Oil on Vapor/Charcol canister connector

[Jeremy2994]

Hello,

I found that one of the 3 connections that go to the Vapor Canister has this weird thick oil coating on it, almost like its leaking oil. Out of the 3 connections it's the center one.

Now long long ago on a thread deep in the web there was a guy claiming that he replaced his Vapor Canister and it cured his stalling when stopping at a light issue. Apparently the canister was soaked in gas and gunk causing stalling. Cleaning the throttle body both sides and disconnecting the battery didn't work for him.

Now I have this issue sometimes! Let's say out of the 10 stops I almost stall out like 2 of the times. Rpms drop to 200 and truck shakes.

Throttle body is polished sparkly clean replaced a while back and yes I disconnected the battery for over an hour. Spark plugs and coils are brand new both AC Delco and 41-103 plugs.

Now what do you guys think of this? Has anyone even ever replaced this part? The stalling issue seems to plague our platform so I thought I'd mention this.

 

[Mooseman]

It is possible if the valve on the fuel tank is allowing liquid fuel into the canister. You could take out the canister and see if there is liquid fuel in there.

There are two or three valves on top of the tank. Not even sure that they are replaceable or how to determine which one is defective.

I could see this issue causing idle problems.

 

[Jeremy2994]

I've replaced the vent valve with the electrical connection to the tank like 3 months ago. I do remember seeing other smaller valves when I dropped the tank to change the pump but I never paid any attention to it. Could it have been the old vent valve that clogged the canister and it's no longer doing its job properly?

I will take a look at the canister this weekend when the weather cools down.

It is possible if the valve on the fuel tank is allowing liquid fuel into the canister. You could take out the canister and see if there is liquid fuel in there.

There are two or three valves on top of the tank. Not even sure that they are replaceable or how to determine which one is defective.

I could see this issue causing idle problems.

 

[Mooseman]

I've replaced the vent valve with the electrical connection to the tank like 3 months ago. I do remember seeing other smaller valves when I dropped the tank to change the pump but I never paid any attention to it. Could it have been the old vent valve that clogged the canister and it's no longer doing its job properly?

I will take a look at the canister this weekend when the weather cools down.

There are valves on top of the tank that prevent liquid fuel from being sucked in. One or more could be defective. Here is a writeup about replacing those because they are normally non-replaceable.
http://gmtnation.com/forums/threads/how-to-replace-broken-vent-valve-in-the-fuel-tank-p0445.12816/

 

[Jeremy2994]

There are valves on top of the tank that prevent liquid fuel from being sucked in. One or more could be defective. Here is a writeup about replacing those because they are normally non-replaceable.
http://gmtnation.com/forums/threads/how-to-replace-broken-vent-valve-in-the-fuel-tank-p0445.12816/

Ahhhh I see thank you I'll look into that thread and I'll take a chance at the canisted first before I decide to get a new tank.

Do you think this issue could be related to oil pressure drop as well when the truck comes to a stop?

 

[Mooseman]

Probably if the idle drops so low the oil pressure drops below the switch's low limit. You do know that the oil pressure gauge is fake right? Readings are produced by the PCM and the sender is just an on/off switch, just like the old idiot lights. If you get 0 and a DIC message, your pressure might have dropped low enough too trigger it.

As per the thread I linked, you can replace them.

 

[Jeremy2994]

Yeah I'm aware the oil gauge is fake but any stupid light that comes on concerns me. That actually makes sense thanks! I never thought about it that way.

I just got a chance to look at it, awesome I'll take a look at those and see what I can make out of all this! Thanks again for your help!

Probably if the idle drops so low the oil pressure drops below the switch's low limit. You do know that the oil pressure gauge is fake right? Readings are produced by the PCM and the sender is just an on/off switch, just like the old idiot lights. If you get 0 and a DIC message, your pressure might have dropped low enough too trigger it.

As per the thread I linked, you can replace them.