Coolant temp sensor and thermostat question

[Deadrodent]

What are some symptoms of a fault cts sensor/thermostat? My car will run fine for 10-15 minutes and then it will not allow me to rev past 2000 rpm. I thought it was a maf problem but i checked the maf's signal with a multimeter and it checks out - plus the car doesn't have the same symptoms when i unplug the maf.

I'm thinking the problem happens whenever my car reaches normal operating temp...maybe the computer is going into safe mode because the coolant is getting too hot? I've been trying to fix this problem for awhile but i can't seem to find it...thanks in advance!

[S13FASTBACKSR]

what exactly were your readings on your maf? also try cleaning it with electronic spray cleaner..and if your thermostat is not opening your temp gauge will read very hot and if your coolant temp sensor is not working then it will give you startup trouble when the engine is warm..neither should give you any driveabilty problems especially not being able to rev over 2krpm..that is usually a maf problem..let us know your readings and try cleaning it..also are you running rich at all?

[FSUDrifter]

try to see if you can find someone with a maf that works for sure and swap them out and see what happens. I've been told several times that cleaning the maf is really hit or miss, sometime you can ruin it. If you have the stock SR maf, then you can use a ka24e maf with no problems. You can also get your maf remanufactured at autozone, advance, or carquest and that comes with a warranty.

Other things to check:- TPS voltage- spark plugs- ignitor chip

Here are the symptoms of a bad CTS given by FRSport.com:"If your vehicle is getting bad gas mileage or is having idling issues after the engine has warmed up, your ecu temperature sensor may be bad.

Replacing this sensor will enable your ecu to measure coolant temperature correctly in order to calculate the right amount of fuel for the engine - otherwise it will run rich constantly."

[Deadrodent]

The problem happens immediately once i reach normal operating temperature

Quote »"If your vehicle is getting bad gas mileage or is having idling issues after the engine has warmed up, your ecu temperature sensor may be bad.

Replacing this sensor will enable your ecu to measure coolant temperature correctly in order to calculate the right amount of fuel for the engine - otherwise it will run rich constantly."

[/quote]where exactly is the ecu temp sensor? by the intake manifold? or by the lower rad hose?

this is pretty much what i'm experiencing. does it make sense that i can't rev past 2000 rpm? does the computer have a "safe mode"? or is it the fact that i'm constantly running rich (from a bad cts) that is actually affecting my maf?
Modified by Deadrodent at 12:41 AM 4/14/2007

[S13FASTBACKSR]

no i dont think there is a safe mode for too much fuel ..when this sensor went bad on my engine i was not running rich, i just could not start the engine when it was already warm because it was being flooded..and i did not have drivability issues..once again what exactly were your readings on your maf?

[Deadrodent]

last time i checked the power was 11.65v and signal was 0.85v. I used the block as a ground...

[S13FASTBACKSR]

hmmm..should get a 12v and .5v ...when you unplug the MAF and try to rev past 2krpm can you? if you can then your MAF is not functioning properly. also do me a favor..start the engine and go behind your ecu and locate the l.e.d. on the back of it and tell me if it is on (remember this is with the engine running) let us know thanks

[corey240]

heres what you do, check the ecu for codes. if you dont know how, just look at the ecu, there is a little cutout with an led inside, utnr the car to the on position, but not on, then youl see the little hole with a white screw in it, turn that screw all the way clockwise for 3 seconds, then turn it back. the ecu will flash in 2 sets of flashes meaning a double digit number, first slow flash/flashs, then fast...

3 slow and 2 fast would be code 32, then check here...http://www.240sx.org/faq/artic...h.htm

see, im throwing a code 13, which is the temp sensor. i also noticed my collant isnt hot at all after turnning the motor ona nd it idles for a couple minutes, i think the thermo is broke, cant you run without a thermo? i have dual flexalite fans hooked up to a switch so it wouldnt be a problem aobut fans kicking on. anyway, im swapong my sensors on the thermo housing with my others and see if i get the code anymore.

[S13FASTBACKSR]

your thermostat lets coolant in by opening..when it goes bad it doesnt open therefore your temperature gauge will read extremely hot..so if you arent reading hot your thermo isnt bad