Nissan 370Z Forum - Car won't rev past 2.5k, idles above 1k.

Nissan 370Z Forum (http://www.the370z.com/)

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- - Car won't rev past 2.5k, idles above 1k. (http://www.the370z.com/forced-induction/134628-car-wont-rev-past-2-5k-idles-above-1k.html)

So the tech just drove the car again. So far so good. He's gonna drive it a few more times after he cleans the MAFs and TBs. Should be good to go. This is my build list if anyone is interested....

2010 manual G coupe

CP Custom Forged Pistons with WPC Treatment
Carrillo Pro H-Beam Forged Connecting Rods with Upgraded Bolts and WPC Treatment
Walboro 520 fuel pump
CJM S1.SE Fuel System
ID 1300X CC Injectors
NGK Sparkplugs
Stillen Supercharger kit with Topgunz Air-to-Air Intercooler Setup and TIAL
Motordyne Longtube Headers
Motordyne Catback Exhaust
Setrab 34-row oil cooler
OS Giken Superlock Limited Slip Differential with GReddy Diff Cover and Whiteline Bushing
OS Giken TR Series Clutch
ZSpeed CSC Slave Cylinder Upgrade
EPS Oil Gallery Gaskets
EcuTek with Speed Density Tuning by Specialty-Z

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Bad news guys. Its still happening. Not sure what the deal is. Shop cant figure it out either.

Quote:

Originally Posted by WillVHR (Post 3957529)

So I replaced the extension harness with a brand new one yesterday. So far so good. No issues at all. Drove the car for 10 minutes. Shop is going to drive the car for the next few days to make sure everything is good to go. Will post update if anything happens.

Expect a P1239 when you least expect it if you're using a TB ext harness. This has been my experience.

Quote:

Originally Posted by Optimiser (Post 3957660)

Expect a P1239 when you least expect it if you're using a TB ext harness. This has been my experience.

Just a guess here but the extension may change the wiring enough that it is acting like an antenna and picking up noise from the other electrical systems. I'd try shielding the harness* - but that may be more work than it's worth.

*Edit: As much of the TB wiring as you can, not just the extension.

Still happening. Shops can't figure out what it is. May have to take it to the tuner (Specialty-Z) to have him figure it out.

Quote:

Originally Posted by WillVHR (Post 3958326)

Still happening. Shops can't figure out what it is. May have to take it to the tuner (Specialty-Z) to have him figure it out.

And mine threw another P1239 again, the day before yesterday! :mad:

Quote:

Originally Posted by SouthArk370Z (Post 3957794)

I think people have done this and it still isn't 100% reliable.

Replaced the TBs. Still having the problem. Gonna have to take it to Specialty-Z to figure out what it is.

Quote:

Originally Posted by WillVHR (Post 3959592)

Replaced the TBs. Still having the problem. Gonna have to take it to Specialty-Z to figure out what it is.

Replacing the TB's has never fixed this problem form what I've found out.

My car is completely stock, and i've experienced a similar issue. car runs perfectly fine 99% of the time. at random the idle will jump to 1k rpms, it will accelerate (past 2.5k rpms) but feels like it has 10% of its normal power. After a restart it will typically be fine. I have brand new MAF's, and new MAF harnesses with perfect continuity to the ecu. No CEL's ever, and doing datalogs i can't see where any readings change to the point that it would cause an issue. I suspect the MAP sensor in the IM may be going bad, but im not sure if the ECU references MAP or MAF until closed loop... I'm interested to see what you find

Things that I replaced:

The ECU
The TB Harness Extension
The TBs

None of the above has fixed the problem. We will see what Specialty-Z says.

It s clear a lot of people don't understand how to troubleshoot complex problems. A diagnostic tool in live mode should reveal plenty information to aid solving this problem.