So, I have had my car to numerous f-con tuners and noone has been able to fix my problem. The car has an irradic idle. Sometimes its good and others it raises to 1800rpms and drops down and then repeats untill it stalls. There is a lean spot at 2250-2500 rpms with alot of bucks. Also after I refill the car with gasoline the cars idle gets worse and dies numerous times until driven for like 10 mins. I am not a tuner but have had my car at numerous shops that are well known but noone has a cure or an idea. Anyone else with these problems?

Thanks,
James

 

Sounds like a MAF problem. Check for any vacuum leak, clean the MAF sensor. Any mods recently?

 

+1

i have a spare maf....

but here s what you do, unplug the mass air flow sensor located in the air intake. do so while the car is running, and if nothing changes as far as idle and rpm. it will be the sensor, if you did any intake mods or re oiled a filter too much this will cause that behavior..

again i do have a spare maf i can sell

 

Do you try a ECU reset and these other reset ?
May be can help !

* Accelerator Pedal Release Position Learning Procedure.

1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.


* Throttle Valve Closed Position Learning

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch is “ON”.
3. Turn ignition switch is “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.


* Idle Air Volume Learning (Throttle Position Learning)

It's best to time with a watch/clock.
1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Conform that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.
Read more at https://my350z.com/forum/maintenance...arating-2.html

 

Could be fuel system resonances causing your lean condition...check this (it's long)

https://my350z.com/forum/tuning/4848...-what-the.html

 

-I thought it might be the maf so I removed my brothers maf off his 350z and placed it on mine but still no progress.

-I have reset the ECU and no change in status.

 

-Has anyone found an easy fuel resonance fix for the AAM return system?

-Its wierd when the car idles perfect the air fuel ratio on the wideband is lean and above 16:1 but when the idle goes crazy it surges from 10-15:1 and dies out.

- I did not have this problem when the motor was stock with twin turbos but once it was built the idle has never been right.

 

Lean spot at 2250-2500 rpm huh? That sounds familiar.

The AAM fuel return replaces the factory fuel rails correct? If that's the case then my adapter won't work for you.

The idle issues you describe sound like something totally different. Did you do the idle air relearn procedure correctly? It's more than just and ECU reset.

 

It's the damn MAF. Tune off MAP. I never hear about these problems and other when such a change of tuning is made.

Just a guess...

 

Is the Fcon setup to use MAF or MAP as a load source?

 

It is setup using the map. So I do not believe that it is the maf sensor, unless the idle is controlled by the ecu and maf.

 

The 'basic' system retains the stock rails, but all their kits delete the stock dampeners. I don't have any lean conditions but the buzz from the regulator through the firewall is annoying.

 

Yeah this pretty much eliminates the MAF as a cause. The only reason it is still there is probably because the Fcon is using it for an air temp sensor.

Do you have the AAM basic fuel return? If so, you might be interested in the return+damper adapter that I have created...

 

MX594- I am not sure if it is the basic system but it consists of fuel rails, fpr, and return line. Please send me information on the return system damper. If it helps in anyway I am really interested in purchasing it.

 

Could be any number of things, including bad tuning, incorrect installation of the fuel system, bad FPR, FPR base pressure set incorrectly...

 

Unfortunately the adapter I created only works with the stock fuel rails. But there is a very good chance that the lean spot at 2250-2500 rpm is a fuel resonance issue. If you are wondering why I think this, you will find more information than you care to know in the this thread (already posted here by djamps):

https://my350z.com/forum/tuning/4848...-what-the.html