CEL Evap ready cycle

Truck sat for a while, now trying to get State inspection passed, but fails for monitor not ready.

The CEL often comes on due to EVAP codes, I generally just reset it and go on with life. But now, it seems EVAP monitor does not "come ready" after driving it for a while. The CAT was not ready also, but that cleared quickly as I drove it.

Wonder what I have to do?

 

Your truck is telling you there is a problem with the EVAP system. You can't just clear the code the expect the problem to disappear like that- you need to actually address the problem and resolve the code.

Do you remember what the actual codes were? Could be anything from a sticky or bad vacuum valve, broken / cracked vacuum line, broken / cracked charcoal canister.

 

For certain monitors to "run" the vehicle has to be put in testing condition. Evap monitors are 2 trip monitors. The fuel tank HAS to be between 1/4 and 3/4 full, 3/4 is better, The engine has to sit a minimum of 8 hrs and the intake air temp sensor has to be withing 10* of the coolant temp. This is how the PCM knows the truck is starting from cold and this has to be done twice.

 

Yeah, but, along the way I have tested a few things and come up empty as far as problems. This particular canister is apparently a 2 year only deal is is close $500 new. So, not today.
Toyota part number is 77740-35470.

 

Ah. It was was under 1/4 and went on reserve today, so I dropped in 4 gallons to get me by. Cold start tomorrow should count as 1, I'll top up and see what happens next cold start.

Thanks.

 

01 2001 TOYOTA TACOMA FUEL VAPOR CANISTER ASSEMBLY 7774035470 | eBay

 

Thanks. I may have a line on one that has the valves/solenoids on it. Looks clean.

 

Need to smoke test it and all the lines around it...

for some reason the ones in engine bay get leaks around the bottom seal...
I've seen where some epoxied em up around the bottom.

old gas caps can cause evap cel's

 

^ This

 

Replaced the gas cap 2 years back. That cured one of the codes but several remained that come back now and then. IIRC the don't seem as frequent if I keep the tank over 3/4. But that can be a hassle. Sometimes I think I smell fuel near the back of the truck. But only a wiff and never consistently.

I'd need some details on the smoke test. I tried that a couple years ago after changing the gas cap, but it did not seem to tell me anything.

I have a line on a used canister that looks in good shape with both the "round things" on it. One of which, from what I can see looking up under the truck, looks quite rusty on mine.

Did an other post asking about how to change the canister. Pull the bed or struggle from underneath?

 

With these canisters $300 ~ $500, I would recommending staying below 3/4 tank....
dont want to flood a $400 canister...

Same of fuel pump....I'd keep 1/4 tank or more......just to be safe.

growing old....sucks....

 

Before you throw money at this- you need to figure out what's wrong. It might not be the canister. You need the codes, and then test the system. It could be a simple vacuum line.

 

I looked up an old thread I posed on this. P0446 seems to be the code. There may have been another one this time, but not sure.

Anyway, one of the solenoids on top of the canister, which is up over the gas tank I can see is quite rusty. This truck had a frame replacement before I bought it along with much other stuff, but that was not one. With 234,xxx miles on it and that rusty solenoid, I am willing to believe a good looking lower mileage canister might be the cure.

 

On limited production stuff ( 1 or 2 yrs)....may not be a bad idea to have a backup while they are available and reasonably priced.

Especially for those rust challenged...

I bought me a new in box canister off the forums here....$100...
with the valves/solenoids it was a no brainer...

got a $75 brandnew booster too...

 

if you’re in CA, evap is the only monitor the state will allow not be ready

 

If you can get your hands on a factory service manual, it includes test procedures for everything you're talking about.

It has instructions on the evap test cycle. The instructions given earlier in this thread are roughly correct from what I remember, but the FSM will give the exact conditions needed for it to run. If you can get the evap cycle to complete, you should get a CEL and be able to read the code again (or no CEL, in which case everything's fine).

The FSM also includes a diagnostic procedure for the charcoal canister, although I don't remember how complicated it was to DIY.

Some members here have PDF copies of the FSM available to share. Ideally you'll find one to match the year of your truck, but I'd guess these test procedures are very similar, if not identical, for all years.

 

Thanks all. I got a PDF copy of the FSM and will attempt a smoke test again.

Turns out, I think NY will allow one MIL monitor to be "not ready", at least they note the EPA allows 1 not ready for that model year. So I may be able to pass Inspection for now, and I can take more time hunting up a new(er) canister and solenoids.