waterthermo sensor wire short

mycarhatesme · Post by **mycarhatesme** » December 6th, 2005, 1:04 pm

1992 RS MTX

code 9 will flash if i touch the sensor wire in the wrong way. if i move the wire on the waterthermo sensor (green one), my idle revs up and down.
must be a short on it.

im looking to re-wire it properly but cant find any information on it. ive checked the local library and such for info, no luck. im not going to the dealership (those basterds)

anyone ever had this problem?
if so, how exactly would i go abouts doing this?

all/any help would be awesome. thanks ahead of time.

Cheers

PATDIESEL · Post by **PATDIESEL** » December 7th, 2005, 12:03 am

It is tricky to rewire a OEM circuit. The wires are old and brittle and you may cause more problems by messing with it. So in short when you tackle this be careful not to pull on other wires.
First thing is; what are you touching exactly when the short seems to occur? The sensor or the sire just outside the sensor or the wire for the sensor somewhere other than right next to the sensor?

All you need is to fix the part of the wire from one termination to another. If it goes through some connector or something like that stop at the connector and only replace the piece of wire from inbetween, not the whole circuit.
Get some 22 guage wire (same as stock). Choose a color that is similar to the temp wire so that you don't confuse yourself or another person later with the wrong colored wire. Maybe even try and find a spare harness from a junk yard and pull the same wire from it. If you can find a harness with decent wires, they might be hard to come by. I have several harnesses that I use for that exact purpose. (well and to replace clips that I break

) Get a soldiering iron and some silver bearing soldier (works much better than rosin core on electrical connections) Take the old wire off by cutting one end at a time. Where it ends in a connector pull the old metal terminal out of the connector. Soldier the new wire to a new same size metal terminal and insert the new terminal in the connector. Most of the connectors will have a VERY small plasitc piece inside them that holds the terminal in place. You'll need to find a tiny screw driver to pry to plastic to get the terminal out. Do the same at the other end. Tape the wire back into the harness and check one end of the new wire to the other while in the car, with the car off and key out, for Ohms. A very small number on the ohm meter means you did a good job. A large number means you have a bad connection somewhere, find and fix it.

It will take some time, but take your time or you'll make things worse than when you started. Patients is the key.
Good luck.

mycarhatesme · Post by **mycarhatesme** » December 7th, 2005, 12:58 pm

hey Pat,

thanks for the push in the right direction.

to answer your question, when i touch the plastic cover around the sensor, arg, im trying to say how i see it, but im not a very good talker, lemme take a breath im getting pissed lol....

k, the sensor has a cover around it, then it has the wire coming out of the cover to the connector. its when i touch the wire that the idle will bounce.

hopefully im making enough sense so u can get what im saying..if not just say "dumbass, make more sense"

and i will try to re-explain it.

mycarhatesme · Post by **mycarhatesme** » December 7th, 2005, 12:59 pm

Post by **Custommx3** » December 7th, 2005, 1:37 pm

Moved to electrical.

this is the FAQ, do NOT post in here.

mycarhatesme · Post by **mycarhatesme** » December 7th, 2005, 1:40 pm

thought i was in electrical....excuse me!

PATDIESEL · Post by **PATDIESEL** » December 7th, 2005, 2:48 pm

I undertand what you are saying.
I should have told you this before, buy anyway. First, try cleaning the metal contacts inside the connecter and sensor with some light-weight sand paper before you go through the trouble of making a new wire. Also put a tad of dilithium electrical grease on the contacts. It will keep the metal from oxidizing and give you a good connection forever.
What color is the connector? Knowing what coonector we are talking about will help me know if I need to give you a bit more direction. The green and grey connectors you'll follow the directions above. The small black one I'll need to look at again. It is a bit different than most of the car's connectors and I might need to give you more info on how to get the terminal out of the connector. Let me know and I'll check the black connecotr if I need to.

mycarhatesme · Post by **mycarhatesme** » December 9th, 2005, 12:06 pm

the sensor has the green plastic on it (water thermo) between the 1st and 2nd injector (on the RS 1.6 engine...mine)

its not the black one on the thermostat housing.

i added a extra ground wire to my tranny hoping that might do it, but no luck, i was bouncing at the traffic lights again.

could it just be that my brake lines have air in them? so when i hit the brake, thats why im getting the bounce?

mycarhatesme · Post by **mycarhatesme** » December 9th, 2005, 12:44 pm

break booster is going maybe.....not sure how to test this..but a trusted mechanic i know suggested it.

jschrauwen · Post by **jschrauwen** » December 9th, 2005, 12:49 pm

Although I don't have my shop manuals with me at work, your green thermosensor may be similar to the V6. At any rate there is probably a prescibed test for it similar to the V6. In the online shop manual it should say what the resistance tolerances are for different temperature ranges. Personal experience has shown me that the integrity of that particular thermosensor can be jeopardized and I didn't find this until I actually removed it. I believe I used a 19mm deep socket for it. the bottom copper portion had separated from the top plastic portion. They can get very brittle over time from the constant heat ranges it experiences. It can be removed and taken inside to do your resistance checks. Haven't thoroughly gone over previous posts but a trapped air lock in the vicinity of that TS can create that hunting idle scenario. If the TS is not in constant contact with the coolant, the wrong temp info will be sent to the ecu which will action that incorrect input and try to adjust the idle to compensate than stop than try to compensate etc etc etc.