Temperature Gauge + Sensor, please help!

[Outatime]

Dear All,

Since the very last time I jump started my D, the temperature gauge never worked!

Well, this is what I have been doing, hoping to solve the problem:

1. All fused checked, even replaced the whole fuse box with a brand new one from specialTauto

2. Changed the temperature gauge (the one on the dash)

3. Changed the temperature sensor (a nightmare job in the engine bay!)

4. I was so fustrated that I even pull the needle out and try to adjust it to a known coolent temperature....

Now... the temperature gauge still doesn't work (it moves, but incorrectly).... Any ideas where things could go wrong? Any resistors that could be burnt??? (I have checked the resistor behind the temperature gauge, it has the correct resistance.

Advance Thanks for any suggestions/tips!

[TheOriginalMrP]

Outatime Wrote:I was so fustrated that I even pull the needle out and try to adjust it to a known coolent temperature....

You know, thats a good idea! Pull the needle off, push it back on to a desired location, then you can do away with the temperature sensor and all the other unnecessary electrics.

Then if you hear bubbling behind you, and you see steam in your rear view mirror, you know shes cooking!

Using this method, you can have a cool engine, trememdous oil pressure and battery voltage, even on tickover and with all accessories on (Thats if you decide to keep them too!)

But the bit I like the best is a full tank of fuel at all times of the day! LOL

Sorry if my method isnt the most helpful post, but it is chrristmas after all!!

Hope you get it sorted John, I'm sure NickT will have the answer.

Meanwhile, the motto of this story..... Avoid jump starting!!

Merry Christmas

Ben

[NickT]

Usual way to test is to put the ignition key into position 2, remove the electrical connector from the temp sender unit and short this to earth/ ground.

If the temp gauge goes to full scale then the wiring and the gauge is OK and the sender unit is duff.

If the gauge does not go to full scale then trace the wiring from the sender to the gauge for continuity.

I am assuming that the other gauges are working OK and that the alternator is giving correct smooth voltage.

The dash sometimes have a voltage regulator in them and if they go then the gauges can show false/ intermittent levels but I am not sure if the Delorean has one as I have not taken one apart yet. The surge from the jump start may have blown it.

Good luck.

NickT.

[stunned_monkey]

The usual culprit is the connector under the coil cover, completely from memory it's one of the pins in the blue connector. As Nick says, the first test is always to ground the connector to see if it pings up. Replacing the sender with a spade type is a) cheaper and b) a lot easier to refit.

I've yet to meet a failed gauge.

[Outatime]

Will I need to remove the coil cover or the intake manifold to get to the blue connector? And what is usually wrong with the blue connector?

[Carl Hammond]

Hey John, Merry Christmas mate.

I had the exact same thing happen with 11777 yesterday morning. We had to jump start her and think we may have touched a sensitive part of the car with the jump leads as at one point the temp gauge needle was pointing completely the wrong way!

It now just sits at the bottom of the scale and doesn't budge when driving! Although the fans are still functioning when engine hits certain temp, which is a relief.

I'll take a look at it in the next few days and let you know if I have any joy. Although after speaking to Chris Nicholson about it, it sounds like I may need a new sender.

Will let you know how I get on buddy.

All the best

[stunned_monkey]

John: The flimsy plastic cover at the front/right of the engine bay, under which all the electrical connectors to the engine reside. One of the pins in the blue multi-way is (IIRC) the sender to the temp gauge.

Carl: You need to unplug the connector to the sender and with the ignition on, ground it a few times while watching the gauge. The gauge has swung round and got stuck. It needs a "nudge" electrically and it'll ping back around and work again. I've seen this more than once.

[Outatime]

I had a look at the blue connector... unplugged it, gave the metal contacts a good clean, plug it back in securely, but it doesn't seems to do anything??

[Dodgy Motor]

Just to warn you about jump starting,
this goes for ANY car with electronics,
follow this procedure and youll never have a problem,Dont and you risk huge expense,
connect POS first,
always connect NEG last and NOT ON THE BATTERY POST. do it on an earth point,
then if needed start the other car,
Start the "dead" car,
THIS IS IMPORTANT.
when your car starts hold the revs up for a short while, 2000 should suffice,
Then switch off the slave car, DO NOT DISCONNECT THE LEADS UNTILL BOTH CARS ARE SWITCHED OFF,AND DONT DICONNECT WITH SLAVE CAR ENGINE RUNNING.
after 10 -15 mins you should be able to turn your engine off, disconnect the leads, in the reverse order of connection.
then start your car,
if you do not follow these steps you risk your alternator spikeing and upsetting your electrical system,
I know most of you will know this procedure but I just felt it best for a short reminder.
Happy jumping :lol:

[Guinney1971]

good tips there mate.

We have all sorts of probs at work with Mercs that have been jump
started (or used to jump start another car) - apparantly you've got to do
some weird procedure involving opening the boot and turning the lights on
or summat before you connect jump leads otherwise you spike lots of nice
expensive ECU's and computers

And people wonder why I like my boggo basic Cavalier (with no electrical
bits to go horribly wrong) .... :wink:

[Dodgy Motor]

YUP. Bring back the Morris Miinor I say :lol:

[Carl Hammond]

Some top tips there matey, thanks.

Only wish I had seen that post before I jumped mine a while back. D'oh! :oops:

Could now be the reason why I am having these other problems (see my post in fuel/emmissions section) on start up...

Almost certain this is what sent my temp gauge loopy.

By the way, Nick, Martin I haven't got round to doing that quick test you both suggested to fix this yet. Might have a go today if I get a chance.

Is it the large blue plug (see pic below) in the top right hand corner I need to fiddle with? If so, is it safe enough to do so with key in ignition? Sorry if that's obvious I'm still learning my way round the car! :oops:



Cheers

Kind regards

[stunned_monkey]

Woops, I forgot to double check this for you and now I'm nowhere near a car.. I'm pretty sure it's not that blue connector. It's the one closest to the bottom/front of the car... if you have a meter, unplug all the connectors and do a continuity test from the sensor itself.

OR, just hold a wire to the top of the sensor and ground it briefly while someone else watches the gauge (ignition ON). Do this a few times until it pings back into place. It's an R to ground so you son't be putting the car or yourself in any danger (except skinned knuckles getting to the sensor!).

...or wait till Monday afternoon and give me a ring - I have an engine loom on the shelf which I can very quicly probe to find the pin in question

[Carl Hammond]

Hey, everyone.

So, naturally I am getting a bit paranoid everytime I take the car out and can't tell what temp she's cooking at (although the fan's seem to be doing their job absolutely fine).

So, how might I ping the needle back to the right position to hopefully get working correctly again please?

Thanks

Kind regards

Carl

[Chris Williams]

Remove the trip reset button and insert a long thin piece of wire?? Taking the binnacle of is not to much of a job either, some fiddly nuts and washers but does not take to long.
Chris