97 850 R Hesitation. Evap check valve blows both ways

gswede · Post by **gswede** » 11 May 2014, 06:10

My 97 R have been running proper strong the last 6 months. Then. all of a sudden - not so much. Slight intermittent hesitation when on throttle. The other day I could smell gasolin, just after having been on throttle.

Sitrep: All ignition parts new, OEM. Fuel damper, MAF, TPS and O2 new also +++

Spent the better part of last night looking through plug threads, also looked at evap threads.

Well, today I pulled the negative for 8hrs and reset adaptation. Took it for a good long drive. Still some hesitation and elevated fuel consumption.

Checked fueldamper - ok - no leak
Checked Evap purge valve (mounted on fan shroud) - ok - held vacuum both ways
Checked check valve between purge valve and intake - NOT OK - could blow just as easy both ways.

While I wait for a new Checkvalve, could anybody elaborate on the driveability issues a faulty evap check valve might cause..??

Pulled the plugs, all looked like this

gswede · Post by **gswede** » 11 May 2014, 07:12

I disconnected the hose from purge valve to inlet and plugged the inlet nipple. Will it throw a code if I run it like this, purge venting to atmosphere?
Hopefully i can get a new valve in a couple of days.

Post by **abscate** » 11 May 2014, 12:34

It will in about 100 miles. The system tests the evap system for integrity by cycling the purge shutoff valve and making sure the car can suck the tank into vacuum condition. If it can't, it will throw a code.

gswede · Post by **gswede** » 12 May 2014, 07:53

Drove it with hose plugged, to the local scrapyard. Found me a few checkvalves (spares

)
Man what a difference in driveabiltiy, pulls strong all day.