Help! Second time failing smog! (1 Viewer)

[RodrigzCrzr]

Hello
All so I have done the tuneup on this truck.
And lean drop as per fsm.
Went back to smog place and failed again.
My CO is just squeaking by but my HC is at 209 15mph and 101 @25mph.
Again I tuned it up timed it and did a lean drop!
Catalytic convertor is still original.
Can it be possible that may be it?
Any suggestions?

 

[OSS]

There was a reason why the idle mixture screw was capped with an anti-tampering plug from the factory. I don't think tuning the idle via the lean drop method described in the manual provides any guarantee that the idle mixture will then be set to pass the tail pipe emissions test.

On future versions of the F engine (carbed 3F) Toyota recommends tuning the idle only by using a wideband oxygen sensor or tailpipe sniffer. There's no mention of attempting the lean drop method.

Since your cruiser has to pass smog to get DMV tags and the idle mixture screw has been fiddled with, the only way I know of to tune the engine correctly to pass an emissions test is to get a wideband O2 sensor (Autometer has a nice one) and have a sensor bung installed into the exhaust pipe to mount it.

While it's possible that the tweaked idle mixture screw didn't cause the fail, in my opinion, everyone who has to pass a smog test with the 2F should have a wideband O2 sensor available to hook up at least before a test is due to make sure everything is ok. It doesn't have to be installed permanently. The sensor can be removed and a cap screwed into the fitting.

Either that or replace the cat. If it's the original cat, it's very likely it's not working as good as it used to

 

[RodrigzCrzr]

Can this be bought at an O’

 

[RodrigzCrzr]

Can this be bought at an O’

Nevermind last reply I found it on amazon.
Ok so without buying that. And looking at the numbers from the test. What or where should I go from here.

 

[OSS]

Well you could try adding alcohol to the tank (10%) and retarding the timing a bit.

Here's the common causes:

What causes high HC? Common High Hydrocarbon Faults.

m.smogtips.com

 

[Spike Strip]

Jorge, you most likely need a CAT if you still have the original. Your O2 numbers are very good, so likely it's the CAT if you're sure the Carb adj was done correctly. Sometimes hard to tell unless you have a A/F meter.

If you get a new CAT, get the Magnaflow, bolt on.

New CATs are also much less restrictive than OE ones, but be prepared for sticker shock 'cuz it's Kalif and C.A.R.B hates us.

 

[RodrigzCrzr]

Jorge, you most likely need a CAT if you still have the original. Your O2 numbers are very good, so likely it's the CAT if you're sure the Carb adj was done correctly. Sometimes hard to tell unless you have a A/F meter.

If you get a new CAT, get the Magnaflow, bolt on.

New CATs are also much less restrictive than OE ones, but be prepared for sticker shock 'cuz it's Kalif and C.A.R.B hates us.

Thanks Spike
I priced out the CAT by maganflow and it is $375. Pricey for sure.

 

[Spike Strip]

Thanks Spike
I priced out the CAT by maganflow and it is $375. Pricey for sure.

Don't be tempted to use the 48-State version, even though it's the same. There are codes stamped into the CARB legal ones and the smog-techs crawl under the truck now and check. If it's a 48 state one, you'll fail.

 

[RodrigzCrzr]

Don't be tempted to use the 48-State version, even though it's the same. There are codes stamped into the CARB legal ones and the smog-techs crawl under the truck now and check.

This one was the CA compliant one. Bolt on.

 

[Spike Strip]

Yes. I was only saying don't use the 48 stater 'cuz some people use that because it's half the price then get stuck when the Tech spots it.

Get the Toyota OE donut gaskets for the CAT ends. The aftermarket don't fit quite right.

as @OSS states, if your retests are free, you could try the Alchy trick and maybe buy some time...

 

[Randy88FJ62]

I abhor CA CARB smog requirements for our landcruisers. It's always a headache to pass.

@RodrigzCrzr,
I see you are in L.A. County Trailcerew 4x4 territory. You should come to our meetings once the pandemic lock downs are over. Cheers.

 

[2mbb]

How is the engine running? I got my truck smogged last week--11th time for me I think. The past three times my HC was near or at the limit, so I was concerned going into the test, but I did pass again. The tech did mention that I had a minor misfire that could be causing my HC to be high. It seems to run "fine" to me but maybe I'm used to it. I don't expect it to be as smooth as my other newer FI vehicles. I'm going to go back through and see if I can find and correct a misfire.

I had a "dark" period in 2002 where I failed smog three times. I ended up installing a new CAT, new/rebuilt AI pump and rebuilding the carb. My o2 levels back then were <1% (yours seem OK) but I was failing HC, NO and CO. According to my records the PO had also replaced the CAT 20K miles earlier, just before I bought it (in 1998). Maybe he put in a crappy CAT.

below are my results as far back as I have records:

 

[Madronesfj62]

Not sure where you are located but I took mine to

Santa Fe Motor Fuels
13363 Telegraph Rd, Whittier, CA 90605

And the guy passed me no problem after failing once and basically being told by 2 other places they couldn't pass me, they didn't try. The tech at Santa Fe motor fuels was chill once he realized I wasn't working for the government.

 

[lcolon]

I agree with the O2 sensor comments above. The one off amazon does require welding a bung into the pipe. It does allow you to get it tuned perfectly so that you can pass smog. Once my carb was rebuilt, that was the only way to get it setup properly again. One note when using the o2 sensor - disable the air injection while doing so as otherwise it will throw off the measurement numbers making things look lean.

I would check the bolts underneath on the exhaust and make sure it is not all rusted together. You will also likely need new hardware. Note that the magnaflow cat is basically impossible to get a warranty on (take a look at the requirements on their website). I had a long conversation with a guy I use for exhaust about it. While I do have a magnaflow personally, the next time I would probably buy something different and have the exhaust shop install it for me. These things seem to get plugged up periodically.

Good luck.

 

[Glnsgrn]

You may want to check the air injection system. Get the emissions Manual and run through the sections on vacuum advance and also air injection. The cat needs air to burn the HC. If you have air coming out of the bypass hose back into the air cleaner your not getting fresh o2 to the cat. You can also test the cat by measuring the temperature of the exhaust pipe before the cat and at the cat itself. Go for a freeway drive then measure the temp differential. An active cat is much hotter than the pipe feeding into it. Save your self some money and get a cheap IR heat sensor from amz or hf.

 

[2mbb]

His test result shows residual oxygen at the tail pipe. But it doesn’t hurt to check all the emission systems.