Running rich cause fouled plugs? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

shift_down · 10-20-2012, 11:43 AM

Hey guys

I had my car running pretty good with idle afrs at 14.5, WOT afrs at 11.5, and the afrs would lean out once I let go of the pedal. So I was very happy with this.

One of my intercooler pipes blew out of the coupler while I was under boost one day.

Now After I put it back together and made sure that there were no vac leaks, my afrs are jacked up.

Idle afrs are 17-18, WOT is about 10.5-11, and I go FULL LEAN after letting go of the gas. The car drives good though.

Could the afrs be bad because my plugs are fouled from running SUPER rich after my intercooler pipe blew out of place?

What do you guys think? Im trying to get my car runing good again. thanks guys

Kingtal0n · 10-20-2012, 11:48 AM

Test for boost leaks, pressurize the plumbing, including the intake boot before the turbocharger.

shift_down · 10-20-2012, 02:25 PM

I pulled my plugs and they were very black. One plug had oil on the threads, so I decided to do a compression test. Compression test reveled 178 across all 4 cylinders. I dont have an air compressor so i cant run a boost leak test right now. I will try to get a hold of one though.

*StryfeS13* · 10-20-2012, 02:58 PM

Compression numbers sound good. Was it oil on the threads or fuel?
Boost leak test!

shift_down · 10-20-2012, 03:01 PM

It was oil, plugs didnt smell like fuel. Maybe its from the oil leaking pass the VC gasket? I have to fab up my own boost leak tester and borrow my dads air compressor and boost leak test the car. Ill robably do that once I finish this microeconomics homework assignment :P

4x4le · 10-21-2012, 04:06 AM

Sounds like you had a boost leak, were tuned for it, finally destroyed that coupler and now that its fixed you need more fuel.

What is your setup

shift_down · 10-21-2012, 12:15 PM

My tune is a base Rom tune. So its not tuned for the boost leak. My bov isn't opening like it was before. Before the pipe came out, I could hear it everytime I shifted. Now I can't hear it at all. This tells me that there is a significant boost leak...I think.

AdamR · 11-07-2012, 11:39 AM

You have a boost and vacuuum leak. And you are supposed to be full lean when off the throttle.

Bentleyness · 11-09-2012, 08:52 AM

I have the same issue as u but only my idle is off now its reading 16-17 afr ever since I blew a coupler racing a g35 coupe. Fixed the piping while ago and is been a month no issue wat so ever with the motor. I'm lost my self wat would cause this. I also have the same set up as u just running 93 gas. I email Jason about this but I still haven't heard back its only been 3days

waxball88 · 11-09-2012, 12:24 PM

YOU HAVE BOOST LEAKS
People are so quick to jump to the tuner as the issue. Your car was running fine, blew a coupler, you put the coupler back on and think its tight but its not. Hook it up and put 25psi in there and it becomes apparent where your problem is. Been through this 100 times. Use soap and water in a spray bottle preferably when the car is cold.

Car is sitting at idle air is entering the system through the leak = lean afr
Under boost air is EXITING the system = Rich

10-20-2012, 11:43 AM	#1
shift_down Zilvia Junkie Join Date: Sep 2012 Location: Tulsa Oklahoma Age: 31 Posts: 313 Trader Rating: (0) Feedback Score: 0 reviews	Running rich cause fouled plugs? Hey guys I had my car running pretty good with idle afrs at 14.5, WOT afrs at 11.5, and the afrs would lean out once I let go of the pedal. So I was very happy with this. One of my intercooler pipes blew out of the coupler while I was under boost one day. Now After I put it back together and made sure that there were no vac leaks, my afrs are jacked up. Idle afrs are 17-18, WOT is about 10.5-11, and I go FULL LEAN after letting go of the gas. The car drives good though. Could the afrs be bad because my plugs are fouled from running SUPER rich after my intercooler pipe blew out of place? What do you guys think? Im trying to get my car runing good again. thanks guys __________________ Ka24 t3/t04b + Z32MAF + 550 subys + Walbro 255 + enthalpy Tune + 91 octane

10-20-2012, 11:48 AM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	Test for boost leaks, pressurize the plumbing, including the intake boot before the turbocharger. __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

10-20-2012, 02:25 PM	#3
shift_down Zilvia Junkie Join Date: Sep 2012 Location: Tulsa Oklahoma Age: 31 Posts: 313 Trader Rating: (0) Feedback Score: 0 reviews	I pulled my plugs and they were very black. One plug had oil on the threads, so I decided to do a compression test. Compression test reveled 178 across all 4 cylinders. I dont have an air compressor so i cant run a boost leak test right now. I will try to get a hold of one though. __________________ Ka24 t3/t04b + Z32MAF + 550 subys + Walbro 255 + enthalpy Tune + 91 octane

10-20-2012, 03:01 PM	#5
shift_down Zilvia Junkie Join Date: Sep 2012 Location: Tulsa Oklahoma Age: 31 Posts: 313 Trader Rating: (0) Feedback Score: 0 reviews	It was oil, plugs didnt smell like fuel. Maybe its from the oil leaking pass the VC gasket? I have to fab up my own boost leak tester and borrow my dads air compressor and boost leak test the car. Ill robably do that once I finish this microeconomics homework assignment :P __________________ Ka24 t3/t04b + Z32MAF + 550 subys + Walbro 255 + enthalpy Tune + 91 octane

10-21-2012, 12:15 PM	#7
shift_down Zilvia Junkie Join Date: Sep 2012 Location: Tulsa Oklahoma Age: 31 Posts: 313 Trader Rating: (0) Feedback Score: 0 reviews	My tune is a base Rom tune. So its not tuned for the boost leak. My bov isn't opening like it was before. Before the pipe came out, I could hear it everytime I shifted. Now I can't hear it at all. This tells me that there is a significant boost leak...I think. __________________ Ka24 t3/t04b + Z32MAF + 550 subys + Walbro 255 + enthalpy Tune + 91 octane Last edited by shift_down; 10-21-2012 at 01:58 PM..

10-20-2012, 02:58 PM	#4
StryfeS13 It's Always Broken. Join Date: Feb 2010 Location: Fresno, CA Posts: 1,363 Trader Rating: (14) Feedback Score: 14 reviews	Compression numbers sound good. Was it oil on the threads or fuel? Boost leak test!

10-21-2012, 04:06 AM	#6
4x4le Zilvia FREAK! Join Date: Nov 2008 Location: Manchester, Tn Posts: 1,253 Trader Rating: (1) Feedback Score: 1 reviews	Sounds like you had a boost leak, were tuned for it, finally destroyed that coupler and now that its fixed you need more fuel. What is your setup

11-07-2012, 11:39 AM	#8
AdamR Leaky Injector Join Date: Jan 2008 Location: Owensboro, KY Age: 37 Posts: 134 Trader Rating: (0) Feedback Score: 0 reviews	You have a boost and vacuuum leak. And you are supposed to be full lean when off the throttle.

11-09-2012, 08:52 AM	#9
Bentleyness Leaky Injector Join Date: Mar 2012 Location: chicago area Age: 33 Posts: 140 Trader Rating: (0) Feedback Score: 0 reviews	I have the same issue as u but only my idle is off now its reading 16-17 afr ever since I blew a coupler racing a g35 coupe. Fixed the piping while ago and is been a month no issue wat so ever with the motor. I'm lost my self wat would cause this. I also have the same set up as u just running 93 gas. I email Jason about this but I still haven't heard back its only been 3days

11-09-2012, 12:24 PM	#10
waxball88 Zilvia FREAK! Join Date: Jun 2009 Location: Gainesville Posts: 1,061 Trader Rating: (9) Feedback Score: 9 reviews	YOU HAVE BOOST LEAKS People are so quick to jump to the tuner as the issue. Your car was running fine, blew a coupler, you put the coupler back on and think its tight but its not. Hook it up and put 25psi in there and it becomes apparent where your problem is. Been through this 100 times. Use soap and water in a spray bottle preferably when the car is cold. Car is sitting at idle air is entering the system through the leak = lean afr Under boost air is EXITING the system = Rich

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