KYL98

I have a 91 Z28 that I want to check the Canister Purge Valve to see if its stuck open or not. The car runs great while cold, but when warmed up or already at operating temp, it smells of gas heavily and idles REALLY rough. I have changed almost everything and checked every sensor, etc with a scantool. I have also just installed new 25lb injectors and changed the PROM to adjust for it. The car did this before the injectors were changed.....thats what I thought it originally was. Just wondering if there is indeed a way to check the purge valve to see if its stuck open...causing a bad idle at operating temp???????? Thanks in advance guys....

ede

gas smell is a very good sign of a problem. pick the canister up and you ought ot be able to see or feel if it's saturated with gas

grndmasnightmar

in the manual ther is a section on checking the canister filter. underneath it says theres a filter that pulls out i guess ....maybe thats clogged , check it out. i dont remember off hand how exactly to do it but i believe you just take the can out and flip it .if u want i can check my manual later.... although a gas fume smell usually comes from a defective charchol canister system.

KYL98

I checked the filter...it seems ok. And there are no signs of liquid fuel anywhere. I was reading the Haynes manual about the signs of a stuck or inoperative purge valve....and it seems very similar to what Im experiencing. I know its not the 02 sensor because one, its brand new and two, I checked it physically and with a voltmeter. The Haynes manual is nice for some things, but doesnt show a way to check the purge valve for proper operation. If you dont mind, give the Chilton's a once over and let me know if it says anything. Thanks in advance....

JamesC

iTrader: (5)

I was under the impression that the newer canisters were closed and did not include a filter.

FYI, I discovered that my 85 IROC had the filter (turn the canister upside down, pull the filter out and stuff the new one in), but probably hadn't been changed in 140,000. The new filter advised replacement every 12,000 or sooner--damn!

JamesC

KYL98

Very true....just found that out. I guess I'll replace the purge valve and see what happens.....

Irocster

Hi guys, I am having the same problems as KYL98. Car is an '89 IROC-Z 350 TPI. I pulled the two large vacuum lines off and they both were all dry and smelled like gas. Also, should I replace the thingy the arrow is pointing to? So should I just take the whole canister out next and check for that filter? That chiltons manual is useless I tell you.

KYL98

What you are pointing to is the Control or Purge valve. Somebody correct me if Im wrong, but vacuum opens the valve and it closes when there is no vacuum. It opens as the engine warms up, or after the car gets above a set speed. If its stuck open, it will cause poor idling, stalling and driveability issues. The purge valve solenoid is on top of the canister itself. Im going to replace the solenoid and the control valve and see what happens.....Ill post results tomorrow.

Irocster

Cool, be sure to let us know. As for the filter inside of the black cylinder, do I just take out the entire thing, and take the filter out from the bottom of the cylinder? I don't think it has ever been replaced so it must be dirty.

Oh, and can someone please tell me what the function of this stupid thing is? Thanks.

Irocster

Today i took out the charcoal canister. I can't figure out how to open the stupid thing to get the old filter out though. So right now I can't drive the car because I don't want to hook it all up again until I figure out how to open it up. Oh, btw, when I shake the canister, it sounds like there is a lot of liquid in there....is that a bad thing? Kind of heavy too. Anyways, if someone can tell me how to open it that would be coolio.

JamesC

iTrader: (5)

Turn the canister over. If it requires a filter, you'll plainly see it on the canister's bottom. The filter is simply stuffed into place. My 85 Camaro Shop Manual indicates that there were two types of canisters: one required a filter, the other was closed (no filter required)--though I assume both types might become so clogged that they'd require replacement. Later models, I believe, were of the closed type only.

JamesC

Irocster

I don't see any way to open it, so I must have the later one (1989 Camaro), right? Is it supposed to have liquid in it? It is heavy and sounds like it is saturated when I shake it. Maybe it would help if I knew what the point of this thing is. Oh, and is there a code for the charcoal cansiter? Because I am getting no code.

JamesC

iTrader: (5)

No liquid. If you'll do a search, you'll find all the info you need.

JamesC

Irocster

Did a search but basically all I could turn up was "do I really need this charcoal canister?" I've got to put this thing back together soon, but I hate to put it back if it needs to be replaced, and that I need to find out.

Irocster

Any updates guys?

mlopezformula

Im having a similar problem with mine too a 89 firebird formula 305 tpi, code 45 is set as for "rich" fuel mixture. it looks like you cant take the canister apart, does your canister have three outlets? mine does one says tank, right above it is another one wich is connected to the TB and the other outlet reads "air". anyways i disconnected mine and the car was idling fine but with everything hooked up it stalls and the idle goes up and down all the time. on way you can check some of these things would be by applying vacuum to the control valve and you can check the purge solenoid by applying Battery voltage to it and see if it moves or does a clicking sound. and if it does check the connector with a voltmeter or test light too see if there is power going to the solenoid. so far what mine does is that fuel goes to the control valve but I cant hear anything inside the canister just "hard sand sound"

rough

Since you brought up a post that is like 7 years old ill chime in Im having the same problem, just replaced the 02 sensor, but last thing i could recall before 45 starting showing up was really cramming gas into the tank, so much it started leaking out the pressure relief valve " mine is off" . After that when i start the car it will idle fine for a few then outa no where sag down to like 200 rps, come back up to 700 ish and continue for minutes, I can feel it gas pedal as well while im driving.

I hear nothing out of my canister, im gonna go tinker with it, and find out some results.

lambo5150

Figure anything out. I got same problem, but it didn't have any issues until I had headers installed. Headers have no o2 sensor plugged in but it wasn't hooked up even on one side of the manifold. Also no catalyetic converter. Idling gets low after about 10 minutes on highway i get a code (11 and 12) and smell of gas comes in the cabin. There used to be heavy pressure in the gas tank. I drilled 2 holes in gas cap but not all the way through. Thissolved the pressure in the tank problem. I did a complete canister swap from a salvage yard but had no change in results. Can I try unplugging canister while the car is running or would this be bad?

ASE doc

Just because the question was asked in this old thread and never properly answered, I will provide this information. Checking for a clogged canister is fairly simple. Detach the hose from the tank to the canister and blow through it(never suck on it) and through the canister. There should be very little resistance to air flow through the canister. To check the purge valve, attach a vacuum pump to the manifold side of the valve. With the valve off, the valve must hold vacuum. Activate the valve either using a scan tool or by grounding the low side of the valve with the key on. The valve should open and release vacuum quickly, then when deactivated, it should seal immediately and again hold vacuum. Check the valve for any charcoal. If there is charcoal in the valve, replace the canister and clear out the valve if possible. If the valve will not return to normal operation, replace it.

Systems that use a pulse width modulated purge valve should only be tested using a scan tool. Activating this type of valve by applying steady power and ground can damage the valve.

JamesC

iTrader: (5)

Another odd piece of useless info is that the older canisters actually had a filter on the bottom side--I doubt that many were ever replaced.

JamesC