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Old 04-30-2011
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Pressure? Positive or negative?

Hi Ford lovers,

I just have a couple questions about the Pressure on the two DPFE lines. Is that negative pressure as in vacuum pressure? And if so is it enough to collapse the lines to cause problems? And what kind of problems will I have? Thanks
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Old 04-30-2011
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Originally Posted by izzy08_03 View Post
I just have a couple questions about the Pressure on the two DPFE lines. Is that negative pressure as in vacuum pressure? And if so is it enough to collapse the lines to cause problems? And what kind of problems will I have? Thanks
When the EGR valve is open, there is flow in the EGR tube from the higher pressure exhaust to the lower pressure intake manifold. The pressure in the two DPFE ports is higher on one side than the other due a restrictor orifice between them. The flow rate through the EGR can be inferred from that pressure difference as measured by the DPFE. Hence the name: Differential Pressure Feedback EGR sensor.

Unless there is a severe blockage in the exhaust side of the EGR tube, there should never be anywhere near enough vacuum to collapse the factory DPFE hoses.
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Old 04-30-2011
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Well I have removed the DPFE sensor and found that the two tubes going to the sensor are very soft just before they connect to the sensor. Thus having crap in the ports of the sensor. I will clean out the "crap" in the sensor replace the hoses and see what happens. I have had two codes time and time again. The codes are Bank 1 lean and Bank 2 lean. Also when under acceleration in gear my vents will go to the default position (defrost). Which I have not found any vacuum leaks. But here is what I have done.
Replaced O2 sensors, replaced vacuum canister (thought check valve might have been bad), replaced half collapsed line going to TPS, cleaned MAFS, replace air filter, cleaned and checked IAC, checked every vacuum line from engine to interior panels, clean the EGR solenoid filters, hooked vacuum tester to top of EGR valve and applied vacuum to it and had a slowed reaction from engine which is meaning the EGR valve is opening and closing. What am I missing for these codes?

And thanks Earl43P awesome site saved to favorites
rwenzing- I was thinking that is wasn't enough to collapse them but needed reassurance so thanks.
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Old 04-30-2011
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The codes are Bank 1 lean and Bank 2 lean. Also when under acceleration in gear my vents will go to the default position (defrost). ....What am I missing for these codes?
Take a look at the plastic vac line running from the reservoir to the HVAC. These can melt against the exhaust or be leaking for any number of reasons.

If everything under the hood seems OK, I would check the HVAC vacuum controls under the dash. There are probably 3 vacuum servos and several vacuum lines. Any leak there could give you both of the symptoms - lean codes and defrost default.

What year is your Ranger? Which engine?
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Old 05-01-2011
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I have a 1998 V6 4.0 4x4 ext. cab
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Old 05-01-2011
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I have a 1998 V6 4.0 4x4 ext. cab
OK, that confirms what I said above. I would start at the reservoir and check the vacuum line back to the underhood HVAC components, then go into the interior HVAC vac controls and vac lines.
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Old 05-02-2011
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well I cleaned out the DPFE and the only other code that has came up is an O2 sensor bank 1 sensor 2. which is passenger side after the cat. converter. so I will clear the code and see if the same one comes back. thanks for the help.
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Old 05-04-2011
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finally no check engine light! What I think was happening was the O2 sensors werent feeding correct results of my emission to the pcm and also the DPFE wasnt able to read correct information cause of the clogs I found. As a result of fixing both I have more response from the engine, a little lower idle and a bit better gas mileage. Now time to get more air intake for even better gas mileage. Thanks again for the help fellas.
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