Hello guys i have a 2003 350z MT, i changed the water pump and 2 camshaft sensors. We did the throttle learning etc and the car behaved fine for around 3 days or so. Now the car overrevs solo between gears i just need to press the clutch and revs goes Up (300rpm or more).

It seems that my car deleted the learning, but we've done it more than 20 times after that and the problem keeps going. If someone could tell me what could it be because i've changed so many things with this 2003 model that i'm pissed

Help me out so i can really enjoy this car

 

we've connected OBD scanners and no codes :S

 

Goes up 300 RPM's from what? I'm not getting this. Say you are at 4000 RPM's when you go to shift - you take your foot off the gas while pressing in the clutch and the revs go to what?

 

let's say i'll shift at 4k RPM, i press the clutch (releasing gas pedal no powershifting) and the revs goes to 4300 or 4400.

 

sounds like you need to take your foot off the gas.

 

That's exactly where I was headed......

 

What happens if you let up on the gas pedal without putting the clutch in?

What happens when you rev the engine with the transmission in neutral, and let up on the gas pedal?

 

maybe the floor mat is getting stuck under the pedal?? any way to take a quick video of the problem??

 

i did this when i first started driving my Z. i learned you gotta take your foot off the gas a little sooner then my previous cars as it takes a second for the rpms to drop.

 

But why would it "behave fine" for several days, and then start acting weird? He's probably had the car long enough to know about the lag on the throttle action.

I'm thinking it's something amiss with the throttle pedal assembly or throttle body, and it's just a coincidence that it started happening when it did.

A sticky throttle pedal wouldn't cause a code because it would look just like the driver was a doofus not letting up on the pedal when he should.

 

i don't think i'm the problem, because i can even stop pressing the gas pedal and try to shift and the revs will go up. Even from a dead start i can roll the car and pass the gears and they will go up, just like when you drive without the learning, but i've done it tons of times and even authorized dealers and i still have the same issue. I'll check the floor mat but i don't think that's the problem.

what about resetting ecu again or something like that? it's very weird.

 

I don't think you're the problem.

Can you answer the questions I asked in post #7? I think that might help us understand the symptoms better.

 

Look for an air leak somewhere in the inlet system. It may be that the engine is changing position slightly and opening up a gap in a cracked hose, fitting, plenum, etc. It would be somewhere after the AFM.

 

i did have a problem with my T.body the butter fly would get stuck in the open position due to the computer/sensor (if thats what its called) on the side. it would take a while to close so my car would die sometimes. so the stealer ship replaced it under warranty.

 

this is for you winchman:

1- if i let it roll the car maintain RPMs for a few seconds then they'll tend to fall like they should. But as soon as i hit the brakes and clutch rpms goes up.

2- If i rev up my car it goes up like it should and when it comes down makes a little stop at like 700rpm then it drops.

i'm very confused, imagine your car without the idle air volume learning, feels the exact same way but we've done the learning several times after cleaning TB, plenum and other stuffs months ago and it took it like a champ.

 

edited

 

in addition to the idle learning, did you do the open throttle and the other learning procedures?

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.

Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning
Operation 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
Operation Procedures

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “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 is better to count the time accurately with a 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. Confirm that the accelerator pedal is fully released, then 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

 

didn't know i have to do them all just because i changed two sensors. My idle is fine as it should be but i'm going to disconnect the throttle and do them all again

 

First time I had my manifold off I did all the relearn and the damn thing kept idling high and acting weird enough I was sure the manifold was leaking. I kept trying the relearns until I read one thread where they just left the battery disconnected for a while and everything was fine after. Tried that and back to normal; I've had the manifold off I think three times after that and never bother with the relearns now.