'91 EB Temp Gauge Questions

[djacksontexas]

I read through about 20 threads with no luck in solving my particular "problem".

My temp gauge does not move at all. Here's what I've done so far:

New ECT Sensor.
New T-Stat.
New Temp Sending Sensor.
Grounded TSS against engine, temp gauge pins all the way to hot when grounded.
Checked ECT Sensor plug for 12V, passed.
Checked ECT Sensor plug for continuity, passed.

All hoses get hot, heater blows nice & hot. (Not much need for in the S. Texas, but works all the same.)

So I've done just about "everything" I could find on here so far.

Any help/guidance in the right direction is greatly appreciated.

It's an Exploder I paid $250 for, so for the time being I'm done throwing money at it until I hopefully get some guidance.

Thanks folks!

-Drew

 

[trashtruck]

i would say check the temp sender. just because its new doesnt mean its good. the gauge works when grounded? gauge and wiring sound intact.

 

[djacksontexas]

Any advice on how to verify the new sensor is functioning? Yep, the gauge works when it's grounded.That's what's got me so stumped.

 

[Maniak]

I'm assuming we are talking the 1 wire engine coolant temp sensor which is the one for the gauge... Disconnect the wire from and put your DVM on impedance. Now check the impedance when the motor is cold (ambient) and then watch it move (should go lower) as it warms up.. and if you ground it to the engine it should peg the gauge.

Post 13 in this thread has the chart with impendence numbers. http://www.explorerforum.com/forums/index.php?threads/ect-sensor-queastions.165007/#post-3459293

If you don't have a good ground between the sending unit and everything else (e.g. you put Teflon tape on the threads) it won't register.

~Mark

 

[djacksontexas]

Thanks for the reply & guidance Mark. Today after work I went ahead & took off the Teflon tape I foolishly put around the threads of the ECT sensor (1 wire), but that didn't make a change in the gauge, still reading ice cold. Hopefully tomorrow after work I'll have a chance to the check the impedance on the ECT sensor to confirm functionality.

If all else fails I'm just going to install an aftermarket water temp gauge, but I'm hoping to get the stock gauge functioning. Thanks again!

 

[larrydd999]

Some of the temperature gauges are a bit sluggish and some are almost scary. My '92 gauge is always showing near half-scale and goes higher quickly when the engine is under load. My '94 gauge barely clears the first bar before the 'n' and rarely goes higher. You may have to end up with an aftermarket gauge. I've checked both engines with a thermal 'gun' and they are almost identical when fully warmed up. I have the same brand and model thermostat in both.

 

[djacksontexas]

I had a chance to check it with my DVM, I couldn't manage to get anything on the Ohms. I'm assuming it's a bad sensor, even though it was purchased brand new. I should have done the boiling water test as I've seen around here, but alas I did not.

I'm going to just go the aftermarket water temp gauge route, it was only $20. I should've just gone the route in the first place, given the age & condition of the X I'm dealing with here.

I appreciate all the help/suggestions/guidance folks. I'm sure I'll be back with another round of questioning, but I'll start a different thread for that. (Brake issues)

 

[djacksontexas]

Sorry, one more question for this thread. When I'm putting in the aftermarket temp gauge, is there anything wrong with me unscrewing the temp sender (1 wire) & just screwing the probe for the aftermarket gauge right in it's place?

Meaning will it affect engine performance or computer communication in anyway? I don't really care that the inside gauge will no longer work after this, as I'm likely to be the final owner of this X.

 

[Maniak]

You should be fine. Unless it fill up the entire cavity (e.g. way bigger on the bulb side) it won't restrict flow. The Computer won't notice you don't have a working 1 wire sensor as it's using the 2 wire sensor.

Another option if you want to know the temperature of the coolant coming out of the engine is to put it in the heater hose. Coolant is always moving through it. Heck, you have a 1991 so you might at well add the heater control bypass valve to help your a/c (keep the hot water out of the heater core while still letting if flow). I still have the factory gauge but I pretty much ignore it and go by the sensor in the heater hose as it seems to be more accurate there.

Here's the "how to" on the heater control bypass valve: http://www.explorerforum.com/forums...orer-heater-bypass-valve-installation.190431/

~Mark

 

[djacksontexas]

Thanks Mark, that's a fantastic read! I'm definitely going to go that route. Currently the A/C isn't even working, not a big deal this time of year in TX, but come June of next year, you bet that A/C will be working. Well I know what I'm getting up to this weekend. Thanks again for everything.