Car vs. Driver

iTrader: (14)

Ok, here's my setup ...

2004.5 350Z, Vortech 2.87, UTEC, DW600's, F:T Fuel Return, Walbro 255, 14lb UR flywheel and a bunch of other misc stuff.

So, my question is about stalling issues. When I slow down for a light, I heel toe normally to down shift, it's just how I drive. However, when I come to a complete stop or get lazy with down shifting and just put my foot on the clutch or go into neutral, the revs drop and about half the time the car will stall. Then I have to deal with the UTEC hot start problem in traffic or at a light.

Any ideas on what could be causing the stall? Do I need to bump up my idle, and if so, how do I do that on a 2004.5? I'm thinking it has to do with the light flywheel and additional rotational load on the car because of the supercharger and an idle bump would fix it.

I have no other problems with the car aside from that, it runs great and pulls like a champ through the gears. It also drives perfectly smooth out of boost as well.

Thx!

UMW350Z

iTrader: (18)

I have this problem after I leave the battery disconnected. It seems to re-learn what to do though, never had this issue before disconnecting. You may need to relearn your idle air volume and I JUST threw away my tech bulletin on this. It could also need to relearn throttle position. I would try there procedures and see what you come up with. The salt finally washed away and I am taking my car out tonight, I will let you know how it comes out.

You can bump your idle with a Consult...your dealer or Dave should be able to do this. Try setting it around 750-850 rpms at idle. Mine was set at 1100, but I dropped it to around 700ish without issue, but I might jump it up another 100 rpms next check-up with my Nissan engineer up here.

Car vs. Driver

iTrader: (14)

Thx, my battery did die from sitting in the garage for two months and I replaced it. The stalling started after a 120 or so mile trip last weekend. I parked it after that and haven't driven it since

I have the FSM, so I'll read up on how to reset everything and see how that goes. Dave did mention that he couldn't bump my idle since it was a 2004.5, I didn't think much of it then .. anyone know why that would be?

frankie945

iTrader: (35)

I'm in the same boat with that problem. Damn JWT flywheel....I'm going to change flywheel's when I pull the motor. And it is loud as hell too. And would like to up my idle as well.

Chef-J

iTrader: (58)

Didn't many members have an issue with utec with big injectors?

iStan

iTrader: (29)

I had my mechanic at Nissan bump my idle. Consult can do it up to a certain rpm, but I think mine is now around 800-900 at idle.

UMW350Z

iTrader: (18)

Mine relearned tonight, the battery was dead and unhooked for a couple weeks. Try unhooking and letting it reset then relearn

str8dum1

iTrader: (11)

why would you think that a relearn would affect stalling?

i've never had that problem and my battery goes dead/ unhooked all the time.

Thats the same problem that people had with teh 1st batch of injen CAI. something to do with a MAF issue or something. have to search for it.

UMW350Z

iTrader: (18)

Not quite sure...I am running a UTEC with 600cc injectors. Maybe idling isn't the right term here since it will idle fine until i rev up then let off, the rpms dip too low, like the injectors didn't know when to turn back on. It only happens after a long battery disconnect so i'm not concerned. It will stumble every now and then as the revs drop to idle, but not low enough to threaten engine shut-off.

I'd log it with my Nissan engineer pal, but I don't THINK I have the same 'issue' as these other guys...mine goes away and stays away.

neosoul

Sweet - thanks to FI'ED G for finding this thread for me. I'm having the exact same problem :/

I thought it was impossible to correct with larger injectors.

UMW350Z - do you have a fuel return system installed? I almost bought one just to correct this issue since TurboXS claims you can not without it.

thom000001

can you adjust the decel tune with the utec or are you relying on the stock ECU for that part?

UMW350Z

iTrader: (18)

No fuel return system here. Not sure if I need one actually

frankie945

iTrader: (35)

If you are using a Utec you are going to have hot start problems if your injectors are larger than 440.

With a Aftermarket Flywheel, Depends on weight of it. You will have stalling issues especially when coming off boost. Unless you up the idle.

Bumping the idle up would also help with city driving, like stop light to stop light, and Bumper to Bumper traffic.

athenG

iTrader: (2)

I have a light FW and my car do stumble when it dip below 700rpm. For some reason my car always idle between 750-900rpm (even after doing all 3 relearn procedure) with my ST and I never bumped my idle.I only have a 440cc injector so it is really not that big so I'm not sure if it is the injector.. I have no complain coz at idle above 750rpm my car is stable..

thom000001

not trying to bash UTEC at all, it does what it does at a good price.

But this shows the true advantage of a full EMS.

tom

Car vs. Driver

iTrader: (14)

so, how do I bump the idle then?

Sharif@Forged

iTrader: (92)

I bet an idle air learn, and TB learn will fix it. This happenes often, when we do a big project, after battery/engine has been out of car. Idle air learn/TB learn usually takes this away. Your local dealer can do this for you...maybe have them also bump on the idle a little, if possible...depends on your ECU.

Car vs. Driver

iTrader: (14)

Thanks Sharif! How do I know if my ECU can accept a idle increase?

If it doesn't, then what do I need to do .. ?

Car vs. Driver

iTrader: (14)

So I just read through the FSM ... here's how to do it without a CONSULT-II.

Accelerator Pedal Released Position Learning
DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time
harness connector of accelerator pedal position sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.


1. Perform EC-42, "Accelerator Pedal Released Position Learning" .
2. Perform EC-42, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications.
13. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried out successfully.

This is all found on pages EC-42 & EC-44 of the FSM.

I'm going to try this in a bit and see how it goes. Still doesn't adjust my idle, but it's worth a shot to at least get everything reset.

neosoul

I read somewhere that this problem is more apparent due to a lightened flywheel (which I have) and vacuum loss due to all the gauges we have.

I currently have mines (boost, UTEC map sensor, bov) running off the service port on the plenum.

Shariff - what do you guys 'T' off for those items? I saw from another forum that some folks 'T' off the larger port from the bottom plenum.

Is anyone using that strategy ? Should we just invest in a TB spacer from AAM with 3 additional vacuum ports?

http://www.alteredatmosphere.com/mm5...de=350Z_INTAKE

EDIT: I just bought it, so i'll let you guys know how it works out.