Gross Polluter

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jwest

jwest

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Joined
Mar 12, 2004
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This is a stock 2F with 110,000 miles. Driven 5K street miles a year.
Looks like it's running real rich and I'm asking for ideas as to why.

Carb was rebuilt before the last test in 2003 and then passed. It was running rich then too, but not this badly.

Cat is 4 years old, new plugs, fresh oil, new distributor cap/rotor. Gas level in sight glass is at 1/2 way point. Just giving the rundown. Overall, it runs great.

After the test, i found that the PCV valve was stuck. I figure it would hurt the HC's but not to the amount it failed. I don't think the K&N would plug up in 5K city miles enought to block that much air.

Where would you start... carb (rebuilt 2 years ago), choke breaker, HAC valve?

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I was pressed for time during the last emissions test and under a specific program, had to choose only from a list of mechanics provided by the state. Once under the program, you have to "let them handle it", so to speak. So when I asked about the carb rebuild, they told me they put in the (rebuild) kit, that's about the extent of it. To their credit, it did run well. How well it was rebuilt, is another matter.
They ran the follow up test themselves and passed it.

I know the BVSV you're talking about. Good... I can check that.

What else?

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Two for Air Injection... ok.

How did you guys determine that. Are the levels so high that it's more likely a lack of O2 in the cat rather than too much fuel?

I see that the O2% in the 2005 VIR reads 0.40 at 25 mph.
In the 2003 VIR it read 1.1 at 25 mph.

That indicates Air Injection?

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My air injection guess isn't really based on your numbers. Its more based on personal experience. When I was having trouble passing the emissions test, I went as far as making a special appointment with an emissions technician to try to figure it out. He commented that 2Fs generally run rather rich and rely on the AI to clean up the exhaust. One of the things he tried was to add some air from a compressed air line into one of the AI hoses leading into the exhaust. The CO number plummeted. The combination of a weak cat and a weak air pump was my biggest problem - there were some others to. The "vacuum switch" mounted on the drivers side fender was bad, and so was the spare vac switch I had. On another 60 I had, the vacuum control valve for the evaporative control system had failed and was allowing liquid gas to get sucked into somewhere it shouldn't. You may have several problems but the major emissions control system is the AI. The factory emissions book has a step by step walk through to test the whole thing as well as each component. If you don't want to do it yourself, find a Toyota specific mechanic who has the book and is willing to do the tests.
 
Thanks for that, 60wag. I have an emissions manual and can go through the various system tests, but I can't determine (so far as I know) if it is a weak AI pump without an exhaust gas analyzer and an air compressor. A gas reading before the cat might be telling, but that too is for an emissions tech. I may just have to leave it to them on this one.

I know that if AI isn't working well, as you mentioned, the cat doesn't have a chance to clean up the HC's and CO's. Your bad evap VCV sounds interesting to me too. Would that affect CO as well as HC?

I like AI as the problem area, but what jumps out at me is High HC, High CO, and LOW 02. To me it signals too much fuel. Anyone else care to throw something in?

High HC, High CO, and LOW 02 = ?
(CO2 could be higher too.)

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60wag said:
My air injection guess isn't really based on your numbers. Its more based on personal experience. When I was having trouble passing the emissions test, I went as far as making a special appointment with an emissions technician to try to figure it out. He commented that 2Fs generally run rather rich and rely on the AI to clean up the exhaust. One of the things he tried was to add some air from a compressed air line into one of the AI hoses leading into the exhaust. The CO number plummeted. The combination of a weak cat and a weak air pump was my biggest problem - there were some others to. The "vacuum switch" mounted on the drivers side fender was bad, and so was the spare vac switch I had. On another 60 I had, the vacuum control valve for the evaporative control system had failed and was allowing liquid gas to get sucked into somewhere it shouldn't. You may have several problems but the major emissions control system is the AI. The factory emissions book has a step by step walk through to test the whole thing as well as each component. If you don't want to do it yourself, find a Toyota specific mechanic who has the book and is willing to do the tests.
Click to expand...

Same...well, sort of.

I went through hell with mine. Had a new air pump, carb, plugs, valve adjustement, timing, wires, rotor, cap, seafoam...rerouted and replaced every emissions hose on my truck...well except for two. When the knucklehead at the Toyota dealership put my smog pump on, he didn't put the pump hoses on the right way. I switched the two hoses to the correct routing and passed with flying colors.

The AI system makes a big difference in what comes out of the tail pipe. The carb only has one real adjustment for fuel to air ratio, and that really only effects the idle ratio. To effect the f/a raition while it's running at speed, you've got to re-jet the thing. IIRC.

Get the manual - even if you're not comfortable working on it. Believe it or not, the system is really, really easy to work on. It takes some time to get used to it, but the manual walks you through everything.
 
jwest said:
I like AI as the problem area, but what jumps out at me is High HC, High CO, and LOW 02. To me it signals too much fuel. Anyone else care to throw something in?

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Click to expand...

The AI system runs in three stages. Up to about 45mph, air is injected directly into the head, which increases the temp at the exhaust valves, IIRC, thus increasing the combustion temp, etc, and burning more of the HCs. Once you're over 45mph, the ASV or ABV (air switching valve or air bypass valve - can't remember which it is of the top of my head) on the DS inside fender switches the air route to force air into the exhaust system pre-cat. This increases the temp of the exhaust gases and the cat, and helps burn off more HCs, etc. Third stage is sort of a safety phase. If the temp in the cat gets too hot (you know that little electronic thing that's stuck in your cat? It takes the cat's temp, basically) the ASV/ABV
takes the air from the pump and forces it into the air intake/breather, thus cooling the cat and the rest of the system.

So basically, that's why you get the read of too much fuel. When my truck was all buggard up, my plugs were a normal tan, but when you blipped the throttle, black carbon smoke, normally associated with running rich, came out of the tail pipe.

I think my thread on what I went through is in the FAQ - also search the board for "running rich" which is what I think one of the thread titles I did on the subject.
 
Swank60, I remember the problem you were having back then. If memory serves, I think I might've been the one that confirmed those misrouted hoses ;) .

Thanks for the info. Let me add though that a carb that needs repair can cause all sorts of problems one of which is running rich. A bad power valve, for example can cause this.

Although a properly working AI system, as I understand it, will lower HC and CO levels, it still needs the proper stochiometry (14.7 to one A/F mixture) for the entire system to work efficiently. And since the 2f's were never equipped with 02 sensors to control air/fuel electronically, they have to be dealt with manually.

So, a rich condition, despite a good working AI and cat, will still show high CO's that a cat may or may not clean up.

I want to pass emissions, but I also don't necessarily want to use the AI and cat to mask underlying problems.

Thing is, I'm 105 ppm over max on HC and 1.32% over max on CO.
Can a weak pump cause this kind of variance?

I'm also running alot cooler (1/3 up the temp gauge) since changing the radiator and rebuiding the fan clutch with 5000cst silicone oil. Fan runs alot stronger.
Sounds far fetched but can I be running too cool and not getting the cat up to temp?

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I went through the same questions on the "running cool" deal too, but my first failure last year was in Feb, and I wound up passing in July - but it still failed in June, too. It COULD be making a difference, actually. Cardboard in front of the radiator?

A weak performing pump could be lowering your numbers, too. It's a volume pump, not a pressure pump, and if the veins in it are eaten up or gone, you're not going to get the volume you need into the system. Interesting comment about the AI running better masking another problem...how many miles are on that carb?

Also, did you do a SeaFoam treatment? If you've got a lot of carbon buildup, that could cause the slightly higher numbers, as could something basic like your timing, valve lash, etc.

On mine, I remember just beating my brains out for months...but my numbers were HUGE. HCs were like 2000PPM over, etc...then, one night as I sat staring at the manual, I looked at the smog pump routing and thought to myself "no friggin' way" - 11pm visit to the garge and sure enough...that sucked bad.

If you've gotta-gotta pass inspection asap, try the seafoam and then add white gas or heet to the tank and take it in...or advance your timing a little.

Are you doing a dyno, 2 speed test, or is it the idle test? (not sure if anyone even does the idle test anymore...)
 
I'm on board with Swank (BTW looks like your keeping the rig Swank?). As I wrote above I think your pump COULD cause this or atleast be a major contributor. 76$ at carquest will get you a new one.

Running cool. I struggled with this for almost a year. Had the radiator flushed and pressue tested. Had the block inspected. Played with the timing and mixutes to no avail. Went through about 4 thermostats (all within 20 degrees BTW).

In a seemingly unrelated issue I had the oil pump fail to prime itself after a routine oil change. Took out the dizzy turned it with a drill and coudl hardly generate pressure. Swapped out the oil pump and cleaned out the pan (was surprising clean in there for having never been done before). Guess what, Pressure was restored and ran at normal temp ever since. NORMAL TEMP!!! I was surprised to say the least. Power was immediatly noticable too.

Maybe you have weak oil pressure which is causing some of your problems???
 
Thanks all for the input.
It's a two speed treadmill test. 5K miles on the rebuilt carb and i decarbonize about twice a year.
It's running cooler and better than it ever has. I'm sure I drove far enough to the smog station to get it hot.

3 for AI... i'm still leaning toward a fuel dumping problem. Especially if something went wrong with the carb rebuild. Power valve, heavy float... ?

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If the float is set incorrectly in the carb, that can cause you to run rich - you've checked the level in the sight glass, right?

(Oh, and yeah, I'm back to keeping it - let's see how long the AC holds up this time around though... :D I'm sure I'll change my mind in a week.)
 
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