Z does not accelerate

Business Kat

Lack of Power - Limp Mode - Shut Offs - SOLVED

Read through the whole thread for details but here's the gist of it.

Car: 2013 370z with stillen supercharger. Installed and tuned in CA. Moved to Texas. Problems started.

Problems: Car hesitated under 3k rpm and then would take off just fine. Random limp modes. Random codes involving throttle body, air flow, etc. Car would sputter at idle. Couldn't find correct idle at idle. Misfires. Stalls. You name it.

Solution: After taking it to a mechanic time and time again to fix whatever problems would happen we finally found the source. Throttle bodies if you catch it too late, otherwise it's the throttle position sensor. When you get Stillens kit they send you an extension cable. This cable is conveniently placed in an area exposed to heat. Here is said sensor:


In my case, so they told me, the sensor would over heat and cause all these problems. Sometimes it would totally shut the car down as a safety mechanism. Also, in my case, we had to replace the throttle body because the little thing the tps plugs into, that's attached to the throttle body, needed to be replaced as it was more or less fried. But they don't make that individual part so we had to replace the whole thing.

Here is the new insulated cable:

As you can see it's much heftier than than before.

Here is the little connector thingy that got fried. Or maybe they upsold me:


And here is another angle of where the cable plugs into the thingy on the throttle body:


And here is a shot of the whole thing because why not:


For my duration with this problem all problems were random and inconclusive. A restart fixed it half the time. One time I waited 2 days and it turn on. Finally had it towed to nissan where the car started right up perfectly fine. Someone with a non supercharged Z please post if this helps because I know you guys have the same problem too and If the remedy is the same then we've found the cure. All in all I'm glad it was solved and I can sell the car knowing the next guy won't have to deal with this nonsense.

Thank you all for your support through this and I hope all you guys with this problem out there get it solved as well.

Ghh0st

What is the part number for the cable, and where can I find the insulated one? Thanks!!

juld0zer

I always thought it was throttle related because i had a bug in my throttle map that would only randomly cause the severe lag where the revs increase extremely slowly. My guess is that the TPS or the throttle body itself would age or gunk up slightly. ECU figures commanded vs actual position isnt right so it goes into limp. After all, these cars emerged around the time of the Toyota floor mat scandal.

The thing that puts me off your overheated TPS theory although you have proof that i don't question is that from factory the throttle bodies are connected to the engine's coolant circuit to warm and stabilise their temperature. Largely to prevent icing but perhaps also to keep them from overheating. In their default location they are subject to coolant temps around 90*c and above, and also convective heat from the headers/cats beneath.

The Stillen kit places the throttle bodies on the hot side of the intercooler. I cant remember if the coolant plumbing is retained? So maybe the coolant really is there to keep them cool?

Personally, i think yours might be an isolated case where something failed and melted the wiring.

It's easy to upgrade this cable - wrap it in exhaust wrap and then some foil tape on top. Alternatively you can buy heat insulation sleeves for ignition leads which will do the job too.

markesc

Just had something similar happen for the first time today:

2014 7AT 41k miles, FI exhaust + K&N drop ins. Cold start, everything seemed fine until about 5 minutes later the car would not go above 4k rpms. Basically no power, a PRIUS would be faster!!! No CEL either.

Now at home with a loaner awaiting the bad news...

So I gather they will try the following:

1) Blame the k/n filters, clean the MAF sensors, coin-toss if it goes away
2) Problem will return, then they will clean the throttle bodies and/or replace.

I have the extended gold warranty or whatever the hell it's called.

Never once had a single problem with the car up until today

P's_Z

Thats best case if the mechanics at the dealer know what theyre doing. Don't let them see your k&n's, that is if they dont blame it on the exhaust as one dealer said to me. They always find an excuse to not honor warranty.

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Zeta

markesc

Well, coulda been much worse.

I'm out $100 for a MAF sensor cleaning and software update. It is what it is, funny the car seems to be much more responsive in the lower rpms. Wasn't going to sit there and argue with 'em, just happy to have it back, but I did let them know that there's multiple mile long threads online about the same issue.

Maybe Nissan has figured it out with this "update" or that was just BS and they just unhooked the neg battery terminal: "that'd be $100" like:

https://www.youtube.com/watch?v=cHUML0EZ1BQ

P's_Z

Good to know you have the car back to normal now. FYI, cleaning the sensor is a breeze, youll have to do it every few miles. As for the TB, cleaning them should also be a maintenance item, every 10k miles for me. Theyre pretty easy to clean but you gotta be careful not to mess em up, as theyre really sensitive. For peace of mind, this is the only reason i take the Z to a dealer.

Good luck!

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Zeta