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Topic
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00 4cyl Camry, 195k miles Cali emissions
A few months and almost 2000 miles ago had P0420. Replaced cats with Cali approved Bosal, and also replaced both sensors with Denso.
Cleared codes, set readiness, has been fine until last night. P0420 returned! My NY inspection is due so I need to get this repaired.
I’ve read that intake leak and injectors can also cause this. I smoked it and found this crack. Would this cause P0420? No other codes current or pending. I have ordered this tube, but won’t be here until tomorrow. I’d like to check other items while waiting, if possible.
How can I check if an injector is leaking?
What else can I check for causing this code?
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[quote=”Elle” post=185411]Toyota Karl, I love your avatar haha. Just watched again the other night. “I’ve come to fix your cable.” haha[/quote]
Karl fixes the cable 🙂
[quote=”Elle” post=185498]New intake tube replaced. Also found upper resonator tube had torn, so replaced that (whole resonator with tube).
Fuel trim at idle
ST -0.8
LT 18.82000 rpm
-3.1
LT 15.6I’m reading long term can take up to ten miles to reset itself. I’m going to drive it tonight and see if still high. If not, back to looking for a leak.[/quote]
OK,
Your Long term fuel trims are high. Not high enough to set a rich condition code, but enough that this can cause extra fuel in your exhaust (which ends up burning up Catalytic converters). Which may explain why yours originally needed replaced.
The rich condition you may be getting could be caused by leaking fuel injectors. You can usually get a set of new Denso’s on Ebay for around $100.00
I noticed you said you had a California Catalytic converter, is this a California car? If so, were the proper O2 sensors for California emissions installed?
If no one has explained, a P0420 is caused by the downstream O2 sensor shifting similarly to upstream sensor, that is what the software is looking for. When they are too close, then the Cat is not doing its job and the software sets this code. A better test is tailpipe test. Toyotas of your vintage were very sensitive to this and some models they reflashed the ECU because this code makes them not pass emissions, but in reality, they still would pass a tailpipe test. Also, some aftermarket cats just don’t work as well as OEM.
Good luck
-Karl (<- This one is not a nihilist!)
Car is Cali, replaced with Bosal cats, and Denso cali sensors. Not ruling them out yet, but I may have something.
I smoked it again after replacing those tubes and see smoke coming from the EGR gasket going into the intake. When gasket area is sprayed, my STFT dove into the negative. Could this be my air leak?
I’ll call Toyota and see if they can set me up with a reflash.
This car is killing me not softly.
[quote=”ToyotaKarl” post=185548][quote=”Elle” post=185498]New intake tube replaced. Also found upper resonator tube had torn, so replaced that (whole resonator with tube).
Fuel trim at idle
ST -0.8
LT 18.82000 rpm
-3.1
LT 15.6I’m reading long term can take up to ten miles to reset itself. I’m going to drive it tonight and see if still high. If not, back to looking for a leak.[/quote]
OK,
Your Long term fuel trims are high. Not high enough to set a rich condition code, but enough that this can cause extra fuel in your exhaust (which ends up burning up Catalytic converters). Which may explain why yours originally needed replaced.
The rich condition you may be getting could be caused by leaking fuel injectors. You can usually get a set of new Denso’s on Ebay for around $100.00
I noticed you said you had a California Catalytic converter, is this a California car? If so, were the proper O2 sensors for California emissions installed?
If no one has explained, a P0420 is caused by the downstream O2 sensor shifting similarly to upstream sensor, that is what the software is looking for. When they are too close, then the Cat is not doing its job and the software sets this code. A better test is tailpipe test. Toyotas of your vintage were very sensitive to this and some models they reflashed the ECU because this code makes them not pass emissions, but in reality, they still would pass a tailpipe test. Also, some aftermarket cats just don’t work as well as OEM.
Good luck
-Karl (<- This one is not a nihilist!)[/quote]
I did a fuel pressure test, started, ran, shut off. I did not get a drop in fuel pressure. But that's as far as I went with the injectors before I switched to replacing that intake tub, and then the upper resonator.
[quote=”Elle” post=185561]Car is Cali, replaced with Bosal cats, and Denso cali sensors. Not ruling them out yet, but I may have something.
I smoked it again after replacing those tubes and see smoke coming from the EGR gasket going into the intake. When gasket area is sprayed, my STFT dove into the negative. Could this be my air leak?
I’ll call Toyota and see if they can set me up with a reflash.
This car is killing me not softly.[/quote]
That may be your issue at last.
My suggestion would be replace the gasket and check the results before investing in a reflash.[quote=”Elle” post=185574]I spoke too soon!! Back to square one tonight. Code returned.[/quote]
Was this after repairing the EGR gasket leak?[quote=”Elle” post=185561]
I smoked it again after replacing those tubes and see smoke coming from the EGR gasket going into the intake. When gasket area is sprayed, my STFT dove into the negative. Could this be my air leak?[/quote]Yes. Replace the gasket (hopefully, it only needs the gasket). Clear the code and, hope that that’s the last issue.
Yes, EGR gasket was replaced last night (Autozone 24 hour to the rescue). Today on way to work my code returned. I cleaned both mating surfaces and there was no longer a smoke leak after the repair.
After last night’s 25 mile ride my LTFT did drop from 18 average to 15ish average, but not good enough
Yes, found a leak on the resonator pipe, behind the resonator section where they weld on an addition plate, the welds were leaking. So replaced the resonator and muffler with bolt on replacements. Have gone up and down the exhaust looking for leaks.
If there was a tiny leak, would it affect the fuel trims?
It is possible …
If there is a exhaust leak, the O2 sensor(s) would give a incorrect reading back to the ECM and in turn the ECM will try to compensate.
Have you examined the exhaust manifold for cracks or possibly broken attaching bolts.
Any evidence of soot deposits, black or white?I just went along the whole exhaust again, and removed the heat shield on the manifold cat. I could be just not hearing it. Can I smoke the exhaust?
[quote=”Elle” post=185603]I just went along the whole exhaust again, and removed the heat shield on the manifold cat. I could be just not hearing it. Can I smoke the exhaust?[/quote]
Yes, but it will require you hand cranking one cylinder to its exhaust stroke, removing that cylinders spark plug and running the smoke machines tube into the spark plug hole and cap off the tail pipe.
That will fill the manifold and exhaust system with smoke.
If there is a leak it should show up.
You can also pump the smoke in from the tail pipe, or you could also remove the O2 sensor from the manifold and feed smoke in from there, but some valves will be in the open position and the smoke will back feed into the engine.
Which may make seeing a leak troublesome.Smoked through the upper o2 port. I think I found a pinhole BY THE DOWNSTREAM SENSOR!!! Found in the middle of the night and had to just walk away.
Tonight going to remove the brand new resonator (where the port is located) and see what I can see.
For the sake of ending this nightmare I hope it is it.
But for my pride, I’m going to need to eat a lot of humble pie!
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