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Electromagnetic Wave :-h
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Thanks. Wanted to make sure the vac line was sealed off. You might want to just cap it at the manifold.
 

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Discussion Starter · #43 ·
Nope, still hesitating.
Thought I had something when I found that the previous owner had spliced what looks like a small capacitor into the post cat O2 sensor harness.

I got to wondering, could this be a stuck vtec solenoid?
 

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Electromagnetic Wave :-h
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An attempt at making a P0420 go away.....
I got to wondering, could this be a stuck vtec solenoid?
Lol... That's Honda. But, you do have a VVT solenoid.
 

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Discussion Starter · #46 ·
Arnt they the same thing???


2000 GTS Turbo
I guess VVT (Variable Valve Timing) is a generic term so it probably covers everybody's technology that performs the same function.

FWIW, I pulled the VVT solenoid and it's little filter and both were clean and when I applied 12v to the solenoid, it moved easily and correctly so i don't think that's it.
 

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I guess VVT (Variable Valve Timing) is a generic term so it probably covers everybody's technology that performs the same function.

FWIW, I pulled the VVT solenoid and it's little filter and both were clean and when I applied 12v to the solenoid, it moved easily and correctly so i don't think that's it.
Its not the same nor is it the same function, to be specific vvt is variable cam timing, the solenoid pushes oil into the cam and that can varry cam timing advanced/retard by a specific amount depending on various factors.

Vtec (honda)is a solenoid that puts oil pressure to a rocker so its rides on the big cam.

Kinda similar effect to what the 2zz has but its activation and system is different.



2000 GTS Turbo
 

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Discussion Starter · #48 ·
Its not the same nor is it the same function, to be specific vvt is variable cam timing, the solenoid pushes oil into the cam and that can varry cam timing advanced/retard by a specific amount depending on various factors.

Vtec (honda)is a solenoid that puts oil pressure to a rocker so its rides on the big cam.

Kinda similar effect to what the 2zz has but its activation and system is different.

2000 GTS Turbo
Ahh, makes sense, I have always roped them together in my mind.
 

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Ahh, makes sense, I have always roped them together in my mind.
Nope, they are different. Understanding correct Terminology is important because you can say one thing and it be completely different from a experience point of view.

If i say your issue is the upstream o2 sensor and you think upstream is the 2nd o2 sensor then you replaced a part for no reason.

Same principle here, if it was a 2zz and i said check your filter for the lift solenoid, and you check the vvt solenoid even though they are the same part theyre on opposite sides of the engine. Then id be trying to help you diagnose a no lift issue with a clogged filter screen with you thinking you checked the filter and it was clear.

2000 GTS Turbo
 

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Discussion Starter · #50 ·
Nope, they are different. Understanding correct Terminology is important because you can say one thing and it be completely different from a experience point of view.

If i say your issue is the upstream o2 sensor and you think upstream is the 2nd o2 sensor then you replaced a part for no reason.

Same principle here, if it was a 2zz and i said check your filter for the lift solenoid, and you check the vvt solenoid even though they are the same part theyre on opposite sides of the engine. Then id be trying to help you diagnose a no lift issue with a clogged filter screen with you thinking you checked the filter and it was clear.

2000 GTS Turbo
The VVT thing I may not have been right on the money, the rest I am.

... and I still haven't solved my problem, despite all this knowledge floating around.
 

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Electromagnetic Wave :-h
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Well.... You replaced the upstream O2... the complimentary sensor is the MAF. MAF measures air in, O2 oxygen out. Cold start & WOT are Open Loop. Everything else is Closed Loop & based on sensor feedback. Really want to see Freeze Frame data on CELs. Best I can see so far is @ -11.7 LTFT, it appears to be running rich. The attempt at masking the P0420 with a capacitor bypass says that the cat has been fouled for a while, likely running rich (MAF, vacuum leaks, upstream O2) and burning oil (pistons & rings). All fairly typical of early 1ZZs.
 

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Discussion Starter · #53 ·
Going on a hunch, I pulled the throttle body off to inspect the IAC valve. Valve was fine but the rubber seal between the IAC and the throttle body was missing a piece, was sure I had found my problem so I ran out and picked up a replacement. Was super careful putting it in. Took the car out for a test drive and it might be running slightly better but the hesitation is still there.
Wood Font Tints and shades Metal Symbol


I guess my best hope is still a smoke test.
Have not had any CEL's in a few days and over 200 miles now so at least I might be able to get state inspection done.
 

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Electromagnetic Wave :-h
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It takes about a tank of fuel for trims to readjust.
 

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Discussion Starter · #55 ·
OK, still fighting this problem. Took it to a friend's auto repair shop who spent 2 hours on it, hooked up all kinds vacuum gauges and scanners. His best guess is either a bad fuel injector or the valve shim on my #3 valve may be out. I stopped by a pick-a-part and picked up 4 more injectors, cleaned and swapped #3 out but didn't make any difference. I also happened to find the airbox flapper so I picked that up and put it back. I don't think the droning sound that a little 1ZZ-FE puts out with the flapper disconnected is really that enjoyable, I think I like the quiet smoothness a little more!

Trying to decide what I'm going to do next. Not too keen on doing a valve job.
 
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