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View Full Version : why isnt my temp sender working? how does it work?



itzdave
08-26-2010, 07:18 PM
short version: temp sender is good, but doesnt work. does it need to be 'grounded' thru the engine?

long version:
on the stock intake manifold, the temp sensor hooks up to the back side of it, between two coolant lines, thats where it reads the temp. HOWEVER, now i have DCOE's and i guess i didnt put much thought into where/how to reinstall the temperature sender.
what i did was, remove the two coolant lines that DID go into the stock manifold, attach them to brass a brass T fitting. two ports for the coolant to flow thru, the other is threaded for the temp sender. BUT, now my temp gauge doesnt work.
so my question is: does the temp sender have to be 'grounded' thru engine in order for it to work? it would make sense because the sender only has one wire going to it, and the temp sensor is really just a variable resistor that changes with the heat (thermistor). so if its not touching the engine, it has no way to complete the circuit????
and i DID check that the wires were getting a signal and sending to the gauge by grounding out the wire to the sender and the gauge 'spiked' up.
any thoughts?
thanks...

lostforawhile
08-26-2010, 07:23 PM
it has to be grounded, I just put mine in the thermostat housing, what type of fitting did you use? it's 1/8 bspt like the oil pressure sender, it's not 1/8 npt

itzdave
08-26-2010, 07:27 PM
i just went to the hardware store and got fittings that would fit it, pretty damn good fit too, then i used a bunch of white teflon tape to make sure it was a solid seal.

lostforawhile
08-26-2010, 07:29 PM
i just went to the hardware store and got fittings that would fit it, pretty damn good fit too, then i used a bunch of white teflon tape to make sure it was a solid seal.

if you ever get a spare thermostat housing send it out here and i'll modify it to hold the sensor, I think the LXI one already has the threads, not sure. the 1/8 bspt threads look just like 1/8 npt but have one more thread per inch, if you aren't careful you can damage the threads on the sender

itzdave
08-26-2010, 07:32 PM
i didnt wanna have to drill, tap, and die it. thought this way would be easier and still effective...

what about the bleed bolt, is it the same thread size? could i just put the temp sender where the bleeder is?

itzdave
08-26-2010, 07:36 PM
ok, just went and checked... the temp sender thread size is NOT the same size as the bleeder(less threads per inch), so thats not an option...

lostforawhile
08-26-2010, 07:40 PM
i didnt wanna have to drill, tap, and die it. thought this way would be easier and still effective...

what about the bleed bolt, is it the same thread size? could i just put the temp sender where the bleeder is?

I think it's different, I think the LXI has the temp sender already on the housing so the threads are there, not sure, someone clarify this, if not I will tig on the bung for you and tap it at 1/8 BSPT I had a hard time even getting ahold of that tap, when you get a spare just send it out here, and TEFLON TAPE??? AUGGHH!! you must just work on the wiring not the airplane engines lol, ask the engine guys what they think of teflon tape? the FAA bans us from using it ANYWHERE on the plane and for good reason. use the permatex or the loctite thread sealer, the tape can also insulate the sender from ground, the liquid sealer lets the threads of the sender make contact with ground. the sealer just stays between the threads

itzdave
08-26-2010, 07:44 PM
haha, yea im an electrician on the planes...
like i said, i didnt think too much about how the sender worked or anything, i just wanted it there and all hooked up, lol. NOW I KNOW that i shouldnt have half-assed it.
and yes, i know that the engine mechs dont use it, just like we dont use electrical tape on anything, only proper splices. i didnt think about loctite at the time cuz i didnt have any with me. oh and btw as an electrician, i use teflon tape on certain things on the planes, lolz...

Ayeobe
08-26-2010, 07:45 PM
I guess you should spot a ground onto that T, and send a wire to the intake mani after you take care of the teflon? Maybe you should touch the engine and the T at the same time with the sensor in. Think that would be a good way of checking?

lostforawhile
08-26-2010, 07:47 PM
haha, yea im an electrician on the planes...
like i said, i didnt think too much about how the sender worked or anything, i just wanted it there and all hooked up, lol. NOW I KNOW that i shouldnt have half-assed it.
and yes, i know that the engine mechs dont use it, just like we dont use electrical tape on anything, only proper splices. i didnt think about loctite at the time cuz i didnt have any with me. oh and btw as an electrician, i use teflon tape on certain things on the planes, lolz...
what it is are the small white tubes of thread sealer by loctite or permatex, they go a long way and will seal a lot of threads for a little tube. You can probably get away with the teflon because you are military and I don't think the FAA oversees your airplanes, I think you guys are self regulated

itzdave
08-26-2010, 07:48 PM
what it is are the small white tubes of thread sealer by loctite or permatex, they go a long way and will seal a lot of threads for a little tube. You can probably get away with the teflon because you are military and I don't think the FAA oversees your airplanes, I think you guys are self regulated

faa does regulate us, ive had to use it on an altimeter that had a shitty fitting and wasnt holding pressure...

lostforawhile
08-26-2010, 07:48 PM
http://www.restockit.com/images/Product/medium/442-56747.jpg

lostforawhile
08-26-2010, 07:49 PM
faa does regulate us, ive had to use it on an altimeter that had a shitty fitting and wasnt holding pressure...

I didn't know that I thought the military stuff was completely separate from the civilian stuff

itzdave
08-26-2010, 07:56 PM
http://www.restockit.com/images/Product/medium/442-56747.jpg

yes im familiar with it

I didn't know that I thought the military stuff was completely separate from the civilian stuff

nope.








so im gunna make a very ghetto 'grounding strap' on the brass fittings and attach that to a ground and see if it works, im hoping that the teflon tape has worn down and it will still have continuity...
if not, ill just take it apart tomorrow and think of somethin else. thing is tho, were having a meet up here tomorrow and its about 2 hours away so i wanna make sure i have a temp gauge for that. usually my car doesnt get driven for more than 20 min at a time so i want too woried about not having the gauge for the last few weeks...

itzdave
08-26-2010, 08:16 PM
SWEET! got it workin! now i just need to do it 'right', now that i know how it works properly and whatnot...
thanks guys!

Ayeobe
08-26-2010, 08:54 PM
Nice. Also, i just re-read my post and i said you should touch the mani and the T but didnt specify you should do it with an electric wire.. lol. Hows that ground strap work, by the way? I dont think ive seen one.. did you just wrap the wire around the T and secure it?

itzdave
08-26-2010, 09:00 PM
Hows that ground strap work, by the way? I dont think ive seen one.. did you just wrap the wire around the T and secure it?

yea man, i just took a wire, stripped off a bunch of the insulation, wrapped it around the sender where it is threaded/where the 'nut' part is. then i just (lost, please dont kill me, its just temporary) taped it all up and put zip-ties around the tape to hold it all together, HAHAHA! it looks like garbage, but its just a temp fix for the time being, and IT WORKS!!!

Civic Accord Honda
08-26-2010, 09:13 PM
did u splice a new end on the wire? thoses contections get corroaded and dont work anymore... had that on the 3g lol just splied a new terminal on the wire and bamo it works

itzdave
08-26-2010, 09:16 PM
did u splice a new end on the wire? thoses contections get corroaded and dont work anymore... had that on the 3g lol just splied a new terminal on the wire and bamo it works

for the other end of the wire, i just loosened a nut and placed the wire in it and tightened back down. i know i know, its hella ghetto, but i just needed to see if this method would even work til i can find something better, lolz.

lostforawhile
08-26-2010, 10:11 PM
did u splice a new end on the wire? thoses contections get corroaded and dont work anymore... had that on the 3g lol just splied a new terminal on the wire and bamo it works

um it wasn't grounded cah, it doesn't work well without a ground. it would have been easier to stick a small hose clamp on it with the wire under it, then tighten it up and instant ground

itzdave
08-27-2010, 12:58 AM
it would have been easier to stick a small hose clamp on it with the wire under it, then tighten it up and instant ground

HA! thats a great idea!

ecogabriel
08-27-2010, 04:38 PM
I think it's different, I think the LXI has the temp sender already on the housing so the threads are there, not sure, someone clarify this, if not I will tig on the bung for you and tap it at 1/8 BSPT I had a hard time even getting ahold of that tap, when you get a spare just send it out here, and TEFLON TAPE??? AUGGHH!! you must just work on the wiring not the airplane engines lol, ask the engine guys what they think of teflon tape? the FAA bans us from using it ANYWHERE on the plane and for good reason. use the permatex or the loctite thread sealer, the tape can also insulate the sender from ground, the liquid sealer lets the threads of the sender make contact with ground. the sealer just stays between the threads

Sorry for the half-ass post; I'm reading a computer file and I reading at the forum at the same time...
LX-i has the temperature sender threaded in the thermostat housing (at the rear side if you look at the engine from the front.
It also has the temperature sensor (for the ECU) and the fan switch, and a wax valve or something of that sort (i think it operates in my case the canister purge)

2oodoor
08-27-2010, 05:06 PM
wow that is interesting, as I was reading this about the sender now not grounded in this contraption Dave has then it dawned on me that teflon tape could possibly insulate a sender from ground if it was wrapped too thick then you guys broke in to that conception and then I remember fittings being sent oem with a thread locker sealer coating but then those were not sensors and then Ive also bought sensors with it on it too but they were oil senders but probably two or three wire and then I know that ATF fittings and carb too would be risky if a piece of teflon got in past the threads and then they would clog up a needle valve or any orifice and then cause problems too and then the same for hydraulics in aeronautics or anything else and then and then and then:)
excellent thread guys, good stuff:cheers:

Civic Accord Honda
08-27-2010, 05:29 PM
i know you got it working but just wondering a question lol


on efi it has a contecter like this sticking up on the sensor
http://www.tme.eu/katalog_pics/2/6/0/2605d58d70d1a0ad1490313b333eb689/st-040_b.jpg
without the plastic piece of course lol

i just cut the old metal one off and crimped one of theses on
http://www.tme.eu/katalog_pics/1/6/a/16a6616d79f1d09ae5f8786f15dbc733/st-050_b.jpg

of course it was grounded to the engine , but just wonder if carb cars are the same way? or are they to 2 wire type with a plastic contecter on the end like on the newer hondas?

lostforawhile
08-27-2010, 06:11 PM
wow that is interesting, as I was reading this about the sender now not grounded in this contraption Dave has then it dawned on me that teflon tape could possibly insulate a sender from ground if it was wrapped too thick then you guys broke in to that conception and then I remember fittings being sent oem with a thread locker sealer coating but then those were not sensors and then Ive also bought sensors with it on it too but they were oil senders but probably two or three wire and then I know that ATF fittings and carb too would be risky if a piece of teflon got in past the threads and then they would clog up a needle valve or any orifice and then cause problems too and then the same for hydraulics in aeronautics or anything else and then and then and then:)
excellent thread guys, good stuff:cheers:yea teflon tape is nasty messy stuff, the liquid thread sealers squeeze out between the threads so you still have metal to metal contact

lostforawhile
08-27-2010, 06:17 PM
i know you got it working but just wondering a question lol


on efi it has a contecter like this sticking up on the sensor
http://www.tme.eu/katalog_pics/2/6/0/2605d58d70d1a0ad1490313b333eb689/st-040_b.jpg
without the plastic piece of course lol

i just cut the old metal one off and crimped one of theses on
http://www.tme.eu/katalog_pics/1/6/a/16a6616d79f1d09ae5f8786f15dbc733/st-050_b.jpg

of course it was grounded to the engine , but just wonder if carb cars are the same way? or are they to 2 wire type with a plastic contecter on the end like on the newer hondas?they are the same, i just think the efi has an extra sender for the computer not sure, the late model ones are the same also just bigger, the two wire connector is eithier the temp sender for the computer or the cold start sender, D series looks just like it but bigger,single contact,plus the computer sender and a two wire sender to tell the computer the engine is cold, OBD2

lostforawhile
08-27-2010, 06:32 PM
Sorry for the half-ass post; I'm reading a computer file and I reading at the forum at the same time...
LX-i has the temperature sender threaded in the thermostat housing (at the rear side if you look at the engine from the front.
It also has the temperature sensor (for the ECU) and the fan switch, and a wax valve or something of that sort (i think it operates in my case the canister purge)

multi quote is broke sorry, all he need to fix this problem with his is an efi housing. the fan switch should be in the bottom of the radiator, thats probably a temp sender for the ecu, not sure, most efi have ones sender for the gauge and one dedicated sender for the computer. he can leave the unused sensors in place and use the temp sender. Itzdave let me know how connecting the hoses together works, i was going to bypass through my manifold, but i can't get the one AN line around the corner of the manifold and I'm going to say the hell with the heated manifold and just run a bypass. you know how it works right? when the thermostat is blocking coolant flow, the coolant is forced through the bypass hose and through the manifold also on the EFI cars some goes through the throtte body, and the carb cars through the carb coolant passage. when the thermostat opens, since the hose and opening is bigger then the bypass, it has less resistance and most cdoolant flows through it, some always continues to flow through the bypass, but not as much. the bigger the bypass hose, the more will flow through it off bypass, thats why the heater hoses are so big and have a valve to shut them off.

ecogabriel
08-28-2010, 11:08 AM
EFI's have two fan switches. The regular one is low in the radiator
The other is the thermostat housing. They look similar but the temperatures at which they switch are different (92C and 104-108C I believe, or close to those numbers)

The one at the thermostat turns on the fans if the engine stops hot and temperature rises a bit more it will turn the fans on (actually I believe it is the smaller fan) for up to 15 min. That switch is connected to a box under the passenger seat that commands the fans.

You can leave the extra switch(es) installed and use the EFI housing.