Emissions Question-CAT on a pre 79

[lobo loco]

I've done a search and not been able to find any good answers to this question. Has anyone added a catalytic converter to a pre-79 FJ40 to aid in getting the truck to pass emissions? The reason I ask is I did get my 78 to pass CA emissions, but it was a bit of a struggle and had to do a lot of messing around with the truck to get it to pass. I will have to do this again in about two years and I'm looking for a way to make this a bit easier of a task. Also, something I found in this last emmissions test episode is even though the EGR is intact, present, and working, it is very hard to get the motor to stumble when it is tested ( this is a std CA test procedure ) when you have CA legal headers and a free flowing exhaust. It seems that there is not enough backpressure to force enough exhaust gas back thru the valve to make the engine stumble. A rag stuffed into the exhaust cured that for the test purposes. So, my thoughts are if I were to add an after-market CAT I would likely increase back pressure which would help with the EGR, and the CAT would improve the emmissions at the tailpipe without as much mickey-mousing with the carb, timing, etc. The truck can be made to run really well, so I hate to have to de-tune it just to pass a dang smog test. I know the state law says you have to have all the smog equipment present to pass, but I can't find anything about the addition of additional equipment. Is this even legal? All responses will be greatly appreciated, and may be of benefit to others facing the same bi-ennial ordeal. TIA

 

[Pin_Head]

Also, something I found in this last emmissions test episode is even though the EGR is intact, present, and working, it is very hard to get the motor to stumble when it is tested ( this is a std CA test procedure ) when you have CA legal headers and a free flowing exhaust. It seems that there is not enough backpressure to force enough exhaust gas back thru the valve to make the engine stumble.

The EGR test is no longer required in CA; just a dyno ride.

The smog techs are ignorant about older trucks like cruisers and you have to school them. The reason that '78 and earlier cruisers do not "stumble" when you pull a vacuum on the EGR is that the EGR outlet enters the carb above the throttle plate, so it does not cause a manifold vacuum leak. It will never stumble at idle when it is working properly. If they flunk you because it fails this test, you have to whack them upside the head with the facts in the factory smog manual and point to the EGR hose at the carb where it enters above the throttle.

No, it shouldn't need a catalyst because the smog criteria for a '78 are pretty loose.

 

[Fast Eddy]

something I found in this last emmissions test episode is even though the EGR is intact, present, and working, it is very hard to get the motor to stumble when it is tested ( this is a std CA test procedure ) when you have CA legal headers and a free flowing exhaust. It seems that there is not enough backpressure to force enough exhaust gas back thru the valve to make the engine stumble.

The tester tries to "make it stumble"? That's pretty hard to believe. What's the procedure for that?

There's no reason you couldn't add a cat. It would run cleaner. You'd get tree-hugger karma points. It would be hot though. The '79's and later have a heat shield above the cat.

If you're just worried about the pipe emissions for the test add a couple gallons of alcohol before the test.

 

[lobo loco]

The tester tries to "make it stumble"? That's pretty hard to believe. What's the procedure for that?

The procedure is to remove the vacuum line from the EGR...motor should stumple and idle speed should drop. This is supposed to prove the EGR is functional.


If you're just worried about the pipe emissions for the test add a couple gallons of alcohol before the test.


Did that after first failure - three bottles of HEET and it passed. But HC went up as CO went down. Just trying tofind a better solution to this riduculous situation with the smog test BS. Who knows what the wizards of bureauacracy will come up with in the future. I'll move out of state before I'll give in to smog business creeps and leeches.

 

[lobo loco]

The EGR test is no longer required in CA; just a dyno ride.

The smog techs are ignorant about older trucks like cruisers and you have to school them. The reason that '78 and earlier cruisers do not "stumble" when you pull a vacuum on the EGR is that the EGR outlet enters the carb above the throttle plate, so it does not cause a manifold vacuum leak. It will never stumble at idle when it is working properly. If they flunk you because it fails this test, you have to whack them upside the head with the facts in the factory smog manual and point to the EGR hose at the carb where it enters above the throttle.

No, it shouldn't need a catalyst because the smog criteria for a '78 are pretty loose.

Appreciate your comments...Had two different smog test only shops fail the truck due to a claim that the EGR was not working. Both shops did the two speed idle tests and not the dyno test...any idea why they chose this method over the dyno? The thought I had regarding the addition of a CAT were along the lines of putting an aftermarket unit like Summit sells as a bolt on and also having a straight pipe made up too. Thought this might be cheaper and less hassle than doing the 'smog test dance' every two years with smog techs that aren't even as old as my truck.

 

[350-78LandCruiser]

I had to add a cat on my 78 to get it to pass. But I have a 350 in it and it is required for that eng. But it does make the inside a little warm in the summer time over here in AZ.

Todd

 

[PabloCruise]

Have you checked the factory emissions maunal?

My fed-spec '78 passes tail pipe test no problem when adjusted...

 

[Ratt]

No one in my area (No. of Sac) has a dyno tester, it is all done with tailpipe tests. So Cal has different rules than us. Personally I'd take a look at the EGR valve and make sure that it was clean. Look at the garbage that piles up on an old exhaust valve, same for an EGR, exhaust is not nice to metal. Just my 2c

 

[Pin_Head]

Both shops did the two speed idle tests and not the dyno test...any idea why they chose this method over the dyno? .

Maybe you are in a dyno exempt county? You get the dyno in smog impacted counties.

You didn't say why it was failing. I just assumed it was because of the EGR test. They don't know about early cruisers. They disconnect the vacuum line at the EGR and pull a vacuum on the actuator to open the valve. On 99% of vehicles this will cause a manifold vacuum leak and it will either stall or it will idle poorly. Cruisers are in the other 1%. If this is the reason that it is failing, a cat won't help. You just have to school them about how a cruiser operates.

 

[Ratt]

Yes we are, Like I said different rules apply down in the LA basin/ LA and OC counties. If you go up into different counties in Nor Cal you might not have to have it smogged at all, like Lake County by Clear Lake, and many others where smog is minimal.

 

[lobo loco]

Maybe you are in a dyno exempt county? You get the dyno in smog impacted counties.

You didn't say why it was failing. I just assumed it was because of the EGR test. They don't know about early cruisers. They disconnect the vacuum line at the EGR and pull a vacuum on the actuator to open the valve. On 99% of vehicles this will cause a manifold vacuum leak and it will either stall or it will idle poorly. Cruisers are in the other 1%. If this is the reason that it is failing, a cat won't help. You just have to school them about how a cruiser operates.

Thanks for your input. Dyno is typically used where I live (at least on my other cars) ... I should have had a clue they didn't know what they are doing when they couldn't figure out how to open the hood and I had to show them the plate on the dash to find reverse! I am now much more knowledgable about the operation of the EGR, and have a 78 emissions manual to back up your info. My mistake in thinking these certified people know their jobs. HC and CO were borderline on the second test and addition of Heet to the tank was the only thing done to get it to pass. A pretty dramatic improvement, I might add. Since it has Downey headers, and a 2" exhaust with a flowmaster type muffler, it's a little loud and the thought of a CAT might bring the noise down and give a margin of safety next time around. I guess my real question is...is it legal to add a CAT to a vehicle that doesn't require one? Appreciate all input.

 

[inkpot]

I had to add a cat on my 78 to get it to pass. But I have a 350 in it and it is required for that eng. But it does make the inside a little warm in the summer time over here in AZ.

Todd

Howdy! In Arizona, you are required to have the same smog gear that the vehicle came with originally. If the 78 never had a cat, then you don't need one for the 350. I also live in Chandler, and my 30 year old 350 passes just fine without one. John

 

[67azcruizr]

There is a bunch of helpful input here but...............

You never told us the reason(s) you failed the test in the first place.

Quote;
So, my thoughts are if I were to add an after-market CAT I would likely increase back pressure which would help with the EGR, and the CAT would improve the emmissions at the tailpipe without as much mickey-mousing with the carb, timing, etc.


To the best of my knowledge a PROPERLY (not a plugged up one) running CAT will not increase back preasure by any huge amount.

It only acts as a super heater, reducing (burning off) harnful emissions.

NOx REDUCES TO N2
HC, CO, O2 OXIDIZES TO H20 and CO2

 

[scouthead]

the smog criteria for a '78 are pretty loose.

No kidding... when I had my '76 done, I was still dialing in the motor (carb mostly) and I wasn't sure if it was going to pass... Certain measured emissions were twice the max allowable level of my '90 suburban's 5.7 liter V-8... and about half of the allowable levels for the cruiser!

Also while puting my FJ55 back on the road, I really wanted to put in a new cam for a little performance, but ended up not doing it because of other's warning it would no longer pass the smog test.
I had toyed with the idea of having a cat with two flanged ends put into my exhaust, to offset emissions of the cam. That way I could also have the exhaust shop make me a piece of straight pipe with flanges on both ends, and I could bolt it in after the test.

 

[Ratt]

I think putting a cat on would be legal, you just can't take any original smog equipment off. I had a truck that wouldn't pass until I put a new cat on it, but it had one in the first place. When you say Dyno do you mean they put the wheels up on a roller and test it under load? Around here they test it at idle and at about 3K RPM while sniffin it.