ZR8ED Posted August 18, 2004 Share Posted August 18, 2004 Hey guys it never ends. The car has been acting up lately..there is a lot to the story which I will omit. I'm working on several things at the same time, and trouble shooting as best I can, but I need an answer to this to help me. I have the Turboxs BOV for the last few years. It works great. till now.. The car is hunting for idle.. 700-900rpm. Problem with the BOV is this. At idle, I can see that it is partially open. If I blip the throttle, it snaps shut. When driving on the street, I can hear it blow off when I shift. When I'm really on the throttle, my boost spikes a bit (14psi) then drops to about 12.. it doesn't matter which gear. Even with my boost controller that I turned all the way! The car is running very rich right now. Back to the idle. If I pull the vacuum line off the BOV, it snaps shut. The idles goes up with the vacuum line open to atmosphere. (normal) When I cover the end with my thumb, the idle drops back down to normal (still surging) BUT. the vacuum on my thumb seems excessive. I alway recall having to hold my thumb on the end to keep it plugged. Now I can easily let go, and it sticks to me...I even have to pull it to get it off my thumb. This part seem very strange. Plugs are black. muffler is black, and spits carbon all over the driveway when reved. backfires under decleration. seems to idle like its running on 5cyl (yet above 1500 rpm, is very responsive with the throttle) (in neutral) A At light loads low rpm, you can hear it miss, as well as higher rpm low loads. it sounds very muffled at the muffler when it does this. Maybe too much info here folks, but I'm dealling with a few things at once, and am not sure which is related to what. ie running rich, can't get boost over 14psi, and won't hold there anyways. surging idle, and missfire/surging while light throttle intown cruising. AHHHH the joys of the Z. Thanks, Scott. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 18, 2004 Share Posted August 18, 2004 Hey sounds just like my car. I thought it was normal? Quote Link to comment Share on other sites More sharing options...
Guest De Schmaydee Posted August 19, 2004 Share Posted August 19, 2004 ..what happens if you put the j-pipe back on? .....s Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 19, 2004 Share Posted August 19, 2004 I have a Turbo XS race type BOV....(bypass valve http://www.turboxs.com/_images/RBV_H-34.jpg ). It IS supposed to be open at idle. That's the way its designed if it's the bypass valve model. That's why it has to be vented back into the intake tract. If you hear it between shifts and you are using the AFM, you are definately going rich. Make sure NO air is getting in or out of the intake system ANYWHERE ANYTIME. The only way IN should be the AFM and the only way out should be the Exhaust. Check for intake leaks. !!Clean all connectors!! Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted August 20, 2004 Author Share Posted August 20, 2004 My BOV vents to atmosphere. So I have no choice on that one. It used to be closed all the time, except during shifts. There is no provision for routing to afm. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 20, 2004 Share Posted August 20, 2004 Scott, can you seal up the BOV with something to effectively eliminate it from the system and see if your problems go away? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 20, 2004 Share Posted August 20, 2004 !!Clean all connectors!! and once you've cleaned them, ALL of them, ECU, AFM, sensors, even injectors, put dielectric grease on all of them stop forgetting that step Cygnus!!! Seriously... after doing this I've had no problem for... what, going on two months now I think? I dont' remember who originally told me to do this but thank you whoever you are! Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted August 26, 2004 Author Share Posted August 26, 2004 The BOV was mearly a symptom! After getting another timing light on the car.. The first timing light bit the dust. Ahh Uhmm.. the timing was a bit shall I say... OFF. how about 0-3 degrees at idle... Whoops! Not sure what happened. I have a reprogrammed ecu in the car car to control the new injects, and somehow it has affected the timing. (the 300zxt ecu controls timing) I readjusted the timing, and the idle smoothed right out, and the BOV valve closed all the way! Looks like clear sailing right?.. well almost. It seems I have detected an exhaust leak, which needs my attention now.. Sheesh! I haven't even been able to test it. O'well. The car sounds much nicer and smoother, I'm sure that was the whole problem. Not sure why the computer change would require me to readjust my timing. SO if you ever notice that your (vent to atmosphere) BOV is partially open at idle, check your timing. Retarded timing creates more vacuum which can pull it open. Thanks all for your imput! Scott. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted August 26, 2004 Share Posted August 26, 2004 I don't see how changing the chip can make a difference. The timing in the chip is unaltered until high load. The only thing I can think of is that when the injectors where changed the timing wasn't properly adjusted. I've reprogrammed many chips and not once has the distributor needed to be adjusted because of it. Perhaps the tps wasn't shorted when the timing was done. Bernard Quote Link to comment Share on other sites More sharing options...
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