Help With Running Rich* - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

nsn240 · 03-10-2006, 03:40 PM

I dunno what else to do... i have gone through every possible thread and tryed everything suggested, My car still dumps in fuel at idle.. pours black smoke and rumbles like a fuck

So far: checked injectors, power balance test.. (completely even, no cylinder was different from the other 3, its just running rich on all cylinders), new plugs/check spark, pulled fuel rail and cleaned, waiting on a new fpr in the mail

I have no idea what else to do, any further suggestions would be great.. thanks

Nizzan4u2nv · 03-11-2006, 12:18 AM

Have you tried a different maf or replaced the 02? Any check engine lights?

SoSideways · 03-11-2006, 01:58 AM

Are any of your injector seals leaking?

Are any of your injectors stuck open?

*fliprayzin240sx* · 03-11-2006, 05:11 AM

Water temp sensor?

motonagam · 03-11-2006, 09:33 AM

do you have any exhaust leaks before the oxygen sensor (for example: cracked exhaust manifold, broken exhaust donut/gasket, etc.)? If you do, it could be sucking in air through the exhaust, misleading the oxygen sensor that it's running lean, which will command the fuel injectors to dump more fuel.

nsn240 · 03-14-2006, 01:44 PM

Update... i got a replacement fpr today and noticed an immediate difference, but it still runs way too rich. The injectors are not leaking or stuck open, i've checked that about 5times now. The MAF is fine, the problem exists both when the MAF is not plugged and plugged in, there are no exhuast leaks either.

The car idles perfect, just like it used to, when i pull the fuel pump fuse.. from the time i pull it until it dies, it idles at ~900 and vaccuum goes to 20hg (exactly what it did before)

Nizzan4u2nv · 03-14-2006, 04:43 PM

Did you rewire the maf? Sounds like mismatched wires or a faulty plug. It does have something to do with the maf if it runs the same plugged/unplugged. I had this problem when rewiring for a z32 maf. Had the wires wrong and it ran pig rich, blew smoke, wouldnt rev, and idled like ass. Bust out the volt meter.

nsn240 · 03-14-2006, 09:18 PM

Im pretty sure its the injectors leaking, i tested to see if they leaked (pull injector harness, plugs and wires.. crank car and see if there is gas in the cylinder) But its probably the O-rings, the car runs like shit when the fuel pump is providing pressure, but when it is turned off, it runs smooth... my thought is the pressure from the pump is enough to make one of the bad o-rings leak and run rich

yusuke1923 · 03-16-2006, 11:22 AM

My car use to be like that also...
I found out it was just a bad switch on the MAF... trying replacing that switch on the MAF... as for me.. I just tapped it and it work fine now.. haha!!

undercoverdjay · 03-16-2006, 12:32 PM

I had this same problem with my stock 92, I pulled the injector harness and then the car would crank and start, clip the harness on there one by one and it'd then eventually die. I swapped out the whole fuel rail, with a known working one and it fired right up. Try the harness test though, its a good way to check for excess fuel.

03-10-2006, 03:40 PM	#1
nsn240 Zilvia Addict Join Date: Aug 2005 Location: pa Posts: 642 Trader Rating: (1) Feedback Score: 1 reviews	Help With Running Rich* I dunno what else to do... i have gone through every possible thread and tryed everything suggested, My car still dumps in fuel at idle.. pours black smoke and rumbles like a fuck So far: checked injectors, power balance test.. (completely even, no cylinder was different from the other 3, its just running rich on all cylinders), new plugs/check spark, pulled fuel rail and cleaned, waiting on a new fpr in the mail I have no idea what else to do, any further suggestions would be great.. thanks

03-11-2006, 12:18 AM	#2
Nizzan4u2nv Zilvia FREAK! Join Date: Oct 2003 Location: San Diego Age: 40 Posts: 1,226 Trader Rating: (3) Feedback Score: 3 reviews	Have you tried a different maf or replaced the 02? Any check engine lights? __________________

03-11-2006, 05:11 AM	#4
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	Water temp sensor? __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

03-14-2006, 04:43 PM	#7
Nizzan4u2nv Zilvia FREAK! Join Date: Oct 2003 Location: San Diego Age: 40 Posts: 1,226 Trader Rating: (3) Feedback Score: 3 reviews	Did you rewire the maf? Sounds like mismatched wires or a faulty plug. It does have something to do with the maf if it runs the same plugged/unplugged. I had this problem when rewiring for a z32 maf. Had the wires wrong and it ran pig rich, blew smoke, wouldnt rev, and idled like ass. Bust out the volt meter. __________________

03-16-2006, 11:22 AM	#9
yusuke1923 Nissanaholic! Join Date: Jul 2004 Location: 818 to da 626 v(^_^)v Posts: 1,661 Trader Rating: (2) Feedback Score: 2 reviews	My car use to be like that also... I found out it was just a bad switch on the MAF... trying replacing that switch on the MAF... as for me.. I just tapped it and it work fine now.. haha!! __________________

03-11-2006, 01:58 AM	#3
SoSideways Post Whore! Join Date: Apr 2003 Location: 你老母 Posts: 4,371 Trader Rating: (4) Feedback Score: 4 reviews	Are any of your injector seals leaking? Are any of your injectors stuck open?

03-11-2006, 09:33 AM	#5
motonagam Leaky Injector Join Date: Jul 2004 Location: San Jose, CA Posts: 91 Trader Rating: (1) Feedback Score: 1 reviews	do you have any exhaust leaks before the oxygen sensor (for example: cracked exhaust manifold, broken exhaust donut/gasket, etc.)? If you do, it could be sucking in air through the exhaust, misleading the oxygen sensor that it's running lean, which will command the fuel injectors to dump more fuel.

03-14-2006, 01:44 PM	#6
nsn240 Zilvia Addict Join Date: Aug 2005 Location: pa Posts: 642 Trader Rating: (1) Feedback Score: 1 reviews	Update... i got a replacement fpr today and noticed an immediate difference, but it still runs way too rich. The injectors are not leaking or stuck open, i've checked that about 5times now. The MAF is fine, the problem exists both when the MAF is not plugged and plugged in, there are no exhuast leaks either. The car idles perfect, just like it used to, when i pull the fuel pump fuse.. from the time i pull it until it dies, it idles at ~900 and vaccuum goes to 20hg (exactly what it did before)

03-14-2006, 09:18 PM	#8
nsn240 Zilvia Addict Join Date: Aug 2005 Location: pa Posts: 642 Trader Rating: (1) Feedback Score: 1 reviews	Im pretty sure its the injectors leaking, i tested to see if they leaked (pull injector harness, plugs and wires.. crank car and see if there is gas in the cylinder) But its probably the O-rings, the car runs like shit when the fuel pump is providing pressure, but when it is turned off, it runs smooth... my thought is the pressure from the pump is enough to make one of the bad o-rings leak and run rich

03-16-2006, 12:32 PM	#10
undercoverdjay Zilvia Junkie Join Date: Apr 2004 Location: Potsdam New York Age: 41 Posts: 594 Trader Rating: (2) Feedback Score: 2 reviews	I had this same problem with my stock 92, I pulled the injector harness and then the car would crank and start, clip the harness on there one by one and it'd then eventually die. I swapped out the whole fuel rail, with a known working one and it fired right up. Try the harness test though, its a good way to check for excess fuel.