that's off.
Vacuum solenoid is another possibilty, or even simply a vacuum hose that's off.
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How do I go about cleaning the EGR ports? Are there any cleaners that I should or should not use? The ports are coated arn't they?.
I didnt notice plugging but I may not know exactly what I should be looking for.
I checked the vacuuum lines they all seem to be attached. I have heard the hard lines have a tendancy to crack. I would like to find a suitable replacement hardline. I have been considering brakeline (which I can find) but would prefer something color coded (which I have not come across).
Is there an easy way to check the vacuum solenoid?
One other thing we have noticed is the Check Engine Light will come one briefly when the vehicle first starts. It goes out after a minute or so.
I didnt notice plugging but I may not know exactly what I should be looking for.
I checked the vacuuum lines they all seem to be attached. I have heard the hard lines have a tendancy to crack. I would like to find a suitable replacement hardline. I have been considering brakeline (which I can find) but would prefer something color coded (which I have not come across).
Is there an easy way to check the vacuum solenoid?
One other thing we have noticed is the Check Engine Light will come one briefly when the vehicle first starts. It goes out after a minute or so.
Last edited by hatch_1989; Mar 7, 2006 at 07:23 PM.
Hotshot
Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
It's the throttle body that has the coating you have to be careful of. As far as cleaning the EGR ports, just remove the EGR and look into the ports, see if there's carbon buildup in there. You can usually break the little chunks out with a small screwdriver. Usually not worth it to use carb claener or anything, it doesn't need to be spotless in there and it gets more carbon/crap fairly quickly.
What we've been calling the EGR vacuum solenoid I believe is actually the EVP sensor. It requires the use of a hand vauum pump and a multi-meter to test it. Here's some info about that.
What we've been calling the EGR vacuum solenoid I believe is actually the EVP sensor. It requires the use of a hand vauum pump and a multi-meter to test it. Here's some info about that.
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I replaced both the egr valve and the sensor on top of the egr valve 10-20,000 miles ago.
A vacuum line runs to the sensor from the solenoid.
As the solenoid was all that was not replaced, I would prefer to test it before replacing it.
A vacuum line runs to the sensor from the solenoid.
As the solenoid was all that was not replaced, I would prefer to test it before replacing it.
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Resolved, again
The check engine light started coming on again. The code scanned gave us a 337 code. A few months ago I replaced the O2 sensor that killed the other codes the vehicle had been throwing.
I went to Ford bought a new EGR valve and EVP sensor and installed them. At the same time I cleaned the IAC. The passage in the throttle body looked clean but i squirted it with a throttle bode cleaner any way and passed an engine brush through the passage.
For what its worth, both the aftermarket sensor that was on the vehicle and the Ford sensor I originally took off read 3600 ohms when the valve was closed, 100 when open. The new one read 4600 ohms when closed 700 when open.
The codes are gone but I am still not sure the IAC is functioning properly. Some times you can hear a slight increase in RPMS when stopping, other times you cannot.
I went to Ford bought a new EGR valve and EVP sensor and installed them. At the same time I cleaned the IAC. The passage in the throttle body looked clean but i squirted it with a throttle bode cleaner any way and passed an engine brush through the passage.
For what its worth, both the aftermarket sensor that was on the vehicle and the Ford sensor I originally took off read 3600 ohms when the valve was closed, 100 when open. The new one read 4600 ohms when closed 700 when open.
The codes are gone but I am still not sure the IAC is functioning properly. Some times you can hear a slight increase in RPMS when stopping, other times you cannot.