problem w/ cooling fans

[92maximase]

lately i noticed my cooling fans don't come on, but the car does'nt over heat.
sometimes when i drive then come to a stop they come on high then shut off.

the gauge would normally stay under the 1/2 mark but not by much.
but it sometimes goes 1/2 or lil more up.

today i took the highway home. she was fine.
when i got off i noticed she was lacking ALOT of power.
and i could hear popping from the intake (which either means an ignition problem or vavle timing OFF).

i looked at my gauge and it was creeping it way up!:ohmy:
at first i thought the gauge was acting up ('c
ause it'll work sometimes, when it does'nt i tap the gauge)

so i quickly put up the heat hit the a/c button so the fans will come on.

once she went to her normal spot the power came back etc.

but the fans don't work on their own.
in order for them to work i have to keep the a/c on.

now i was looking at the online manual that colobianmax sent me and it looks like the ecm controls the fans....what going on?

p.s. sorry for the long a$$ story

[walec05]

maybe you have a bad coolant temp switch, which is pretty common.....switch does not send accurate info to ecm, therefor your fans dont turn on...

[DasTeknoViking]

Coolant temp sensor is VERY common problem on the 3rd gen. I would replace that switch.

My old 90 SE 5spd I had wouldn't restart after the car was runing for more than 1min. I sold her with 340k miles on the odo, original VG30E.

[92maximase]

yea i have that problem too!
i thought it was becuase of the missfire...but when i looked at the manual it shows it's "normal".

now your talking about the switch by the temp. gauge sensor?

[Brian]

CTS is the red connector
unplug it and see how things work. it should cause your fans to run constantly.

[walec05]

there are two engine coolant temp sensors......one is a two prong conector, the other one is a single prong connector......i forget which is which, but one is for the guage, and the other for the ecm.

[Brian]

1 = gauge (SENDER)
2= ECU (SENSOR)
sensor: http://www.internetautosupply.com/catalog/images/tx18.jpg

[walec05]

yeah, thats what i thought too brian, but i just wanted to make sure.....

[92maximase]

thanks! good news....well i got it to work.
the connectore is corroded, i cleaned it a lil' bit i i'll finish it some more tomarrow.

here's the weird thing, i removed the connector, the fans came on about 5 seconds later.

but no check engine light?
no running in mpfi?
i think my ecu is screwed up.

[Brian]

no CEL is pretty common on the 3rd gen.
I NEVER had one no matter what was wrong

[DasTeknoViking]

Old Nissans do not code for sh!t. I ran around with no 02 sensor for a while in my old SE-R and there was no code. Only the Cali Spec ECUs would throw codes for some weird reason.

[92maximase]

damn thats not good.
it could be a tps sensro and it may not know.

good thing the tranny has it's own ecu

[Brian]

the ECU still reads the sensors, but it doesn't trigger the light.

[92maximase]

oh...
i guess thats a good thing.
has everything under control.

when i had the coolant sensor removed the car still started!
on my acura and pontiac they would'nt even start! lol.

okay but that popping from the intek indicates:
ignition system.
or valve train system.

but i drove her alot today...a pretty tough car

[Brian]

popping indicates timing way off

[92maximase]

ignition?or valve?

[Brian]

ignition timing