Dose any one have info on the operation of the EGR valve? I just got my emissions done and it just failed because of high Nox.I should be around 2635 ppm and I came in at 3640 ppm and I was told because of a inoperitive EGR, well the EGR is some what new and the ports in side are not pluged, and under the vacuume check is opening the diaphram. The test showed that the motor RPM was around 830 during the test. The CAT temps were around 609 or so. My Question is the EGR vave in operation at that that given RPM. The sticker on the frount grill calls for 2300 +/- 300 RPM. Any one with some info please report. If the next time it Fails the truck is off the road. I'm not going to soak $660.00 to line the states pockets> JH. Thanks

 

Since you didn't identify what engine you're working on (year and size), I can only provide you with a link to http://www.smpcorp.com/download/view/tt2q00.pdf and http://www.smpcorp.com/download/view/Tt4Q98.PDF (Page 4) for an overview on how the Ford EGR system works from the computer's standpoint.

Is the CEL on? Any stored codes?

This article from Wisconsin's DOT, intended for the repair technician, also provides insight into high NOx readings and what to do to troubleshoot them: http://www.wivip.com/3_5_1.PDF

This article, from Missouri's GCAP is also helpful: http://www.gatewaycleanair.com/mechanic/air4_3/nox.htm

Remember, the EGR is a SYSTEM, not a single component. While you might have a new part or two in there, that in no way means the SYSTEM is operating.

Remember, NOx is produced when combustion temperatures are too high. High combustion temps may also be cause by anything that causes a lean mixture or by incorrect timing. The EGR system seeks to insert exhaust exhaust gasses back into the combustion chamber to dilute the mixture and cool the combustion temps.

Is your engine operating at normal temps? What is the condition of your ECT?

FWIW, the EGR system should not be activated at or near idle speeds...

There's plenty to it.


Steve

 

Thanks Steve!
Thanks Steve the info that you gave me was a huge help.I called the moter vehical Dept.,Emissions branch and indicated to them that the test was done at a low or near idel speed of 830 rpm and they agreed this was the wrong. A free retest is forth comming on Friday 1/2/04. Sorry for the lack of info i was almost late for work. The vehical is a 1986 F-150 4.9L 6 cyl with a EEC IV controls. I,ll be going through the egr sysm today with some of the info you gave me. Thanks again!!

 

After Calling the my emissions dept. a retest was done. They said that I had to have the test done within 5 days for the recall. I showed up and half the MV dept was there waiting for me, and to oversee the test. The tech pulled the truck in and right away they noticed that the GVW on the first report was wrong and the RPM was less than half of what is required for the EGR system to work. The test began, the rep. from Agbar did the test and checked his equipment and continued. The truck passed much below what the standard called for. The people at the test facility didn’t even look at me. BAM done deal. This is a few numbers from the first test.
(#1) Hc170-140 pass / Co. 2.0 - 0.0 pass / Nox 2634 -3630 FAIL /Gas cap pass..
Second test
(#2) Hc 170-132 pass / Co. 2.34-0.0 pass/ Nox 2634 - 340 pass/ Gas cap pass.
I have failed emissions in the past but no readings were taking on the RPM of the engine. The test person would go through the gears and the test would be done in third gear and bog down the motor to maintain 25 MPH on the Dino.. It cost me big bucks 4 years ago and a waver of $450.00 and the looks from the MV. Like you dirty air violator. Incompetent test people.
This is to show that a lot of people may fail if they are not aware of the RPM during the test period. This test is somewhat specific only for the Dino and tail pipe exhaust test in the older model cars or trucks. BE AWARE The New wavers are $660.00 Pretty sad for an RPM problem.JH.