`93 F150 4.9 2wd. KOEO code 334. KOER codes 334 and 411.
334 - EGR closed valve voltage high
411 - Cannot control RPM during KOER low RPM check.
Where do I go next? I checked the pins on the EVP sensor and they looked good. How do I test the sensor itself? Haven't checked the EGR valve with a vacuum pump yet. Anything else to look at for code 334? Also, I have no clue where to start on the 411 code. Anybody have any ideas for me??? Thanks!

 

Here's a good site to keep in favs.

http://www.troublecodes.net/Ford/

That's the best I can help without putting my hands on.

 

Always fix codes in order they appear. Most times the secondary codes are present because of the first code. EGR problems can cause idle fluctuations.

 

Just Got around to testing the EGR valve itself seems to be working. I have vacuum at the EGR valve when I get the RPMs up so the control solenoid is working. That leaves me with the EVP sensor. How do I test this other than making sure it's not an open circuit?

 

Depending what color of the evp you have the gray one starts out with 0.5 volts and as you apply vac with a hand pump it goes to 3.9. The blk one starts at .90 volts and goes to 4.40. As you pump the volts should be moving smooth. This with KOEO. At idle it should read .24-.67. To measure the resistance take the connection off and measure between the svp and the varf terminal on the svp and it should be about 5000 ohms. Apply 10 inHg and it should drop down to about 100 ohms. I`ll post a pic of the connection to help.

 

https://www.f150forum.com/attachment...1&d=1363190804

This should be a pic of you connection.

 

Oops, forgot to test for volt between the SIG RTN and the vref and it should be 5 volts.

 

That's what I'm talking about! Thanks a million man! Tested the sensor and it was shot. Thanks again!