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Discussion Starter #1
I have an 02 tacoma with S/C and URD 7th injector, its that pesky time and the smog is due. Went in to get it smogged only to find out the old boy is a GROSS POLLUTER. Didnt see it coming as it was smogged 2 years ago no problem and only 10k miles have been put on it since.

Barely passed the 25mph test, grossly failed at 15mph The NOX and HC was off the charts, NOX at 1900, 500 is allowed, HC at 260, 100 is allowed.

Checked my cats first, one was completely toasted, replaced it, brought the NOX down to 1600, and HC 160, not really that big of a change, the other cat looked decent, no rattling or holes, doubt it would throw it off that much.

I know the other obvious culprit is running lean, i tuned the truck 3 years ago when first got the S/C on it and havent touched it since, plus correct me if im wrong, but the URD controller only takes over in open loop, in closed loop the stock ECU handles shit as normal???? So adjusting the timing on the URD really wouldnt help.

keep in mind my CO readings were good.

Other things that could be making it run lean is MAF and front O2 sensor, both have been replaced about 25k miles ago.

With the readings being that far off makes me think there is a much bigger problem, like blow by, head gasket etc. I dont have any check engine lights nor is it running hotter than usual based on my temp sensor.

Any ideas????
 

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NorCal Chapter Pres
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It's running lean. You need to solve that problem as it is the primary cause for high nox
 

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Discussion Starter #3
Do you know if retarding the timing using the URD controller will effect it at closed loop when the smog is being done?
 

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NorCal Chapter Pres
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You need more fuel. A 7th injector that adds fuel during boost or larger injectors that's controlled with a fuel controller will solve your problem
 

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^Doesn't he have a 7th and URD kit?

Loober, what fuel pump?

What do your spark plugs look like?
 

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Discussion Starter #6
Yes i have the 7th injector from URD with the piggyback controller, I have the walbro fuel pump, like i said ive been running this for 4 years as it is, with a successful smog 2 years ago. I have not checked the plugs yet, just trying to narrow it down.

Ive read a lot of threads on this and i know it can be a million things, what throws me off is that both HC and Nox are off the charts usually its just the Nox if its a lean issue.
 

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put some tiny tires on it(or huge r&p), since you passed at 25 mph, the ratio change could pass you as a bandaid fix. had the same problem, changed all kinds of parts and still failed; was way cheaper just to find a shady smog or registration work around.
 

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Discussion Starter #8
yea its fucked, my registration is already 5 months over due. Ive tried very hard to find a shady smog place, but the state is really cracking down on it so everyone is terrified of doing it now. Yea ive thought about the smaller tires, but my numbers are so off i doubt it will get it there, id rather just get it fixed so im not going through this again in 1.5 years. As much as I hate to do this ill have to take it to the dealer to get diagnosed instead of blindly throwing parts at it.
 

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did you put factory cats on it? theyre strict on that shizzle. some legit shop was telling me ridiculous stuff about how they have to be brand new replacements with no signs of welds and stuff; which idk how one would accomplish unless they sell em all ready to bolt up for each model. I put a vatozone " california legal" one on and the thing failed just the same as the factory old one.

one possibility is maybe pull the blower and put the original intake on. i know it sucks but that could be the ticket to registration stickers.
 

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NorCal Chapter Pres
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yea its fucked, my registration is already 5 months over due. Ive tried very hard to find a shady smog place, but the state is really cracking down on it so everyone is terrified of doing it now. Yea ive thought about the smaller tires, but my numbers are so off i doubt it will get it there, id rather just get it fixed so im not going through this again in 1.5 years. As much as I hate to do this ill have to take it to the dealer to get diagnosed instead of blindly throwing parts at it.
The dealer won't be able to touch the urd stuff ...
 

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Did you use a denso o2 sensor? Any exhaust or intake leaks? Def check plugs n wires. Any stored engine codes? The urd can change many things, depending on which one you bought. Btw to those saying he needs a 7th injector, he is lean on part throttle (where the 7th is not in play) 7th only kicks in for heavy throttle... The stock injectors are large enough.

Now, have you checked your fuel filter? Injectors ever been cleaned?
 

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Walbro fuel pumps can and do shit the bed. Your truck is running lean to the point of missfiring under load, that's why the HC is high too. I would check the fuel pressure, which is kind of a bitch on these trucks because you need an adapter banjo bolt to tap into the rail.
 

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Discussion Starter #13
Took it to the dealer to get everything diagnosed instead of just throwing parts at it. The fuel trims were spot on and comparable to a stock 3.4, so cant be a lean issue. Compression and leak test showed everything to be top notch, they even scoped the cylinder walls and the tech was surprised how clean they were. MAF was questionable so I had them replace that, the AFR and O2 sensor were both testing within range, no exhaust or vacuum leaks. Basically all signs are pointing back to the Cat. I only replaced the rear cat, b/c it was easier to get to, the tech thinks I replaced the wrong cat, since the front cat is the one that does 80% of the work, I did not know this I thought they were both the same.

I will replace the front cat today, throw some new spark plugs in her and give it another shot.

BTW, my wife works at a toyota dealer so I get cost on all the parts, my price on a replacement cat from dealer was 1100, so its probably like 1400 normally. Found a local muffler shop who quoted me for an OBDII CA legal weld in cat for 300, makes me worry why such a huge diff in price. Obviously im going with the 300 one.
 

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If I had known the difference I never would have bought a CA emissions truck. No testing here, but I want it to run right.

The Kauai Toyota tech suggested punching them out:D

Here they want my retirement fund for a cat as well.
 

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Took it to the dealer to get everything diagnosed instead of just throwing parts at it. The fuel trims were spot on and comparable to a stock 3.4, so cant be a lean issue. Compression and leak test showed everything to be top notch, they even scoped the cylinder walls and the tech was surprised how clean they were. MAF was questionable so I had them replace that, the AFR and O2 sensor were both testing within range, no exhaust or vacuum leaks. Basically all signs are pointing back to the Cat. I only replaced the rear cat, b/c it was easier to get to, the tech thinks I replaced the wrong cat, since the front cat is the one that does 80% of the work, I did not know this I thought they were both the same.

I will replace the front cat today, throw some new spark plugs in her and give it another shot.

BTW, my wife works at a toyota dealer so I get cost on all the parts, my price on a replacement cat from dealer was 1100, so its probably like 1400 normally. Found a local muffler shop who quoted me for an OBDII CA legal weld in cat for 300, makes me worry why such a huge diff in price. Obviously im going with the 300 one.
Good luck. With non-OEM cats you roll the dice if they actually work.
 

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Discussion Starter #16
Just to update everyone, finally got the truck smogged with 2 replacement magnaflow cats. It didnt pass with flying colors by no means, it was pretty much at the limit but it passed. I don't think there is anything wrong with my truck that made the numbers higher then it should, the non OEM cats are definitely not as good, but they are a 1/4 of the price, the way i see it is still worth it to go that route, we'll see what happens to them in 2 years.
 
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