1993 temp gauge readings

[woknap]

Hi
my '93 has been displaying cold temp when the engine is warmed up.
I bought a new temp sending part that connects to the single wire just to the left side of thermostat on manifold.
I have been reading many different threads and one of them talked about sender grounding to the manifold? I read someone used teflon on threads and the new gauge did not work because it insulated the sender from ground.

If true,
why did my new part come with teflon on the threads...I should take it off?
thanks greg

 

[Anime]

The stuff on the threads from the factory is probably not teflon, but a locking thread compound both so it seals the threads from leaks, and to prevent the sensor from backing out and causing damage if coolant leaked out rapidly and the engine overheated.

The teflon usually talked about, that can isolate the metal parts, is teflon tape, the white stretchy tape used in plumbing. Used sparingly, with one or two wraps around threads, it can seal liquids from getting by, but also allow the threads to cut-in so there is metal-to-metal contact where it needs it.

I'd suggest installing the sensor as-is and see what you get, before messing with anything that's on there.

If you can't get a gauge reading with the new sensor, then you might consider cleaning off the threads to check if that's the issue.

Be sure to check the wiring from the sensor to the gauge, including under the dash and behind the gauge cluster, before messing with the new sensor though. You don't want to mess up a new sensor and find out later that it was just a shorted wire or even a bad gauge.

 

[Number4]

I have a similar issue. Mostly reads cold, sometimes goes to normal. In speaking with my dad, who bought it new in 94, he stated he'd had the dealer look at it at least 3 times. I believe they kept replacing the sensor. This would have all taken place pre 2002. It's irritating to say the least. I've yet to mess with it.

 

[Kingphil]

If you have already replaced the temp sending unit, the problem most likely lies with the wiring or the gauge itself, take some time and try to find either a break in the wires or a short somewhere between the unit and gauge, the gauge could also be bad

 

[woknap]

some success except for a couple codes

Hi
My problem was open thermostat and now gauge shows needle on "o" in normal, rpms are lower at about 750, and has good performance.
Next I will check to see if mpg came back up from 10 to 15.

I took her out and got CEL. Thought it was a few minutes after starting, but tested idea tonight and it seems the CEL shows when going 50 to 60 mph.
Just did quick pull with engine on and codes were;
000 111 10 113 122 123 157 158 172
113 122 123
I know this is not a complete story, but I am wondering if the computer needs some time to adjust to a good mix because I went three weeks running very rich?
I just tested on the road again and CEL went on at 50 for a couple minutes, went out when I slowed down for turn, and did not come back on for the return trip at 45mph.
My other thought is about a very small coolant leak possibly leaning out the mixture on that right side?
Thanks greg

 

[natenkiki2004]

It would be good to disconnect the battery to clear all the codes and have the computer re-learn everything. That thermostat likely threw everything out of whack. Once it's cleared, drive it around and see if you get CEL. Then pull the codes and see what you have.

 

[larrydd999]

With regard to the original issue - when I first bought it about 3 years ago the temperature gauge on my '94 Limited would barely go into the normal range. Changing the sender did little or no good. I ended up using contact cleaner (the type that does not attack plastic or rubber) on the connectors and it has been working well since. Occasionally it takes a bit longer to get to its usual spot (around the 'o') but it's probably just a sluggish needle bearing in the gauge.

 

[Number4]

I'll have to look at the wiring.
I'm currently yanking the engine and overhauling the vehicle.
In pulling the thermostat and housing out, the tsat looked horrible. I'll have to go back and see if it is stuck open.

 

[Exploring XLT]

I'll have to look at the wiring.
I'm currently yanking the engine and overhauling the vehicle.
In pulling the thermostat and housing out, the tsat looked horrible. I'll have to go back and see if it is stuck open.

I know this is old, but did you end up solving it?

 

[Number4]

I know this is old, but did you end up solving it?

Well, been a while. I’m pretty sure I put in a new T-Stat as well as a new sensor. I didn’t do anything with the wiring.
It’s been reading just below the middle of the gauge at operating temp.

 

[allmyEXes]

I may be wrong on these newer vehicles but can you not ground the tempurature sender wire to the engine block and if the wiring is good it should peg the gauge all the way HOT?

 

[Exploring XLT]

I may be wrong on these newer vehicles but can you not ground the tempurature sender wire to the engine block and if the wiring is good it should peg the gauge all the way HOT?

You are right in theory... I didn't actually confirm. I think mine was just a mostly broken wire, my reading was just barely up, and would occasionally jump to normal, I replaced the sensor, and then swapped the instrument cluster, and I ended up needing to run a new wire from sensor to dash.