Car won't rev past 2.5k, idles above 1k.

WillVHR · 09-02-2020, 02:38 PM

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

WillVHR · 09-02-2020, 08:00 PM

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

Optimiser · 09-03-2020, 01:15 AM

Quote:

Originally Posted by WillVHR

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.

SouthArk370Z · 09-03-2020, 11:35 PM

Quote:

Originally Posted by Optimiser

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.

WillVHR · 09-08-2020, 10:16 AM

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.

Optimiser · 09-09-2020, 01:47 AM

Quote:

Originally Posted by WillVHR

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!

Optimiser · 09-09-2020, 02:01 AM

Quote:

Originally Posted by SouthArk370Z

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.

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

WillVHR · 09-15-2020, 02:04 PM

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

Optimiser · 09-16-2020, 01:13 AM

Quote:

Originally Posted by WillVHR

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.

Chaluska · 09-16-2020, 09:56 AM

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

WillVHR · 09-16-2020, 01:03 PM

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.

MrJdmNismo · 11-04-2020, 03:44 PM

Any update?

HOODEY · 11-13-2020, 08:12 AM

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.

09-02-2020, 02:38 PM	#16 (permalink)
WillVHR Base Member Join Date: Feb 2012 Location: Irvine, CA Posts: 169 Drives: 2009 G37S 6-MT Rep Power: 13	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 Rusty and ZoomZ like this.

11-04-2020, 03:44 PM	#27 (permalink)
MrJdmNismo Base Member Join Date: Jan 2011 Location: Kissimmee/Orlando Posts: 115 Drives: 2011 NISMO 370z Rep Power: 3369	Any update? __________________ YouTube=MrJdm350z 2011 #0093 NISMO 370z:OWN 2007 350z:SOLD

11-13-2020, 08:12 AM	#28 (permalink)
HOODEY Base Member Join Date: Aug 2013 Location: Barbados Posts: 41 Drives: Uk spec 08 350z gt Rep Power: 12	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. Last edited by HOODEY; 11-13-2020 at 08:17 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
I've posted in the past but...	James512	New Forum Member	7	02-21-2020 02:50 AM
Help! Car Idles Rough, Won't Accelerate, Service Engine Soon Light Flashes, Code P300	NeoNz	Engine & Drivetrain	20	12-17-2015 07:02 PM
Can't go past 2500 RPM! Help!	Corona370z	Nissan 370Z Warranty / Scheduled Maintenance / Servicing / Repairs	25	06-11-2014 11:45 PM
post your past z's.	dirTy_shoeZ	Other Vehicles	18	04-29-2011 12:53 PM
Got my Z this past Saturday	gleonard	New 370Z Owner	8	07-23-2009 12:28 AM

09-02-2020, 08:00 PM	#17 (permalink)
WillVHR Base Member Join Date: Feb 2012 Location: Irvine, CA Posts: 169 Drives: 2009 G37S 6-MT Rep Power: 13	Bad news guys. Its still happening. Not sure what the deal is. Shop cant figure it out either.

09-08-2020, 10:16 AM	#20 (permalink)
WillVHR Base Member Join Date: Feb 2012 Location: Irvine, CA Posts: 169 Drives: 2009 G37S 6-MT Rep Power: 13	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.

09-15-2020, 02:04 PM	#23 (permalink)
WillVHR Base Member Join Date: Feb 2012 Location: Irvine, CA Posts: 169 Drives: 2009 G37S 6-MT Rep Power: 13	Replaced the TBs. Still having the problem. Gonna have to take it to Specialty-Z to figure out what it is.

09-16-2020, 09:56 AM	#25 (permalink)
Chaluska Base Member Join Date: Jul 2020 Location: Houston Posts: 1 Drives: 2013 370z 6MT Rep Power: 5	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

09-16-2020, 01:03 PM	#26 (permalink)
WillVHR Base Member Join Date: Feb 2012 Location: Irvine, CA Posts: 169 Drives: 2009 G37S 6-MT Rep Power: 13	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.