Unsolvable Issue Please Help

Maui2Thicc · 11-20-2019, 01:03 AM

Hi to everyone reading and thank you for your time.
I made the transition from a 2017 86 to a z34 for almost a year now.
A 2009 Base to be specific.

Info on the car:
Automatic Originally
Drives fine atm
93k on odometer
Last work done on car was Bank 2 Sensor 1 replacement
Service Engine Light On (P0850)

YES, you read that right. Originally automatic. I am the 4th owner and one of them did a auto to manual transmission swap. Something to remember for later in the post.

Where it begins..
So im driving and suddenly throttle cuts off. Rpms are limited to about 2.5k.
Car did not shut off! I then rolled into a parking lot, turned her off and on, no throttle response. Get her towed to the shop they say it was caused by one of the Variable Timing Solenoids failing. Cool, get it replaced and everything is fine....for a month and a half or so. Then same thing happens, take her back to the shop. This time it was the second VT Solenoid. Cool, get it replaced and alls good. Right? Nope.
A few months later same thing happens This time they cant figure it out. No thrown code. They traced the problem to a relay and replaced it. That same day it happens again at night.
Im stumped, the shop is stumped and i refuse to go to nissan due to pricing and experience with dealer mechs.
Then a code pops up. A P0850. I buy the Park Postion switch and when they are about to install it... There is no connector. Upon further inspection, they come to find out that the car was manual swapped. Im shook because I never expected that. So I call Nissan give them my VIN and BAM. Automatic comes up for transmission. So I go to another shop for a second opinion and they say the same thing. Also they say it was done correctly.
But why am I bringing all this up about the transmission? If it was done correctly.
Except the wiring and ecu.
They kept the stock ecu, which makes it an automatic base ecu. Which is also why the car is throwing the P0850. Some other red flags are that the reverse lights dont turn on when in reverse gear.

Now How does this tie into my limp mode/throttle loss problem?
So When it happened again i decided to completely disconnect the battery (positive and negative terminals) to reset the ecu.
I then did all the relearn procedures for Throttle and pedal.
BAM, Shes back to normal and driving.
So now reseting the ecu is my only fix but it started happening every FEW miles. So i let her sit for 2 weeks straight. I started driving her since last friday, 15th of November. There are no issues so far and she has been driving fine even under light stress. Now im shot and am focusing on the ecu as the main culprit. Friday i will be ordering a same model year ecu from a base manual and will be trying my luck. I believe some wiring still needs to be done. But I want ANY feedback and questions. Please.

MY Questions are:
-If the code suddenly popped up and the sensor was never connected to anything then shouldnt the code have been present even during the test drive and purchase of the car? as well as through out the whole time of ownership?
-Did the ecu have to be tampered with in order for the car to even accept the manual tranni?
-If ecu was tampered with could the ecu have just gone bad over time since it was first swapped?
-Is it even the ecu?

Current issues with car other than the ecu problem are that the ac compressor needs to be swapped, the power steering pump and sensor as well. I will be ordering those soon as after the ecu.

Sorry for the long read and thank you again for your time.

JARblue · 11-20-2019, 07:33 AM

Maybe these one of guys can help?

Click the little blue arrow next to their user name and it will link you to the thread

( Click to show/hide )

Quote:

Originally Posted by andy_meng1024

There are almost 10 370Z/G37s that have converted from 7AT to 6MT including mine here in Taiwan. I have been driving it for almost 3yr without problem.

To answer your question, you can either swap to 6MT ECU or use your original ECU to re-flash it to the version you want.

Quote:

Originally Posted by Megan370z

What is your big reason to do the swap ?
you mentioned there that you were thinking about tracking the car.

But how much tracking will you do ?
next
what type of tracking ? could be road race / time attack / lapping days / HPDE / autocross.

so if you DO NOT intent to participate in any road race or hardcore time attack meaning pushing the tranny & car to 110% !!! and concerned about the fraction of second you needs over other peoples.
I strongly suggest you to keep the 7AT.

If you only intent to do lapping days / HPDE / autocross.
I strongly suggest you to keep the 7AT.

Why did I swap the 6MT??? It is mostly because I blew one of my VVEL head.
the next plan was to swap the HR head on the VHR block which would need the HR ECU.
I already had an engine/tranny spare hiding in the garage of my cousin from my 350z times.

so doing the swap from nothing will cost you an arm !
then its up to how much you are willing to keep everything OEM looking
For my case I don't really care about all those red light that pop up on the dask cluster. (ABS/VDC/Airbag/Key/engine codes........

On the 350z side, one of the guy kept his Auto ECU and it was working fine.
IMO, I would stick with an ECU which is setup for the 6MT.

the bare minimum is

Clutch Pedal assembly
Clutch Master Cylinder
Clutch Master Cylinder Oil Reservoir
Cutch hose up to the Clutch Slave cylinder
*option* HD CSC (lookup Z1 one...)
Flywheel/clutch ( I took the JWT combo ) *They have 2 version of clutch* (organic only & organic/metallic )
Flywheel BOLTS !!!
Clutch/pressure plate BOLTS !!!
6MT
Will it come with the shifter assembly ? if not , you need this too !

once this is installed, you might want to get the gasket/plate/boots assembly that bolt on directly on the frame/floor
Part # 74963 , 75960N , 74940

then I will let you find the platic interior trim that you might want for OEM looks.

The OEM 7AT cluster (RPM/Speedo) will work just fine with the 6MT. you will not have the same functionnaly as what the true 6MT 370z has..
At that point again its up to you to find that part...

Don't think about the Rev-Matching option .. at this point you are better selling the car as is and get the 6MT !

once everything has been installed. you will need a little wiring job.At this point then its up to you to look into the FSM to find what needs to be done.
I cant really help you on this because Im using the HR ECU.

But you will need to find out how to wire up the Neutral Position Switch and the Back-Up Lamp Switch to your ECU/BCM.
Without those 2 sensor switch on the 6MT , you will not be able to start the car or/and get the back up light to lid!
You will not have the same wire setup as the 6MT on the BCM side because yours is 7AT. IF you can understand a wiring diagram, you will be able to wire them to make it work, as I did.

So you still want to do the 6MT swap on your 7AT 370z ?

If not ,

vtec to vvel · 11-21-2019, 01:54 AM

Quote:

Originally Posted by Maui2Thicc

Im stumped, the shop is stumped and i refuse to go to nissan due to pricing and experience with dealer mechs.
Then a code pops up. A P0850. I buy the Park Postion switch and when they are about to install it... There is no connector. Upon further inspection, they come to find out that the car was manual swapped. Im shook because I never expected that. So I call Nissan give them my VIN and BAM. Automatic comes up for transmission.

I understand that a code popped up, but before you discovered your car was originally an auto, why did you buy the parking position switch for a manual?

Maui2Thicc · 11-22-2019, 02:41 AM

Quote:

Originally Posted by vtec to vvel

I understand that a code popped up, but before you discovered your car was originally an auto, why did you buy the parking position switch for a manual?

Didn’t really think that one through tbh.

I just looked up the code, got the part and took it to the shop since I couldn’t do it at my place.
I’m ordering the ecu regardless tomorrow so hope to have it before the holiday next week.

vtec to vvel · 11-22-2019, 03:51 PM

After some light research, it seems as if you can use an automatic ECU in a manual car, but not the other way around. You stated your car has 93k miles and, granted the ECU is the original, it has ran all this time. So i think you could probably eve get the ECU reprogrammed.

AyoMykey · 09-18-2020, 10:44 PM

Your issue with the code is because they are located on different pins of the bcm. Buying the switch won’t change a thing. In fact you can compare the park neutral circuit for an auto and manual with a diagram and relocate the wire yourself

11-20-2019, 01:03 AM	#1 (permalink)
Maui2Thicc Base Member Join Date: May 2019 Location: Tustin, CA Posts: 2 Drives: 09 Nissan 370z Rep Power: 6	Unsolvable Issue Please Help Hi to everyone reading and thank you for your time. I made the transition from a 2017 86 to a z34 for almost a year now. A 2009 Base to be specific. Info on the car: Automatic Originally Drives fine atm 93k on odometer Last work done on car was Bank 2 Sensor 1 replacement Service Engine Light On (P0850) YES, you read that right. Originally automatic. I am the 4th owner and one of them did a auto to manual transmission swap. Something to remember for later in the post. Where it begins.. So im driving and suddenly throttle cuts off. Rpms are limited to about 2.5k. Car did not shut off! I then rolled into a parking lot, turned her off and on, no throttle response. Get her towed to the shop they say it was caused by one of the Variable Timing Solenoids failing. Cool, get it replaced and everything is fine....for a month and a half or so. Then same thing happens, take her back to the shop. This time it was the second VT Solenoid. Cool, get it replaced and alls good. Right? Nope. A few months later same thing happens This time they cant figure it out. No thrown code. They traced the problem to a relay and replaced it. That same day it happens again at night. Im stumped, the shop is stumped and i refuse to go to nissan due to pricing and experience with dealer mechs. Then a code pops up. A P0850. I buy the Park Postion switch and when they are about to install it... There is no connector. Upon further inspection, they come to find out that the car was manual swapped. Im shook because I never expected that. So I call Nissan give them my VIN and BAM. Automatic comes up for transmission. So I go to another shop for a second opinion and they say the same thing. Also they say it was done correctly. But why am I bringing all this up about the transmission? If it was done correctly. Except the wiring and ecu. They kept the stock ecu, which makes it an automatic base ecu. Which is also why the car is throwing the P0850. Some other red flags are that the reverse lights dont turn on when in reverse gear. Now How does this tie into my limp mode/throttle loss problem? So When it happened again i decided to completely disconnect the battery (positive and negative terminals) to reset the ecu. I then did all the relearn procedures for Throttle and pedal. BAM, Shes back to normal and driving. So now reseting the ecu is my only fix but it started happening every FEW miles. So i let her sit for 2 weeks straight. I started driving her since last friday, 15th of November. There are no issues so far and she has been driving fine even under light stress. Now im shot and am focusing on the ecu as the main culprit. Friday i will be ordering a same model year ecu from a base manual and will be trying my luck. I believe some wiring still needs to be done. But I want ANY feedback and questions. Please. MY Questions are: -If the code suddenly popped up and the sensor was never connected to anything then shouldnt the code have been present even during the test drive and purchase of the car? as well as through out the whole time of ownership? -Did the ecu have to be tampered with in order for the car to even accept the manual tranni? -If ecu was tampered with could the ecu have just gone bad over time since it was first swapped? -Is it even the ecu? Current issues with car other than the ecu problem are that the ac compressor needs to be swapped, the power steering pump and sensor as well. I will be ordering those soon as after the ecu. Sorry for the long read and thank you again for your time.

11-22-2019, 03:51 PM	#5 (permalink)
vtec to vvel A True Z Fanatic Join Date: Feb 2015 Location: 813 Posts: 3,915 Drives: 13 Z Rep Power: 502909	After some light research, it seems as if you can use an automatic ECU in a manual car, but not the other way around. You stated your car has 93k miles and, granted the ECU is the original, it has ran all this time. So i think you could probably eve get the ECU reprogrammed. __________________ Don't like what I post? Too bad. I really don't give a sh!t

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09-18-2020, 10:44 PM	#6 (permalink)
AyoMykey Base Member Join Date: May 2018 Location: SC Posts: 4 Drives: VQ37 s14 Rep Power: 7	Your issue with the code is because they are located on different pins of the bcm. Buying the switch won’t change a thing. In fact you can compare the park neutral circuit for an auto and manual with a diagram and relocate the wire yourself