some info on sensors

[Skeeg]

i have a 95 240sx SE, and my check engine light is on... i took it to my mechanic to run it on this computer and came up with a few ecu errors.

ones that i remember are, knock sensor, 02 sensor, tps sensor, and possibly one more but i forgot it :ugh:

1st thing, 02 sensor is bad would my car idle funny or anything? it idles fine and i dont notice anything when driving either.

i think i read that the knock sensor rarely fails and usually is a false error from the 02 sensor being bad?

tps sensor i dont really know haha, right now it seems like a few hundred for the new sensors. but the thing is i dont notice anything wrong with the car running and my gas millage seems fine also.

basically im wondering if there is a way to test the sensors individually by inspection and what to look for as far as that goes, or possibly reading the voltage of the sensor could give me the info?

sorry if this makes no sense, its my 1st 240 :bigok:

[SexPanda]

could be old codes that were stored.

[Skeeg]

i have another question.... the car came with a cold air intake by AEM, looking at others write ups they have a sensor after the maf. mines has the maf, then the intake. im not sure, but is that needed?

guy said i did need a tps sensor, so could that be setting off the others? or completely unrelated? i sure hope those were just stored haha, save me the troubles.

[SexPanda]

Im guessing your cars OBDII... Shit, im glad im obd1. 89 baby! lol.
anyhow.
A sensor after the mass airflow... hmm... If its there, i wouldnt screw with it. I cant think of what that could be though. Im still learning all this stuff in school. My car is my lab basically. If i learn anything new, i use it on my car first.

But id change your o2 sesnor and see if that helps. I know when mine was bad i had a few other codes too. Just make sure they werent stored. Sorry i cant help you any more than that.

[Skeeg]

ok i found the name... its called a IAT sensor. im about 90% sure its not on my car anymore haha, yea.. 02 sensor pretty cheap i figured i would go with a uni. 02 and crimp or splice it in.

[SexPanda]

Oh the temp sensor. Damn i knew that one. It tells you how hot/cold in intake temp is. Damn i need this summer to end. get back to tech school.

[Skeeg]

lol, that is a needed part then correct? i will probably have to get ahold of that also then, and rig up some kind of coupler for it... yay love diy.

02 and tps sensor i will be fixing 1st, hopefully my engine light will go off so i can get a e-check.

[projectRDM]

IAT is used for diagnostics only, you'll get a check engine light but it does not affect engine operation or performance in any way.

O2 will run open loop if it's bad, the car will drive fine but lag a little as the fuel curve is dead flat.

TPS problems will cause erratic idle and lopey acceleration, clear the codes and see if it comes back.

The knock sensor usually trips only when another sensor has gone out, like the O2, or you could have run some low octane gas on a hot day and it pinged a little, don't even stress it until everything else is cleared/repaired.

[fliprayzin240sx]

You can cheat the Air temp sensor but sticking a 10k ohm resistor on it. See if that helps.

[Skeeg]

You can cheat the Air temp sensor but sticking a 10k ohm resistor on it. See if that helps.

thanks for the tip, since i do have e-check and all this would pass any visual or anything correct?

i run the middle grade gas, 89octane. i don't ever experience any of the symptoms for the sensors... seems weird to be haha, i think im going to have the codes cleared and see what comes back up.

thanks for all the help.