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I had a problem passing due to high NOX also, what my friend did was disconnect the EGR valve from the carb, (2 hoses connect together on the passenger side of the engine) and plugged them with a screw.

Then he took it through there and it passed with flying colors. I guess my EGR is toast.

I also have an LG4.

 

hmmm. Im not sure how that would work, I know the egr is used to lower the nox. so if its plugged its not functioning which is not gonna do its job to lower it, wonder what changed to make it work for you.

 

nox is normally a bad egr valve, or clogged passages. Test ur valve at idle and see if rpm varies.

 

Well my buddy said that we wanted to get maximum heat across the engine as well. so the gas would burn cleaner. Im not sure how this worked, but it seemed to do the trick.

 

I know thats what I said in my first post. Im not sure how to test it, thats what im asking as well as other suggestions on it.

 

Interesting, once I figure out how to test the EGR If its bad I will probally replace it so it works right, thanks for your input though.

 

With the engine idling, apply vacuum directly to the valve. If the engine dies, the valve is working. If the engine does not die, either the valve is not working or the passages are plugged.

If the engine dies, that doesn't mean the EGR "system" is working. Vacuum is applied to the valve per ECM commands via the EGR solenoid. Make sure the vacuum to the solenoid is proper. To verify the solenoid is working, determine which wire is power. With the wires connected, ground the other one - the solenoid should cycle, applying vacuum to the valve, the valve should open and kill the engine at idle.

Excessive ignition advance will also raise NOx. Make sure it is set properly.

 

Is it often for these componets to go bad and not set off an engine light? will the timming effect the nox that much if its off?

 

The electrical circuit of the EGR solenoid is the only thing the ECM can detect. I haven't had any failures in 9 years, even though the exhaust passages were plugged up in the original manifold.

Timing advanced too far will have a definite effect on NOx levels.

 

All of those emission numbers seem a bit high. Not just the NOx.

A comparison for you:


You're on the right track with the timing. I was adjusting mine last week. I found it absolutely amazing how even a little teeny tiny change would move the timing by 2 degrees. Definitely made me realize that timing by ear is pretty much impossible.

Let us know how it works out.

 

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Not opening, or doesn't kill the engine when vacuum is applied at idle?

Switching it out is pretty straight forward. If the exhaust port is clogged, though, that's a lot more involved.

 

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To test the solenoid:

Hook up a vacuum gage to the hose going to the EGR valve so that you can watch the gage while driving. If the gage never shows vacuum under any driving conditions, the solenoid isn't working for one reason or another. The solenoid itself is mounted to a bracket on the passenger side rear corner of the intake manifold - one bolt, one connector, two hoses - piece of cake to replace.

You don't need a vacuum pump to test the EGR valve. Just borrow an engine vacuum port and hook it directly to the EGR valve while the engine is idling - it should kill the engine. If it doesn't, you can feel under the valve while hooking up the vacuum for the diaphragm moving.

If the diaphragm moves but the engine doesn't die, your exhaust passages are plugged. Could be the valve exhaust passage, but not likely.

 

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do you really think the shop pulled the intake to clean the ports out? Doubtful, did you test as five7 described? It will take a matter of seconds and give you a difinitive answer to if it is in fact the valve or not. Seafoam should be ok as long as you dont pour too much in. We use a similiar product made by BG at my work to do "egr services". Basically you fill a hopper with cleaner and it bolts to where the egr valve goes and slowly administeres a measured amount of cleaner while the engine is running to help clean the passages up some.

 

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Mine set a code but didn't turn the SES light on. Weird, never knew that would happen.

Plugs, wires, and oil tend to have an effect on CO and HC, although raised CO or HC can lower NOx.

 

Ok, thanks for the info! I will post up again as soon as the part comes and i get it changed.

 

Ok the new one came in today. I got the new one and pushed the disc up and then covered te hole and it would stay up. I tried that with the new one and it would just fall, so I guess it was leaking or just gone out. also with the egr off i tried to start the car and it would run a second and then die I figured that was normal. Anyways I got the new one on there and it was much easier than I was expecting. Now if I reach on the underside with the car runnining it starts stumbling like crazy, hopefully it will pass now, will post up when it does.

 

sounds like you defently found your problem and got it fixed. Good luck with the inspection, you should be good to go!

 

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Confusing. Anyway did it still fail for nox?

 

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Should a good EGR solenoid allow vaccuum to pass through when it's off the car?

Is there an ohm check for it?

I can look in Helms tonight but I'm at work.

(87 LG4 application. Valve holds vaccuum / moves freely. Intake passages are clear.)