89FrontPorsche

My temp gauge quit and while I was pondering the cause and fix for the problem, I was also considering a digital solution. One that mates well with the existing dashboard that could be easily/economically incorporated with the dash as-is.

That is to say, a "stick-on" digital display that doesn't look tacky or "stick-on" to the degree that appears cheap and bubble-gum.

Any ideas?

ROG100

IIRC the gauge gets its signal from the left side mirror. It also could be a loose connection in the door or ?
Swap your mirror for one that reads temperature and has a compass as well as homelink.

worf928

Unless it's the analog engine temperature gauge in which case the sender is on the left-side of the water bridge (passenger-side for you right-side drivers...)

89FrontPorsche

My mistake...Was talking about the analog engine temperature gauge. Sorry for the confusion.

So, yeah...any small digital readouts available that are 12V, easily wired in and placed next to the analog engine temp gauge?

Sorry guys. I will endeavor to be more clear. I completely forgot about the temp readout setup for the digital displays for OAT. (Outside Air Temp for you non-aviation types).

daveo90s4

Why not figure out the cause of the problem 1st - may be a trivial matter to fix? You can use the digital dash to display the water temp. reading codes that you can then convert to degrees. That might be one way to help determine where the fault lies?

89FrontPorsche

In addition to troubleshooting the analog gauge and getting it to work again, they are known to be relatively unreliable. I would like to have an actual temp readout to keep an eye on it. The digital dash, so far as I know, doesn't have a selection for engine temp, when I cycle through the options, though I suppose I can check the OM and see if that's in there somewhere.

EDIT: Nope, not available.

DR

89 was the first year they changed that to a molded type connector for the temp gauge sender and usually they are rarely a problem. Try verifing the pins of the senor and connector are not corroded and make sure it is seated properly and "locked" on securely.

Trivia, prior to 89 the temp sensor used 2 simple blade/spade connectors and IMHO more suspect to corrosion, damage and/or "decay" issues.

The gauge temp sensor is located to the left/driver side (right side standing facing the front of the engine) of the oil filler neck mounted in the top of the coolant crossover, it is a 2 pin brown molded connector that looks similar to the Fuel Injector connectors.

FYI, the identical molded connector (but Blue) on the other side of the oil filler neck (right/passenger side), (again mounted in the coolant crossover) is the temp sensor for the engine computers. I would check the condition of the pins on that too while you are at it.

This pic below from Tony Harkin's most excellent "Under the Hood - What is It -What does it do " webpage shows them clearly #2 is Temp II sensor (for engine computers) and #4 is Temp Gauge sender (#4 shown is the earlier spade connector type prior to 89), you should bookmark Tony's page and his website, it will be a great reference for you. http://members.rennlist.com/v1uhoh/underthe.htm




Hope that helps,

Leon Speed

Let me play the devlis advocate here. What will an more accurate reading accomplish? It doesn't change the operating temperature. Overheating alarm is triggered by the sender. Besides, who knows what the exact operating temperature should be?

worf928

Known by whom?

I've found the engine temp gauges from 89 onwards to be, in most cases, dead nuts accurate. Now, the pre-89 with the bare connections (as per D.R above) are usually inaccurate.

daveo90s4

89frontporsche - YES, the digital dash DOES have an option for engine temperature. But you need to put it into diagnostic mode, not normal operating mode. Can display lots of info, including oil pressure too, etc. The procedure is in the manual. I was just suggesting you could do this to see what temp. code the temp sender and wiring was sending to the analogue gauge. Or you could take the temp sender out and stick it in hot water, with a thermometer and a multimeter to see what electrical reading you get at different temps. When / if the analogue gauge is made to function, the then easiest way to calibrate it is to ensure the engine is at normal operating temp with an IR gauge and if necessary pull the needle off and slide it back on so its reads in the middle for normal engine temp.
HTH

89FrontPorsche

Dave, I had no idea that was possible. Pretty cool, that. Thanks for telling me.

Worf, I had an '87 where the gauge was wonky. I did not know of the reputation for the '89, which is very good to know.

Aryan, I just wanted to have a number. But given the input by Worf, I now consider that to be unnecessary. I did know that the warning light and gauge came from different sending units, though.

Thanks all for your excellent suggestions! I definitely feel more educated on the matter now and I've noted the connections on the sending unit are good but need to put the meter on it....I suspect the gauge in the dash has a bad connection somewhere; Doesn't read anything but stone cold all the time.

Summer's here and though I don't think there's a lot to worry about, I just like having the gauge there to keep me "informed".

But I am eternally grateful for everyone's help. Lots of smart people here! This is what makes this site so very, very valuable and the character of the people here is very high. All willing to help, intelligent input and, of course, telling me things I never, ever knew.

THANKS!