Unreliable Corolla Update

[Dr. Zoidberg]

So as you knowwwww the wife's car started have trouble starting again a week or so ago. Yesterday, it took 1 billion attempts for her to get home from work. Was tough to start today (she took my car to work) for me. Run and drives fine once fired up, yadda yadda. Her commute is only a few miles.

Anyway, tonight I went back to testing the battery, alternator, fuel pump relay, various fuses pertaining to the ignition system. I also took out the fuel pump to inspect and test, and reinstalled veerrrrry carefully. For shits and giggles, I put the original fuel pump back in, and it wouldn't start at until I put the new one in again. I reinspected the evap tube thingie return connected to the fuel pump assembly just to make sure that was attached correctly.

But -- I just realized something in common with all of these instances. The car is nearly impossible to get to start... when the gas tank is FULL.

Apparently, this isn't entirely unheard of on the 1ZZ-FE (specifically the Corolla '03-'08). Sometimes the culprit canister purge valve. I have no idea what the part is, but apparently if it's not working well it will tell the the thing with the air the wrong stuff and have trouble starting yet still run okay, and stuff? I mean it's attached the the outside of the throttle body so sure, could be.

It may also be other aspects of the evap system. My issue is I have no codes to steer me one direction or another. Back in March, we threw a P0455 code that went away when I tightened down our gas cap. Within a month, the starting problems appeared, then went away for 6 months, and now have reappeared.

I slapped the car back together tonight and it started, drove around for a while to see if anything else popped or if any new codes would appear. I will be starting and driving it (assuming it starts) indefinitely while I read up on the evap system. I want to run the gas low and see how it behaves as the fuel level. Obviously, if it has intermittent starting problems regardless of fuel level, usage, temperature, etc., the canister purge valve, specifically, becomes less likely to warrant the parts cannon.

Aaaaannyway, the Lexus is currently the only car that be driven 1) reliably, and 2) after dark.

I took it on the chin for my leaking roof so there is no money at the moment for a new truck or a new wife-mobile, unless we want to gamble and swap her piece of crap for a similarly-valued piece of crap that we can hope won't have problems by virtue of being an similar old piece of crap.

The good news is my vacation starts in two weeks, so I'll have lots of free time to facepalm.

[CB]

@dr-zoidberg Well, I'll donate to the "LS swap the Dr. Mrs. Zoidberg Ponyota Fund".

[Dr. Zoidberg]

@cb But won't that just negate my contributions to the CB Definitely Needs a 2nd Husky Fund?

[Just Jeepin']

Well, heck, if the problem is as easy to fix as "never completely fill up the tank" then that's a pretty good problem to have, in the grand scheme of things.

[Boxer_4]

@dr-zoidberg The short explanation: the purge valve controls the movement of fuel vapors from the charcoal canister to the engine to be burned. The purge valve or purge solenoid seals the system to prevent the vapors from escaping when the engine is off, and allows the vapors to be burned by the engine when the engine is running.

[Dr. Zoidberg]

@just-jeepin It is currently an unsubstantiated --

[checks thesaurus]

-- "hy-po-THES-is."

[Dr. Zoidberg]

@boxer_4 So then what is it about a bad one that could prevent an engine from starting? Gives the throttle bottle the incorrect information?

[Exage03040]

@dr-zoidberg said in Unreliable Corolla Update:

@boxer_4 So then what is it about a bad one that could prevent an engine from starting? Gives the throttle bottle the incorrect information?

Hope this is helpful!

[Krusty Walnut]

@dr-zoidberg We had a Yukon that had an intermittent canister problem and sometimes when we tried to fill up the gas tank, the pump nozzle would act like the tank was full and not pump gas. They had put the solenoid for the evaporator system valve over the spare tire where it would get road grime and salt over time (especially New England). The dealership made it sound like it was a common problem. It was replaced under warranty so that was good.

[Snuze]

@Dr-Zoidberg The evap purge valve might be getting stuck open. If its connected to the throttle, and its open, then during starting its letting extra air into the engine, leaning it out. During engine starting you actually want the engine a bit rich (this is what chokes do non EFI engines). Its possible the solenoid is intermittent, meaning sometimes it works as intended, sometimes it gets stuck open, which is what's causing your issue.

[AdverseMartyr]

@dr-zoidberg Just curious is there any chance the gas cap could need replaced? You said you had a code throw from the cap not being tight enough... Have you found anything in your reserach to suggest it could be a problem?

[Dr. Zoidberg]

@adversemartyr I mean at this point, I have no authority so say "no." A loose gap cap should throw a code but maybe it's not bad enough to trip the computer? No idea whether a bad cap would cause a lean start...

[MM54]

I would be very surprised for it to be the gas cap, but if the purge solenoid vents into the plenum and is sticky, that could be related.