Revvs hover when pedel is released - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Tantwoforty · 10-19-2009, 07:36 PM

So this may be a pointless thread but i did a little searching and it didnt really come up with anything useful so here we go.
92 KADE, exaust, intake filter.
When i hold the revvs at say 1500 for a few seconds, and let of the pedel the rps's will just hover at that exact sopt for 2-4 seconds then drop.
this points me to
1. Vaccume leak
2. Injector leak

I bring up injector leak since i have had problums with that in the past, And i have also delt with a nasty vaccume leak from my egr.

Now what puzzles me is the car idles at 800rpm pretty steady, it dose have some studering and "jumping" you can feel in the car. the car also failed smog pretty bad and is showing a "egr" and "knock sensor" code.

And when i had my vaccume leak the car would idle super high, and this is not the case at all here once the car warms up the idle is at the right number.

When i had a leaky injector it was expelling alot of black smoke and almost dieing. Wich its not at all doing now.

So before i start ripping things apart, Has anyone had a problum like this and could point me in the right direction?

i can make a video if need be.
thanks in advance

SR240DET · 10-19-2009, 09:37 PM

Did you do a self diagnostic test? If so what did you get?

Tantwoforty · 10-19-2009, 10:01 PM

as in pull the codes off the ecu?
because yes i did that and got egr and knock.
or is there a ecu mode im missing

*let5l1de* · 10-19-2009, 10:14 PM

Fix the problems/codes first. Just try cleaning the EGR free of carbon and make sure the actuation of the valve is free. also check the diaphragm for proper function. Replace the knock sensor.

A vacuum leak is very possible. If the symptoms persist, also clean and test the IACV and look at the vacuum components on the back of the head.

~mario

blackrms13 · 10-19-2009, 10:21 PM

u sure u dont just have a auto ECU?

Tantwoforty · 10-19-2009, 10:23 PM

sweet thanks for your input

Tantwoforty · 10-19-2009, 10:27 PM

Quote:

Originally Posted by blackrms13

u sure u dont just have a auto ECU?

I might, i had to replace mine, and the one i baught had the same #30 on it as my old one, he said it was a 5 speed ecu, but im not 100% on that
maby this will help, sometimes it will randomley revlimit me at around 4.8k ish

blackrms13 · 10-19-2009, 10:40 PM

look at the number under the big #30, there should be something that starts with Axx-xx-xxxx or something like that

post that...

Tantwoforty · 10-19-2009, 11:05 PM

#30
A11-b46 g72
after a quick search i found it is from a 91 5 speed... mine is a 92 if that would matter.

blackrms13 · 10-19-2009, 11:55 PM

Quote:

Originally Posted by Tantwoforty

#30
A11-b46 g72
after a quick search i found it is from a 91 5 speed... mine is a 92 if that would matter.

alright nvm then

cuz if u do have an auto ECU, it will hold idle high for a sec or two then drops to normal

but try to clean out ur EGR tube if ur getting a Code from the ECU for that

and replacing the knock sensor isnt as hard as you think
u can actually get ur hand underneath the intake manifold and get the KS in
took me about 20min max...
if you need to ill meet you in riverside and show u how...lol

SR240DET · 10-20-2009, 12:59 AM

also when cleaning out the IACV spray some carb cleaner down the big hose and let it sit for a few minutes, or take it off the intake manifold if you like, but its a bitch to get at while still on the car.

Tantwoforty · 10-20-2009, 01:03 AM

yea it was a bitch to get back on when i replaced my headgasket

s13Carlo · 10-20-2009, 07:07 PM

its a 240 let it be

JEDIs13 · 10-20-2009, 07:36 PM

Quote:

Originally Posted by s13Carlo

its a 240 let it be

people that say stupid shit like that make me wish i never bought my 240 in the first place. i bet your car is a POS

joey, if you need help with your car man feel free to bring it by my house.. you know where i live lol

s13Carlo · 10-20-2009, 10:46 PM

waht difference does it make if your idle is off for 2 seconds. your one of those people who buy 240's and expect them to run like a ferrari

JEDIs13 · 10-21-2009, 03:10 AM

Quote:

Originally Posted by s13Carlo

waht difference does it make if your idle is off for 2 seconds. your one of those people who buy 240's and expect them to run like a ferrari

no im one of those people who buy a car and make sure it runs properly.
i dont half ass shit.. if something is wrong, fix it.. if not let it be.
in this case something is wrong

dick

Tantwoforty · 11-04-2009, 11:57 PM

Quote:

Originally Posted by JEDIs13

no im one of those people who buy a car and make sure it runs properly.
i dont half ass shit.. if something is wrong, fix it.. if not let it be.
in this case something is wrong

dick

rofl thanks nick.
and yea i agree. i got this car with a bad engine, bad tranny ect.. and im doing what i can to make it roon as good as i can.. why evin buy a 20 year old car with the intent of makeing it nice and say meh its a 240.. lots of poeple have crappy 240s so that makes it ok for mine to be crappy...

annnyway yeah nick i might come by one day, bring some are approved bevrage and rip off my intake side..

rioredstang · 11-06-2009, 08:21 PM

It still sounds like a small vacuum leak. Knock sensor does not have anything to do with idle. If it was EGR it would idle very rough and die. I stiil think you have a vacuum leak. Call a few shops in your area and ask if they can do a smoke test on the intake system. It only takes a few minutes and takes all the guess work out of the way. It will pinpoint your leak. After that recheck, timing, and base idle.

10-19-2009, 07:36 PM	#1
Tantwoforty Zilvia Junkie Join Date: May 2009 Location: Riverside ca Age: 20 Posts: 343 Trader Rating: (1)	Revvs hover when pedel is released So this may be a pointless thread but i did a little searching and it didnt really come up with anything useful so here we go. 92 KADE, exaust, intake filter. When i hold the revvs at say 1500 for a few seconds, and let of the pedel the rps's will just hover at that exact sopt for 2-4 seconds then drop. this points me to 1. Vaccume leak 2. Injector leak I bring up injector leak since i have had problums with that in the past, And i have also delt with a nasty vaccume leak from my egr. Now what puzzles me is the car idles at 800rpm pretty steady, it dose have some studering and "jumping" you can feel in the car. the car also failed smog pretty bad and is showing a "egr" and "knock sensor" code. And when i had my vaccume leak the car would idle super high, and this is not the case at all here once the car warms up the idle is at the right number. When i had a leaky injector it was expelling alot of black smoke and almost dieing. Wich its not at all doing now. So before i start ripping things apart, Has anyone had a problum like this and could point me in the right direction? i can make a video if need be. thanks in advance __________________

10-19-2009, 10:14 PM	#4
let5l1de premium bullsh!t sifter Join Date: Dec 2007 Location: 626DRIFT, ca Posts: 1,053 Trader Rating: (23) Rides Gallery: let5l1de	Fix the problems/codes first. Just try cleaning the EGR free of carbon and make sure the actuation of the valve is free. also check the diaphragm for proper function. Replace the knock sensor. A vacuum leak is very possible. If the symptoms persist, also clean and test the IACV and look at the vacuum components on the back of the head. ~mario __________________ Don't Know How To Install? IM/PM Read My Sales Review 626 Friday Nights San Gabriel

10-19-2009, 10:21 PM	#5
blackrms13 Nissanaholic! Join Date: Jul 2007 Location: 626/Riverside Posts: 1,860 Trader Rating: (9)	u sure u dont just have a auto ECU? __________________ 91' 240sx Fastback

10-19-2009, 10:23 PM	#6
Tantwoforty Zilvia Junkie Join Date: May 2009 Location: Riverside ca Age: 20 Posts: 343 Trader Rating: (1)	sweet thanks for your input __________________

10-19-2009, 10:40 PM	#8
blackrms13 Nissanaholic! Join Date: Jul 2007 Location: 626/Riverside Posts: 1,860 Trader Rating: (9)	look at the number under the big #30, there should be something that starts with Axx-xx-xxxx or something like that post that... __________________ 91' 240sx Fastback

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10-19-2009, 09:37 PM	#2
SR240DET Zilvia FREAK! Join Date: Mar 2002 Location: Niceville, FL Age: 23 Posts: 1,453 Trader Rating: (0)	Did you do a self diagnostic test? If so what did you get?

10-19-2009, 10:01 PM	#3
Tantwoforty Zilvia Junkie Join Date: May 2009 Location: Riverside ca Age: 20 Posts: 343 Trader Rating: (1)	as in pull the codes off the ecu? because yes i did that and got egr and knock. or is there a ecu mode im missing __________________

10-19-2009, 11:05 PM	#9
Tantwoforty Zilvia Junkie Join Date: May 2009 Location: Riverside ca Age: 20 Posts: 343 Trader Rating: (1)	#30 A11-b46 g72 after a quick search i found it is from a 91 5 speed... mine is a 92 if that would matter. __________________

10-20-2009, 12:59 AM	#11
SR240DET Zilvia FREAK! Join Date: Mar 2002 Location: Niceville, FL Age: 23 Posts: 1,453 Trader Rating: (0)	also when cleaning out the IACV spray some carb cleaner down the big hose and let it sit for a few minutes, or take it off the intake manifold if you like, but its a bitch to get at while still on the car.

10-20-2009, 01:03 AM	#12
Tantwoforty Zilvia Junkie Join Date: May 2009 Location: Riverside ca Age: 20 Posts: 343 Trader Rating: (1)	yea it was a bitch to get back on when i replaced my headgasket __________________

10-20-2009, 07:07 PM	#13
s13Carlo Leaky Injector Join Date: Feb 2008 Location: 805 Posts: 103 Trader Rating: (0)	its a 240 let it be __________________ Team Redline Slideways

10-20-2009, 10:46 PM	#15
s13Carlo Leaky Injector Join Date: Feb 2008 Location: 805 Posts: 103 Trader Rating: (0)	waht difference does it make if your idle is off for 2 seconds. your one of those people who buy 240's and expect them to run like a ferrari __________________ Team Redline Slideways

11-06-2009, 08:21 PM	#18
rioredstang Join Date: Jan 2009 Location: Chattanooga, TN Age: 52 Posts: 29 Trader Rating: (0)	idle It still sounds like a small vacuum leak. Knock sensor does not have anything to do with idle. If it was EGR it would idle very rough and die. I stiil think you have a vacuum leak. Call a few shops in your area and ask if they can do a smoke test on the intake system. It only takes a few minutes and takes all the guess work out of the way. It will pinpoint your leak. After that recheck, timing, and base idle.

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