Turbo question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

RacNgi · 02-05-2002, 01:24 AM

Ok I stalled a XS kit on my 97 240.  The problem is that the car keeps stalling when I take my foot off the gas at lower rpms.  Now I checked all the vac. lines.  Could it be a leak from the EGR pipe that has been blocked off or that the hose coming off the bipass valve  to the intake isnt clamped and just placed on?

s15dude · 02-05-2002, 01:31 AM

on  240's aren't you supposed to reroute the air from the bov to the intake because the computer thinks your gonna burn that air but then you don't and the mixture gets screwed up. Don't quote me on this but I think thats how it works. Anyone else heard of this?

02-05-2002, 08:53 AM

On a s13 you're supposed to rerout the air coming out of the bypass valve to back into the intake.  If you have an aftermarket BOV and its stalling you probably need to tighten the valve on the bov.  I bet you got your bov set to be able to go off at low rpm's.  when you have it set like that the computer reads the air coming in and adds more fuel but when it gets dumped by the bov at low rpms the engine starts to stall out.  all you have to do is tighten the valve on the bov and it should fix the problem.

RacNgi · 02-06-2002, 12:09 AM

ok the problem with that is its the HKS pop-off valve and it doesnt have any adjustment to it so can it be anything else.  

02-06-2002, 08:08 AM

I'm not really sure what it looks like.  the only HKS bov that i've seen are the SQV and the old model, and they both were adjustable becuase I had both of them in the past.  You're saying that it doesn't have anykind of screws on it anywhere??  If thats the case you can have the ecu rewritten to stop the car from stalling I can't remember who does that though.  Maybe JWT.

uuninja · 02-06-2002, 08:27 AM

2 things to check.

1) Bypass valve should be clamped tight. If metered air escapes then the car will run rich and bog.

2) IAA valve is clean. It is the valve that draws air when the throttle plate is shut. If this is dirty then the car will stall. Use Intake cleaner to clean it out. It is harder for the valve to draw air with the turbo and IC in front of it at Idle.

JaySpec7 · 02-06-2002, 09:23 AM

I'm a friend of racngi who help do the install..

Yes it is running rich and it does stall..  I'm thinking the kit came w/ a HKS bypass valve that routes back to the intake pipe.. all hoses are clamped and no vacuum leaks..  we haven't had a chance to clean out the TB or replace or regap the plugs..

What's IAA?  Idle Air Control?

Here is a pic of the Bypass valve included in the kit..

JaySpec7 · 02-06-2002, 09:35 AM

Yes, we know you stalled!! LOL

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from RacNgi on 1:24 am on Feb. 5, 2002
Ok I stalled a XS kit on my 97 240.
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02-06-2002, 01:59 PM

Like I've pointed out several times on this forum and on FA.

Get a can of throttlebody/carb cleaner and go to town on the throttle body, and the idle air control valve (IACVor IAA). This is the 1/4" hard pipe that's to the right of the throttle body where you had to connect a rubber tube from the I/C piping from. Go crazy... It helps. Worked for me, Robthechef, and many others.

alchemist · 02-06-2002, 02:08 PM

the air is supposed to be rerouted to the intake just after the MAF so that the metering doesnt get screwed up.  where do you have the air going

JaySpec7 · 02-06-2002, 02:17 PM

Yes.. i saw.. thanks.. we are just getting as much info as possible..  we are goin to try that tonight..

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from '91 D21 beater on 1:59 pm on Feb. 6, 2002
Like I've pointed out several times on this forum and on FA.

Get a can of throttlebody/carb cleaner and go to town on the throttle body, and the idle air control valve (IACVor IAA). This is the 1/4" hard pipe that's to the right of the throttle body where you had to connect a rubber tube from the I/C piping from. Go crazy... It helps. Worked for me, Robthechef, and many others.
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JaySpec7 · 02-06-2002, 02:22 PM

That is where it is routed..

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from alchemist on 2<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>8 pm on Feb. 6, 2002
the air is supposed to be rerouted to the intake just after the MAF so that the metering doesnt get screwed up. where do you have the air going

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crazycuban · 02-06-2002, 02:56 PM

You don't HAVE to recirculate it - it just runs rich if you don't.  Take it to a dyno tuning shop and they'll fix that without having to make your blow off valve recirculating instead of atmospheric - atmospheric just sounds so much cooler.

02-05-2002, 01:24 AM	#1
RacNgi Leaky Injector Join Date: Jul 2001 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	Ok I stalled a XS kit on my 97 240.  The problem is that the car keeps stalling when I take my foot off the gas at lower rpms.  Now I checked all the vac. lines.  Could it be a leak from the EGR pipe that has been blocked off or that the hose coming off the bipass valve  to the intake isnt clamped and just placed on?

02-05-2002, 01:31 AM	#2
s15dude Zilvia Junkie Join Date: Oct 2001 Location: San Diego Age: 41 Posts: 503 Trader Rating: (0) Feedback Score: 0 reviews	on  240's aren't you supposed to reroute the air from the bov to the intake because the computer thinks your gonna burn that air but then you don't and the mixture gets screwed up. Don't quote me on this but I think thats how it works. Anyone else heard of this?

02-05-2002, 08:53 AM	#3
Guest Posts: n/a	On a s13 you're supposed to rerout the air coming out of the bypass valve to back into the intake.  If you have an aftermarket BOV and its stalling you probably need to tighten the valve on the bov.  I bet you got your bov set to be able to go off at low rpm's.  when you have it set like that the computer reads the air coming in and adds more fuel but when it gets dumped by the bov at low rpms the engine starts to stall out.  all you have to do is tighten the valve on the bov and it should fix the problem.

02-06-2002, 12:09 AM	#4
RacNgi Leaky Injector Join Date: Jul 2001 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	ok the problem with that is its the HKS pop-off valve and it doesnt have any adjustment to it so can it be anything else.

02-06-2002, 08:08 AM	#5
Guest Posts: n/a	I'm not really sure what it looks like.  the only HKS bov that i've seen are the SQV and the old model, and they both were adjustable becuase I had both of them in the past.  You're saying that it doesn't have anykind of screws on it anywhere??  If thats the case you can have the ecu rewritten to stop the car from stalling I can't remember who does that though.  Maybe JWT.

02-06-2002, 08:27 AM	#6
uuninja Zilvia Addict Join Date: Dec 2001 Location: Reston, VA Age: 47 Posts: 812 Trader Rating: (0) Feedback Score: 0 reviews	2 things to check. 1) Bypass valve should be clamped tight. If metered air escapes then the car will run rich and bog. 2) IAA valve is clean. It is the valve that draws air when the throttle plate is shut. If this is dirty then the car will stall. Use Intake cleaner to clean it out. It is harder for the valve to draw air with the turbo and IC in front of it at Idle.

02-06-2002, 09:23 AM	#7
JaySpec7 Join Date: Aug 2001 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	I'm a friend of racngi who help do the install.. Yes it is running rich and it does stall..  I'm thinking the kit came w/ a HKS bypass valve that routes back to the intake pipe.. all hoses are clamped and no vacuum leaks..  we haven't had a chance to clean out the TB or replace or regap the plugs.. What's IAA?  Idle Air Control? Here is a pic of the Bypass valve included in the kit..

02-06-2002, 09:35 AM	#8
JaySpec7 Join Date: Aug 2001 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	Yes, we know you stalled!! LOL </span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from RacNgi on 1:24 am on Feb. 5, 2002 Ok I stalled a XS kit on my 97 240. </td></tr></table><span id='postcolor'>

02-06-2002, 01:59 PM	#9
'91 D21 beater Guest Posts: n/a	Like I've pointed out several times on this forum and on FA. Get a can of throttlebody/carb cleaner and go to town on the throttle body, and the idle air control valve (IACVor IAA). This is the 1/4" hard pipe that's to the right of the throttle body where you had to connect a rubber tube from the I/C piping from. Go crazy... It helps. Worked for me, Robthechef, and many others.

02-06-2002, 02:08 PM	#10
alchemist Zilvia Member Join Date: Oct 2001 Posts: 192 Trader Rating: (0) Feedback Score: 0 reviews	the air is supposed to be rerouted to the intake just after the MAF so that the metering doesnt get screwed up.  where do you have the air going

02-06-2002, 02:17 PM	#11
JaySpec7 Join Date: Aug 2001 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	Yes.. i saw.. thanks.. we are just getting as much info as possible..  we are goin to try that tonight.. </span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from '91 D21 beater on 1:59 pm on Feb. 6, 2002 Like I've pointed out several times on this forum and on FA. Get a can of throttlebody/carb cleaner and go to town on the throttle body, and the idle air control valve (IACVor IAA). This is the 1/4" hard pipe that's to the right of the throttle body where you had to connect a rubber tube from the I/C piping from. Go crazy... It helps. Worked for me, Robthechef, and many others. </td></tr></table><span id='postcolor'>

02-06-2002, 02:22 PM	#12
JaySpec7 Join Date: Aug 2001 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	That is where it is routed.. </span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from alchemist on 2<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>8 pm on Feb. 6, 2002 the air is supposed to be rerouted to the intake just after the MAF so that the metering doesnt get screwed up. where do you have the air going </td></tr></table><span id='postcolor'>

02-06-2002, 02:56 PM	#13
crazycuban Zilvia Junkie Join Date: Nov 2001 Posts: 526 Trader Rating: (0) Feedback Score: 0 reviews	You don't HAVE to recirculate it - it just runs rich if you don't.  Take it to a dyno tuning shop and they'll fix that without having to make your blow off valve recirculating instead of atmospheric - atmospheric just sounds so much cooler.