Emissions Help Needed! (1 Viewer)

[AdamKFarmer]

So, I'm not a 60 guy per se. I have an '82 FJ40 but the emission system is the same as the early 60s so I think posting this here will be more fruitful than in the 40 section.

I'm just about done re-smogging my 2F in order to pass emissions testing in Denver. I would like it all to work properly so I can pass the first time honestly. When I purchased it it had been desmogged with a holley carb. So, everything is back to stock and connected. I went through the install with the emissions manual and I think it is all hooked up correctly. So, here is my problem. I am testing the AI system and it won't come out of by-pass. It seems to me that the VSV that controls it won't ground and sent it to the cat. I have replaced the computer with two other ones to know avail. I tested the VSV and it switches when supplied power and ground. I have 12V at the plug and the comptuer's ground is grounded. Just doesn't want to switch. Any suggestions? Thanks!!

 

[GeoEng]

Check your VSV's . On page 3-19 of the FSM 2F emissions manual there is a spec for resistance of 38-43 ohm for the switches. mine failed this test so I replaced then with used units from $OR and they met the spec and now my ABV pumps air to the cat.
Good Luck

 

[Spike Strip]

Frequently the ABV is full of crap that keeps the valve from working. Might have to take it apart and clean it. Screws are in tight.

 

[AdamKFarmer]

Hummm, I checked the resistance on them, it was pretty close, and the open and close easy enough so I figured they were okay. The ABV switches to the cat when I disconnect the vacuum line running from the VSV(2). (even though the line doesn't hold vacuum it leads directly to the air cleaner)

 

[AdamKFarmer]

Bump for help!

 

[AdamKFarmer]

Well, I got it to pass smog but still doesn't inject right. Anyone an expert on this smog stuff?

 

[cruiserfj45]

I don't have my book in front of me. What are the conditions for sending air to the cat. I thought it needed to be driving down the road.

 

[Pin_Head]

My recollection is that the computer gets inputs from the manifold vacuum and speed sensor to control the ABV. Maybe a few more too. If the sensors don't work, then the VSV won't work either. The wiring needs to be good too. Usually the smog book has a trouble shooting guide or at least an explanation of how the system works.

 

[AdamKFarmer]

I've posted the conditions for AI from the emissions book. So, my problem is that it stays in by-pass. For it to bypass to the air cleaner the temp has to be hot, I don't have my cat sensor mounted but since it is not hot it shouldn't be injected, even when I unplug it, it still injects. The fuel deceleration system might be suspect, but since it only is comprised of the vacuum switch and the carb, I've tested the switch and it tests fine so I think that wouldn't be it. One curious note is that when doing the tests per the FSM it didn't idle rough when pinching the vacuum hose and revving up. All the VSVs check out.... still stumped.

 

[AdamKFarmer]

Anyone have any thoughts on the deceleration fuel cut system thing?

 

[Finnyfam60]

That's the ICS. It actuates during decel to not waste fuel, so i thought...

 

[AdamKFarmer]

Right, well I did the test per the FSM (pinch the vac line and accelerate from 1.2k to 2k and see if it misfires slightly) which it didn't. I might have performed the test incorrectly. I'm just trying to chase down what I need to test to get this system working correctly.

 

[Toadhopper]

I had the same problem on my 60 and although the VSV got replaced and tested OK the wire leading to it was faulty. Like Pin said whatever is sending the message TO the VSV may also have an issue.

 

[AdamKFarmer]

Toad-
Not a bad thought, I did do a continuity test between the pins and the plug and that tested okay, I didn't check the resistance though... How did you fix your problem?

 

[AdamKFarmer]

Bump! Any other thoughts?

 

[Finnyfam60]

Did you test ICS? (disconnect and connect to hear click) but it sounds like you are not having any idle issues, so seems ICS is working fine (though maybe not closing upon deceleration (negative acceleration really, but that's a physics conversation))
I dunno...

 

[AdamKFarmer]

The idle circuit switch? Yeah, that is running fine... when I disconnect the computer the engine dies. The fuel cut solenoid didn't test well earlier..

 

[2mbb]

The temperature condition mentioned in the table above is monitored by the thermo sensor in the CAT. If this sensor is no good and reading "hot" all the time, then the system will be in "bypass" at idle and will only got out of bypass when decelerating under compression (high vacuum and high engine speed). what I don't remember is if the sensor opens or closes when it is too hot. You can pull the probe and test for a resistance change when heating the probe with a torch or other hot flame.

Refer to the Catalyst section of the emissions manual for resistance spec's for the thermo sensor.

Edit: here is an old thread with some more information. It seems that if the thermo sensor or wires are shorted out, it could put you in bypass all the time. https://forum.ih8mud.com/60-series-wagons/25907-cat-therm-sensor-bad.html

 

[AdamKFarmer]

So, I have a few updates on this situation, maybe you all can offer some insights. I'm pretty sure all the components are working or, if something isn't it's not involved in the AI system. I bought a new thermo sensor and checked for a short circuit, all checks out fine there. I ran through and checked some grounds and found something particular. According to the emissions FSM the pin number 4 on the emissions computer should be the negative terminal for the coil, but I only get continuity on 6. Well, anyway I'm under the impression that the VTVs always have power but the computer is the one that applies ground, so I check the voltages on the pins on the plug and never get any voltages readings, unless I use an outside ground and then I get 12+ V. So, the computer isn't sending the grounds and the thermo sensor is good. I pulled the cluster and checked for the speed sensor and it had continuity with the computer but I don't have a floor jack in order to do the FSM test. This is my 3rd computer to try, and it was off a low mileage FJ60.
So, that is where I am now. At least it passed emissions, but this problem is really bugging me.

 

[1911]

... the VTVs always have power but the computer is the one that applies ground, so I check the voltages on the pins on the plug and never get any voltages readings, unless I use an outside ground and then I get 12+ V. So, the computer isn't sending the grounds ... This is my 3rd computer to try...

The "computer" circuit board was cold-soldered at the factory, and particularly where the harness connector is soldered to the board, the solder is very well-known to crack, leaving open circuits and the "computer" inoperable. Some people have reported success by carefully heating each of the connection solder joints with a soldering iron and re-flowing the existing solder. Alternatively, you can just ground the wire from the ICS to the computer and the ICS will always be on with ignition.