jwteknix

well had the car in the shop today kev and i found most of the vac leaks, but i have a wierd one the bov/bypass valve is vented to atmosphere so when idling the cars rpm very execept for when u cover the end of the bov then it idles fine kev thought it was b/c the vac line to the top of it is routed to the wrong spot of the tb/uim found the line t'd in to the pressure sensor and boost gauge so basically is the bypass vavle faulty b/c its causing a leak or is the line routed to the wrong location? b/c kev pulled the thing off and blew through it and it was holding pressure on all sides does that mean the valve is good and it just seeing vacume in the wrong place? thanx

james

1988RedT2

You say the BOV is vented to atmosphere. On the stock setup, it's vented back into the intake, after the MAF. If you're running the stock ecu, the ecu has accounted for that air and is basing the injector pulse on the premise that that air will be going into the engine.



Also, since the BOV opens on high vacuum, it might well be functioning as a big intake leak at idle. Either plumb it back into the intake, or run an aftermarket BOV.

jwteknix

yeah i just talked to kev i have a spare bypass valve so im gonna see if i swap them if it stops happening if not i was gonna take the butty **** tid that someone put on there off and replace it back to stock. so it doesnt matter where that vac line goes? i guess then the bypass valve is doing its job but then y run it atmosphereically other then the sound if its gonna cause a large vacume leak? thanx

james

1988RedT2

As long as it's seeing manifold vacuum/pressure it should work okay. Yeah, whoever figured they could run the stock valve to atmosphere didn't think long enough.



My understanding is that an aftermarket BOV has a stronger spring and won't vent at idle. Pretty sure mine is adjustable. Been a while since I messed with it.



I actually have this one, and I piped it back into the intake, even though I don't have a MAF anymore. I don't need the cute noise. I ain't no damn ricer.



Racing Bypass Valve Type H34 (RBV-H34) US$189.00

Racing Bypass Valve Type H34 vents excess pressure back into the car’s air intake making the valve ideal for Mass Air Flow (MAF) metered cars where venting to atmosphere can create a "rich" air/fuel ratio right after the valve goes off. The Racing Bypass Valve Type H is CNC machined out of billet aluminum and brass. Valve operation, while louder than most stock valves, is quiet compared to a BOV that is vented to atmosphere like our BOV-H or BOV-H-RFL.

jwteknix

ok so i did a little expierimenting today, i swapped bypass valves and problem got worse wouldnt hold an idle at all. so i said **** it ran to my other garage full of stock **** and grad the old TID from my 88 motor put it on and bam car idles. fucked with the idle for like an hour its soo much better but not prefect still have to set the tps. now it look even more stock but i was kinda happy to get rid of the hidious TID that some one put on there. more to come

james