Sr20det Gurus...heres one for you - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

the3SecondJerk · 08-29-2003, 09:33 PM

ok, here it is. My 94 blacktop has been running rich since I installed it a few weeks ago. So today I started checking things and looking to see if the ECU is throwing any codes. I got one...55 dammit! So to see if the ecu is acting ok I unpluged the o2 sensor. It ran identical to how it was all day today. I get home to check codes expecting to see at least an o2 sensor code....i get 55 again. I am sure if I unhooked the mafs the car would run similar. Probably running off the stock map. So now I know something is way off. Here is what I have on the car.

89 chassis
94 blacktop s13 sr20det
s-afc (useless without o2 signal)
hks ssqv
2.5 catback
cone style intake

I do not have the ECU mounted as of yet....does it have to be to be grounded?

Please help!

radrex88 · 08-29-2003, 09:50 PM

Ok code 55 is normal, no problem there, did you make sure you where in mode 3, If not Ill give you a site that will tell you how to do it. Also, you say the s-afc isnt working, is this because of the 02 sensor, just trying to figure out why the afc isnt functioning, cause that could fix your problem of running rich with the press of a few buttons.

aeontony · 08-29-2003, 10:41 PM

By running similar with the MAFS off, do you mean that the car won't rev above 2500 rpm? Your car just doesn't rev above 2500 no matter what?

Also, if I am right it takes 2 runs with a problem before the ECU will throw a code. Similarly, it takes 3 runs without a problem for the ECU to remove the code.

DudeYourSoOOJDM · 08-30-2003, 01:39 AM

code 55 - no marlfurnction.

the3SecondJerk · 08-30-2003, 08:48 PM

car is idleing at 1000-1200rpm. sometimes it'll get as low as 800 but rarely. But I still get no codes. I took the MAFS off and the car almost shut off and wouldn't rev over 2000rpm. So the ECU isn't malfunctioning. I am stumped. HELPPPPPPP!

Bill Roberts · 08-30-2003, 09:01 PM

So you did a full reset of the ecu? (I would also ground it)

It is a 16 bit computer and based on the knowledge I obtained....when the engine will not rev past 2 grand..the ECU is in safe mode and I do not know if their is a code for that.

Did you try running filterless (cone) to see if this improves things? Also check your Fuel pump pressure in line. The gauges are dirt cheap (look good too) and perhaps the fuel management system is freaking out.

Other than what I said..(which is minimal) this would be my first steps...just start from scratch...look at all ground wires and step by step testing.

I found that most of my problems have been grounds.

I do not have an SR so I am going on borrowed knowledge here..I just want to throw my 2 cents in to see if what I said has been covered.

the3SecondJerk · 08-30-2003, 09:05 PM

I have a NISMO fuel pressure regulator and walbro 255 pump. ECU has been reset many times. I will leave the filter on. However with MAFs disconnected it runs crappy.

The car runs great. turbo is spooled by 4000 and boosts all the way to redline. Only problem is its running rich.

TheTicTac · 08-30-2003, 09:09 PM

That should be fine it's ok to run rich. It's sorta natural, better than running lean that's for sure.

Bill Roberts · 08-30-2003, 09:25 PM

Yep..lean is V-Bad.

I read somewhere and I am not quoting the source...but something about running duel fuel filters, one at the pump and one at the engne solved a guys richness problem (black smoke and smell at 2KRPM) on a BMW M5.

I wonder if this is viable at all and would help?

The car will only usually take in only the amount of fuel it needs...but also some of the bimmer guys are posers making $hit up on the fly...so I have no idea if this is even do-able to solve anything.

Just knowledge (good or bad) exchange.

08-29-2003, 09:33 PM	#1
the3SecondJerk Zilvia Junkie Join Date: Jul 2002 Location: Fort Collins, CO Posts: 305 Trader Rating: (3) Feedback Score: 3 reviews	Sr20det Gurus...heres one for you ok, here it is. My 94 blacktop has been running rich since I installed it a few weeks ago. So today I started checking things and looking to see if the ECU is throwing any codes. I got one...55 dammit! So to see if the ecu is acting ok I unpluged the o2 sensor. It ran identical to how it was all day today. I get home to check codes expecting to see at least an o2 sensor code....i get 55 again. I am sure if I unhooked the mafs the car would run similar. Probably running off the stock map. So now I know something is way off. Here is what I have on the car. 89 chassis 94 blacktop s13 sr20det s-afc (useless without o2 signal) hks ssqv 2.5 catback cone style intake I do not have the ECU mounted as of yet....does it have to be to be grounded? Please help! __________________ Drive it like you stole it.

08-29-2003, 09:50 PM	#2
radrex88 Leaky Injector Join Date: Mar 2003 Location: Japan Age: 44 Posts: 113 Trader Rating: (0) Feedback Score: 0 reviews	Ok code 55 is normal, no problem there, did you make sure you where in mode 3, If not Ill give you a site that will tell you how to do it. Also, you say the s-afc isnt working, is this because of the 02 sensor, just trying to figure out why the afc isnt functioning, cause that could fix your problem of running rich with the press of a few buttons. __________________ Signature exceeds 400x200 picture size limits set by the User Agreement.

08-29-2003, 10:41 PM	#3
aeontony Zilvia Junkie Join Date: Jan 2003 Location: Norcal Posts: 303 Trader Rating: (0) Feedback Score: 0 reviews	By running similar with the MAFS off, do you mean that the car won't rev above 2500 rpm? Your car just doesn't rev above 2500 no matter what? Also, if I am right it takes 2 runs with a problem before the ECU will throw a code. Similarly, it takes 3 runs without a problem for the ECU to remove the code. __________________ S14.5 for sale. Must move on with life...=( http://www.zilvia.net/f/showthread.php?t=56822 Au no wa wakare no hajime...

08-30-2003, 01:39 AM	#4
DudeYourSoOOJDM Zilvia Junkie Join Date: Jan 2003 Location: Palmdale CA Age: 42 Posts: 479 Trader Rating: (0) Feedback Score: 0 reviews	code 55 - no marlfurnction. __________________ Since 2001.

08-30-2003, 08:48 PM	#5
the3SecondJerk Zilvia Junkie Join Date: Jul 2002 Location: Fort Collins, CO Posts: 305 Trader Rating: (3) Feedback Score: 3 reviews	car is idleing at 1000-1200rpm. sometimes it'll get as low as 800 but rarely. But I still get no codes. I took the MAFS off and the car almost shut off and wouldn't rev over 2000rpm. So the ECU isn't malfunctioning. I am stumped. HELPPPPPPP! __________________ Drive it like you stole it.

08-30-2003, 09:01 PM	#6
Bill Roberts Zilvia FREAK! Join Date: May 2003 Location: S FL. Posts: 1,538 Trader Rating: (0) Feedback Score: 0 reviews	So you did a full reset of the ecu? (I would also ground it) It is a 16 bit computer and based on the knowledge I obtained....when the engine will not rev past 2 grand..the ECU is in safe mode and I do not know if their is a code for that. Did you try running filterless (cone) to see if this improves things? Also check your Fuel pump pressure in line. The gauges are dirt cheap (look good too) and perhaps the fuel management system is freaking out. Other than what I said..(which is minimal) this would be my first steps...just start from scratch...look at all ground wires and step by step testing. I found that most of my problems have been grounds. I do not have an SR so I am going on borrowed knowledge here..I just want to throw my 2 cents in to see if what I said has been covered.

08-30-2003, 09:05 PM	#7
the3SecondJerk Zilvia Junkie Join Date: Jul 2002 Location: Fort Collins, CO Posts: 305 Trader Rating: (3) Feedback Score: 3 reviews	I have a NISMO fuel pressure regulator and walbro 255 pump. ECU has been reset many times. I will leave the filter on. However with MAFs disconnected it runs crappy. The car runs great. turbo is spooled by 4000 and boosts all the way to redline. Only problem is its running rich. __________________ Drive it like you stole it.

08-30-2003, 09:09 PM	#8
TheTicTac Zilvia Junkie Join Date: May 2002 Location: CA Posts: 449 Trader Rating: (0) Feedback Score: 0 reviews	That should be fine it's ok to run rich. It's sorta natural, better than running lean that's for sure.

08-30-2003, 09:25 PM	#9
Bill Roberts Zilvia FREAK! Join Date: May 2003 Location: S FL. Posts: 1,538 Trader Rating: (0) Feedback Score: 0 reviews	Yep..lean is V-Bad. I read somewhere and I am not quoting the source...but something about running duel fuel filters, one at the pump and one at the engne solved a guys richness problem (black smoke and smell at 2KRPM) on a BMW M5. I wonder if this is viable at all and would help? The car will only usually take in only the amount of fuel it needs...but also some of the bimmer guys are posers making $hit up on the fly...so I have no idea if this is even do-able to solve anything. Just knowledge (good or bad) exchange.