FJ40 Colorado emissions fail

[The Colonel]

Hey guys, let me give you the breakdown and hopefully you can help guide me.

I have a ’76 FJ40. It was sitting for 6 years and finally was given new life thanks to a replaced clutch. I went to get it tested (it’s not exempt because I let the registration lapse when they changed the law), and the CO and HC failed. CO was close. HC was over quite a bit. I did notice it was backfiring through the carb when I shifted.

I took it to a local shop, and they wanted to rebuild the carb (it’s a 10 year old Aisan). I decided to hold off, and here I am.

What would you say are my best options?
• Lean out the carb, get the engine super hot, and try again?
• Try a fuel additive like BG 44K or Heet (the gas tank and fuel filter are brand new, as is the fuel).
• Rebuild the carb myself (I saw Pinhead’s 7-part series on YouTube, and while I don’t have the precision of a Swiss watchmaker, I could probably figure it out).

Thanks in advance.

-Craig

 

[White Stripe]

I have a relative with a cruiser shop in Colorado. He does good work. Colorado Toyota specialists. He has a 5 gas analyzer. U could try waving magic wands at it and putting additives in the gas. But without a analyzer you'll never be sure until u go to testing. U could also check your distributor and see if the vacuum advance is bad

 

[fyton2v]

My amateur advice. Ensure your timing is set correctly. It's probably not. When adjusted correctly check for vacuum leaks. Fix leaks. Then do a search on how to set the correct idle speed and mixture for your carburetor. Set those correctly and ensure you're engine is pulling the best vacuum it can at idle. If you don't have a timing gun, vacuum gauge, and a tester for RPM.... they're pretty cheap and worth the investment.

Doing the above helped me get through the CA smog process. Keep in mind, my truck is stock and still has all the original emissions gear. If you're missing your emissions components... Best of luck .

 

[Fast Eddy]

HC will be reduced with a smaller primary jet and properly functioning air injection. If CO was close, it may just come along for the ride. If not, the EGR needs to be working.

You didn't say what part of the original systems may or not be in place.

Also what elevation? If you're at higher elevation, and you have a 'normal' carb instead of a 'high elevation' carb, Bob's your uncle.

 

[Jpilot]

I am dealing with the exact same thing, though mine is a 350 tbi. I read that running e85 fuel is the best to get through the test. Check that timing, I just got a timing light at harbor freight for only about 20$. Open the throttle boddies and spray carb cleaner, wipe as much as you can so the throttle flap can fully close at idle. Check all air hoses and make sure you air filter is super clean or new. Spray carb cleaner around the base of the carb while engine is running, check for idle increase which will signal a vacuum leak. Good luck.

 

[unklwedy]

Assuming all bits(carb, intake manifold gasket, etc.) are OK. Try

1) Plug vacuum advance line with nail, so it don't show.
2) Raise Idle to 1000RPM.
3) Set timing to TDC.
4) Readjust idle speed to ~900RPM.
5) Adjust idle mixture screw for optimum speed/vacuum.
6) Then screw in idle mixture screw until RPM drops ~ 50RPM.

 

[rlong]

In CO, you would typically time it 3 - 5 degrees advanced from factory (see level) spec. And tune as stated above, it should pass, the limits are fairly generous for a 75', it just "runs bad" now : ) And you won't have annual testing either.

Bob in CO

 

[Rat Rod Rusty]

Did you know you can buy 5-year vintage plates and emissions are then nor required...cost my a couple hundred bucks but well worth it...just a suggestion

 

[Downey]

FWIW, In Cali we've found that adding a new cat. converter to a rig that doesn't require one usually lets the rig pass the tail pipe sniffer test. Plus we've tested, and the cat. convt. didn't hurt performance at all, in fact it acted like a second muffler.

 

[SteveH]

Be sure your engine's air pump is actually putting out air, and that the air is getting to the exhaust system. Also, run E85 or several bottles of Heet in a nearly-empty gas tank. You're trying to get tons of oxygen into the system to burn the HCs. A clean air filter and clean oil are always good, too.

Also, good emission testers won't snap the throttle open or shut on a carbureted vehicle - they will gradually open/close, but you can't count on most shops knowing this. When you abruptly change the throttle, you tend to see a big spike in HCs/unburned fuel.

 

[The Colonel]

Thanks for all the advice guys! I just passed (3rd time is a charm). A combination of Seafoam, leaning out the carb, spraying carb cleaner, adjusting the idle, and driving it a ton and getting it super hot seems to have done the trick. Either that or the kid doing the testing really dug it and let me slide. Either way, I'll take it and won't have to deal with it for another 5 years.