well the PCV valve didnt work either...

 

Hey. My car came down with the same issue yesterday. I was how ever happy to find this thread it saves me alot of guess work to start with all the people i spoke to said about the same thing as you have found but to no reward i will keep looking into it if you do find the fault please just post it here i will check. I will do the same... good luck and thanks

 

bumpp =(... still no luck... I got uprev so we will see what happens when I flash the ECU... oh and BTW my cruise control doesnt work either .. wtf... ughhhhhhhhh

 

Use Cipher and log APP, TPS, MAF while the problem occurs. Also check for CEL codes stored in the ECM. Did you go through the TB and APP relearning before starting the car after an ECU reset (just turning key to on position but without cranking and go back to off and repeat several times, as I recall)?

I know you replaced the TB, but perhaps something is messed up in the TB harness - bent pin? Really sounds like TB or APP sensor.

 

Thanks for the reply!

Post office was closed but Ill log it in tomorrow. Yeah I have tired all the relearning procedures ='( but nothing..

Can I buy the Throttle body harness separately? what is the APP sensor?

happy new years guys!

 

Solution: Yes I solved this.

Have you checked your brake lights...and their fuses?

Have you changed the taillight bulbs at any time....to aftermarket LEDs?

Have you altered your brake pedal switch wiring?

You see, the ECU takes brake pedal signal readings through the tailight circuit. If that circuit is open, or shows very low current draw, you simply will not be able to rev past 3000 RPM while driving - and there won't be any indication as to what the problem is.

Someone needs to post this up on a FAQ someplace.

Let us know if this works out for you.

 

wait wait... U just lost me by a mile..

Break lights? what does that have to do with it?... hmm.. Break lights work fine..

- Yes I have changed the taillights to aftermarket LEDs..

Its not that I CANT rev past 3.. I can rev fine and red line it if I want to.. Just when I go WOT.. it falls on its face.. ( RPMs still climb past 3K ) Just doesnt go anywhere..

 

I agree with rcdash; log the accel pedal pos sensor and throttle pos sensors to make certain the ecu isn't cutting throttle.

 

Cool , will do that!.. when you say logging the accel pedal and throttle pedal.. do you mean just like a regular log? Iam log retarded lol.. I will contact Hal and see what he says when I flash the ECU tomorrow.

 

Interesting about the brake light LEDs (is it hard to swap back to test?). There might be something to that, but I'd have to study the FSM. There is brake/stop lamp signal that the ECU receives via pin 101 and if a signal is not intermittently received it can cause odd throttle issues (but it should throw a CEL also)... Brake boosting can be accomplished by disabling that signal so lots of folks have played with it and KPierson prototyped a module but it wouldn't work reliably on all cars - caused intermittent throttle issues.

 

Yeah, just a regular log while doing a WOT run.

 

gotcha! ^

out of curiosity can I buy the accel sensor harness separately? I saw somewhere that some guy did buy it separately so.. just wondering..

 

After re-reading the thread, I don't think your pedal pos sensor is the problem, seeing as how you are able to free rev to redline.

 

Yeah I mean swapping back the stock tails is no prob for me.. Im just waiting to head back from nismoZ123.. and see what he says... Ive never messed around with the break boost so..

 

.. I mean its not like " limp mode " when the rpm just cant go past that.. It revs fine.. it drives around city fine.. but when i give it more than half way throttle it just doesnt pick up.. or WOT.. just falls straight on its face..

... BUT, sometimes it picks up.. like it would rev and push me into my seat until like 5K and then goes out again.. you know.. Im starting to think its an electrical glitch.. definitely NOT vaccume leak.. it like hesitates.. it " tries " to rev but it cant, in a way.. sometimes you can go WOT and it just doesnt do anything .. sometimes it picks up for a sec , and then down again..

Hopefully that explains it better

 

Ok so I finally got a chance to flash the ECU with uprev today. I took it for a ride after the flash procedure.... same ****ing problem!!!...

I have to give it a try today and get a log so I can show it to you guys... anything I should look for ?? with the uprev I can " monitor all of ECUs perimeters " is there anything I should keep an eye on.. voltage? anything??

This is making me sick to my stomach..

 

Oh okay, I understand a little better now.

So in that case, log the TPS and APP at WOT (a lot of acronyms there) and make sure that their voltage stays consistent throughout the run. If one drops off, that's your problem.

After reading your above reply, I'd almost be willing to bet that the problem is related to your pedal pos sensor.

 

Alright cool. I will try that first thing in the morning. Are you familiar with OSIRIS?.. anyway.. when I do the logg.. im only supposed to be checking the box and logging the TPS and APP?.. and what gear do you think is best to do it? ( I used to do logs on my UTEC and usually it was 3rd gear at around 40- redline ) same or should I logg it differently ?

Thanks for the help man, I really appreciate it.. Im going to take a look at the pedal pos sensor.. im going to stop by nissan and see if they have a part for it...

 

ok so I changed the pedal pos sensor.. still nothing =( =(

 

Did you do any logging?