CA Smog - High NOx (1 Viewer)

Guster

SILVER Star
Joined
Jan 13, 2008
Messages
320
Location
SoCal
Greetings,

First smog check on an 85 FJ60 to try and get titled in CA . Only failed section was high NOx. The EGR valve and BVSV test good and a brand new cat has already been installed. The VSV does not open at 1,500 RPM but does open when I apply 12v. When above 1,500 RPM is the ECM supposed to send out the signal to open the VSV? I checked the ECM for cracked solder connections but am not seeing anything obvious. I'm still ordering an ECM from Engineer8000 that has tested as good in case I end up needing one. I've also ordered a new EGR vacuum modulator, Vacuum Solenoid Modulator EGR Valve Fits: 4Runner Celica Corolla Land Cruiser & | eBay - https://www.ebay.com/itm/192195496936, I think SpikeStrip provided that link in some other smog post. Any tips on how to find out why the VSV is not opening above 1,500 RPM?

vsv.jpg



fj60-smog.jpg
 

2mbb

SILVER Star
Joined
Sep 1, 2003
Messages
5,654
Location
WC, CA
It looks like the ECM provides the ground for the EGR VSV. You can check to see if your ECM is well grounded through PIN 7. It looks like there are other devices like the fuel cut solenoid and VSV 1 & 2 for AI that are also grounded through the computer. So you can check to see if those are working properly to help isolate the issue. The ground point for the ECM is "under left front pillar". You should see it behind the kick panel near the floor I think.

1663715505576.png
 

Guster

SILVER Star
Joined
Jan 13, 2008
Messages
320
Location
SoCal
Thanks @2mbb. Based on that information I did some testing with a test light and the circuit (ground) does enable over 1,500 RPM. I'm not sure what happened when I originally tested the VSVs and connection yesterday. I have an extra VSV, one of them is stuck open, you can blow air through without any voltage applied and the second one is stuck closed, will not open with voltage applied. I have this in my spare parts pile and it works so I'll give it a try, just gotta figure out how to get it connected.

vsv.jpg
 

CruiserTrash

SILVER Star
Joined
Jul 15, 2020
Messages
1,003
Location
Denver
@Guster I had high NOx here in Colorado, but passed on the 2nd test after swapping the modulator so I think you're on one of the right tracks with the EGR system.

There is a BVSV in the thermostat housing (upper one) that controls the EGR modulator as well. Don't forget that. It keeps the EGR off under all conditions until the engine comes up to temp.

I've also heard you can retard your timing 1-2 degrees to cut NOx a little. I'm not sure how that works, but it's all over the internet so it must be true, right? haha

Best of like, keep us updated.
 

fjc-man

SILVER Star
Joined
Mar 21, 2014
Messages
1,477
Location
Commerce City, Colorado
Get a mitivac handheld vacuum tester, apply vacuum to the egr valve ( engine running ) and the engine should die immediately. If it has no effect, the EGR valve is either stuck or the diaphragm is ruptured. If it dies, then it’s a control side problem.
 

cruiserdan

SupportingVendor Emeritus
Moderator
Joined
Mar 27, 2003
Messages
25,435
Location
Land Cruiser Heritage Museum broom closet
Is there a path to waiver it if there are "no parts available" to repair it?
 

Guster

SILVER Star
Joined
Jan 13, 2008
Messages
320
Location
SoCal
Get a mitivac handheld vacuum tester, apply vacuum to the egr valve ( engine running ) and the engine should die immediately. If it has no effect, the EGR valve is either stuck or the diaphragm is ruptured. If it dies, then it’s a control side problem.

Thanks, I applied manifold vacuum direct to the egr valve and it killed the engine so that part looks good.

Is there a path to waiver it if there are "no parts available" to repair it?

Good question, my gut feeling is since it's CA that answer is no but I'll see what I can find out.
 

Guster

SILVER Star
Joined
Jan 13, 2008
Messages
320
Location
SoCal
I now have a working VSV in place and ran the tests on the EGR vacuum modulator. I found another used modulator in my parts pile and also have a new one from ebay. Step #5b was successful, low vacuum at 2,500RPM. Step 5d was not successful, vacuum measured the same (low) at 2,500RPM. Results were the same with the used and new modulators. What should vacuum measure on the vacuum hose connecting to port P of the modulator at 2,500RPM? If I'm reading the diagram correctly that line is also connected to the distributor vac advance and VCV for the charcoal canister, with all of those connected to the BVSV. Is it possible there is not enough vacuum to open whatever is supposed to open in the modulator? Thanks

egr-modulator.jpg
 

Guster

SILVER Star
Joined
Jan 13, 2008
Messages
320
Location
SoCal
Took it in with the new modulator and it passed! EGR valve gets stuck open pretty often which is messing up idle but it's probably been a really long time since that valve has had vacuum and any movement.
 

Users who are viewing this thread

Top Bottom