djamps

iTrader: (1)

Seems like a transmission issue to me, especially since your tq converter never locks up... if the ECU were in limp mode you'd have a CEL and associated christmas tree (slip/vdc/ect). My guess is a bad tq converter.

amr_electron

iTrader: (8)

Will a bad torque converter prohibit the engine from revving while driving?, You can see in the video that the RPM is almost not moving while accelerating by the pedal.

The TCM uses various signals to control the shift points & lock-up, APPS, Fluid temp sensor, veichle speed sensor, stop lamp switch and others .... But, shouldn't the MIL light up or the AT Check blink in such a case?, The AT Check still comes for 2 seconds when the key is ON ( as the FSM states ) which means no errors were detected.

One VQ mechanic checked the car yesterday, He thinks that it's the transmission that need to be checked. He said the car idles fine & revs OK in neutral Plus no codes.

One thing that i noticed lately,,, While driving & accelerating by the pedal, I can feel the engine stressing to keep its speed, Once i switch to accelerate using the cruise control the engine sound is totally different ( sounds normal ), No hmmmmming noise & i can feel the power at the moment .

Zazz93

iTrader: (2)

The ECU is telling the engine not to rev further. With Nissan, they include a ton of safety features in the programming to prolong the engine's life (with problems) and alert you to problems. The hard part in this case will be going through the Service Manual and deciphering the clues.

amr_electron

iTrader: (8)

When i press the gas pedal, You can hear the engine trying to rev, But for some reason it's not able to, It's exactly as if it's starving for gas or air.

I'm starting to think that the link between the pedal & the throttle body is causing the problem & this is why i can accelerate with cruise control switch, But again i'm asking myself why it's working from a dead stop & at idle ?

winchman

Have you made any progress on getting this resolved?

terrasmak

iTrader: (8)

I think i would have installed a stand alone by now.

amr_electron

iTrader: (8)

Talked to NISSAN regional office & showed them all the invoices. They offered a repair with no labour charge & a parts discount ( if needed ), But they will not refund any money. My car will be in next Thursday.

I will let you know how it goes.

amr_electron

iTrader: (8)

You think a stand alone ECU will fix this ?

winchman

So, got any info on what was causing the problems yet?

bbs350z

iTrader: (85)

if its the pedal assembly i got the oem throttle sensor i can send you for free and have no use for

amr_electron

iTrader: (8)

Man, I'm so fraustrated.

It has been one week & Still the dealer can't figure it out, I talked to one senior nissan tech & he said that a consult III test showed that non of the sensors are failing.

A compression test was also done, A full fuel system diagnose. He was thinking about opening the transmission, But he eliminated the idea since it pulls hard with the cruise switch.

When accelerating by the pedal, The engine will rev higher than normal to stay at constant speed, Once switching to the cruise control, The RPM will drop down & the engine sound will be normal ( No humming sound ).

He's running out of idea but he's excited to know what is the problem.

amr_electron

iTrader: (8)

Thanks man, I already swapped the pedal assembly with no luck, Appreciated.

winchman

Bummer. I was hoping it would be fixed by now. I hope they figure it out soon. Please keep us posted. I have a feeling it's going to be a real face-palmer.

SniperHunter

iTrader: (9)

You know what...I just rewatched the video and it struck me, my girlfriend and my cousin had the same issues with their cars. One an Audi and the other a Mazda.

Both turned out to be timing chain related. My cousin's Mazda CX7 needed a new tensioner. My girlfriend's Audi A4 needed a new timing chain actuator. I'm pretty sure both are actually the same thing, or close to it. In any case, have them take apart the chain cover and look at that. If Nissan is going to foot the bill, replace the entire assembly.

I have a very good feeling this is the issue.

Edit: And btw, neither car threw any codes.

winchman

Wow. Seems like a problem with the chain tension bad enough to cause the OP's problems would make serious noise on startup. And, it's still a mystery why bringing the car to a complete stop resets the ECM for one acceleration cycle.

I'm still thinking it's something to do with wheel and/or transmission speed sensors, transmission control, or the associated wiring.

SniperHunter

iTrader: (9)

Timing issues won't always make the same noise - a tension issue will make a loud ticking for example, but other things won't. I think something isn't jiving with the timing and causing the throttle to go cold.

winchman

I see your point, but it's going to be a hard sell to get the repair guy to go that far into the engine without more evidence. That's a lot of work for a "maybe this is it".

amr_electron

iTrader: (8)

I talked to the technician trying to give him a heads up about the timing chain, But he didn't accept the idea since there's no noise, He also believes that it's not a mechanical failure !!!

SniperHunter

iTrader: (9)

I'm not saying it's the timing chain, but it is related to it for sure. There's more to it than just the chain. If there's no noise, then the chain and tension are fine. One recommendation was to remove the cover on the assembly to inspect for anything visually off. But there are a variety of other factors that are involved in driving the timing correctly, many of which will not make any noise when they've gone faulty - also because a lot of them are electronically activated. Having said that, the more I think about this issue, I believe cam components would be the ideal place to have looked at.

Have you had your cam shaft inspected, for example? If the solenoids don't actuate the valves, you will get no response from the engine, as the timing chain and cam shaft are directly linked. I found the warranty work order from my girlfriend's A4. It said that a cam shaft replacement fixes the loss in power (exactly the same demonstrated in OP's car), and that an actuator in timing assembly was replaced to fix the noise. Initially, the cam follower needed to be replaced, but the worn follower ended up slightly damaging the cam shaft, in which case it was all replaced.

Basically, it seems like the timing is all sorts of screwed up on the car. So my recommendation, again, is to look at timing components. The cam shaft would probably be a good first start. It could be something as simple and cheap as a follower, or worst case the entire cam assembly.

Btw, where do you live? If you're near the New York area, we have a shop that will be able to help. I can show them your video too.

winchman

So, how do you explain the fact that the engine runs well immediately after the car is brought to a stop, but only until the first time the throttle is released. Also, why would the engine run well when the cruise control buttons are used to accelerate the car.

If it's something with the engine, I don't think it would magically cure itself like that, and then go bad when you use the throttle pedal after it's been released one time.