SR20DET rough idle after decel/stalling

[MOSTDOUBTED]

Hey guys, my first ever post. Bought my first S13 Blacktop SR20DET just over a week ago. Bought it with the issue as you slow down to a stop or suddenly stop clutch in it'll almost stall, couple times it has stalled.

Now I have googled this, been through the forums.
I've read that people have been through every single step possible and still have this issue which confuses me.

I've never worked on an SR engine, I'm previously a skyline owner and still am.

Whats my first point of attack? IACV, pull it out and clean it. If thats not the issue whats next?

Cheers for any help.

[Tyler_240]

Is there a BOV and is it open atmosphere or recirculated? If its open atmosphere, that's definitely the problem if it still uses a MAF sensor.

If it is recirculated already, I'd ensure it is closed tight at idle, if it is adjustable. Then check for boost leaks if that doesn't do it.

[MOSTDOUBTED]

It is atmospheric, what is my option to do now then? Replace with a new BOV or somehow recirc it?

[Tyler_240]

what brand is it? Most make a recirc fitting you can swap in and then run a vacuum tube to your intake pipe (after your MAF and before your turbo inlet) or you can just delete it all together...enjuku sells a hotpipe with no bov flange..jus sayin

I think most people prefer the sound of the atmospheric bov, personally i dig a good running vehicle and recirc sounds great to me.

I picked up the swap and deleted mine about 5K miles ago. there will be naysayers who will chime in, but i havent had any issues and did a lot of research before making the change.

[MOSTDOUBTED]

I'm unsure what brand of BOV it has, it does have a vac line running back to in the intake but I believe thats about it. I'll have a look once I get home later tonight and try see what brand it is.

Could you link me to the blanking pipe so I can see how they've done it, unfortunately I'm on the otherside of the world so shipping it may be way more expensive and probably just get one made here.



My BOV is on my cold side, would that possibly make any difference?

[Frank_Jaeger]

I'm unsure what brand of BOV it has, it does have a vac line running back to in the intake but I believe thats about it. I'll have a look once I get home later tonight and try see what brand it is.

Could you link me to the blanking pipe so I can see how they've done it, unfortunately I'm on the otherside of the world so shipping it may be way more expensive and probably just get one made here.



My BOV is on my cold side, would that possibly make any difference?
You can get off the shelf hot / cold pipes without a flange for a BOV.

There are also metal V band block off plates. Personally as a temporary fix (my bov was in the way of my battery) I used the plastic bottom cut from a contact lens bottle and formed it around the flange using a heat gun. I ran up to 16psi without any leaks.

A blow through MAF or a MAP setup would also fix the issue but both of those involve tuning.

[Tyler_240]

You can get off the shelf hot / cold pipes without a flange for a BOV.

There are also metal V band block off plates. Personally as a temporary fix (my bov was in the way of my battery) I used the plastic bottom cut from a contact lens bottle and formed it around the flange using a heat gun. I ran up to 16psi without any leaks.

A blow through MAF or a MAP setup would also fix the issue but both of those involve tuning.

+1

and this is what we're talking about. http://cdn2.bigcommerce.com/server2400/79xyvl/products/31892/images/59307/plainhotpipe_60415_zoom_90069.1399296938.1280.1280 _11597.1408637152.1280.1280_29359.1447866732.1280. 1280__06145.1452550231.500.659.jpg?c=2

Don't confuse the vacuum line for a recirc fitting. A recirc fitting is going to be a hose, like 5/8th heater hose size, going to the intake of the turbo. The vac line running to an intake manifold or throttle body is your signal line.

[MOSTDOUBTED]

Here is a photo of my blow off valve, sorry was abit dark when I got around to doing it. Should I just get a 2 bolt blank flange to block it off and see if thats my issue? Then just block the blue vac line running from the top of it?


92457

[Frank_Jaeger]

Here is a photo of my blow off valve, sorry was abit dark when I got around to doing it. Should I just get a 2 bolt blank flange to block it off and see if thats my issue? Then just block the blue vac line running from the top of it?


92457
That's not a V band flange. If you want to get creative you could cut a strip of aluminum sheet or gasket paper out the size of the flange. Cut holes for the bolts and then sandwich it between the bov and the flange to block airflow. This will let you know if it's the problem (which is certainly is to an extent) and then you can get a proper pipe or block off plate.

[MOSTDOUBTED]

So you're saying it might be leaking between the flange and the bov? I will look at making or buying a blank for it tomorrow. So i'll see how I go.


if I do blank it off and the bov is my issue. What is my next step?

[Tyler_240]

Here is what I would do at this point.

First, disconnect the blue vac line to the BOV and cap the open port on the Throttle Body or Intake Manifold. Drive car gently for now and see if the behavior goes away.

Yes, then it is not leaking at the flange, but is a problem with your setup. Either delete the BOV all together or recirculate for now. Read a few posts up where frank suggested blow through + tune.

No? then make block off plate to see if the leak is at the flange or the spring in the BOV has failed or needs adjustment.

[Frank_Jaeger]

So you're saying it might be leaking between the flange and the bov? I will look at making or buying a blank for it tomorrow. So i'll see how I go.


if I do blank it off and the bov is my issue. What is my next step?
No, we're saying your BOV is leaking at the BOV (atmospheric which dumps metered air).

Blocking the BOV at the flange would prevent this. You would essentially be using the BOV itself as a block off plate.