sr20det running lean at wot - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

upstate240sx · 07-06-2009, 07:53 PM

im having a problem with my 200sx (yes its a fwd, who knows why i traded my sr s13 for it) any how i have a turbo sr20de+t 97 200sx ser. at wot it runs very lean to the point where i hear it misfire . basically if i floor it , from 4500rpm and up to redline it will misfire. it does this alot at wot but less if i slowly accel through the powerband. it also doesnt seem to do this when cold.

i have a gtir t28 at 11psi. when i run 7psi i dont hear it misfire.
im running bkr7e gapped at .028 and my timing is 15btdc
i have a jwt ecu that is tuned for my siemens 72lb injectors at 3 bar and cobra maf . i also have a aeromotive fpr set to 3 bar with the vacuum line off. in addition i have a walbro 255lph fuel pump that i just bought maybe a month or 2 ago. i set my fpr to 4 bar to see if i could richen it up , with no luck, i also installed a neo to richen it up again no luck. still misfires. im out of ideas . i regrounded the maf as well. tried rotating the maf too. im running blow through setup as well with at least a foot of straight pipe after my maf and into the tb. i have never blown a coupler and pipes seem to be tight, and they are clamped as much as possible with solid t clamps.

ive also posted this on the sr20forum but im getting no where
mid to high end popping wot - SR20 Forum

any ideas?

cotbu · 07-07-2009, 02:02 AM

Do you have a wideband? With a wideband we could see when you go lean, if that's what's happening. Do you hear a brapp brapp brapp type of sound when it happens?

If you're running a Nismo FPR, get rid of it and go to a stock FPR, or an Aeromotive unit. Nismo FPR's suck balls
I hope this isn't why you have an aeromotive unit.

upstate240sx · 07-07-2009, 05:08 AM

nah ive had a aeromotive from day one, i dont have a wideband at the moment but im saving up for one, its not really a brap brap brap, its more of a softer deeper tone, ill get a camera and record it today while im driving

boost · 07-07-2009, 04:11 PM

when my friend had a similar problem, it turned out to be the drivers side fmic coupler had a small tear so it would only open up enough under higher boost. kind of sounded like a mild version of a two-step rev limit but a little different. though i don't know about in your case since it acts different in cold. anyway just throwin that out there.

Autobacs · 07-07-2009, 08:33 PM

How can you tell you're running lean?

I recommend not even boosting hard until you get a wideband.

You're plug wires may be shot so you're acting up at high RPM same as what bad coilpacks do on an SR20DET.

You might have a bad fuel filter or bad MAF.

godsmack · 07-07-2009, 10:06 PM

i agree with what autobacs said. you can't rule out the plug wires or something in that area. do you have a a/f guage to tell you that you're leaning out? or are you just going by sound? if by sound change out your plugs, wires, and cap and see if that works.

twisties · 07-08-2009, 08:05 PM

what is your duty cycle

upstate240sx · 07-09-2009, 05:17 AM

Quote:

Originally Posted by Autobacs

How can you tell you're running lean?

I recommend not even boosting hard until you get a wideband.

You're plug wires may be shot so you're acting up at high RPM same as what bad coilpacks do on an SR20DET.

You might have a bad fuel filter or bad MAF.

i just got a new fuel filter, and i think my maf is ok because it doesnt do this when its cold, its just warm at wot. would should my maf voltage be say at 7psi wot, or 12psi wot, or 15psi wot?
also would plug wires do this only at wot from 4.5k to redline?

Quote:

Originally Posted by godsmack

i agree with what autobacs said. you can't rule out the plug wires or something in that area. do you have a a/f guage to tell you that you're leaning out? or are you just going by sound? if by sound change out your plugs, wires, and cap and see if that works.

well i pulled my plugs repeatebly and the electrodes appear to be lean? here is a picture of them
Spark plugs

im not sure of my duty cycle , i cant imagine that a t28 at less then 15psi would run 72lbers out. i ordered a wideband today it will be here tomorrow. how can i figure out my duty cycle?

anyone in the upstate ny area lol?

upstate240sx · 07-12-2009, 11:31 PM

ok, i guess fuel and tuning wasnt the problem, because i installed my windeband today (aem) and my afr are good, 11-13s at anything over 50% throttle, idle and low throttle is around 15-17.... im starting to point the finger at ignition?

*fliprayzin240sx* · 07-13-2009, 01:15 AM

Timing? Might be too advanced...

Autobacs · 07-13-2009, 07:11 AM

Try to swap out plug wires with someone and see if that is it.

*handinpants* · 07-13-2009, 07:27 AM

is your car running rich at idle? \

upstate240sx · 07-13-2009, 01:36 PM

nope at idle its 16-17 afr

upstate240sx · 07-13-2009, 01:36 PM

could i be runnign too rich cause some times at wot closer to redline my afr is like 10ish

upstate240sx · 07-13-2009, 01:49 PM

my timing is at 15btdc at idle,? is there any other way this could over advance itself other then normal means, next step plug wires i guess

hottscennessey · 07-13-2009, 03:42 PM

Quote:

Originally Posted by upstate240sx

could i be runnign too rich cause some times at wot closer to redline my afr is like 10ish

I'm confused, I thought you said it was running lean from 4.5k-redline WOT?

If you're at 15* BTDC at idle with the car fully warmed up that sounds about right. I don't know what you mean about over-advancing itself, but the answer is probably no, not possible.

upstate240sx · 07-13-2009, 09:47 PM

Quote:

Originally Posted by hottscennessey

I'm confused, I thought you said it was running lean from 4.5k-redline WOT?

If you're at 15* BTDC at idle with the car fully warmed up that sounds about right. I don't know what you mean about over-advancing itself, but the answer is probably no, not possible.

i thought it was lean because of the popping and the plugs but i got a wideband and its not running lean

upstate240sx · 07-14-2009, 09:01 AM

also given that its has correct afr, what would make this happen while the engine is warmed up as opposed to when it is cold

Autobacs · 07-14-2009, 09:13 AM

Check your plug wires first and then theorize afterwards. LOL.

upstate240sx · 07-14-2009, 02:14 PM

will do when i get paid

Autobacs · 07-14-2009, 02:45 PM

Try to borrow one first to be sure that is the problem before you put down your money to buy a set.

BlitzRPS13 · 07-14-2009, 03:48 PM

Quote:

Originally Posted by boost

when my friend had a similar problem, it turned out to be the drivers side fmic coupler had a small tear so it would only open up enough under higher boost. kind of sounded like a mild version of a two-step rev limit but a little different. though i don't know about in your case since it acts different in cold. anyway just throwin that out there.

Off topic.. but your post made me remember that i had a small rip in one of my fmic endtank couplers.. take a look at it.. i tore a huge crack in it.. hopefully thats why my was misfiring. So just goes to show you.. when you throw stuff out there... it still helps. Thanks.

hottscennessey · 07-15-2009, 10:10 AM

OP sounds like a boost leak to me. You also need a tune, you shouldn't have AFR's in the 10's if you cars tuned.

07-06-2009, 07:53 PM	#1
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	sr20det running lean at wot im having a problem with my 200sx (yes its a fwd, who knows why i traded my sr s13 for it) any how i have a turbo sr20de+t 97 200sx ser. at wot it runs very lean to the point where i hear it misfire . basically if i floor it , from 4500rpm and up to redline it will misfire. it does this alot at wot but less if i slowly accel through the powerband. it also doesnt seem to do this when cold. i have a gtir t28 at 11psi. when i run 7psi i dont hear it misfire. im running bkr7e gapped at .028 and my timing is 15btdc i have a jwt ecu that is tuned for my siemens 72lb injectors at 3 bar and cobra maf . i also have a aeromotive fpr set to 3 bar with the vacuum line off. in addition i have a walbro 255lph fuel pump that i just bought maybe a month or 2 ago. i set my fpr to 4 bar to see if i could richen it up , with no luck, i also installed a neo to richen it up again no luck. still misfires. im out of ideas . i regrounded the maf as well. tried rotating the maf too. im running blow through setup as well with at least a foot of straight pipe after my maf and into the tb. i have never blown a coupler and pipes seem to be tight, and they are clamped as much as possible with solid t clamps. ive also posted this on the sr20forum but im getting no where mid to high end popping wot - SR20 Forum any ideas?

07-07-2009, 02:02 AM	#2
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	Do you have a wideband? With a wideband we could see when you go lean, if that's what's happening. Do you hear a brapp brapp brapp type of sound when it happens? If you're running a Nismo FPR, get rid of it and go to a stock FPR, or an Aeromotive unit. Nismo FPR's suck balls I hope this isn't why you have an aeromotive unit. __________________ LoverTechnologies "Half Broken Things!"

07-13-2009, 01:15 AM	#10
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Timing? Might be too advanced... __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

07-13-2009, 07:27 AM	#12
handinpants FreshColdBeer.com Join Date: Feb 2008 Location: California Age: 42 Posts: 2,665 Trader Rating: (48) Rides Gallery: handinpants Feedback Score: 48 reviews	is your car running rich at idle? \ __________________

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07-07-2009, 05:08 AM	#3
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	nah ive had a aeromotive from day one, i dont have a wideband at the moment but im saving up for one, its not really a brap brap brap, its more of a softer deeper tone, ill get a camera and record it today while im driving

07-07-2009, 04:11 PM	#4
boost Zilvia Member Join Date: Nov 2001 Location: cupertino Posts: 232 Trader Rating: (6) Feedback Score: 6 reviews	when my friend had a similar problem, it turned out to be the drivers side fmic coupler had a small tear so it would only open up enough under higher boost. kind of sounded like a mild version of a two-step rev limit but a little different. though i don't know about in your case since it acts different in cold. anyway just throwin that out there.

07-07-2009, 08:33 PM	#5
Autobacs Leaky Injector Join Date: Oct 2003 Location: Washington Posts: 96 Trader Rating: (3) Feedback Score: 3 reviews	How can you tell you're running lean? I recommend not even boosting hard until you get a wideband. You're plug wires may be shot so you're acting up at high RPM same as what bad coilpacks do on an SR20DET. You might have a bad fuel filter or bad MAF.

07-07-2009, 10:06 PM	#6
godsmack Zilvia Addict Join Date: Feb 2009 Location: Allentown, PA Age: 39 Posts: 652 Trader Rating: (0) Feedback Score: 0 reviews	i agree with what autobacs said. you can't rule out the plug wires or something in that area. do you have a a/f guage to tell you that you're leaning out? or are you just going by sound? if by sound change out your plugs, wires, and cap and see if that works.

07-08-2009, 08:05 PM	#7
twisties BANNED Join Date: Jul 2009 Location: east coast Age: 37 Posts: 31 Trader Rating: (0) Feedback Score: 0 reviews	what is your duty cycle

07-12-2009, 11:31 PM	#9
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	ok, i guess fuel and tuning wasnt the problem, because i installed my windeband today (aem) and my afr are good, 11-13s at anything over 50% throttle, idle and low throttle is around 15-17.... im starting to point the finger at ignition?

07-13-2009, 07:11 AM	#11
Autobacs Leaky Injector Join Date: Oct 2003 Location: Washington Posts: 96 Trader Rating: (3) Feedback Score: 3 reviews	Try to swap out plug wires with someone and see if that is it.

07-13-2009, 01:36 PM	#13
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	nope at idle its 16-17 afr

07-13-2009, 01:49 PM	#15
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	my timing is at 15btdc at idle,? is there any other way this could over advance itself other then normal means, next step plug wires i guess

07-14-2009, 09:01 AM	#18
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	also given that its has correct afr, what would make this happen while the engine is warmed up as opposed to when it is cold

07-14-2009, 09:13 AM	#19
Autobacs Leaky Injector Join Date: Oct 2003 Location: Washington Posts: 96 Trader Rating: (3) Feedback Score: 3 reviews	Check your plug wires first and then theorize afterwards. LOL.

07-14-2009, 02:14 PM	#20
upstate240sx Zilvia Member Join Date: Jun 2008 Location: US Posts: 281 Trader Rating: (3) Feedback Score: 3 reviews	will do when i get paid

07-14-2009, 02:45 PM	#21
Autobacs Leaky Injector Join Date: Oct 2003 Location: Washington Posts: 96 Trader Rating: (3) Feedback Score: 3 reviews	Try to borrow one first to be sure that is the problem before you put down your money to buy a set.

07-15-2009, 10:10 AM	#23
hottscennessey Leaky Injector Join Date: Nov 2008 Location: Richmond, VA Age: 38 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	OP sounds like a boost leak to me. You also need a tune, you shouldn't have AFR's in the 10's if you cars tuned.