Emission Impossible-Gremlins may be real (1 Viewer)

[Whoops]

Hi All,

I’m working on getting my stock 85 fj60 with 2f engine smogged in CA (I know, big fun). The first sniff test showed HC too high and it was running poorly. Some digging had me discovering that the valves were horribly misadjusted. Set them and the tail pipe smells that had plagued me were gone completely. Also RPM at idle shot to 1250. Reset the carb, per the lean drop method and noticed the cat was working pretty hard, light smell of sulfur at the tail pipe and pretty hot fumes. Took it in for a test and got the results in the first image. Everything went great except the CO at cruising, I might mention it was 110 degrees outside and my smog guy suggested it might be throwing things off. Emissions manual suggests that an obstructed air filter could cause the high CO, so a new one was installed and maybe 12 miles was put on the thing before this morning’s test (80 degrees outside). Next two photos are the idle and cruising readings…my TLC seems to have had a major malfunction in the week between tests and no one I’ve asked can think of any explanation for these numbers. The cat has about 200 miles on it (it’s been off a lot for diagnostic purposes) and the thing is running better than it ever has since I bought it. Also I replaced all the vacuum hoses about 4 years ago I would love to hear any ideas other than gremlins. Thanks!

 

[CruiserTrash]

I have to do dyno roller smog tests here in Colorado, and I live & die by this graph. Hope it helps.

I don't take the actual numbers into account on this, just the general behavior of the curves. Always do tune up stuff first - new plugs, fuel filter, air filter, change the oil, address any vacuum leaks (check it ALL), and adjust the valves. Sounds like you did some of that, which is good.

If I had to guess, I might look at your EGR first since that operates starting at about 2000rpm. I would check that using the procedures in the Emissions manual. I had a similar test failure a few years ago because the EGR valve was clogged up. Be aware the valve & modulator may pass the tests, but could still be operating suboptimally. Also, the input from EGR valve to the intake manifold can get completely plugged with carbon. Might be worth having a look in there.

 

[OSS]

Your air injection system isn’t working properly. Welcome to the club.
That’s why your Carbon monoxide levels (CO) are high: the cat doesn’t have enough oxygen to convert the CO to CO2.
The clue to this is your O2 readings. Your test shows zero. It shouldn’t be zero.
Mine O2 were 2.6 & 2.2.

 

[71-CRUISER]

Pull a small vacuum line during the rolling test portion if they will let you.

 

[elripster]

If you pull the air pump hose from the air filter part of the intake and you have air coming out, the valve that switches air to the exhaust is not switching. It's stuck in "recirc" where it just pulls in filtered and and dumps it back upstream of the air filter. I have a trick for testing the air valve. The switch air is likely venting to atmosphere out the back (fender side) of the valve which is how it is turned off. Swap the hose on the engine side (that goes to the switching valve) with the filter on the back. Now vacuum should operate the switch and air should not be dumping back into to air cleaner housing. If that''s the case, then air IS pumping into the exhaust pipe. Also if that's the case, the switch is bad. If so, PM me and I might be able to assist.

Frank