Idle Dips at Complete Stop - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

powersteeringless180sx · 01-01-2008, 02:38 PM

About every other time I come to a complete stop my idle will start dipping and stall if I don't feather the throttle. I also found out my idle would go back up when I start pumping on my brake pedal. I'm thinking it's my brake booster. Can anyone confirm?

GSXRJJordan · 01-01-2008, 02:39 PM

Could just be the vacuum line going to the brake booster - it runs from the back of the intake mani up over the brake hardlines, and takes a lot of heat. Try replacing that first.

bcbs13det · 01-01-2008, 03:31 PM

what motor and what bov.
if an sr then sometimes if you arent runing recirc it will do this.
maf based systems do it alot when you run atmospheric blow off.

is there a check valve in the vac line for the brake booster?

smelly240 · 01-01-2008, 04:26 PM

is the car boosted? if not disregard the bov talk. And start looking if it does it only when u hit the brakes and whatnot. if so - start at the booster - if not look eslewhere.

g6civcx · 01-01-2008, 04:49 PM

Check the one-way check valve between the booster and the manifold. The valve should only open one way to let vacuum into the booster. Vacuum should not be going the other way.

Matej · 01-01-2008, 05:20 PM

My car does that when my MAFS is loose, check if yours is plugged in all the way.

powersteeringless180sx · 01-01-2008, 06:49 PM

Quote:

Originally Posted by Matej

My car does that when my MAFS is loose, check if yours is plugged in all the way.

naw for sure my maf's connected and secure.

Quote:

Originally Posted by GSXRJJordan

Could just be the vacuum line going to the brake booster - it runs from the back of the intake mani up over the brake hardlines, and takes a lot of heat. Try replacing that first.

yea i'll try replacing that vacuum hose. it doesn't even feel like rubber anymore. it feels more like a hard piece of plastic now from all the heat.

Quote:

Originally Posted by g6civcx

Check the one-way check valve between the booster and the manifold. The valve should only open one way to let vacuum into the booster. Vacuum should not be going the other way.

i'll try checking the valve when i get some free time during the day.

powersteeringless180sx · 01-12-2008, 12:40 AM

update

i checked my hoses that go from the booster the motor. the hose is a lil hard but there aren't any cracks or leaks on it. i ordered a new brake booster check valve from westco nissan a couple days ago. still waiting for it in the mail. i'm gotta refiberglass and bondo my bumper tomorrow. so while the bondo dry's i'm gonna change out my pcv and my fram fuel filter to a nissan one. maybe changing those out will help.

greddyguy · 01-12-2008, 01:00 AM

mine does the same exact thing. i need to figure it out as well.

Antihero983 · 01-12-2008, 01:44 AM

post up pics of when you replace your PCV. ive been told its a bitch to get to....

***S14DB*** · 01-12-2008, 03:12 AM

On the KA,
Undo the ALT bolts.
Remove the belt.
remove the top bolt on the alt.
swing the alt so it hits the frame rail.

This should give you lots of room to work on the pcv. If not pull the bottom bolt and remove the alt completely.

You may want to buy a catch can and put it inline between the pcv and the T bar on the manifold. This will filter all the nasty vapors and crap coming out of your block into your manifold.

bziggers13 · 01-12-2008, 08:50 AM

my newer daily does it too..
lights dim, idle drops 50 or so.

I thought my alt was bad, never got around to replacing it. too lazy.

unicoladron · 01-12-2008, 09:30 AM

i had the SAME exact problem but wasn't related to brakes. i set my CAS timing and cleaned my IACV and my idle problems went away, it was great. but yeah, i had to do the same thing (feather the throttle) to prevent the idle from going so low. Also it is a known problem when SR's (or perhaps any other 4cyl engine) have lightened flywheels. but the idle doesn't drop to 50, it drops to more like 550-700.

it appears he has an SR due to the red SR icon he put in the title.

note: i believe the brake booster line is supposed to be hard so it doesn't flex and pinch under all of the vacuum suction...

anyone have a new car to actually confirm this?

***S14DB*** · 01-12-2008, 01:48 PM

Bah, is this a KA or SR then?

powersteeringless180sx · 01-13-2008, 02:56 AM

sorry if people got confused but i have an SR. i thought the red SR symbol was enough to indicate it. The pcv was super easy to change out since it's on the rear of the valve cover on the intake side.

i changed out the pcv and fuel filter today at my buddy's house. i drove home and idle seems to be stable at 850 w/ no dipping at the stop light. so far so good. i'll be putting in the brake booster check valve next.

240trooper · 01-13-2008, 03:24 AM

my friend has the same problem but with his 91 ka , goes to a fast stop and car dies , we changed tha alt didn't fix it , is has a rebuilt maf so thats not the problem . today we riped off the intakes mani off a extra 95 ka laing around at his house , the pcv's at the bottom , ima tell him to change that and see what happens. my old sohc was so much easier to fix lol . I thought maybe it could be his egr..

powersteeringless180sx · 01-14-2008, 01:57 AM

drove around today and it's still dipping every now and again. still waiting for the check valve. if that doesn't fix it i guess i'll check my cas timing next.... argh...i don't feel like buying a timing gun.. i just want my shit to run right.

***S14DB*** · 01-14-2008, 02:24 AM

http://www.boostpro.net/prodtester.html

powersteeringless180sx · 01-24-2008, 12:15 PM

i installed the check valve and still the same thing. i put in some fuel injector cleaner in a couple weeks ago and the car has actually been idling like a champ until this week. it started dipping again and idling rough but not as often. so now i'm assuming it's a fuel problem? i'm gonna get an inline fuel pressure gauge to see if the fp is normal.... i dunno..... the search continues.

powersteeringless180sx · 01-28-2008, 02:11 PM

i cleaned out my throttle body and iacv valve over the weekend. my idle's been pretty stable and hasn't dipped at all durning stops. so far i think i've solved my problem.

A Spec Products · 01-28-2008, 03:05 PM

When I had my KA a while ago, I had similar issue

Revs would dip low (almost dying) at stops

It was the coolant temp sensor (the one at front of motor by upper radiator neck I think?)

Sometimes they go bad, and the wires from the harness get corroded

I got a new sensor, respliced new wires from the point where it was corroded/not corroded, and after that it was all good

I'm not a mechanic though, so not sure if that is your problem

98koukile · 01-28-2008, 06:55 PM

Mine did this when I needed a new o2 sensor, I'm sure you would have thrown a code though

01-01-2008, 02:38 PM	#1
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	Idle Dips at Complete Stop About every other time I come to a complete stop my idle will start dipping and stall if I don't feather the throttle. I also found out my idle would go back up when I start pumping on my brake pedal. I'm thinking it's my brake booster. Can anyone confirm?

01-01-2008, 02:39 PM	#2
GSXRJJordan Post Whore! Join Date: May 2006 Location: San Diego, CA Posts: 9,135 Trader Rating: (19) Rides Gallery: GSXRJJordan Feedback Score: 19 reviews	Could just be the vacuum line going to the brake booster - it runs from the back of the intake mani up over the brake hardlines, and takes a lot of heat. Try replacing that first. __________________ Jordan Innovations has a new web site! www.JordanInnovations.com -- All your favorite FD Pro Drifters love it, trust me -- www.JordanInnovations.com

01-01-2008, 04:26 PM	#4
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 46 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	is the car boosted? if not disregard the bov talk. And start looking if it does it only when u hit the brakes and whatnot. if so - start at the booster - if not look eslewhere. __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

01-12-2008, 01:44 AM	#10
Antihero983 Post Whore! Join Date: Feb 2005 Location: Gilmanton, NH Age: 39 Posts: 4,409 Trader Rating: (2) Rides Gallery: Antihero983 Feedback Score: 2 reviews	post up pics of when you replace your PCV. ive been told its a bitch to get to.... __________________ "So here I am, right back at it again, just like I've always been"

01-12-2008, 03:12 AM	#11
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	On the KA, Undo the ALT bolts. Remove the belt. remove the top bolt on the alt. swing the alt so it hits the frame rail. This should give you lots of room to work on the pcv. If not pull the bottom bolt and remove the alt completely. You may want to buy a catch can and put it inline between the pcv and the T bar on the manifold. This will filter all the nasty vapors and crap coming out of your block into your manifold. __________________ Comments should be taken as Opinions not as Statements of Fact

01-01-2008, 03:31 PM	#3
bcbs13det Leaky Injector Join Date: Dec 2003 Location: houston, tx Posts: 78 Trader Rating: (1) Feedback Score: 1 reviews	what motor and what bov. if an sr then sometimes if you arent runing recirc it will do this. maf based systems do it alot when you run atmospheric blow off. is there a check valve in the vac line for the brake booster?

01-01-2008, 04:49 PM	#5
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	Check the one-way check valve between the booster and the manifold. The valve should only open one way to let vacuum into the booster. Vacuum should not be going the other way.

01-01-2008, 05:20 PM	#6
Matej Post Whore! Join Date: Feb 2007 Location: N/A Posts: 9,423 Trader Rating: (39) Feedback Score: 39 reviews	My car does that when my MAFS is loose, check if yours is plugged in all the way.

01-12-2008, 12:40 AM	#8
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	update i checked my hoses that go from the booster the motor. the hose is a lil hard but there aren't any cracks or leaks on it. i ordered a new brake booster check valve from westco nissan a couple days ago. still waiting for it in the mail. i'm gotta refiberglass and bondo my bumper tomorrow. so while the bondo dry's i'm gonna change out my pcv and my fram fuel filter to a nissan one. maybe changing those out will help.

01-12-2008, 01:00 AM	#9
greddyguy Zilvia Member Join Date: Dec 2007 Location: boise idaho Age: 36 Posts: 175 Trader Rating: (0) Feedback Score: 0 reviews	mine does the same exact thing. i need to figure it out as well.

01-12-2008, 08:50 AM	#12
bziggers13 Leaky Injector Join Date: Nov 2007 Location: Camden Age: 47 Posts: 58 Trader Rating: (0) Feedback Score: 0 reviews	my newer daily does it too.. lights dim, idle drops 50 or so. I thought my alt was bad, never got around to replacing it. too lazy.

01-12-2008, 09:30 AM	#13
unicoladron Zilvia Junkie Join Date: Jul 2007 Location: Long Island, NY Age: 40 Posts: 568 Trader Rating: (0) Feedback Score: 0 reviews	i had the SAME exact problem but wasn't related to brakes. i set my CAS timing and cleaned my IACV and my idle problems went away, it was great. but yeah, i had to do the same thing (feather the throttle) to prevent the idle from going so low. Also it is a known problem when SR's (or perhaps any other 4cyl engine) have lightened flywheels. but the idle doesn't drop to 50, it drops to more like 550-700. it appears he has an SR due to the red SR icon he put in the title. note: i believe the brake booster line is supposed to be hard so it doesn't flex and pinch under all of the vacuum suction... anyone have a new car to actually confirm this? __________________ 1993 KA24DE for sale with 180k..running when pulled.... need to get rid of ASAP...i'm moving Last edited by unicoladron; 01-12-2008 at 09:32 AM.. Reason: brake line note

01-12-2008, 01:48 PM	#14
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	Bah, is this a KA or SR then? __________________ Comments should be taken as Opinions not as Statements of Fact

01-13-2008, 02:56 AM	#15
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	sorry if people got confused but i have an SR. i thought the red SR symbol was enough to indicate it. The pcv was super easy to change out since it's on the rear of the valve cover on the intake side. i changed out the pcv and fuel filter today at my buddy's house. i drove home and idle seems to be stable at 850 w/ no dipping at the stop light. so far so good. i'll be putting in the brake booster check valve next.

01-13-2008, 03:24 AM	#16
240trooper Zilvia Addict Join Date: Sep 2003 Location: Torrance, California Posts: 791 Trader Rating: (10) Feedback Score: 10 reviews	my friend has the same problem but with his 91 ka , goes to a fast stop and car dies , we changed tha alt didn't fix it , is has a rebuilt maf so thats not the problem . today we riped off the intakes mani off a extra 95 ka laing around at his house , the pcv's at the bottom , ima tell him to change that and see what happens. my old sohc was so much easier to fix lol . I thought maybe it could be his egr.. __________________ 2.7L

01-14-2008, 01:57 AM	#17
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	drove around today and it's still dipping every now and again. still waiting for the check valve. if that doesn't fix it i guess i'll check my cas timing next.... argh...i don't feel like buying a timing gun.. i just want my shit to run right.

01-14-2008, 02:24 AM	#18
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	http://www.boostpro.net/prodtester.html __________________ Comments should be taken as Opinions not as Statements of Fact

01-24-2008, 12:15 PM	#19
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	i installed the check valve and still the same thing. i put in some fuel injector cleaner in a couple weeks ago and the car has actually been idling like a champ until this week. it started dipping again and idling rough but not as often. so now i'm assuming it's a fuel problem? i'm gonna get an inline fuel pressure gauge to see if the fp is normal.... i dunno..... the search continues.

01-28-2008, 02:11 PM	#20
powersteeringless180sx Zilvia Addict Join Date: Mar 2006 Location: SoCal (Orange County) Age: 42 Posts: 868 Trader Rating: (1) Feedback Score: 1 reviews	i cleaned out my throttle body and iacv valve over the weekend. my idle's been pretty stable and hasn't dipped at all durning stops. so far i think i've solved my problem.

01-28-2008, 03:05 PM	#21
A Spec Products Post Whore! Join Date: Mar 2005 Location: Socal! Off 60/605 Posts: 7,256 Trader Rating: (27) Feedback Score: 27 reviews	When I had my KA a while ago, I had similar issue Revs would dip low (almost dying) at stops It was the coolant temp sensor (the one at front of motor by upper radiator neck I think?) Sometimes they go bad, and the wires from the harness get corroded I got a new sensor, respliced new wires from the point where it was corroded/not corroded, and after that it was all good I'm not a mechanic though, so not sure if that is your problem __________________ A SPEC PRODUCTS CORP AME Wheels, Advan, ARC, Gram Lights, Nardi, Personal, Recaro, Works Bell, Work Wheels, Volk Racing, 5Zigen, & more! 626.618.1100 x 103 / aim: aspectuan Advertiser's Specials! Read / Give Feedback! Please Rate Us!

01-28-2008, 06:55 PM	#22
98koukile Zilvia Addict Join Date: Jan 2007 Location: Western Mass Age: 37 Posts: 949 Trader Rating: (3) Feedback Score: 3 reviews	Mine did this when I needed a new o2 sensor, I'm sure you would have thrown a code though __________________ Just talking about cars, one at a time Horsepower sells cars torque wins races -Shelby