SR20det problems... $25 REWARD for getting this fixed for me! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

anyotherone · 12-28-2007, 02:53 PM

I have been working on an SR20det and it is about to be the death of me. Here's the low-down:

It's a totally stock redtop swap in an S14. It runs pig rich at idle and goes dangerously lean under any boost. Here's what has been checked:

Fuel pressure is good

Mafs (Z32) is good, safc settings at 2in 6out, but changes make no difference!

Wiring harness checks out, only there is no knock sensor?

Coolant temp sensor new

TPS is good per fsm

compression good

New CAS, timing set to 15degrees using correct procedure

Two ECU's, both 62's, one starts the car and runs as stated above, light comes on but will not let you pull the code, the other ecu throws code 55 cranks, fires, and dies immediately... wideband reads lean.

Any help would be greatly appreciated!

*MELLO*SOS* · 12-28-2007, 02:59 PM

dunno if SR ecu will throw a code 34 for missing knock sensor... on the KA it retards timing from 3000 onward and the engine feels sluggish. Probably not your problem but thought I'd throw it out there maybe someone else knows.

Have you built a pressure tester and checked your charge piping and IM gaskets for leaks?

edit: just saw you have the z32 and safc combo. Have you tried stock ECU/MAF and unhook the SAFC? Are your injectors stock sized btw?

Gl

anyotherone · 12-28-2007, 03:21 PM

Stock injectors

Yes, I went back and tried a stock mafs and no safc

Yes, I've tested for leaks

Thanks for the input though!

jspec kid · 12-28-2007, 03:27 PM

Pinched fuel injector O-ring? If you have changed out injectors or they have been tampered with I would possibly look there.

tig_tech · 12-28-2007, 06:04 PM

Sounds like it could be the 02 sensor. Either its bad or check the wiring to it. Or disconnect it when it runs and see if anything changes.

*fliprayzin240sx* · 12-28-2007, 07:37 PM

I know this is a stab in the dark but how are you reading your AFR? Are you using an actual wideband or you got one of those christmas tree lights attached to your stock o2 sensor?

drift_student · 12-29-2007, 12:15 AM

Its says wideband in his original post.

My red top did something similar, just not dangerously lean. It turned out that my spark plugs (which were only a day old) had tiny little cracks in the porcelain (white part) which I couldn't see until I touched one with an oily finger.

They crack like that when they are dropped while in the box or over torqued upon installation.

HalveBlue · 12-29-2007, 01:19 AM

I don't know if it'll solve your problem, but get that Knock Sensor installed.

Without it the ECU will run a fail-safe rich fuel map.

Other than that I'd say check the fuel rail and injectors.

Who knows, maybe you have an obstruction like a spider somewhere in the rail that's preventing proper flow. Don't laugh, it's actually happened.

Good Luck!

12-28-2007, 02:53 PM	#1
anyotherone Zilvia Junkie Join Date: Jun 2005 Location: Dallas, TX Posts: 330 Trader Rating: (8) Rides Gallery: anyotherone Feedback Score: 8 reviews	SR20det problems... $25 REWARD for getting this fixed for me! I have been working on an SR20det and it is about to be the death of me. Here's the low-down: It's a totally stock redtop swap in an S14. It runs pig rich at idle and goes dangerously lean under any boost. Here's what has been checked: Fuel pressure is good Mafs (Z32) is good, safc settings at 2in 6out, but changes make no difference! Wiring harness checks out, only there is no knock sensor? Coolant temp sensor new TPS is good per fsm compression good New CAS, timing set to 15degrees using correct procedure Two ECU's, both 62's, one starts the car and runs as stated above, light comes on but will not let you pull the code, the other ecu throws code 55 cranks, fires, and dies immediately... wideband reads lean. Any help would be greatly appreciated!

12-28-2007, 06:04 PM	#5
tig_tech Zilvia Junkie Join Date: Dec 2007 Location: J-ville Age: 40 Posts: 455 Trader Rating: (25) Feedback Score: 25 reviews	Sounds like it could be the 02 sensor. Either its bad or check the wiring to it. Or disconnect it when it runs and see if anything changes. __________________

12-28-2007, 07:37 PM	#6
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	I know this is a stab in the dark but how are you reading your AFR? Are you using an actual wideband or you got one of those christmas tree lights attached to your stock o2 sensor? __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

12-28-2007, 02:59 PM	#2
MELLOSOS* LAID OUT Join Date: Mar 2004 Location: LAS VEGAS Age: 43 Posts: 2,015 Trader Rating: (1) Rides Gallery: MELLO*SOS Feedback Score: 1 reviews	dunno if SR ecu will throw a code 34 for missing knock sensor... on the KA it retards timing from 3000 onward and the engine feels sluggish. Probably not your problem but thought I'd throw it out there maybe someone else knows. Have you built a pressure tester and checked your charge piping and IM gaskets for leaks? edit: just saw you have the z32 and safc combo. Have you tried stock ECU/MAF and unhook the SAFC? Are your injectors stock sized btw? Gl

12-28-2007, 03:21 PM	#3
anyotherone Zilvia Junkie Join Date: Jun 2005 Location: Dallas, TX Posts: 330 Trader Rating: (8) Rides Gallery: anyotherone Feedback Score: 8 reviews	Stock injectors Yes, I went back and tried a stock mafs and no safc Yes, I've tested for leaks Thanks for the input though!

12-28-2007, 03:27 PM	#4
jspec kid Join Date: Oct 2007 Location: california Posts: 27 Trader Rating: (0) Feedback Score: 0 reviews	Pinched fuel injector O-ring? If you have changed out injectors or they have been tampered with I would possibly look there.

12-29-2007, 12:15 AM	#7
drift_student Leaky Injector Join Date: Jan 2006 Location: Houston, TX Posts: 118 Trader Rating: (1) Feedback Score: 1 reviews	Its says wideband in his original post. My red top did something similar, just not dangerously lean. It turned out that my spark plugs (which were only a day old) had tiny little cracks in the porcelain (white part) which I couldn't see until I touched one with an oily finger. They crack like that when they are dropped while in the box or over torqued upon installation.

12-29-2007, 01:19 AM	#8
HalveBlue Zilvia FREAK! Join Date: Mar 2004 Location: I'm somewhere where I don't know where I am! Posts: 1,549 Trader Rating: (0) Feedback Score: 0 reviews	I don't know if it'll solve your problem, but get that Knock Sensor installed. Without it the ECU will run a fail-safe rich fuel map. Other than that I'd say check the fuel rail and injectors. Who knows, maybe you have an obstruction like a spider somewhere in the rail that's preventing proper flow. Don't laugh, it's actually happened. Good Luck!