Pulsing idle, no bov, tach? Searched

[Bad40r7]

Well guys, im a new guy here and new to the sr20. Ive been an FD rx7 guy for a while now, and decided to buy a DD and the sr20 was the best. I have a 95 s14 with a redtop s13 in it. First is my idle. It idles perfect, but when i slow down and push the clutch in, it will come down and pulse 2 times, and then idle normally. Is there a certain valve that would cause this?

Next is the BOV. It is a greddy type S that is not recirculated(i know, i just got it at 10 last night :)) But it does not make ANY noise. From my experience, greddys are loud and ALWAYS go off, this does not. I have done a mid second gear pull, to about 4.5k and i heard a very slighty *woosh* It is plugged into the port that is right on the front of the intake manifold.

And last the tach. It doesnt work, at idle is shows about 450rpms...but it studders kinda, while bouncing. When im driving, ive never seen it go about 1.5k. Is this a sensor in the tranny(if there is one), or wiring?

Thanks
-Alex

[Sileighty_85]

the Plusing idle when stopping is kina normal for swaps but its usually due to incorrect Vacuum routing (ppl say its because Atmos. BOV but its not) The BOV and FPR should be on the same line only on the top left of the T/B, W/G is on the cold Pipe nipple (if running Side mount)

But mainly due to ppl not connecting the Crankcase/Vave cover Breather "T" to the Turbo Intake Pipe (your Crankcase needs a negitive Vacuum pressure)

As for the BOV is there and Ajustment Screw? Loosen it if there is, make sure there are no leaks in the lines.

The tach not sure but next time to drain the Trany fluid pull out the sensor and make sure its all there

hope this helps Peace

[Silverbullet]

Bad40r7: Its most likely your BOV. It only makes that chirping noise when theres enough air coming out and if the outlet is small enough. Tighten it all the way so you know it isn't opening and see if you still have that problem.


Sileighty_85: BOV routing shouldn't make a difference. They both work. Why? because they are in the same medium. Its impossible to have two different gradients of pressure (they reach an equilibrium at the rate of the pressure difference divided by the volume) with in the same medium.

[BlackTruenoAE86]

Tighten your BOV, the idle is normal for it to drop if you have and non recirculated BOV just get used to it.Your tach is bad just change it. The tach has nothing to do with the tranny...

[Sileighty_85]

Bad40r7: Its most likely your BOV. It only makes that chirping noise when theres enough air coming out and if the outlet is small enough. Tighten it all the way so you know it isn't opening and see if you still have that problem.


Sileighty_85: BOV routing shouldn't make a difference. They both work. Why? because they are in the same medium. Its impossible to have two different gradients of pressure (they reach an equilibrium at the rate of the pressure difference divided by the volume) with in the same medium.

I really dont think its the BOV Im running a Greddy Type-R on my setup and I dont have that problem. And nobody else did When I was Living in Okinawa.

As for the Hose routing if you look at the T/B the hole for that line is somewhat is behind the Butterfly Valve so when you snap the T/B close the pistons pull that air from that side that the T/B which will pull the air from the BOV directly, this is also the OEM routing.

[Silverbullet]

I really dont think its the BOV Im running a Greddy Type-R on my setup and I dont have that problem. And nobody else did When I was Living in Okinawa.

As for the Hose routing if you look at the T/B the hole for that line is somewhat is behind the Butterfly Valve so when you snap the T/B close the pistons pull that air from that side that the T/B which will pull the air from the BOV directly, this is also the OEM routing.


Greddy Type Rs come with very tight springs. Chances are its not venting on low load when your normally driving so you dont expirience it. Most ppl with atm BOVs adjust their BOVs tight enough so they dont stall out.

OEM routing or not, its all the same chamber. the nipple your referring to and the nipple right next to it go to the same medium, so it dosn't matter which you use. The BOV piston dosn't pull anything. The piston gets pulled from the negative pressure in the manifold. Its the same pressure at any point in the manifold.

[Bad40r7]

Well i did some looking, and my BOV screw is ALL the way tight, is this so the car wont stall? I can live with the idle, i was only making sure there wasnt a problem with it. As for my tach, i have watched and wondering....When i start the car, it will jump to about 750 rpms, i assume that is about my idle. Well as the car sits and idles, the tach rpms will slowly lower until its at about 250rpms and the tach bounces. If i give it gas and hold it, it was come up, bounce around like its searching and then find somewhere to stay steady.

[Silverbullet]

-check your timing
-make sure theres no vacuum leaks

these are just common things.

[Sileighty_85]

Greddy Type Rs come with very tight springs. Chances are its not venting on low load when your normally driving so you dont expirience it. Most ppl with atm BOVs adjust their BOVs tight enough so they dont stall out.

OEM routing or not, its all the same chamber. the nipple your referring to and the nipple right next to it go to the same medium, so it dosn't matter which you use. The BOV piston dosn't pull anything. The piston gets pulled from the negative pressure in the manifold. Its the same pressure at any point in the manifold.

Not all Greedy Type R's come with Tight springs its an option though for it. My Type R does blow off on low loads every time so thats not why mine runs fine. Its cuz I know first hand how everything goes and didnt half ass anything.

Yes im aware the BOV piston doesnt pull anything i was reffering to the Engine's Pistons.

But whatever What do I know?

Its not like I Lived in Japan for 3 years and worked on SR20's while I was there or that I have a perfect running Fully built SR20DET that I tore apart shipped home and rebuilt Myself from the crank up with Performace parts, dropped the engine in on the first day and got it running on the second and DD since then.

Dont judge me cuz I only got one little Green Square.

Im not saying im always right, Cuz I didnt do his swap. Im just saying to look in to it

Im only goin off my encounters and this Atmos. BOV thing has never been an issue on any SR I worked on.

[Bad40r7]

I think we are all good on vac leaks...the car idles fine and pulls 7psi. I have an HKS actuator on there, i think i have read somewhere i can adjust that instead of hooking up an MBC...true? If so, is it just loosening and readjusting that nut?

[Silverbullet]

Bad40r7: putting on a boost controller results in what you can do just by turning the threads on the actuator rod. To lower your boost, make the rod longer, to run more boost, make the rod shorter.

Sileighty_85: i dont go by any blocks. I'm going by the principle of what the ECU does on a closed loop MAF car. Your MAF reads X amount of air in the intercooler/intake and assumes it going into the combustion chamber. When some of the air gets blown off in the atm, x-2 units of air is going into the engine when it thinks its x+0. That rsults in a rich mixture. If its too rich, the engine stumbles.

Off the top of my head, there are a couple variables that may keep the engine from running too rich. Most modified SRs run richer than from the factory because we put on high flow fuel pumps without changing to an adjustable fuel pressure regulator. By running a high flow FP, the engines actually run slightly richer... thus if you have an adjustable FPR, you'll suffer less from stalling on rich conditions durring blow off. Another variable is the BOV isn't venting enough to make it stumble. With the combination of the two its possible you can blow off fine without any RPM drop. Perhaps your IAC is cleaner than most cars, that can also be a factor. Every motor is just different.