TPS woes S.A.D.B.O.Y.Z - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

LoganDavenport · 08-28-2014, 11:49 PM

Hello gentlemen,

So I just got my SR running and it actually runs pretty decent. I tried to adjust my idle speed via the the plastic bolt inside the IM, without researching the process before doing so (I don't have an internet connection at home when my cell phone runs out of data). And I did so with the car idling and my TPS plugged in, only to later on research the process and realize I did it all kinds of messed up

So my question is, If I did so in the manner stated above...could i have damaged my TPS? I went to walmart today and picked up a digital multimeter and plan to test the tps tomorrow, but it is weird what it is doing.

What happens is, If I start the car with the TPS plugged up it runs good for about two minutes of idling. During that time everything seems to be operating properly, until a few minutes of idling. Then it starts to act as if it is now in limp mode, wont rev past 3K. And also, you cant hold the throttle at a steady rpm I.E. 1500, 2000rpms etc.

So I figured maybe the TPS is just messed up, but what has me confused is something I never ran into before...the car seems to operate properly (if not better) with the TPS unplugged completely?

Any ways I will be troubleshooting tomorrow and will post what my TPS is putting out and see if maybe i just needs adjustment.

FOR EXTRA INFO on things Ive troubleshooted and ruled out so far:
With car at idle..
*Unplugged MAF-Car dies (operating as it should)
*Unplugged CAS- Car dies
*Unplugged TPS- Car still runs, if not better with it unplugged.
*All new vacuum system and is set up properly
*All new fuel lines, new filter, FPR adjusted to 44psi at idle (no vac) dropped to desired range with vacuum hooked up (39 psi) new walboro 255
*no boost leaks that should interfere or send car into limp mode, although I could use new t-bolt clamps
*I would pull codes from the ecu, but someone has either broken or removed the diagnostic screw

(if you know of a write up that could show how to repair this I would love you forever haha) last known code was coolant temp sensor. It has now been replaced, and wired in properly.

I know that the last few things that I listed shouldn't be too terribly related but I just wanted it known that they have been ruled out and shouldn't be causing this issue. Thanks for any advice as to if this is unusual or normal for the motor to behave this way.

LoganDavenport · 08-29-2014, 12:12 AM

Just spoke with a guy at the plant I work with and he says he knows how to desolder and solder on a new potentiometer, if anyone knows where I can buy a replacement one and could lead me in the right direction then I'll have that fixed and can pull codes. Let me know thanks guys.

LoganDavenport · 08-29-2014, 11:33 AM

***UPDATE***
I am now able to pull codes off my ecu, I'm reading 11 and 13. Camshaft position sensor and coolant temperature sensor. I was wondering if there was any way you can adjust a cam position sensor via a multimeter, or do I have to take off my valve cover and 're adjust it that way. Will probably just replace coolant temp sensor.

LoganDavenport · 09-02-2014, 01:07 AM

BUMP.
I have read the write ups on this process and understand the process of how to adjust the ecu but I am kind of at a stand still because I honestly have no idea how to use a multimeter. In order to test it at closed throttle and WOT I know I need to be checking for DC voltage. So where on the multimeter do I turn the dial? I am using the "ETEK" one from walmart. I will include the link, PLEASE will someone give me a bit of advice! Thanks!

Multimeter:http://www.walmart.com/ip/Digital-Mu...10709/14521541

08-28-2014, 11:49 PM	#1
LoganDavenport Leaky Injector Join Date: Jul 2013 Location: Tyler, Texas Age: 27 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	TPS woes S.A.D.B.O.Y.Z Hello gentlemen, So I just got my SR running and it actually runs pretty decent. I tried to adjust my idle speed via the the plastic bolt inside the IM, without researching the process before doing so (I don't have an internet connection at home when my cell phone runs out of data). And I did so with the car idling and my TPS plugged in, only to later on research the process and realize I did it all kinds of messed up So my question is, If I did so in the manner stated above...could i have damaged my TPS? I went to walmart today and picked up a digital multimeter and plan to test the tps tomorrow, but it is weird what it is doing. What happens is, If I start the car with the TPS plugged up it runs good for about two minutes of idling. During that time everything seems to be operating properly, until a few minutes of idling. Then it starts to act as if it is now in limp mode, wont rev past 3K. And also, you cant hold the throttle at a steady rpm I.E. 1500, 2000rpms etc. So I figured maybe the TPS is just messed up, but what has me confused is something I never ran into before...the car seems to operate properly (if not better) with the TPS unplugged completely? Any ways I will be troubleshooting tomorrow and will post what my TPS is putting out and see if maybe i just needs adjustment. FOR EXTRA INFO on things Ive troubleshooted and ruled out so far: With car at idle.. Unplugged MAF-Car dies (operating as it should) Unplugged CAS- Car dies Unplugged TPS- Car still runs, if not better with it unplugged. All new vacuum system and is set up properly All new fuel lines, new filter, FPR adjusted to 44psi at idle (no vac) dropped to desired range with vacuum hooked up (39 psi) new walboro 255 no boost leaks that should interfere or send car into limp mode, although I could use new t-bolt clamps *I would pull codes from the ecu, but someone has either broken or removed the diagnostic screw (if you know of a write up that could show how to repair this I would love you forever haha) last known code was coolant temp sensor. It has now been replaced, and wired in properly. I know that the last few things that I listed shouldn't be too terribly related but I just wanted it known that they have been ruled out and shouldn't be causing this issue. Thanks for any advice as to if this is unusual or normal for the motor to behave this way.

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08-29-2014, 12:12 AM	#2
LoganDavenport Leaky Injector Join Date: Jul 2013 Location: Tyler, Texas Age: 27 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	Just spoke with a guy at the plant I work with and he says he knows how to desolder and solder on a new potentiometer, if anyone knows where I can buy a replacement one and could lead me in the right direction then I'll have that fixed and can pull codes. Let me know thanks guys.

08-29-2014, 11:33 AM	#3
LoganDavenport Leaky Injector Join Date: Jul 2013 Location: Tyler, Texas Age: 27 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	*UPDATE* I am now able to pull codes off my ecu, I'm reading 11 and 13. Camshaft position sensor and coolant temperature sensor. I was wondering if there was any way you can adjust a cam position sensor via a multimeter, or do I have to take off my valve cover and 're adjust it that way. Will probably just replace coolant temp sensor.

09-02-2014, 01:07 AM	#4
LoganDavenport Leaky Injector Join Date: Jul 2013 Location: Tyler, Texas Age: 27 Posts: 86 Trader Rating: (0) Feedback Score: 0 reviews	BUMP. I have read the write ups on this process and understand the process of how to adjust the ecu but I am kind of at a stand still because I honestly have no idea how to use a multimeter. In order to test it at closed throttle and WOT I know I need to be checking for DC voltage. So where on the multimeter do I turn the dial? I am using the "ETEK" one from walmart. I will include the link, PLEASE will someone give me a bit of advice! Thanks! Multimeter:http://www.walmart.com/ip/Digital-Mu...10709/14521541