rebuilt jimwolf KA runs rough. documented tests. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

kroos268 · 11-01-2009, 09:52 PM

I've searched, and read, and tested many systems. Looking for more advice.

SYMPTOMS
1. idle is rough, and periodic. smooth, then rough, changing every few seconds. sometimes you may think you hear pop or backfire at idle, but could also be sounds of the engine choking.
2. vacuum gauge inside manifold shows flutter ~3unit only when idle is rough. otherwise steady.
3. pop\backfire can be heard at higher RPM and almost always during deceleration.
4. acceleration is usually nice.
5. power fluctuation can be felt while driving and holding RPM constant, at the same rate as idle fluctuation.

CURRENT HYPOTHESIS 's
jim wolf pre-programmed on the rich side?
there's an air leak im' just not finding it

TESTS COMPLETED
1. compression - PASS all cyl ~150
2. air leak - PASS. soaked intake mani and intercooler pipe seals.
3. MAF - PASS. multimeter\blow test on signal wire.
4. Cylinder drop - PASS. all injectors fire.
5. Timing - tuned? Advanced\Retarded timing for best idle. Distributor is on factory tooth, rotated to limit counter-clockwise. An additional tooth in the same direction did not benefit, spooled too soon(?), and ran hot.

CONFIGURATION
rebuild ka24de
yellow top injectors, nismo
Z32 MAF
jimwolf ATX ECU programmed for MTX
GT28 ball bearing turbo
intercooler
walboro 255

ps. I also see some oil pool up in the turbo inlet/outlet flanges.

thanks!
steve

kroos268 · 11-01-2009, 10:05 PM

also, the second o2 sensor is not hooked up. only the sensor directly after the turbo downpipe. i read this didn't matter.

kroos268 · 11-16-2009, 09:27 PM

bump? bump?

*DreamN* · 11-16-2009, 09:42 PM

Hook up your second o2 sensor.

kroos268 · 11-16-2009, 10:00 PM

are you certain it is important? Not to downplay, but why... that is a significant install for I have new piping all the way out.

*ManoNegra* · 11-17-2009, 09:27 AM

Quote:

Originally Posted by kroos268

also, the second o2 sensor is not hooked up. only the sensor directly after the turbo downpipe. i read this didn't matter.

S14? 2nd O2 is for emissions, monitors the cat. check engine light on?

intermittent vaccum leak would be my guess.

kroos268 · 11-17-2009, 04:44 PM

Quote:

Originally Posted by ManoNegra

S14? 2nd O2 is for emissions, monitors the cat. check engine light on?

intermittent vaccum leak would be my guess.

yes it is on. I have done the starter fluid test. Can an auto shop test for leak from my turbo outlet all the way to manifold?

Gorilla Unit 33 · 11-17-2009, 05:46 PM

My O2 snesor has never been plugged in since i bought the car and it never gave me any problems like this..... then again im OBD1

mattsil80wis · Yesterday, 01:48 PM

Pressure test your system, from the turbo inlet. Fluctating vacuum at idle is a suretell sign of their being a leak someplace, not so much on the pipes, but also the IM itself.

11-01-2009, 09:52 PM	#1
kroos268 Join Date: Apr 2005 Location: South Carolina Posts: 24 Trader Rating: (0)	rebuilt jimwolf KA runs rough. documented tests. I've searched, and read, and tested many systems. Looking for more advice. SYMPTOMS 1. idle is rough, and periodic. smooth, then rough, changing every few seconds. sometimes you may think you hear pop or backfire at idle, but could also be sounds of the engine choking. 2. vacuum gauge inside manifold shows flutter ~3unit only when idle is rough. otherwise steady. 3. pop\backfire can be heard at higher RPM and almost always during deceleration. 4. acceleration is usually nice. 5. power fluctuation can be felt while driving and holding RPM constant, at the same rate as idle fluctuation. CURRENT HYPOTHESIS 's jim wolf pre-programmed on the rich side? there's an air leak im' just not finding it TESTS COMPLETED 1. compression - PASS all cyl ~150 2. air leak - PASS. soaked intake mani and intercooler pipe seals. 3. MAF - PASS. multimeter\blow test on signal wire. 4. Cylinder drop - PASS. all injectors fire. 5. Timing - tuned? Advanced\Retarded timing for best idle. Distributor is on factory tooth, rotated to limit counter-clockwise. An additional tooth in the same direction did not benefit, spooled too soon(?), and ran hot. CONFIGURATION rebuild ka24de yellow top injectors, nismo Z32 MAF jimwolf ATX ECU programmed for MTX GT28 ball bearing turbo intercooler walboro 255 ps. I also see some oil pool up in the turbo inlet/outlet flanges. thanks! steve

11-16-2009, 09:42 PM	#4
DreamN Premium Member Join Date: Nov 2006 Location: SoCal (818) Mon★ Rep Power: ∞ Age: 24 Posts: 8,030 Trader Rating: (29) Rides Gallery: DreamN	Hook up your second o2 sensor. __________________

11-17-2009, 05:46 PM	#8
Gorilla Unit 33 Zilvia Member Join Date: Oct 2006 Location: Philly Posts: 280 Trader Rating: (1)	My O2 snesor has never been plugged in since i bought the car and it never gave me any problems like this..... then again im OBD1 __________________ gorillaunit33.wordpress.com

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11-01-2009, 10:05 PM	#2
kroos268 Join Date: Apr 2005 Location: South Carolina Posts: 24 Trader Rating: (0)	also, the second o2 sensor is not hooked up. only the sensor directly after the turbo downpipe. i read this didn't matter.

11-16-2009, 09:27 PM	#3
kroos268 Join Date: Apr 2005 Location: South Carolina Posts: 24 Trader Rating: (0)	bump? bump?

11-16-2009, 10:00 PM	#5
kroos268 Join Date: Apr 2005 Location: South Carolina Posts: 24 Trader Rating: (0)	are you certain it is important? Not to downplay, but why... that is a significant install for I have new piping all the way out.

Yesterday, 01:48 PM	#9
mattsil80wis Leaky Injector Join Date: Jan 2008 Location: nj Age: 22 Posts: 88 Trader Rating: (3)	Pressure test your system, from the turbo inlet. Fluctating vacuum at idle is a suretell sign of their being a leak someplace, not so much on the pipes, but also the IM itself.