SR running REAL rich - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

copmagnet · 01-17-2010, 02:40 PM

Ok I have a redtop SR20DET in my 91 240 and recently it started running REALLY rich. It's got basic mods, boost at 10psi, FMIC, 3" turbo back, not much. My wideband has always read a bit rich, 13.5 idle/light throttle 10.5 WOT and full boost but recently its started reading 10.5-11.0 at light throttle sometimes dropping down to 9.0 (maybe worse, gauge bottoms out at 9) It's also kinda erratic, from what I can tell it depends on RPM's. Cruising in the 2500 RPM range its steady at about 9.2, but if I wind it up on the highway it reads 13.0 or so at 3k RPM's and up, but occasionally drops back down in the 10's.

O2 sensor and coolant temp sensor are maybe 6 months old, same with sparkplugs. 7 heat range NGK's at a hair less than stock gap. I am not a master engine tech, but I do know my way around an engine usually, just new to turbo setups. Any ideas? I checked for boost leaks and fixed a couple small ones, but that was a little bit before this started. Also replaced the IACV because the old one was making weird noises and idle wasn't right when it was cold. Would mass air meter cause this? Coilpack? Injectors? How do I test these? Help!!

rb25s13vert · 01-17-2010, 03:43 PM

just a thought, but maybe your fpr is taking a crap.

rb25s13vert · 01-17-2010, 09:12 PM

are you running a stock fuel pump?

copmagnet · 01-17-2010, 09:38 PM

I have no clue what kind of fuel pump is in there, I bought the car with the swap done and thats one thing I didn't ask about. The fpr was going bad a while back, pressure was like 56psi with the vac line hooked up. I replaced it a few months ago with a no-name adjustable one, and set it at the factory setting. Could that cause this but still read the normal pressure on the built-in gauge? It ran great for quite a while afterwards.

*brndck* · 01-17-2010, 10:04 PM

double check your fuel pressure setting and also check to see if it holds pressure with the engine off. my first guess would be that you may have a leaking injector or o-ring.

steve shadows · 01-17-2010, 11:24 PM

What ecu are you using?

Are you running stock maf?

Are you running stock purpler 370 cc inj?

I would double check all theses,

It could be a maf issue even

copmagnet · 01-18-2010, 02:33 PM

Stock E5 ecu, stack MAF, stock injectors. Like I said the engine is basically stock, just exhaust, FMIC, and a couple extra pounds of boost. The gauge on the FPR reads 43 while idling with the vacuum line attached, I turned the key off and watched it under the hood til the turbo-timer let the engine die and it immediately dropped to 10psi, I'm talking 1/2 a second and POW no pressure. Now I don't know a lot about SR20's, but normally that should hold pressure a while longer than THAT, right? Second test I performed was turned the ignition on and watched the gauge. Spiked up while the pump was cycling, and as soon as the pump stopped buzzing POP pressure dropped to 15 or so. So...I'm guessing an issue with the injectors somewhere? How should I test those for leaks, I'm thinking pull the fuel rail off and lay it over a piece of cardboard, then turn the ignition on and see whether they start dripping or if they stay dry? Any other way or things I should do to test it?

copmagnet · 01-20-2010, 06:21 PM

pulled the injectors, the front one is dribbling gas constantly when the key is turned on. I'll be replacing it this weekend, and we'll see how it is after that. Thanks for help, I hope this is all thats wrong!

KoukiMonsta · 01-20-2010, 07:35 PM

Quote:

Originally Posted by copmagnet

pulled the injectors, the front one is dribbling gas constantly when the key is turned on. I'll be replacing it this weekend, and we'll see how it is after that. Thanks for help, I hope this is all thats wrong!

im betting thats all thats going on...

steve shadows · 01-21-2010, 12:51 AM

REAL rich as opposed to FAKE rich?

copmagnet · 01-21-2010, 05:38 PM

yep. lol anyway I was frazzled when I wrote that cause some jackass backed into my car in a parking lot and took off. A witness saw him do it, yelled into the Auto Zone and gave me a description, so I chased him down and called the cops. Anyway, I want to get this fixed ASAP now cause I am getting the back end repainted, so I don't want to blow black crap from the exhaust all over fresh paint. Ugh.

01-17-2010, 02:40 PM	#1
copmagnet Leaky Injector Join Date: Mar 2009 Location: clarksville IN Age: 46 Posts: 83 Trader Rating: (2) Feedback Score: 2 reviews	SR running REAL rich Ok I have a redtop SR20DET in my 91 240 and recently it started running REALLY rich. It's got basic mods, boost at 10psi, FMIC, 3" turbo back, not much. My wideband has always read a bit rich, 13.5 idle/light throttle 10.5 WOT and full boost but recently its started reading 10.5-11.0 at light throttle sometimes dropping down to 9.0 (maybe worse, gauge bottoms out at 9) It's also kinda erratic, from what I can tell it depends on RPM's. Cruising in the 2500 RPM range its steady at about 9.2, but if I wind it up on the highway it reads 13.0 or so at 3k RPM's and up, but occasionally drops back down in the 10's. O2 sensor and coolant temp sensor are maybe 6 months old, same with sparkplugs. 7 heat range NGK's at a hair less than stock gap. I am not a master engine tech, but I do know my way around an engine usually, just new to turbo setups. Any ideas? I checked for boost leaks and fixed a couple small ones, but that was a little bit before this started. Also replaced the IACV because the old one was making weird noises and idle wasn't right when it was cold. Would mass air meter cause this? Coilpack? Injectors? How do I test these? Help!!

01-17-2010, 11:24 PM	#6
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	What ecu are you using? Are you running stock maf? Are you running stock purpler 370 cc inj? I would double check all theses, It could be a maf issue even __________________ Like Me on FaceBook !

01-21-2010, 12:51 AM	#10
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	REAL rich as opposed to FAKE rich? __________________ Like Me on FaceBook !

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01-17-2010, 03:43 PM	#2
rb25s13vert Leaky Injector Join Date: Jan 2010 Location: mcas beaufort, sc Age: 41 Posts: 58 Trader Rating: (0) Feedback Score: 0 reviews	just a thought, but maybe your fpr is taking a crap.

01-17-2010, 09:12 PM	#3
rb25s13vert Leaky Injector Join Date: Jan 2010 Location: mcas beaufort, sc Age: 41 Posts: 58 Trader Rating: (0) Feedback Score: 0 reviews	are you running a stock fuel pump?

01-17-2010, 09:38 PM	#4
copmagnet Leaky Injector Join Date: Mar 2009 Location: clarksville IN Age: 46 Posts: 83 Trader Rating: (2) Feedback Score: 2 reviews	I have no clue what kind of fuel pump is in there, I bought the car with the swap done and thats one thing I didn't ask about. The fpr was going bad a while back, pressure was like 56psi with the vac line hooked up. I replaced it a few months ago with a no-name adjustable one, and set it at the factory setting. Could that cause this but still read the normal pressure on the built-in gauge? It ran great for quite a while afterwards.

01-18-2010, 02:33 PM	#7
copmagnet Leaky Injector Join Date: Mar 2009 Location: clarksville IN Age: 46 Posts: 83 Trader Rating: (2) Feedback Score: 2 reviews	Stock E5 ecu, stack MAF, stock injectors. Like I said the engine is basically stock, just exhaust, FMIC, and a couple extra pounds of boost. The gauge on the FPR reads 43 while idling with the vacuum line attached, I turned the key off and watched it under the hood til the turbo-timer let the engine die and it immediately dropped to 10psi, I'm talking 1/2 a second and POW no pressure. Now I don't know a lot about SR20's, but normally that should hold pressure a while longer than THAT, right? Second test I performed was turned the ignition on and watched the gauge. Spiked up while the pump was cycling, and as soon as the pump stopped buzzing POP pressure dropped to 15 or so. So...I'm guessing an issue with the injectors somewhere? How should I test those for leaks, I'm thinking pull the fuel rail off and lay it over a piece of cardboard, then turn the ignition on and see whether they start dripping or if they stay dry? Any other way or things I should do to test it?

01-20-2010, 06:21 PM	#8
copmagnet Leaky Injector Join Date: Mar 2009 Location: clarksville IN Age: 46 Posts: 83 Trader Rating: (2) Feedback Score: 2 reviews	pulled the injectors, the front one is dribbling gas constantly when the key is turned on. I'll be replacing it this weekend, and we'll see how it is after that. Thanks for help, I hope this is all thats wrong!

01-21-2010, 05:38 PM	#11
copmagnet Leaky Injector Join Date: Mar 2009 Location: clarksville IN Age: 46 Posts: 83 Trader Rating: (2) Feedback Score: 2 reviews	yep. lol anyway I was frazzled when I wrote that cause some jackass backed into my car in a parking lot and took off. A witness saw him do it, yelled into the Auto Zone and gave me a description, so I chased him down and called the cops. Anyway, I want to get this fixed ASAP now cause I am getting the back end repainted, so I don't want to blow black crap from the exhaust all over fresh paint. Ugh.