1997 - 2003 F-150

99 4.2 Cel

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Old Nov 12, 2014 | 10:25 AM
  #1  
Mrmarcio02's Avatar
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99 4.2 Cel

Hello everyone! I have an 99 F150 4.2 with 203.000 on it and one I had the Cel on with P0401 error insufficient flow I changed the DPFE sensor with aftermarket sensor not Motorcraft,after that my Cel turns on again at the same hour with P0171 and P0174 saying it is a Vacuum Leak.Do you guys think this is because the DPFE is not Motorcraft or can be anything else?? Thanks
 
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Old Nov 12, 2014 | 10:52 AM
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Bluegrass's Avatar
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From: Easton, Pa.
The 401 and 171/174 usually are not related.
Do you still have the 401 code?
The DPFE would not be the cause of an air leak.
It's outside the intake system and senses exhaust pressure to measure that flow through the tube it's connected to.
I would say that the combination if intake vacuum and exhaust pressure contribute to the flow test and could fail a 401 test if the vacuum available was down, but most unlikely that would happen unless all the EGR ports in the v6, inside the intake were plugged..
Be awhere that aftermarket DPFE sensors may not work correctly because of manufacturing tolerances.
The 401 testing is very tight on tolerance failure limits.
Good luck.
 
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Old Nov 12, 2014 | 12:17 PM
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Mrmarcio02's Avatar
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Originally Posted by Bluegrass
The 401 and 171/174 usually are not related.
Do you still have the 401 code?
The DPFE would not be the cause of an air leak.
It's outside the intake system and senses exhaust pressure to measure that flow through the tube it's connected to.
I would say that the combination if intake vacuum and exhaust pressure contribute to the flow test and could fail a 401 test if the vacuum available was down, but most unlikely that would happen unless all the EGR ports in the v6, inside the intake were plugged..
Be awhere that aftermarket DPFE sensors may not work correctly because of manufacturing tolerances.
The 401 testing is very tight on tolerance failure limits.
Good luck.
No I don't have the 401 code only 171/174 but I"ll check my pcv and spray some Eletronic Cleaner and try to find this leak and btw I'll swap the DPFE asap,Thanks
 
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Old Nov 12, 2014 | 12:48 PM
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From: Live Oak, FL
OP, do a search for those codes in these forums. The 4.2L is notorious for those codes and there is a myriad of vacuum lines you can trace down to identify your problem.
 
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Old Nov 12, 2014 | 01:41 PM
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glc
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I'd leave the aftermarket DPFE on as long as you don't get any EGR codes. They aren't all bad.
 
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