jereli

So I just came from the smog.. And I failed the ignition timing and NO. The ignition timing is off by 5 BTC which I can just adjust but will that cause high NO (nitrous oxide I think it is)? At 15mph max is 704 I was at 1428.
25mph max is 866 I was at 1454.

No more then 100miles ago I did new cat and muffler, oxygen sensor, spark plugs and wires, oil change, coolant, timing belt and valve adjustment.

jereli

Anyone have any ideas? I am not sure where to start to troubleshoot high "NO".

RJR

NO forms at high cylinder combustion temperatures and pressures.

Things that can lead to high NO

- non working EGR system
- overly lean mixture
- defective cat converter
- overly advanced timing

Probably others, but those are where I'd start.

jereli

What can I do to troubleshoot my egr system?
Thanks

Punchy

Make sure all the hoses running from the throttlebody to the EGR modulator (black thing on front of intake manifold) to the manifold hardlines to the green VSV on the passenger fender, Then back to the manifold hardlines up to the EGR dashpot are all good.


Set your timing first.


Here is a quick test for the main EGR valve.
While the engine is idle, Put a vacuum to the EGR dashpot (you can use a longer hose to reach and suck on it yourself or to one of the vacuum ports on the passenger side of the manifold)
If the engine stalls or almost dies, Its working normal, If nothing happens then the dashpot has a leak or the tube running up to it from the exhaust manifold is plugged.


If you have a long vacuum hose you can test the EGR modulator and green VSV by running the hose from the vacuum line of the EGR dashpot to a gauge you can temporarly duct tape to your windshield and take a drive.


You should get a vacuum reading when your above 25mph and no load on the engine (cruising), If not The VSV or EGR modulator are faulty.


Denso O2 sensor?


If you think any coolant has gone down the exhaust the cat or O2 sensor could be bad now.

jereli

No its a Ntk oxygen sensor.

So i found about 3 metal vacuum lines that are clogged.

The metal line going under the throttle cable from Throttle body "R" going to EGR VM "R" is clogged.

Metal line from pressure regulator to vsv is clogged.

EGR VM "Q" to vsv is clogged.

Havent not set timing yet or troubleshoot the egr valve but all I did so far was blow into one end and see if i felt it on the other end and nothing. So I am assuming their clogged.

Terrys87

iTrader: (1)

As far as EGR, here is some info. There is a thread on here somewhere that a guy had high NO numbers and some basic maintainace had him to pass with flying colors. You dont say which motor but 86-95 was 22r or 3.0 so most of this will apply to a 3.0

Here it has the pipe full of rock solid carbon. I use a drill bit to get it cleaned out. If you get an EGR code, it is usually the hoses not hooked up right or just needs carbon cleaned out. Messsy.


Here is me using a drill bit. I have never gotten as screw out with a Phillips screwdriver. Ususally rusted to bad. I use vise grips, then getting the pipe out is another job in itself. Take your time, you have to get this out to get all the carbon out.


The Modulator can get a little dusty. The black cap just pops off and pay attention to how the filter element comes apart and go easy on it as the foam can seperate in layers. Use a screw driver to lift the edge out, ( a fish hook works too if you are not ambitious enough to get a screw driver) and I used a air hose to blow the dust out.

Also I had the 2 center lines of the metal rail hoses clogged. I used some WD 40 to soften the clog and after letting it soak about 30 minutes I was able to clear the clog out of the metal lines. The rubber hoses were not clogged. Checking all of the items in a system is easily over looked as well. Just trying to cover all of my bases while I got it apart.

jereli

Okay so I fixed timing... I just bypassed the hardline vacuum lines with just rubber hoses. I did suck on the egr dashpot and it did sound like it was about to stall. I do not have a vacuum gauge so I cannot test to see if I have a vacuum on if above 25mph.

Soo.. I ended taking it back to re test the smog now that my vacuum lines weren't clogged and timing fixed and turned out that it got Worse! I am gross polluter now Lol. not good.

Thanks for picture's on the egr cleaning I will have to try that to see if its clogged with carbon. It looks like the modulator thing is new but I'll try cleaning out that filter too.

jereli

Okay so here is what I found after removing egr... I would blow through the vacuum line port and hear air flowing out through the diaphragm. I would try sucking on the vacuum port and could not pull the diaphragm down. Turns out there's a hole in it.

jereli

Okay question... On the egr modulator there is 3 vacuum lines.. I can feel vacuum on my finger on the one that is labeled "P" when I give it some throttle. I cannot feel vacuum on the one labeled "R". Does that sound right? Both lines are coming straight out the throttle body which makes me think they should be have vacuum.

scope103

http://personal.utulsa.edu/~nathan-b...77exhaustg.pdf
You get no (or very little) vacuum on R until the throttle is open "a little." That's why there are multiple vacuum lines; to sense throttle opening.

jereli

Nice.. just what I needed. I will look more into testing the egr system tomorrow. I wish I had a vacuum gauge.

jereli

So found that my green vsv valve is clogged up. I blew air into it like the procedure I received from you guys and nothing. I applied power to it and blew into it and nothing, not even a click noise. So I found a replacement that works. Now I tried testing the brown vsv the same way and i can't blow air out the filter section. Does not click. Is this bad as well?

If so can I use another green vsv valve in place of that brown one? Are they the same except for color?

jereli

Does anyone know if the two parts are interchangeable? I have two known working green vsv solenoids. Can I replace the brown solenoid with a green one?

jereli

Does anyone know what the brown vsv solenoid is for? Does it have anything to do with the egr system? And do i test the brown vsv the same way as the green vsv? because I applied 12v to it the same way I tested the green vsv and the solenoid did not switch on.

Punchy

The brown is actually red, Its the fuel pressure up.
It closes when you step on the accelerator and opens when idle. (the ECU sends the signal depending on IDL signal from the TPS)
If the red VSV is stuck closed you just get a little more pressure to the injectors during idle, The ECU will try and compensate (Not saying it always will).


Yes, You can use the red VSV in place of the green if you rewire it since the plugs between the red and green are different.
Don't just use swap hoses or it will really run like crap since the ECU opens and closes them differently.

scope103

Fascinating.

The Fuel Pressure Up "is energized during hot engine cranking and for up to two minutes after the engine starts." http://www.autoshop101.com/forms/h22.pdf It has nothing to do with the accelerator or idle.

I can't comment on the color of the VSV; it's not specified, and I would trace the connections before relying on the color of a generic part.

But if the one you are concerned about is connected to the fuel pressure regulator, it is unlikely to have anything to do with the EGR or high NOx.

Punchy

Beg to differ, Page 9 of the link you posted "Heavy load, High speed"
Also if you hook up a vacuum gauge you can watch it, I do this all the time as I move my vacuum gauge to the various vacuum points from time to time.


Agree it will have nothing to do with high NOX.

jereli

Hmm I was hoping it had affects on high NOx since I found that it was bad. I believe I read somewhere that a faulty pressure regulator could contribute to high NOx levels but maybe not then.

The weird part is that after I replaced the egr vsv I took it to smog for pre test and it passed. The NOx levels did not even come close to the upper limits. Then he did the real test and failed. Did pre test again right after and started failing.

Punchy

Jereli, Check the EGR main dashpot diaphragm and make sure its not damaged and sucking air in.


Bad fuel pressure regulator (assuming it was just letting fuel bypass and creating low pressure) Would kill top end and hard acceleration, If you are able to get over 3k rpm from a standing start I doubt the FPR is bad.
If its stuck closed raising the pressure, The ECU will compensate.


You sure there are no airleaks in the air intake tubes?


Just off the for S&G, What trans, Gear ratio and tire size?