Windstar with P0401 code

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  #1  
Old 12-14-08, 12:15 PM
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Windstar with P0401 code

I have a 98 Ford Windstar with the 3.0 liter engine and high miles, about 178,000. There's a P0401 code -- insufficient EGR flow detected -- that I just can't make go away.

To make a long story shorter, I've replaced the flow sensor, the EGR valve, and the EGR solenoid. The hoses look fine and if I pull a vacuum on the EGR valve at idle, the idle drops and roughens but the engine doesn't stall. The sensor voltage at idle (or with key on engine off) is about 1 volt (it's the new plastic version). With the EGR open at idle the sensor signal rises about 0.05-0.07 volt, and during some limited testing while driving, the sensor signal goes as high as about 1.5 volts.

From some of the other test data I can pull from the computer, it fails two diagnostic tests: the EGR Lo Flow is about 3.5 - 4.5 in H20 with a minimum 6.0, and the EGR open duty cycle is 88-89% with a maximum of 80%. But those sound like the symptom and not the problem.

Is it possible the intake manifold is partially restricted where the EGR valve connects? What else am I missing here?

Thanks for your help!

Randall
 
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  #2  
Old 12-15-08, 07:34 PM
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the rubber hoses that connect to the flow sensor might be restriced inside
 
  #3  
Old 12-16-08, 10:04 AM
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They're OK, but I haven't had the pipe that runs from the exhaust to the EGR valve off the car yet. The EGR system seems to be working, just no gas flowing, so there may something stopped up inside that tube.

- Randall
 
  #4  
Old 12-16-08, 05:01 PM
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I would suggest taking off the egr and cleaning the manifold ports, this may require that you take off the upper intake plentum to make sure that none of the crud gets in the cylinders.
good luck
 
  #5  
Old 12-16-08, 08:53 PM
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During prior removals of the EGR valve -- I'm getting pretty good at this -- there wasn't much crud in the valve or the plenum as far in as I could reach with a small brush. This is the 3.0 liter engine which I'm told has an entirely different intake manifold (and plenum) than the one on later 3.8 engines. From reading of other Ford forums, some of the 1999 and later engines were prone to clogging of the EGR intake passages and cleaning them often fixed the flow problem. Does anyone have experience on this engine? I'm just trying to avoid having to pull the plenum ....

Randall
 
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