Ok this is part II of my original post
https://g35driver.com/forums/showflat.php?Cat=&Board=13&Number=281383&page=1&vi ew=collapsed&sb=5&part=

Well first off I reset my ECU using the battery disconnect option after my service department told me it was a sure way to do it myself. 2 Days later I headed to a local dyno (not the same one unfortunately because that dyno is 80miles north of here, this one was 2 miles from my job) The car dynoed 231hp 223tq but still ran very lean, It wasnt the scary 16:1 from the last dyno but the car was in 14.8:1 till like 5400 then went to 14:1 to 6300 where it started to go back up.

After spending hours online here and at my350z.com starting at dyno results, I am officially going nuts, I dont know why my car is running so lean ? I have seen many dyno sheets with people running less mods than me and the air/fuel ratio reading better than myself. I have a couple more questions for you guys.....

1) Could heat affect my air/fuel ratio so much ? It was about 90 outside when the car was dynoed last 2 times.

2) Could it be something to do with the automatic transmission.

3) Should I try putting my stock air box back on ? Could the nismo intake that I put on that is a 350z part be sucking in hotter air, where its placed causing the car to lean out ? By the way anybody with a nismo intake does your car whistle at high rpm's right before a shift ?

4) Could I be leaning the car our since I am running factory cats with after market headers ? I seem to be the only person I can find online running headers and factory cats. If anybody else is doing the same can I see your dyno sheet ?

What I would like to try is

1) Get a wide band o2 sensor like this
http://www.fastwrx.com/wio2sekit.html

2) Get Helix Test Pipes

3) Purchase an AFC

4) Cut out the front openeing for my intake

---------------

Ok im out of ideas, all your input is appreciated.... -Thanks


Caribbean Blue 2004 G35c w/Navi
19x8.5 Racing Hart CR's 245/35/19 on Toyo T1-S
19x10 Racing Hart CR's 275/35/19 on Toyo T1-S
TEIN Basic coilovers
Nismo Intake
DC Sport Headers
Greddy Exhaust<P ID="edit"><FONT class="small"><EM>Edited by notstr8mia on 06/27/04 09:51 AM.</EM></FONT></P>

 

dyno sheet old

Caribbean Blue 2004 G35c w/Navi
19x8.5 Racing Hart CR's 245/35/19 on Toyo T1-S
19x10 Racing Hart CR's 275/35/19 on Toyo T1-S
TEIN Basic coilovers
Nismo Intake
DC Sport Headers
Greddy Exhaust<P ID="edit"><FONT class="small"><EM>Edited by notstr8mia on 06/27/04 09:54 AM.</EM></FONT></P>

286876-g35dyno.jpg

 

dyno sheet new

Caribbean Blue 2004 G35c w/Navi
19x8.5 Racing Hart CR's 245/35/19 on Toyo T1-S
19x10 Racing Hart CR's 275/35/19 on Toyo T1-S
TEIN Basic coilovers
Nismo Intake
DC Sport Headers
Greddy Exhaust

286880-dynog35.jpg

 

i think you are running a lean condition too....


it is very possible that the headers and intake are the culprits.....

as for the difference in the dynos' well, one is in STD values (typically 2-3% higher than SAE, for my area at least)

you need some fuel management, for certain. If you arent unhappy w/ the car's performance, i wouldnt start removing items just yet.....

consider some ignition and fueling controls first, BUT do be cautious about this lean burn you're having....


-es

ps- the STILLEN VQ-PRO is a unit that can control a/f and ignition timing, and works off the stock ECU.... id look into that , seriously....

 

Damm with all of this running lean and everything, im worried about putting in my Helix test pipe's, borla exhaust and maybe kinetix or crawford plenum w/out the TS ECU. Do I really need it?? Opinions are needed!


Martin
2003.5 BS G35
Nismo Aero/Sport Package
Injen CAI
B+G Springs
ADR M-Classic 19's..

 

Get the TechnoSquare ECU.. that'll fix your lean issues, as well as bring all your mods together.

Cheers, Ted
(247rwhp)


'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS or Vote at Online Showoff

 

Dynojets don't load the car properly and allow the engine to accelerate roughly twice as fast as real world on highway conditions.

Besides being way optimistic [4-10%] in reported power output this lack of proper load can make things appear leaner sometimes.

Mostly the ERRORS in A/F ratio are from inaccurate uncalibrated AF equipment and monitoring after the catalytic convertors instead of welding new bungs on the manifold to install the sensor correctly.

The G35 engine all really run very very rich especially above 5,000 rpm. There is no way such simple things as CAI, air filters, or headers or exhaust or plenums could change this significantly.


http://www.technosquareinc.com/g35.htm

 

After I installed a Nismo CAI, Crawford Plenum and Crawford Cats, I tripped my Service Engine Soon light. It was fine with everything up until the drivers side Cat. Q45Tech, is it improbable that the error was a lean condition in your opinion? What does that leave left, a damaged O2 sensor?

Will have a diagnosis later this afternoon but I'd love to hear any speculations.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5/Crawford Cats/ Service Engine Soon

 

If you are concerned that your car is running lean with all your intake/exhaust mods, as i was prior to the TS solution, simply pull spark plug #1.... that'll show you whether or not you are running lean.

Speaking from experience, not theory.

Cheers, Ted


'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS or Vote at Online Showoff

 

If I pull a spark plug, what should I be looking for? Burnt tips, clean tips, no tips???

<font color=blue>The above statements are only my take on the issue. If you disagree with anything I typed then you are 100% right!</font color=blue>

 

How could it run lean the MAF reads the air flow which cannot change significantly.......as the cylinder volume hasn't changed........sure the mods can effect things a few percentage points but not much.

2% more air will only change the AF by 2%.......if 11.0000AF oem then 11.220000 AF after mods.

ODB2 [2nd O2] checks the QUALITY of the catalytic convertors........do they store and release oxygen at the as designed oem rate.
Changing cat types without reprogramming ecu can affect the testing greatly.

Besides being a FELONY to change out working cats, the problems that develop are the usual punishment.

Dropping O2 or breaking internal wires? What code does the MIL indicate it will tell you the exact problem.

My friend owns a REAL speed shop Dynos, rebuilds engines , turbo, superchargers, etc........does show cars for SEMA builds Nissan and Honda race cars.

All the after market cats are of lower quality [honeycomb thickness] necessary to flow better thus fail quickly [don't meet emission dyno test after a year or two.....25,000 miles.

They are orginally designed as a cheap fix to get an old car to pass one more year...........some how [marketing] they became known as performance cats for use on off road cars only.

 

i feel the crawford cats are as good as stock (in build assembly and fit-n-finish) .....

they dont have the bundled junk inside them (failing on several RT's i hear) but rather a more oem - like waffle setup.....

my car still smells clean (almost, cept for the initial break-in of them) and has a pleasant exh. note too.....

im with Q-tech about the dyno being suspect.... but two dynos????

perhaps, the tailpipe isnt ideal for readingf a/f, but if other similarly equipped cars (tested in the similar climate) produce LESS leanout, then id begin to worry again.....

i have a upstream bung welded to my crawford, in anticipation of my aem setup next month (or whenever egg gets the triple pod!)

 

Error "171".

Lean Condition, bank 1.

So maybe,
The A/F sensor was damaged?
The intake connections were loosened and there's an air leak after the MAF?



2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5/Crawford Cats/ Service Engine Soon

 

This part is for those with aftermarket sparks....
=======
A spark plug is called a hot plug when the insulator is longer than an OEM spark plug. Hotter plugs operate with a higher insulator temperature. Cold plugs have an insulator that is shorter, and the spark plug insulator operates at a lower insulator temperature.

If the plugs are too cold, they will accumulate deposits, may not fire every time they are supposed to, and can possibly cause the engine to lose power, while getting poor gas mileage.

There should be no sign of any melting/erosion of that outer electrode. If so, you have a case of pre-ignition or detonation.


Reading your sparks
====================
A grayish tan to white coloring indicates the correct heat range spark plug is in use…fuel and ignition systems are in good shape the engine is functioning properly.

Worn, rounded center, or ground electrodes indicate excessive wear and can cause misfires during acceleration, hard starting or reduced fuel economy. They can also cause damage to secondary ignition components e.g., spark plug wires, coils …with continuous use.
When a plug has this type of appearance, it has simply exceeded its useful life.

In cases of light detonation, small black or gray spots will be noticed on the core nose of the spark plug. In cases of severe detonation, insulators may be cracked and/or chipped. The same high pressure waves created during detonation can break spark plugs, damage intake valves and break pistons. Make sure that the correct octane fuel is being used, assure proper operation of emission and computer systems, and assure the correct heat range of spark plug is being used.

Bent and/or broken electrodes and core nose indicate mechanical damage caused by foreign objects in the combustion chamber, improper reach spark plugs, or plugs that were dropped during installation. Never ever keep a dropped plug, even for use as an emergency spare.

Chalky white insulator with little or no coloration, accelerated electrode wear, blistered or pitted electrodes are indications that a plug has overheated. The shell may also be discolored from light gray to a dark blue, almost black. Check for the correct heat range spark plug. Verify that ignition timing and air fuel mixtures are adequate. Engine overheating and restricted exhaust systems can also cause this condition.

Light brown deposits encrusted on the ground and/or center electrodes indicate ash deposits. This situation is caused by oil and/or fuel additives. When the deposits are found on only one side of the spark plug core nose, it is usually considered to be a problem with the cylinder head (valve stem seals or valve guides). When they are found on both sides of the spark plug, it is often considered to be a problem sealing at the piston rings. This condition can mask the spark and, in some cases, contribute to misfire. Check for worn valve guides and valve stem seals and/or piston rings. The spark plug is the correct heat range and was a victim of the engine's condition, not the cause of it.


Info gleened from first hand knowledge and various pages on the web, to make sure I was right in my historical/pre-ECU knowledge.


'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS or Vote at Online Showoff

 

1. Check plugs
2. Get TS ECU reflash ASAP
3. Install WB 02 sensor to monitor your a/f
4. While keeping your car NA get Apexi S-AFC II and tune it


'04 G35/5AT sedan Silver/Black
DYNO: 209.2whp@209.4wtq (bone stock)