Fixing My Emissions Problem

[Von Hayek]

The 62 failed for high NOX in October. I just got around to testing the EGR system, and here is what I found.

When I applied vacuum to the EGR valve with a hand pump, nothing happened. Sounds like a problem, right? But when I ran a line from the EGR valve to the manifold, it killed the engine instantly. So, does this sound like it is operating properly to you guys?

Second, I tested the EGR modulator following the FSM. So I blocked off two of the ports and blew into the other. Air is supposed to move "freely" through but it took some effort. You are then suppose to ramp the RPMs up to 2.500 and then air is supposed to be effectively blocked. It felt the same at both idle and at 2,500 rpms. Culprit?

 

[Stumpalama]

Most likely, also make sure the vac hoses are hooked up correctly, the two on the one side can get crossed and cause problems.

Though, I suppose you didn't muck with anything under there since the last time you had the emissions tested. That would lead me to suspect a failure of a component.

BTW, I have a spare smog pump setting in the back of the parts truck. Too bad I'm so far away, I'd loan you my EGR modulator (assuming it works too).

 

[jcj_78FJ40]

How does drive? My modulator crapped out but it was pretty obvious when driving. I had a big dead spot around ~2000-2200 rpm.

I had a Denso part and you could pop the top and clean the element however mine was too far gone. At the time, I was able to get the same Denso modulator from Autozone.

 

[Von Hayek]

Most likely, also make sure the vac hoses are hooked up correctly, the two on the one side can get crossed and cause problems.

Though, I suppose you didn't muck with anything under there since the last time you had the emissions tested. That would lead me to suspect a failure of a component.

BTW, I have a spare smog pump setting in the back of the parts truck. Too bad I'm so far away, I'd loan you my EGR modulator (assuming it works too).

Most likely what? The valve? I'm afraid it might be pointing towards the cat.

How does drive? My modulator crapped out but it was pretty obvious when driving. I had a big dead spot around ~2000-2200 rpm.

I had a Denso part and you could pop the top and clean the element however mine was too far gone. At the time, I was able to get the same Denso modulator from Autozone.

It actually drives well, so perhaps that is not it. The element is pretty torn up, but does not appear to be too filthy. I blew it out anyway.

 

[Stumpalama]

Most likely what? The valve? I'm afraid it might be pointing towards the cat.

"most likely" was the answer to your question whether the the EGR modulator was the culprit.


If you've run through the emissions diagnostic steps and the an individual part failed any one of the tests then it should be replaced... but you know this.

After rereading you post I'm more confused. You say the hand pump didn't actuate the EGR valve, but engine manifold vacuum did, correct? That sounds like either you didn't pull enough vacuum with the hand pump, or the hand pump is broken.

So, it could be a combination of the EGR system and the cat.

 

[Von Hayek]

"most likely" was the answer to your question whether the the EGR modulator was the culprit.


If you've run through the emissions diagnostic steps and the an individual part failed any one of the tests then it should be replaced... but you know this.

After rereading you post I'm more confused. You say the hand pump didn't actuate the EGR valve, but engine manifold vacuum did, correct? That sounds like either you didn't pull enough vacuum with the hand pump, or the hand pump is broken.

So, it could be a combination of the EGR system and the cat.

It is a brand new vacuum pump. I was able to pull vacuum with no problem with my finger over the hose coming off of the pump. But when I hooked it up to the EGR, I simply could not pull vacuum no matter how fast I ran the pump.

I initially thought this indicated a bad EGR, but I ran a line to the manifold just to be sure and it killed the engine immediately.