P0452 OBD2 code?

[kn1ght]

Nah, we pulled it all apart. took off every piece of emission junk on it, put on an edelbrock performer manifold and a Holley 650, it was a night and day difference between TBI and carb.

 

[flyboy1294]

yeah. personally the light would drive me insane....

I am super **** about the SES light. I can't STAND that thing on.

'eh, the problem with that is that the SES light is very useful, it does help indicate when some problems arise long before they can be felt/heard/etc, so I'm not a fan of leaving it on, or blacking it out, etc...some of the codes like the gas cap stuff are annoying, but there are many things that the SES can indicate before you have a physical problem. personally, since I have the ability to tune my PCM, I prefer to just turn the less-useful codes off, but leave the majority of them functioning.

also, pre-98 trucks won't get the gas cap code, because there is no EVAP pressure sensor used in the GMT400 until 98.

+1. Again, I like my SES light.

Well I got a new gas cap. I drove it home, turned it off, then started it back up and the light went off.

The bad news is it randomly came back on today. I suspect it will be the same code, but I am getting ready to take it Advanced Auto zone to check. Man those guys hate me lol.

I'm really getting tired of this damn light being on. Hopefully I can get to the bottom of it soon...

 

[flyboy1294]

Well, it is the same P0452 error code. Any other ideas on what could be causing it?

 

[Aloicious]

well, the code is that there is a leak in the EVAP system, so it's possible that you have a EVAP line, or something that is cracked and leaking...which shouldn't be hard to fix, the bad news is that it may be a complete PITA to find...

 

[flyboy1294]

well, the code is that there is a leak in the EVAP system, so it's possible that you have a EVAP line, or something that is cracked and leaking...which shouldn't be hard to fix, the bad news is that it may be a complete PITA to find...

I figured as much. Where should I start looking?

 

[Aloicious]

well, its kinda hard to say, but on my truck the little rubber attachment points for the EVAP started getting old and cracking up at the canister, but mine is a '96, so my EVAP system is a bit different than yours...I'd start by tracing the EVAP line that goes from the tank to the canister and look for any problem points. the sensor that is throwing the code is actually on the fuel pump sending unit assembly on the top of your gas tank, so the pressure will be bleeding off from the tank itself.

 

[wewsel]

Sorry to dig up an old thread but I have the same code with a new gas cap. Also, every time I go to add gas, there is so much pressure that if I take it loose too quickly, it will shoot the gas cap across the gas station. No kidding. I have to bleed the pressure off for about 10 seconds before I can fill up. Any ideas fellows?

 

[twomanymontes]

If it's holding pressure, then you obviously don't have a leak. Most likely the EVAP canister vent valve is stuck close or the vent hose is plugged. It should start to vent off as soon as the key is turned off, so no real pressure in the tank.