Leaning out at high rpm...just bolt-ons...KA

[alkemyst]

98 240sx, 248/232 cams, Injen CAI, header, 3" cat, 80mm exhaust. New deutschwerks injectors, new NGK v powers, new accel 300+ wires, new front and rear O2 sensors, rotor and cap ~15k ago.

I am leaning out at high rpms...talked to JWT and I am going to check fuel pressure tomorrow, anyone know the best way to do this? I have this gauge coming tomorrow: Amazon.com: Actron CP7818 Fuel Pressure Tester Kit: Automotive (http://www.amazon.com/Actron-CP7818-Fuel-Pressure-Tester/dp/B0006V2BI2)

I also picked up a new Wix 300zx fuel filter (mine is about 15k old now, but they didn't have the 300ZX one in stock at the time from a 'better' brand).

JWT says on an NA car it's usually a rich condition causing problems and leaning out with just simple bolt-ons indicates a problem.

My power is way down on the dyno and the car is not running like it should. As far as the engine I am at 175 across all four cylinders.

[72nismo]

I have a JWT tune and I also was running lean when boosting.I just recently upgraded fuel pumps to the wahlbro and noticed that that I am running rich.Hope that helps.

[ROIDMONKEY]

was having that problem last week . It was the Nismo FPR . Went bad . Or if u runing a walbro fuel pump check the clamps . If u have a fuel pressure gauge check the gauge with ignition on . If you loose pressure ( a lot ) when u key off most likely is the fpr. U can double check by tapping the returning line with a plier

[BiG MiKE86]

Get ur FUEL pump wired with Relays - My buddy was at the dyno and the tuner noticed the car leaning out at about 5500 rpms - turns out the Pump wasnt recieving the full 12V - Got it rewired and put down some nice power - Hope this helps - goodluck

[alkemyst]

Get ur FUEL pump wired with Relays - My buddy was at the dyno and the tuner noticed the car leaning out at about 5500 rpms - turns out the Pump wasnt recieving the full 12V - Got it rewired and put down some nice power - Hope this helps - goodluck

I did just have to replace my battery...I didn't think it mattered once the car was started but my stereo I know sounds better.

I did replace the fuel filter and pressure test. I got around 35psi with the vacuum line on. I could not find the FPR...I have a 98 and the picture in the FSM looked like nothing I could find. Where is it exactly?

I am going to drive it in an hour or so once I get done with some work BS here.

[BiG MiKE86]

I did just have to replace my battery...I didn't think it mattered once the car was started but my stereo I know sounds better.
LoL What? My post deals with RE-Wiring the Fuel Pump - Search for the Relay Mod - goodluck

[alkemyst]

being that I had to replace my battery, I may not have been getting 12V at the fuel pump either.

[KA-T_240]

JW: Why do you have bigger injectors on a bolt on NA motor? What are you using to tune for the bigger injectors.

[louisdaboois]

I did just have to replace my battery...I didn't think it mattered once the car was started but my stereo I know sounds better.

I did replace the fuel filter and pressure test. I got around 35psi with the vacuum line on. I could not find the FPR...I have a 98 and the picture in the FSM looked like nothing I could find. Where is it exactly?

I am going to drive it in an hour or so once I get done with some work BS here.

the fpr is bolted on the fuel rail closest to the firewall. also, check your plugs they may be fouled. you could be running rich enough to foul the plugs which in turn doesnt allow complete combustion and the O2 sensor will read lean conditions.

If possible, rewire your fuel pump to a relay. definately helps out alot since it tends to be one of the last things to get a 12v source to the battery.

Just buy a 4 pin relay that are marked (30, 87, 86, and 85). basically heres the wiring:
30- + side of the battery
85- chassis ground
for 86 and 87, you need to cut the fuel pump wire from the ecu in half (black and yellow wire, iirc) and connect:
87- from ecu
86- to fuel pump.

[alkemyst]

JW: Why do you have bigger injectors on a bolt on NA motor? What are you using to tune for the bigger injectors.

They are stock injectors from Deutchwerks.

[alkemyst]

the fpr is bolted on the fuel rail closest to the firewall. also, check your plugs they may be fouled. you could be running rich enough to foul the plugs which in turn doesnt allow complete combustion and the O2 sensor will read lean conditions.

If possible, rewire your fuel pump to a relay. definately helps out alot since it tends to be one of the last things to get a 12v source to the battery.

Just buy a 4 pin relay that are marked (30, 87, 86, and 85). basically heres the wiring:
30- + side of the battery
85- chassis ground
for 86 and 87, you need to cut the fuel pump wire from the ecu in half (black and yellow wire, iirc) and connect:
87- from ecu
86- to fuel pump.

I may look into the relay...the plugs have been looking decent at each pull.

I am sure if I did all high rpm's though they'd show a lean appearance.

I need to drive it some more to see. Last night there were FHP everywhere for some reason so I couldn't open it up.

[steve shadows]

Check your base timing.

Also what Plugs are you currently using what gap?

Check the voltage at the power for the fuel pump under load if possible too.

Voltage may be dropping over line. Common issue for high rpm lean out on nissans'

[alkemyst]

Check your base timing.

Also what Plugs are you currently using what gap?

Check the voltage at the power for the fuel pump under load if possible too.

Voltage may be dropping over line. Common issue for high rpm lean out on nissans'

Timing was checked at 20BTDC, upping it a few degrees made about 10WHP more.

NGK V Powers as noted for a 1998 240SX KA24DE at factory gaps.

I am going to look into the fuel pump voltages...this may be where the problem lies.

[steve shadows]

My next question has to be...what is your idea of leaning out at Higher RPMS?

I would not suggest raising timing from base more to 2 degree more or more than that unless you are using 93 octane btw.

FYI NA Cars make there best power at a 12.5:1 to 13.0:1 AFR.

Turbo Cars typically do so at a 11.5:1 to 12.0:1 AFR ( Sometimes 11.0:1 is better for certain apps).

[alkemyst]

My next question has to be...what is your idea of leaning out at Higher RPMS?

I would not suggest raising timing from base more to 2 degree more or more than that unless you are using 93 octane btw.

FYI NA Cars make there best power at a 12.5:1 to 13.0:1 AFR.

Turbo Cars typically do so at a 11.5:1 to 12.0:1 AFR ( Sometimes 11.0:1 is better for certain apps).

On the dyno my car went beyond 15 and flagged the alarms. Between JapTrix and Jim Wolf Tech, both said something is not 'right'...they usually see rich conditions on these cars with only bolt-ons.

my AFR stays nice until around 5k rpms and then leans out fast.

I only use 93 octane.

It's should be pretty easy to hook up a relay to the fuel pump as I have a distribution block setup in the trunk already with a 1/0 lead feeding it from the battery.

[BiG MiKE86]

my AFR stays nice until around 5k rpms and then leans out fast.
Wire Up the fuel pump Relay - Im willing to be this will solve ur problem.
Like I said in a previous post my buddys car had the SAME EXACT SYMPTOMS - the tuner used 3 relays tho for the wiring and it dyno'd perfect no leaning out

Goodluck

[alkemyst]

How did they use 3 relays?

[BiG MiKE86]

How did they use 3 relays?
I guess they wired em in series? if that makes any sense? Ill try and take a pic tonight of the setup - But that worked miracles for my buddy - the extra relays were said to be a back up should 1 fail

[mondojackal]

ok, maybe i'm just being completely noob-ish here, but wouldn't running the s13 intake cam cause you to lean out some at high rpm? (where the 248 cam would be making the biggest difference over the stock 232 s14 intake cam)

you said "just bolt ons" but the s14 didn't come with a 248 cam stock. it just came with two 232's IIRC.

[alkemyst]

ok, maybe i'm just being completely noob-ish here, but wouldn't running the s13 intake cam cause you to lean out some at high rpm? (where the 248 cam would be making the biggest difference over the stock 232 s14 intake cam)

you said "just bolt ons" but the s14 didn't come with a 248 cam stock. it just came with two 232's IIRC.

cams should not cause a leaning out condition in this case...most tuners have cause the problem usually is too much fuel / running rich vs any kind of leaning (assuming the rest of the systems are fine).

I will do some troubleshooting at the fuel pump next and give the relay a try.