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1G SpeedDensity BOV help!

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BoostedS256

Proven Member
42
7
Oct 11, 2018
Olympia, Washington
Okay so did some searching and found most people recommend the IAT 3-6 inches before the TB but then other people saying it doesn’t matter that much. The cars idle will drop low occasionally and act like it wants to die and leans out on the wideband like there’s a vacuume leak but there isn’t one anywhere, also don’t make fun of me but is my bov half recirculating and half atmosphere cause it has the hole going back into the intake and the hole going out into the atmosphere so confused on that.

So question is would moving the IAT post bov closer to the TB be worth the effort and possibly help my idle or is it not that big of deal?
Second question what’s the situation with my BOV? Hope to hear some anwsers thank you!
 

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The iat sensor has little if anything to do with your idle. Yes The Iat sensor should be closer to the tb. No your bov isnt half and half. Its either designed to recirc or not. As far as your idle, Id look at your tune. For one make sure your front o2 sensor is functioning properly ie make sure
The voltage is cyling. If your using the wideband to simulate the narrow band signal make sure its set up properly. Before all of this double check base timing, fuel pressure and iac position.
 
So it’s a big enough deal that I should move it closer your saying? Since I’m running speed density does that mean I should delete that hose on my bov and plug both ends?
O2 is functioning properly and fuel pressure is good so guess I’ll search how to check timing and iac position.
 
I'm not sure how that BOV works, but most BOVs will have one exit that shoots air into the intake or to the atmosphere. Yours has both. I'd look up the manufacturer directions on that. If it's setup improperly then that could be your problem. I doubt the change in IAT position will affect anything. People recommend to put it as close to the tb as possible because (I'm assuming) it will give the most accurate indication of what the intake manifold temp will be. Maybe if you redo your piping one day then change it. If not, don't worry for now. Most idle drops are do to an improperly adjusted isc/biss screw.
 
So it’s a big enough deal that I should move it closer your saying? Since I’m running speed density does that mean I should delete that hose on my bov and plug both ends?
O2 is functioning properly and fuel pressure is good so guess I’ll search how to check timing and iac position.
If you're running speed density, the BOV has setup has considerably less affect on how the car runs. I wouldn't bother messing with the BOV in that case. The setup tends to have a bigger effect when you're running a maf sensor.
 
Yeah that’s what was throwing me off I’ve never seen a bov like that but yeah I’ll look it up and see what the deal with that is, also just noticed the idle switch doesn’t have a wire anywhere to hook up to it at all could that be the culprit or does dsm link run without that?
 
I'm not sure how that BOV works, but most BOVs will have one exit that shoots air
I'm not sure how that BOV works, but most BOVs will have one exit that shoots air into the intake or to the atmosphere. Yours has both. I'd look up the manufacturer directions on that. If it's setup improperly then that could be your problem. I doubt the change in IAT position will affect anything. People recommend to put it as close to the tb as possible because (I'm assuming) it will give the most accurate indication of what the intake manifold temp will be. Maybe if you redo your piping one day then change it. If not, don't worry for now. Most idle drops are do to an improperly adjusted isc/biss screw.
Just read that since I’m speed density the air is metered from the intake through the map sensor of course so the isc and BISS wouldn’t effect idle
 
The idle switch can be simulated if you are running ecmlink. If not, you need to hook it up asap and adjust it per spec. Also, ISC and BISS absolutely effect idle. The ISC/BISS are almost the sole way to get the idle dialed in.
 
The idle switch can be simulated if you are running ecmlink. If not, you need to hook it up asap and adjust it per spec. Also, ISC and BISS absolutely effect idle. The ISC/BISS are almost the sole way to get the idle dialed in.


Okay really need to get my laptop fixed so I can get into ecmlink and see what all is going, and alright I guess that post I read he must have been mistaken or something I’ll check on both of those, timing,iac and the tune itself and go from there
 
Get the laptop logging and go into the idle box on the SD VE table and richen up the mixture in that box and some of the surrounding boxes. You can't really goof it up. I take a picture of it and if it gets weird, I put my values back to where they were. My recent swap to SD on my daily had me dialing in that specific thing to keep it from leaning out and dying. I also played with my deadtime a little bit but was only dialing in stock 390 injectors. Once I got the idle mix richened up, my car starts up first crank now.....and I am about to swap in 1120s so I'll be doing it all again real soon. It's more of a game and fun for me than anything serious but it gets the job done. If you have V3 link you can go for a 20 min cruise and then do a SDADJust by right clicking in the log and going to the ve table and see what it is recommending and apply those values. It has worked real good for me.
And I have my IAT sensor about 6" from my TB on the daily but it is just after the BOV on my profile car. Doesn't seem to matter. My O2. :)
Marty
 
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