Please enlighten me on 900s 1994 EVAP SYSTEM PURGE VALVE should this valve be making a loud ticking noise while at idle ? I have been replacing vac line on fuel pressure regulator , crank breather fitting and lines and clean and lub Idle control valve . First thought the ticking sound was from the IACV then I thought it was the fuel rail now I can feel the vac line on the EVAP pulsing with the ticking sound , Enlighten me how to test - CEL wont give out any fault codes (earth top 6th pin ) . Thanks Guys .
Go to post 7 from Saaboheme. This is really good - when and if I ever have trouble in this area, I will go there.
Rather than replacing(after the diagnostic conclusion), I'll try to repair the EVAP purge valve..
The vacuum hose to the purge valve pulsing ?, and this can be sensed ?
Good work..
Quite serious, but not so serious that a CEL is triggered
Many thanks for the link Earthworm , I can feel the soft hose that goes from the evap to the manifold housing pulse in time with the loud ticking of the valve , if I start up the SAAB a few minutes later evap starts up for a while then stops ,that I can understand but after a drive evap is ticking away non stop that it can be heard over the engine at idle while standing next to the SAAB now that I can't understand - I will testing out the evap system tommorow , come to think about it last week there was a strong fuel vapour smell when I parked at home around the back of the SAAB but I put it down to the hot day (our summer now ) fuel cap ! how much does that infuence to system? . I was shocked at the prices for an evap NZ$ 291.38 and a charcoal canister NZ$308.00 with a five day wait for the part to come in from Australia to the stealership ( SANTA BUDDY ) not a big Saab part market over here in New Zealand , hope nothing is broke now on the system . I enjoy my SAAB and spend a lot of time on her to keep her just so fine :cheesy: - :nono; have to becareful before my wife gets jealous .
The ticking or clicking sound is not directly related to the valve failing, just to age and wear.
The valve is on a rubber hanger to prevent sound being transmitted to the strut tower, and from there into the cabin. When things shift around a bit (like they did on my car), the plastic barrel of the valve can make contact with metal, and the ticking suddenly becomes loud.
To stop the sound, all you have to do it move the valve away from the metal a bit, a piece of foam rubber around it or between the valve and the car body... etc.
Used valves are a few dollars from a salvage yard, and there is no real point in replacing the charcoal canister. After a few years, the charcoal does abosolutely nothing, the canister might as well be empty for all the good it has been doing for emissions for the last 7-8 years!!
The only reason to replace the evap purge valve, is when it stops working and causes a CEL, or if it sticks open and causes a vacuum leak.
On some cars, people have successfully capped the system off w/o any bad effects or a CEL. Unfortunately, there are about three versions of the EVAP system just on the NG900, and on my car it causes a CEL when disabled (the evap system is also used to check for fuel tank air leaks and loose filler caps).
Save yourself some money, take your wife for a nice drive, and send the EPA agency in the US a nice thank-you card for making every Saab owner's life a little more fun... :cheesy:
Thanks PMI Yea I have just started to remove the canister and was taken back on it size I figured the is not much I could do with it right now but to let it air out I will now tackel the EVAP valve and make sure its a ok and free standing . I have been wondering(Junior member thinking ) what is telling the ECU to open the EVAP as the EVAP should be working for short periods of time if I think about it , is the EUC getting a reading from the tank or fuel pressure or a valve further back . Things to ponder :cheesy: . Yea looking forward to Christmas going on a big drive around New Zealand in the SAAB (wifes idea) . well let me finish up as I have to also polish my wifes rice rocket (toyota) today. :nono; GOT TO BE CAREFUL NOW MY SAAB WILL GET JEALOUS . Cheers !
When the engine warms up, the valve starts to cycle on and off to draw air through the charcoal canister and presumably burn any hydrocarbon fumes stored in the charcoal. It cycles only when the engine is warm, only during vacuum in the intake (not during boost), and only for a few minutes at a time. Then it stops for some time (not sure how long), and the cycle starts over. A few minutes on, a few minutes off.
The reason why it pulses open and closed rapidly (the ticking), is to limit the flow of extra air into the intake.
There is also a canister close valve at the canister, and a pressure sensor at the fuel tank. Some time after each engine start, the purge valve, the other valve, and the sensor are used to test for leaks in the fuel tank. If the test fails several times in a row, there is a CEL and a fault code.
There are at least three versions of the evap system, depending on model and model year.
In the US, it can cost up to $1000 to repair the system if it breaks down, and in many states the car will not pass the annual emission test with a bad evap system.
EVAP valve is good I will watch EVAP for awhile to see it cycles , now I will go down the line towards the tank to look for other valves , I have checked if the filler cap is breathing , a ok ! but it is looking worn and brittel around the edges , I have had a look under the back seats for acess to valves ect but only came up with a compartment holding two electrical conection so I thinking the only way to get to fuel pump is to drop the tank , I want to check the lines are good and have no crackes or leakes and not the cause for the fuel smell the last week when I parked at the end of the day , but that will have to wait for a while for my cracked rips to heal up . I'm thinking to just go and get exhaust gas analysed . New synthetic oil , bosh spark plugs , oil fillter , fuel fillter , air fillter ,fuel pressure vac line ,crank breathers updated lines and valve , ATF , coolant ,IAC valve cleaned and lub , MAF cleaned , water pump , serpent , idle pulleys ,distributor cap and rotor and last solder light control unit to get the high beam working ; good service fun on SAAB :cheesy: . SID reads 10.2/100km in town and on highway 6.8 or 7.2/100km speed limit 100km/hr on highway and 50 km/hr in town .
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