Temp. Gauge Fluctuations - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

kanekz · 10-08-2003, 04:21 PM

My original post a few months ago covering this issue:
http://www.zilvia.net/f/showthread.p...threadid=19884

Since then, I installed a thermostat..but that didnt fix the problem. I am thinking it is my Engine Temp. Someone suggested that it could be the sensor behind the gauge cluster. The fluctuations are not as bad pre-new thermostat, but still happen. I notice that when the engine is not warmed up, it tends to do it more often as well. Any ideas? Is it the engine temp sensor??

kanekz · 10-09-2003, 06:25 PM

anyone have opinion on this?

negular · 10-09-2003, 09:41 PM

it would seem to me that if the temperature gauge fluctuates with your rpms... it would be an air pocket which you can fix by running your car with the cap of for a minute or two to let the air circulate out after the thermostat opens. yet, you say you just replaced your thermostat... ummm. you could try to change your temperature switch.

switch

anybody else?

phatsx · 10-10-2003, 07:36 PM

What brand thermostat did you install?

pr240sx · 10-10-2003, 09:13 PM

think that your problem is more electrical than mechanical. Try testing the ECU coolant temp sensor (with a MDM is a brezze) or a voltmeter.

You have 2 sensors. Single wire for the dash stupid neddle and the 2 wire for the ECU.

Or you can use a aftermarcket gauge for thesting if your car coolant temp

Even without thermostat, coolant temp should get to normal operating range AT IDLE just take longer
Also, the radiator will not be cooling water as efficient because water will pass too fast.

My sugestion:

1.Check your engine ground, 90% of all 240 sensors playfullness is caused by faulty engine grounds

2.Check coolant temp by other method (MDM-100 or aftermarket gauge)

3.Remove the thermo for test

kanekz · 10-10-2003, 11:05 PM

phatsx, I installed a Nissan OEM

pr240sx, yea I was going to get a voltmeter to test some sensors. But what is a MDM?

pr240sx · 10-11-2003, 12:39 PM

is a nice small black box that you plug to your car CONSULT port
it reads all the data that the ECU is monitoring real time.
You can check it out at
www.techtom.com

Very nice peice for doing diagnostics

kanekz · 10-11-2003, 03:38 PM

Quote:

Originally posted by pr240sx
is a nice small black box that you plug to your car CONSULT port
it reads all the data that the ECU is monitoring real time.
You can check it out at
www.techtom.com

Very nice peice for doing diagnostics

Link dont work. BUT I think I know what your talkn about. I would rather get a voltmeter and check the sensors though.

pr240sx · 10-12-2003, 07:06 PM

Will post the correct link anyway

http://www.technosquareinc.com/techtom.htm

A DVOM is cheaper though

phatsx · 10-12-2003, 07:16 PM

Does anyone know where you can buy the Techtom data computer?

Thanks,
Ted

10-08-2003, 04:21 PM	#1
kanekz Zilvia Addict Join Date: May 2002 Location: California Posts: 802 Trader Rating: (0) Feedback Score: 0 reviews	Temp. Gauge Fluctuations My original post a few months ago covering this issue: http://www.zilvia.net/f/showthread.p...threadid=19884 Since then, I installed a thermostat..but that didnt fix the problem. I am thinking it is my Engine Temp. Someone suggested that it could be the sensor behind the gauge cluster. The fluctuations are not as bad pre-new thermostat, but still happen. I notice that when the engine is not warmed up, it tends to do it more often as well. Any ideas? Is it the engine temp sensor??

10-09-2003, 09:41 PM	#3
negular Dr. Neg Join Date: Nov 2001 Location: Platt, NY Age: 41 Posts: 571 Trader Rating: (0) Feedback Score: 0 reviews	it would seem to me that if the temperature gauge fluctuates with your rpms... it would be an air pocket which you can fix by running your car with the cap of for a minute or two to let the air circulate out after the thermostat opens. yet, you say you just replaced your thermostat... ummm. you could try to change your temperature switch. switch anybody else? __________________ The louder the radio, the better I sing.

10-10-2003, 07:36 PM	#4
phatsx Leaky Injector Join Date: May 2002 Location: NC Posts: 144 Trader Rating: (0) Feedback Score: 0 reviews	What brand thermostat did you install? __________________ Nsport turbo kit, JWT ecu, JWT fuel rail, MSD 72lb injectors, Cobra MAF,SPEC clutch, KYB agx shocks, Eibach Pro springs,Apexi GT Spec exhaust, 18x8 Konig flight wheels, BFG KDW 265/35/18 (rear) Dunlop fm901 225/40/18 (front), indash tv and dvd player with ps2 and some more stuff that I probally can't remember 1/4 Mile:13.9 @ 105 / 7lbs of boost w/o JWT mods http://www.eframes.com/default.asp?g...bum=38203.2910

10-10-2003, 09:13 PM	#5
pr240sx Zilvia Addict Join Date: Jan 2002 Posts: 627 Trader Rating: (0) Feedback Score: 0 reviews	I think that your problem is more electrical than mechanical. Try testing the ECU coolant temp sensor (with a MDM is a brezze) or a voltmeter. You have 2 sensors. Single wire for the dash stupid neddle and the 2 wire for the ECU. Or you can use a aftermarcket gauge for thesting if your car coolant temp Even without thermostat, coolant temp should get to normal operating range AT IDLE just take longer Also, the radiator will not be cooling water as efficient because water will pass too fast. My sugestion: 1.Check your engine ground, 90% of all 240 sensors playfullness is caused by faulty engine grounds 2.Check coolant temp by other method (MDM-100 or aftermarket gauge) 3.Remove the thermo for test

10-11-2003, 12:39 PM	#7
pr240sx Zilvia Addict Join Date: Jan 2002 Posts: 627 Trader Rating: (0) Feedback Score: 0 reviews	MDM is a nice small black box that you plug to your car CONSULT port it reads all the data that the ECU is monitoring real time. You can check it out at www.techtom.com Very nice peice for doing diagnostics

10-09-2003, 06:25 PM	#2
kanekz Zilvia Addict Join Date: May 2002 Location: California Posts: 802 Trader Rating: (0) Feedback Score: 0 reviews	anyone have opinion on this?

10-10-2003, 11:05 PM	#6
kanekz Zilvia Addict Join Date: May 2002 Location: California Posts: 802 Trader Rating: (0) Feedback Score: 0 reviews	phatsx, I installed a Nissan OEM pr240sx, yea I was going to get a voltmeter to test some sensors. But what is a MDM?

10-12-2003, 07:06 PM	#9
pr240sx Zilvia Addict Join Date: Jan 2002 Posts: 627 Trader Rating: (0) Feedback Score: 0 reviews	Will post the correct link anyway http://www.technosquareinc.com/techtom.htm A DVOM is cheaper though

10-12-2003, 07:16 PM	#10
phatsx Leaky Injector Join Date: May 2002 Location: NC Posts: 144 Trader Rating: (0) Feedback Score: 0 reviews	Does anyone know where you can buy the Techtom data computer? Thanks, Ted __________________ Nsport turbo kit, JWT ecu, JWT fuel rail, MSD 72lb injectors, Cobra MAF,SPEC clutch, KYB agx shocks, Eibach Pro springs,Apexi GT Spec exhaust, 18x8 Konig flight wheels, BFG KDW 265/35/18 (rear) Dunlop fm901 225/40/18 (front), indash tv and dvd player with ps2 and some more stuff that I probally can't remember 1/4 Mile:13.9 @ 105 / 7lbs of boost w/o JWT mods http://www.eframes.com/default.asp?g...bum=38203.2910

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