need some help
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New User
Joined: May 2009
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From: Milton, FL
need some help
1990 F-150 4.9L /300 E4OD transmission 147k miles
I ran EEC-IV self test and got 2 codes
1. KOEO(key on engine off) Code 34 - PFE or EVP circuit above the closed limit of 0.67 volts.
2. CM (Continuous Memory) code 34 -PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
i have found some sources that say that the PFE sensor changes backpressure into an anolog voltage signal. This signal is sent to the
it also said High backpressure could cause this code to appear. And she runs EXTREMELY RICH like 10 mpg and will choke you out if you stand beside it.
can anyone give me some insight or pictures of this "PFE" sensor because i have yet to find any. My EVP sensor is maybe 1 1/2 years old as well as the EGR valve.
I ran EEC-IV self test and got 2 codes
1. KOEO(key on engine off) Code 34 - PFE or EVP circuit above the closed limit of 0.67 volts.
2. CM (Continuous Memory) code 34 -PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
i have found some sources that say that the PFE sensor changes backpressure into an anolog voltage signal. This signal is sent to the
computer to control EGR flow, ignition timing and the air/fuel ratio, And that the Failure symptoms are
Rough idle (Yes it does),
pinging( only in idle in park),
loss of power( oh yeah),
and overheating ( doesnt go past the R in NORMAL on the gauge but it feals hot enough to easily fry bacon on)
Rough idle (Yes it does),
pinging( only in idle in park),
loss of power( oh yeah),
and overheating ( doesnt go past the R in NORMAL on the gauge but it feals hot enough to easily fry bacon on)
it also said High backpressure could cause this code to appear. And she runs EXTREMELY RICH like 10 mpg and will choke you out if you stand beside it.
can anyone give me some insight or pictures of this "PFE" sensor because i have yet to find any. My EVP sensor is maybe 1 1/2 years old as well as the EGR valve.
Posting Guru
Joined: Sep 2004
Posts: 1,915
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From: Yokosuka, Honshu, Japan
Cats plugged or the EGR valve is bad or a combination of both. Worst case (and almost as costly as a new cat) is the EVP/PFE (I think they are one in the same...) sensor for the EGR is bad. Did you do a wiggle test on that sensor to see if the connections were good?
Post Fiend
Joined: Jan 2007
Posts: 7,021
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From: Almost Heaven
Sorry I couldn't be of more help. =/
Thread Starter
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New User
Joined: May 2009
Posts: 15
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From: Milton, FL
Cats plugged or the EGR valve is bad or a combination of both. Worst case (and almost as costly as a new cat) is the EVP/PFE (I think they are one in the same...) sensor for the EGR is bad. Did you do a wiggle test on that sensor to see if the connections were good?
no i didnt do a wiggle test on the EVP , i will though, even though it is only a year or 2 old. The local Ford Know-it-All says its the cats and that i should straight pipe it or pipe it to a muffler with no cats
Posting Guru
Joined: May 2007
Posts: 1,208
Likes: 2
From: North Reading Mass
Before cutting up your exhaust get a vacuum gauge and test to see if the exhaust system is plugged. The gauge should read 20" @ 1000 to 1500 rpm. If the gauge slowly drops towards 0 then the exhaust is plugged.
Regards
rikard
Regards
rikard
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