January 23, 200620 yr Today Austin and I put new tensioners, idler pully and timing belts on my XT. I ran some GUNK engine degreaser in the oil for 5 minutes and put in new Schaffer oil in it. While the car was running he pulled the oil cap off the filler tube and the car all most dies. Just curious what the reasoning is behind this. I have never seen a car do this before. Is this because of the turbo?
January 23, 200620 yr you might check your PCV, the only thing i can think of is that its sucking in air through the PCV and thats leaning it out, its a long shot, but the best i can come up with.
January 23, 200620 yr Crankcase is under a vacuum from the pcv system,You create a vacuum leak when you remove the cap.Probably normal? Can a subi tech verify this? Im just a gm tech,lol
January 23, 200620 yr Crankcase is under a vacuum from the pcv system,You create a vacuum leak when you remove the cap.Probably normal? Can a subi tech verify this? Im just a gm tech,lol Just a GM tech? I think everyone here knows that its not easy keeping the General on the road, you're no tech, you're a miracle worker.
January 23, 200620 yr Turbo engines are a closed system. When you take the cap off it causes a big vac leak and dies.
January 23, 200620 yr I don't normally answer a thread where someone has already given the answer, but Turbone is entirely correct. Speculation sometimes takes people on a long trip to nowhere.
January 23, 200620 yr It's normal. When you take the cap off you're letting air into the engine that didn't go through the MAF sensor first so the ECU doesn't know about it and can't adjust the fuel to compensate for it.
January 23, 200620 yr i've seen NA EA82's do this as well. i've replaced the oil cap o-ring, on an EA82 that wouldn't idle unless i pressed really hard on the oil cap?? weird, but i'm an XT6 owner and they don't do that. always wondered why.
January 23, 200620 yr It's normal. When you take the cap off you're letting air into the engine that didn't go through the MAF sensor first so the ECU doesn't know about it and can't adjust the fuel to compensate for it. Ya,maf does get confused,Some cars are more sensitive than others.For example the chevy cobalt will set a check engine light (lean dtc) if the oil cap is off or dip stick isnt seated. And Ive seen some german cars hunt and stall when the cap is removed.Some cars you dont even see a change,Ok this topic is definately beat into the ground now!LOL
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