Two Freak Occurences With No Power
 

2013 Nismo

Ok so here we go, about a month after I got the car (July) I started her up and let her warm as usual. Got in her and went off down the road and it had no power at all. Stillen Gen 3s and a catback. It didn't miss, clutch didn't slip, nothing out of the ordinary besides feeling like it had about 200 less horsepower maybe more. Revved all the way through the range to red line even driving just no power at all. Factory tune. Shut her off. When I got to my destination went inside for a while and when I left she was perfect again.

Gas gauge was screwing up as well with an MIL and codes were fuel level sending units. Had both replaced and fixed that and the light. No other codes. Never happened again and I wrote it off as some freaky weird ****.

Well today she does it again. Sounds perfect, revs all the way, however slowly, no MIL and nothing else seems wrong besides the same absolute lack of power... And guys I mean quite literally a 1994 civic base model could have destroyed me taking off. Every gear the same no difference other than the gradual slow down in acceleration due to hearing. Not really noticeable with no power though. So I left off and hit it in 3rd and not even any kick as far as sudden deceleration/acceleration. She still rev matched on downshifts just slowly. It was like a valet mode or something with power cut. So I pulled over shut the car off. Opened the door and closed it. Locked her as if I got out. Unlocked, opened closed, start, takeoff and she's perfect again... What gives anyone ever hear of anything like this???

Thanks in advance and yes I did a search please read all before assuming... No clutch slip, no funny sounds, no MIL, just extremely slow in every gear like someone tuned all the power out of her. Temps on both days by the way we're well above freezing 60's/70's first time in Arkansas second time in Dallas where I am now. Both times she was let to warm up and sit running while I got ready for school or work.

have a look at my sudden power loss thread. i went thru pretty much every troubleshooting procedure that i could do at home. dealer found nothing and it never had any fault codes.

my first guess is the brake switch.

does your power loss occur immediately from when u start the engine or does it appear randomly?

you said you have a stock tune. have you done any software tweaks of any kind? in the end, my random lag issue was due to a buggy throttle map which i loaded with Uprev

When I depress the brakes at all even a hair there is no acceleration at all. No matter the throttle position when I hit the brakes... Loses everything. I was able to hit 80 no problem when this occured it was just extremely slow.

that's how Nissan designed the system. it prevents brake launches in 7AT. on either transmission, the max throttle position is the throttle position at the moment the brake switch was tripped.

So if you are cruising on the motorway at 60mph with say 20 degrees throttle opening, then you decide to step on the brakes gently out of curiosity (enough to bring the brake lights on but not cause significant deceleration) while maintaining constant pressure on the gas pedal, the car should not accelerate any faster if it is level ground. if you depress the gas pedal further, the throttle opening angle should not open beyond 20 degrees.

With that in mind, the same throttle limiting also occurs when accelerating from a stand still. This is what happens in a faulty brake switch scenario where the switch is defective or incorrectly adjusted. In this scenario, the throttle position when the brake switch was tripped = idle throttle position. So that's why when you come to take off, everyone's left you and you're struggling to even get off the line
You probably have noticed that around 3500rpm the limiting seems to relax and the car suddenly breaks free and roars, then u change gear and the limiting happens again... then 3500rpm and roar again. I had no speed limit either. Like yours, mine just took an eternity to reach redline. I actually ran out of road before it reached redline in my neighbourhood testing

Hope that helps

Nope no limiting, take off the line is just fine other than being underpowered severely. Pulling is completely steady from 3000-7600 in 1st through 3rd. Even when floored in 3rd as soon as I touch the brake pedal just enough for lights to come on she falls on her face and decelerates under normal conditions (Car is at full power) it only lasts until I shut off the car, get out, lock it, unlock, get in (simulated by door openings), start up and go. Literally only one drive cycle each time it happened and 5 mobfgs apart. Also both times I had used the trunk unlock buttons to unlock the car to start it as I was putting stuff in the trunk for school.

Going to the dealer to hook up a scan tool and try various ways of unlocking the car and getting in to see if anything triggers it and to watch tps, tpps, maf, and other values. I'll report if I can duplicate it again and see what they say. It literally feels like a low power valet mode being activated. Wonder if it's possible somehow. I'm the first owner it's a 2013 nismo with Bose/reverse camera etc. Never had a valet mode tuned into her though. When it happened before it was stock tune this time it's on the current tune.