What's the code? Could be a few things.... take a look at
Have a 1997 Ford TB 4.6. Bought this car new, has only 36,000 miles on it.
Question is: This is the 4th time I've had to replace the EGR valve.
Anyone have any ideas why this is happening?
Thanks in advance for any input or comments.
Thanks for the info. Car read a P0402 trouble code. Ford replaced the EGR
valve. Display monitor DPFE read 2.3 volts hot idle/Koer exesive EGR flow/
pin point replace EGR valve clear codes retest OK now Pass drive, Postest
DPFE read .99 volts hot idle. (Taken from Ford readout).
In the past the DPFE sensor has been replaced, and the EGR replaced twice.
Fuel injector service has been performed, so no carbon buildup to blame.
Will see how it performs this time. Again, thanks.
Funny you should mention brand of gas, have always been "brand loyal" using
Shell gasoline, recently used BP Amoco. Will rule brand(s) of gas out.
Although this is a low mileage vehicle, most of miles are interstate miles,
so will rule out second suggestion. Maybe should start challenging local
tuner cars at red lights??
Thanks for advice, but still at a loss.... Glad Ford has 12/12
In my experiance it is the DPFE that fails almost ALWAYS on that year. The
older ones would build up carbon and block the passage. Does your car warm
up proberly I wonder? It shouldnt take more than a few minutes to reach
Differential Pressure Feedback EGR sensor. It is a solid-state sensor that
measures the pressure difference between two ports on the pipe that exhaust
gas flows through when the EGR valve is opened. In the middle of the pipe,
between the two pressure sampling ports, there is an orifice that generates
a small amount of pressure drop. The flow of exhaust gas in this pipe is
proportional to the pressure drop, which allows the engine management
computer to calculate the actual amount of exhaust gas flowing when the EGR
valve is opened.
If the DPFE is defective, or if the pressure sampling ports or the hoses
attached to them are clogged with deposits, the computer will think there
is less or more EGR flow than there actually is, which can cause problems.
I have looked over some of the other replies to your
problem. One question I have is; has anyone cleaned the EGR
port in the intake? They have a tendency to foul and
restrict or outright plug the EGR gas flow. Mine has
plugged to the point that I could completely remove the EGR
valve with no effect on performance or idle. It can and
many time does give a code for improper DPFE readings. I
have had the same problem with my CV. It is a bit of an oil
burner and the problem will go away for 25-30K miles after a
good cleanig and always shows up as a DPFE problem. Your
low mileage indicates it may not always be operating at high
enough temps to keep itself clean even though many of the
miles are highway miles.
egr systems are carburation legacy devices! when the throttle
closes with your foot off the accelerator intake vac goes hi and
subsequently the mixture rich and unburned hc hi. opening egr valve
dilutes rich intake mixture and thus reducing unburnt hc. you know
the egr system is working when you coast off the freeway and the
engine stumbles or dies when you subsequently step on the accelerator.
with cumputerized sfi there should be no reason for egr systems
except that CARB likes them, manfacturers get by making you pay for
them, and dealers
get to sell you stuff and charge you $$$ to put the mil out! the
amount of nox the egr system reduces is about zero. i've been getting
a pi407 code for quite sometime on my 95 TB 4.6L. i just reset it with
my obd2 codereader. maybe one of these times i'll try and clean the
egr passage in the intake manifold. over the last 30+ yrs i've
plugged vac lines to egr valves, blocked off valves
and cleaned a few. i replaced one before i found out they were
cleanable. who stuck us with this neusence CARB? the lord? the
devil? obviousely i don't
do this for a living -- i would not be complaining! the Charles O
on ford fuel injection is the best i've read on gasoline burning
engines in years.
Your mileage is very low for the vehicle year. Do you make a lot of short
trips? Or does the vehicle just not get a lot of use? Either way you're a
candidate for getting a lot of sludge buildup due to the motor not getting
good and warm when you drive. Condensation is your biggest enemy, and the
only way to keep it down is to drive the car a decent distance at least once
every 2 weeks or so in order to get it good and warm, and give it time to
burn off the condensate. Another problem may be oil change intervals.
Frequent short trips is severe duty, not light, and you should change the
oil more often. Cutting the crud buildup will keep your EGR (and the rest of
the motor!!!) cleaner and will make it last longer. I generally change the
EGR valve every 2 years, but that's at the 25,000-30,000 mile time. They
still rattle when I replace them.
Every day is a good day- it's just that some are better than others.
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