Egr valve po401

[?x?]

I did a code scaneer at murray and got ths code.
A mechanic at my neighboorhood told me that many times its not the egr valve that goes wrong but the other part of the system, "selenoid" (right ?) is there any way to find out wich one?How can i check the selenoid or the valve?
Thanks in advance.

[Davescort97]

What is the year and engine of your Escort?

[?x?]

97 purple colour,i have seen other cars like that,anyway engine is 2.7

Does Egr have anything to do with error P0172?I got that error as well,it said system too rich bank 1.

Thanks for the interest Dave.

[Davescort97]

Well... PO401 is EGR flow insufficient. PO172 is overly rich bank 1. The 2 codes are directly related.

The EGR (Exhaust Gas Recirculation) artificially leans out the mixture and lowers the temperature of the combustion gas by recirculating the exhaust gas back through the intake. This reduces NOX (oxide of nitrogen). In consideration of the second code the failure of the EGR flow being insufficient is making bank 1 too rich. There's only 1 bank on an Escort.

You are right. There is a solenoid that controls the EGR. It is an electrical switch that provides vacuum to the EGR valve which has a vacuum diaphragm that controls how much gas goes back into the intake. You can find the EGR valve by looking right behind and to the left of the IAC (Idle Air Control). It's just behind the throttle body. You'll see a diaphragm with a vacuum line running to it. It's right on top. Back track the vacuum hose on the EGR to find the Solenoid.

Make sure all the vacuum lines are attatched and the hoses aren't bad. When the engine is cold there should be no vacuum to the EGR valve. If there is vacuum to the EGR valve when cold the solenoid should be replaced.

There should be no vacuum to the EGR valve when the engine is warm at idle.

There should be vacuum to the EGR valve above 1500 rpm.

With the engine at idle put a vacuum pump of 8 inches of vacuum to the EGR valve diaphragm. The valve stem should move opening the valve and the engine should stall or run roughly. IF the engine doesn't respond remove and clean the inlet and outlet ports with a wire brush. Don't use gasoline or damage will result.

With the engine at idle pull 4 inches of vacuum to the valve. Vacuum shouldn't drop more than 1 inch in 30 seconds. If it does replace the valve.

Get a hand held vacuum pump to carry out the tests.

[?x?]

I tried to check the egr with a vacuum pump but i couldnt get any result.
When i would stop in lights the car would stall and turn off so i took it out and what a surprise: The egr was like a coal mine.
Any way i cleaned it up a little but ended up puting a new one,i bought it 2 days ago.It started fine but damn it it turned off again.I did a code scanner and i didnt get any rich bank error but i got the same code.Any idea?

[Davescort97]

Well the new EGR must be working because you haven't been getting overly rich bank 1. Still getting "Insufficient flow EGR? Sometimes it takes a cycle of starting your car a number of times to reset the code before it will go away. You can achieve this now by taking your negative battery terminal loose for 15 minutes. This will reset the computer. Your light may go away and not come back. btw. Is the solenoid good?

[mightymoose_22]

Did you also clean out the passage through the head? If the EGR was that plugged up you likely had significant buildup in the head too. You can take off the intake hose and use a cleaner that is safe for electric parts to spray around in there and make sure the passage is clear from the EGR.

I also recently had a similar stalling problem. I also had a plugged up EGR and replaced it since it was 12 years old :P The car kept stalling though.

In the end I found that I had a vacuum leak from the intake manifold that was hard to detect. I eventually found it by using the old rubber tube trick... just got in close and listened for it.

[?x?]

Yeah it had carbon on the head,i tried my best with a picking tool but couldnt do much,i was afraid of scraping the engine.I suspect it might be what you are saying moose,i will try again this weekend.
I cleaned the codes with the scanner,but anyway 1 day later the engine light came back.
Is there anything to clean up carbon nice and smoothly other than scraping the area?

[12Ounce]

The EGR valve is almost never the problem. Sometimes the solenoid valve is ... but most likely the EGR flow sensor (DPEgrF) sensor is the culprit. High failure rate on Fords. $30.