Problems installing water temp gauge, electrical experts where you at? - Honda Prelude Forum

BlueShadow · 07-10-2003, 11:55 PM

Hi guys,

I am having some issues installing my Nordskog digital water temp gauge. Here is how the instructions say to wire in the gauge. Since it's a general type question, I thought I'd ask them on here.

RED wire = + 12V source
BLACK wire = ground
BLUE wire = temperature sender
PURPLE wire = dimmer switch

And here is how I wired things up:

RED = fuse tapped into ignition
BLACK = grounded in the engine bay (same loaction as grounding straps
BLUE = temp sender, sender is located on thermohousing...same place most everyone else uses
PURPLE = for max illumination, this wire has to be grounded.

For the temp sender installation here is how I have everything attached onto the sender screw from top to bottom. Retaining nut, locking washer, BLUE wire coiled around sender screw, "cardboard-looking" washer. Normal operating temps for an FD is ~200-210 degrees F, 230 on up is when the engine overheats and when the engine fails.

Upon starting the car to warm it up, indicated temps are very erratic. Temps are bouncing back and forth between 330-340 F and 350-360F. If this was true my motor would be toast, but there is more. Out of nowhere the temps will drop down to 210-220/230-240 F (still behaving erratically. Then it will bounce up again to the 300 range. Quickly revved engine to 4-5K RPMs, temps went to max reading of 375 F.

Some tests I did, grounds checked out ok, power source is ok. Tested dimmer switch byt applying +12 V, gauge disply darkened (dimmed). Removed cardboard looking washer thingy temps shot up to indicated 375 F and stayed there. Possibly bad wiring from BLUE wire to temp sender. Unsure of where to put cardboard looking washer. Gauge will show a steady 375 F UNLESS the cardboard washer is on the bottom (washer a problem?). All wire connections were done by cutting off plastic sheath on end of wiring and winding the wires together (problem maybe). Wires used were also used speaker wiring for homw entertainment system Another problem maybe?)

tomorrow I will buy some good wire to wire connectors and a wire to ground connector. Will also buy some 18G electrical wiring and use that. So anyways what do you guys think my problem might be?

TIA

schwett · 07-11-2003, 12:43 AM

almost all problem i hear like this are grounding problems. try moving the ground around. there are lots of good body grounds locations in the cockpit of a lude. try those as well as the engine ground you've been using. where is the sender grounded?

BlueShadow · 07-11-2003, 12:57 AM

Quote:

Originally posted by schwett
almost all problem i hear like this are grounding problems. try moving the ground around. there are lots of good body grounds locations in the cockpit of a lude. try those as well as the engine ground you've been using. where is the sender grounded?

For the main gauge ground I tried one location in the cabin located under the shifter console (pic #1). Then I tried one in the engine bay right under where the hyper ground cables bolt to the frame (pic #3). It's dark right now, so tomorrow I may try to attach the main gauge ground directly to the engine.

And for the sender, at first I didnt think it needed a ground since it was in contact with an adapter which was in contact with the thermohousing (pic #2). I then wired a ground from the sender to the same bolt for the hyper grounding wires (also pic #3). Unfortunately that didn't seem to help so I removed the sender ground.

Do you think I should install it back on? I just realized I didn't have the cardboard looking washer on the bottom when I was testing out the ground for the sender. Moving the cardboard washer to the bottom changed the gauge from displaying 375 F to the erratic temps I talked about earlier.

pic #1 (under shifter console)

#2 (temp sender in thermohousing--shown with ground and gauge wire--cardboard looking wire is right underneath the coiled left wire)

pic #3 (main gauge ground--used sender ground at same location)

SuperSH · 07-11-2003, 02:01 AM

Alright, you can't take this the wrong way but... Your wiring is the worst I have seen. But you have atleast made a good attempt by reading the instructions and asking for help.

#1 get rid of the speaker wire and get some automotive color coded wire, it makes a diffrence.

#2 Use crip connections at the very least, soldering is the best. Use butt connectors for wire to wire connections and ring terminals for the ground and sender to wire connections. When you just wrap the wire arround the post or another wire the voltage and signal won't be constant and will give you nothing but problems, not to mention it can cause your car to catch on fire.

#3 There is only one wire that comes from the sender and goes to the guage according to the instructions that you have given. I see one coming from the ground and another wire going to the guage. Its grounding itself out.

#4 Take the black wire from the guage and attach it to a body ground (the instructions suggest somewhere in the engine compartment) but NOT to the sender.

#5 use a ignition switched 12V power source for power (red wire)
and use an in line fuse, please.

#6 Attach the blue wire ONLY to the sender. I think your putting to much detail on that cardboard washer thingy. If it gives a detail on how to do it then do it that way.

#7 attach the purple wire to ground if you want full illumination all the time (and thats probably best)

Thats how I see the guage to be installed according to the instuctions you have given. And only one wire to the sender!

BlueShadow · 07-11-2003, 02:32 AM

Quote:

Originally posted by SuperSH
Alright, you can't take this the wrong way but... Your wiring is the worst I have seen. But you have atleast made a good attempt by reading the instructions and asking for help.

#1 get rid of the speaker wire and get some automotive color coded wire, it makes a diffrence.

#2 Use crip connections at the very least, soldering is the best. Use butt connectors for wire to wire connections and ring terminals for the ground and sender to wire connections. When you just wrap the wire arround the post or another wire the voltage and signal won't be constant and will give you nothing but problems, not to mention it can cause your car to catch on fire.

Yah, you got me there, somebody on the RX7 forums said that I should be ok twisting things together and wrapping it with electrical tape. I'll just go to NAPA and pick up some good connectors and some 18 guage electrical wiring.

Quote:

Originally posted by SuperSH
#3 There is only one wire that comes from the sender and goes to the guage according to the instructions that you have given. I see one coming from the ground and another wire going to the guage. Its grounding itself out..

I dont quite understand what you are saying, but if you are referring to the wiring on the second pic, I no longer have it set up like that. The second wire was the wire that I was using to give the sender a good ground. Using it didn't have any changes though, so it is no longer on there.

The whole time I had the gauges main ground to it's own grounding location. First location I use under the shifter console, second location is now in the engine bay on the frame (pic #3). But I think I will ground it to the engine bolck instead.

Quote:

Originally posted by SuperSH
#6 Attach the blue wire ONLY to the sender. I think your putting to much detail on that cardboard washer thingy. If it gives a detail on how to do it then do it that way.

The only reason I mention that cardboard or plastic looking washer is because that was what changed my temps. Before I had everthing wired u the display would just show 375 F. Changed ground locations for gauge and dimmer switch, still showed 375 F. Tried using a grounding wire for the sender probe, still 375 F. During all that the BLUE wire was at the bottom of the sender screw, when I moved the cardboard washer to the bottom then my indicated temps started to change. When I removed it, my temps went back to 375 F.

That cardboard or plastic looking thing seems to be part of the puzzle. But I will find out for sure when I get some good connectors for all the wiring.

BlueShadow · 07-11-2003, 02:35 AM

Oh and about my car catching on fire, that is already something you have to worry about even on a stock RX7. What with all the leaky injectors and exploding coolant tanks and everything.

One of my future mods will be a fire extinguisher in one of my rear bins. Dont want an engine fire to own me.

Ludatic · 07-11-2003, 02:42 AM

Quote:

Originally posted by SuperSH

When you just wrap the wire arround the post or another wire the voltage and signal won't be constant and will give you nothing but problems, not to mention it can cause your car to catch on fire.

agreed.

wtf is this??

yea man you'll wanna make sure everything is secure.. try to avoid stuff like that in the future.

edit: no offense, but when i saw that pic i was like wtf.

BlueShadow · 07-11-2003, 02:53 AM

Quote:

Originally posted by Ludatic

agreed.

wtf is this??

yea man you'll wanna make sure everything is secure.. try to avoid stuff like that in the future.

edit: no offense, but when i saw that pic i was like wtf.

No offense taken hehehe, the wires in that pic is by no means the finished product. I just quickly threw a spare wire on there to test out the sender (to see if it needed a ground).

I previously had the wire all wound up nice and neat with the stray wires snipped off, but then my problems arose. So I had to do a bunch of tests to locate the problem(s), and I didn't need the wiring to be nice and neat for that.

SuperSH · 07-11-2003, 02:58 AM

[quote]Originally posted by BlueShadow

Quote:

I'll just go to NAPA and pick up some good connectors and some 18 guage electrical wiring.

Yep.

Quote:

The second wire was the wire that I was using to give the sender a good ground. Using it didn't have any changes though, so it is no longer on there.[/b]

Good.

Quote:

First location I use under the shifter console, second location is now in the engine bay on the frame (pic #3). But I think I will ground it to the engine bolck instead.[/b]

You can do both. But for the best ground use the one that connects the block to the body, best of both worlds. Make sure there is no paint on the connection to ground only metal to metal.

Quote:

The only reason I mention that cardboard or plastic looking washer is because that was what changed my temps. Before I had everthing wired u the display would just show 375 F. Changed ground locations for gauge and dimmer switch, still showed 375 F. Tried using a grounding wire for the sender probe, still 375 F. During all that the BLUE wire was at the bottom of the sender screw, when I moved the cardboard washer to the bottom then my indicated temps started to change. When I removed it, my temps went back to 375 F.

That cardboard or plastic looking thing seems to be part of the puzzle. But I will find out for sure when I get some good connectors for all the wiring. [/b]

Your on the right road. Shoot that guy that said that twisting wire and elec. tape fixes everything. Read thru the instructions again and find out whats missing with the plastic and fiber washer.

BlueShadow · 07-11-2003, 07:05 PM

hello again everybody,

I just got done re-wiring everything and guess what? still no worky. I used top quality butt connectors and the cconnectors with the circles for the grounds and still same symptoms as before.

One thing I did do different is the main ground. I grounded the gauge to the frame at first...indicated temps were 375 F. Moved the gauge ground to a 12 mm bolt on the TB, temps went down to 340-350 (back and forth).

So does my problem seem to be me getting a good ground? Also when I moved the ground to the TB I didn't remove the cardboard/plastic looking washer on the sender. I have to wait for the engine to cool down some. But I still have not been able to find the significance of this funky looking washer. Do all temp senders from Autometer, Greddy, etc have a washer that is not made of metal?

When the engine cools down I'm gonna remove my filler cap and take that washer off yet again. and try out different ground locations. I'm also still not sure if the adapter plug is in far enough in the thermohousing. When the car gets warmed up the coolant in the thermohousing expands and rises to the top right? I was thinking that maybe the water isnt touching the sender inside the housing. I will also get some boiling water and test out the sender to make sure it works.

BlueShadow · 07-11-2003, 08:52 PM

Hey guys,

I was doing some more tests in my car and I found that the temps could be changed by turning certains things on/off/up/down.

Once again here's how I have everything wired up:

Red +12V = ignition slot--above fuses under dash slot on the right

Blue = sender--wire is away from alternator

Purple = dimmer--gounded under shifter console

Black = gauge ground--12 mm bolt on upper part of throttle body

Remember I'm not an electrical expert so I have no idea why my car would be behaving this way.

stock temp reading is one tick below mid-point

364 F = all accesories off
360 F = fan 1 (idle ~500 rpm)
360 F = fan 2 (idle ~500 rpm)
349 F = fan 3 (idle ~800 rpm)
345 F = fan 4 (idle ~800 rpm)
338 F = AC on fan 4 (idle ~800 rpm)
360-364 F = hazards on--temp cycles between 360-364 same time as lights
357 F = foot on brake
364 F = window(s) down
360 F = window up
353 F = both windows up
360 F = pop up headlight button (returns to 364 F when headlights are up
360 F = parking lights on
345-349-334-338 F = headlights on
277 F = AC on, fan 4, hazards on, foot on brake, both windows going up, foot on gas @ 3.5K rpms
345-349 F = testing complete

what do you guys think?

Jacques · 07-11-2003, 09:43 PM

Shouldn't this be in GD?

SuperSH · 07-11-2003, 09:56 PM

Im going to need more information about the guage your using.
What is the model number of the guage and sender your using.

Is it the M9013 guage or is it the B2513 guage and S8013 Sender? And if not what is the model number.

You are most likely going to need some shelded wire to the sender to prevent the changes that your guage sees from the diffret engine/acc loads.

SuperSH · 07-11-2003, 10:03 PM

I did some more reading and the guage that your using is highly susceptible to interference. Check this page out that gives specific info on the guage your using.

Nordskog Tech page

This should provide some better info.

BlueShadow · 07-11-2003, 10:24 PM

Yah, the alternator in the RX7's are pretty close to the sender location. But to my knowledge, no one else has reported similar problems in their RX7s with the sender located in the same place. The location I used is actually pretty common, but I still wont rule out electrical interference as the cause. The how-to sites I've visited for the electrical gauge install made no mention of having to deal with any electrical interference too.

EDIT: also the gauge I have is the 2 1/16" temp gauge (M9013) and of course the sender kit is (S8013).

SuperSH · 07-12-2003, 10:54 PM

Other than using shelded cable I have no other sugestions for you. I was courious how you got a max temp of 375 on your first post and the temp guage specs state that the max temp for the guage is 350, weard. Try routing the wire to diffrent locations away from high voltage/interferance equipment. I have read at other times about people having problems with this particular guage manufactuer. I can't beleave I forgot about it. Im going to do some more reasearch.

BlueShadow · 07-15-2003, 11:58 PM

SuperSH,

I e-mailed Nordskog and asked about the temp gauge. I had asked about the fiber washer, and they said it was necessary to provide resistance for the wiring.

Nordskog said that I could use any non-conductive type washer (plastic, rubber, fiber). I bought some extra rubber and plastic washers and tried them out, but still the same problems. Tomorrow I will try to wire in the main gauge ground to the engine block instead of the TB. If that doesn't work I will try to get some shielded wiring to see if that helps. I will also take off the sender from the thermohousing and test it out in a cup of hot water to see if the sender or gauge myay be the problem.

SuperSH · 07-16-2003, 02:11 AM

Sweet. Oh ya, with the shilded wire usualy you get the best results if you ground one end of the shielding not both and try either end to see if there is a diffrence. Im still trying to figure out that waser thingy. Can you post a picture of the sender stud without any wires or washers on it. If its what im thinking the stud is insulated from the body of the sender and the insulated washer prevents the wire connection (blue wire) from touching ground/sender body. If thats the case then that would explain the grounding problems your having, sorta. Try it out and get back with me.

BlueShadow · 07-16-2003, 09:31 PM

Hello again guys,

So there I was messing with the wiring yet again, trying to figure out what could be wrong. I had the sender wires completely away from the alternator no longer making that a factor. The readings would stay the same when I changed the main ground locations around, so that couldn't be the problem. The 12V source is the same place that lots of other people use, and the alternate grounding locatio under the shifter was also good.

I was quite sure that everything was hooked up to the right place....except for the blue (sender) and purple (dimmer) wires. I was having a hard time telling which one was which, so I had always made sure to swap wires around whenever I was running a test. It turns out the dimmer switch was wired up (and grounded) to the sender so the display was bright like it was supposed to be. The sender wire was also grounded under the shifter console. I didn't think there was any possible way for me to mix up the wires, but I swapped them around anyways. I snipped off the butt connectors, and switched wires (yet again) and tested out the sender.

I attached a grounding wire frome the engine to the sender and dipped the whole sender assembly in a container of hot water...140 F on the gauge **yay**. At this point I proceeded to rapidly slap myself in the forehead 20 times, afterwhich I placed the sender back in the thermohousing and fired the car up again. The temps showed an indicated 170 F and rising. Took the car out for a 45 minute cruise on the highway and got the normal readings.

Cliff Notes: My color blind ass wired up the gauge wrong.

Thanks to all that responded to this thread