Dummy VSV's? Charcoal Filter Related Question

[atv_freak]

Hello everybody! I just got myself a 1999 Solara 5-speed v6... it's got almost 170k miles on it, but it seems to be in pretty good shape.

I am getting the P0446 code and from what I've read that code usually means one of the vsv sensors are bad and possibly the whole charcoal filter.

From what I can tell the charcoal filter does not add any value to the way the car runs... who the heck cares if some gas vapor escapes when I turn the car off! So I have a real problem with the possibility of spending hundreds of dollars trying to get this code to go away so I can pass stupid emissions! Am I wrong here? If the charcoal filter is not working properly, will it adversly affect my car's drivability?

In the chevy truck world (where I've been for years), I know there are dummy o2 sensors that can fix any codes thrown from a catalytic converter delete. How exaclty do the vsv sensors work (completes a circuit, a certain impedence, etc?) and is there any way to fool the toyotas computer into thinking the charcoal filter is working properly even if it isn't?

Thanks for any insite!

[Mister_Perkins]

Check to make sure you dont have a perforated or torn air valve at the front of the charcoal canister. A lot of times You will get the P0446 indicating a Bad VSV, but its actually a problem with the Air Valve. Hopefully it is just a VSV though..

Test the electrical connection of the VSV on the canister first to make sure that its working properly (Applying 12v+ across the connections confirming its opening and letting air through).

if its working properly, it could also be a Rotted or cracked line. Check / confirm that all EVAP lines are not cracked. A Crack in the rubber lines is a Vacuum leak and will trigger a CEL. (Replace as necessary)

There will not be any adverse effects of the CEL though. You may notice a slight decrease in MPG if the Charcoal canister is purging more fuel than its supposed to (Saturated). But other than the MPG That POSSIBLY might happen, you really wont notice a difference. Well, besides the dummy light on the dash. hehe


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and as far as spending hundreds of dollars ; you could always go to a you-pull-you-save and pull a charcoal canister for way less than an OEM, but that is a crap-shoot because the charcoal canister could be bad on the car your pulling it from. But then again, it could be good!

[atv_freak]

Yeah, if I didn't have to pass emissions I wouldn't worry about this stupid thing, because I'm not noticing any drivability issues and I'm getting close to 28mpg highway.

So nobody has attempted any dummy sensors of any kind?

[Mister_Perkins]

You can get a Oxygen Sensor Simulator. This will fool the ECU and possibly pass emissions

http://www.o2simulator.com/

[atv_freak]

I had to replace one of the o2 sensors so I think I'm good in that area.

I guess I was talking about dummy sensors for the vsv's. What kind of signal do they send to the ecu and what is the range that results in a good reading for the ecu?

In Altanta, "emissions" testing is just checking for check engine lights and checking the gas caps. They don't actually test what is coming out of the tailpipe.

[Mister_Perkins]

I dont believe there is a VSV simulator. like I said if you apply voltage to the VSV and it lets air pass through it its good. If it doesn't allow air to pass its bad.

I have a suspicion that the Charcoal canister air valve is culprit, but I cant really confirm that without you actually physically checking the VSV and EVAP Lines.

[atv_freak]

Well, I changed my o2 sensor (to correct the P0135 code) last night and reset the codes... so far I've driven about 35 miles and no check engine light... *crossing fingers, knocking on wood, etc*

Not sure why that would help the P0446 code though.

[Mister_Perkins]

^^^

Im guessing you changed the downstream (After the cat) as far as this quote goes

Originally Posted by atv_freak

I had to replace one of the o2 sensors so I think I'm good in that area.

[atv_freak]

Nope, it was the before cat sensor behind the engine.

So far still good on no light... sitting at about 45 miles now I think.

Is it a full 100-150 miles before the the ecu runs a full cycle (or whatever it is called... whenever I can go get emissions tested)?

[Mister_Perkins]

Typically ECUs require a certain number of cold and warm starts to Cycle the ECU. Driving it 100 - 150 miles will do nothing.

[dudutzu]

Originally Posted by Mister_Perkins

Typically ECUs require a certain number of cold and warm starts to Cycle the ECU. Driving it 100 - 150 miles will do nothing.

+1
needs 3 full cycles to check everything
but I think that the ECM doesnt check the EVAP when the gas tank is more than 3/4 full or something like that, so just keep the fuel level above that and the light will go off

[Mister_Perkins]

OBDII EVAP detects a Pin-Hole leak so even if the tank were completely full with gas if one of the EVAP lines anywhere in the system gets a small hole it will detect a leak and the MIL will light up. Just sayin

Reason I know its OBDII is because he is listing OBDII codes. I could be wrong. If its OBD1 the emissions standards are different too

[dudutzu]

it's an 99 so its an OBDII

[Mister_Perkins]

lol guess it does say 1999 . haha im dumb

[atv_freak]

Originally Posted by dudutzu

I think that the ECM doesnt check the EVAP when the gas tank is more than 3/4 full or something like that, so just keep the fuel level above that and the light will go off

I think you might be right... I made it 190 miles before the light came back on... inbetween 1/2 and 3/4 full. Unfortunately I was out of town at the time so I couldn't get it tested, so I filled the tank and reset the codes before I drove back this morning. I got it tested at 3/4 full @124 miles and passed! And then the check engine light came on as I was driving out of the parking lot... screw you georgia clean air act!!!!!

So, I'm good for a year now. Thanks for all your input guys!