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skintrade230
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Joined: Dec 14, 2011
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PostPosted: Wed Dec 14, 2011 12:06 pm Reply with quote Back to top

I have recently changed from an Audi A3 1.8 20v sport to an Audi 80 1.8 20v cabriolet.

Its a 2000 V with an ADR engine.

I have the common problems associated with both fuel gauge and the temperature sensor.

Firstly the fuel gauge. Its over/under reading and generally moving around giving me false readings. I have had diagnostics and the suggestion was to first replace the voltage stabiliser and or the circuit board. I ordered the VS from Audi and when I went to replace it the parts were different. With much discussion with Audi they have said that the part from my car was not an original. They seemed to have modified the part an added a smaller screw and a brass heat sink. No difference with either module and I have a good reading from a voltage meter so I'm guessing its not either. Next course of action may be to take a look at the fuel sender?

Secondly the temperature sensor has worked a few times but again giving the wrong reading (72). On investigation the sensor had been replaced with an A3 sensor (Black/yellow) and a square cap. I have been to Audi and with my ADR engine I have a choice of only 3 or 4 pin either square cap or oval blue or green. I have only TWO wires coming from the loom not 3 or 4. I have tried the green 4 pin with no joy.

Another suggestion was a 2 pin sensor from a 2.0 A4!?

many thanks
 
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CCV6
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PostPosted: Thu Dec 15, 2011 5:40 pm Reply with quote Back to top

If both the fuel gauge and temp gauge go bad then its usually the voltage regulator. Usually the voltage regulator is ok its just the terminals that are bad or furred up/corroded. It can be intermittent. The gauges tend to go to zero.

If the temp guage is reading low this is more complex and is down to resistance in either the wiring, the gauge circuit board and even the sender. Usually its the contacts on the circuit board via a screw bolt are bad and simply by tightening, sanding the contacts or using a shake proof washer it improves the reading. See picture.

I am not sure the senders for the A3 or A4 will work as they use a completely different ohm range. (partly to get round this issue of minor variance on ohms with old age) .

If you search some of the old posts you will see some simple tests with resistors you can do to prove the temp gauge.
















http://www.bentleypublishers.com/tech/vw/bentley.vw1301.testing.htm

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Audi Cabriolet 2.8 2000
Audi A4 TDI 2000 (180k on Veg oil)
Audi 80 TDI 1993 (190k) Written off
Passat 1979 scrapped 
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skintrade230
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Joined: Dec 14, 2011
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PostPosted: Thu Dec 15, 2011 8:35 pm Reply with quote Back to top

Thanks for the help.

I will definately try your suggestion with regards to the temp gauge.
But any further help to identify which colour/shape temperature sensor to replace it with would also be helpful as I know I have the wrong one installed and I only have two wires from the loom...

The fuel gauge does read fuel but just not correctly and it goes down when you go uphill or round corners Sad but I have not taken a look at the screws and I will add some spring washers & see what happens. The contacts seemed to be clean...
 
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CCV6
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PostPosted: Thu Dec 15, 2011 9:54 pm Reply with quote Back to top

Not sure on this engine but there are normally two temperature senders. One for the instruments (3 pins or 4 pins) and one for the engine management computer (possibly 2 pins).

The gauge temp sender type is dictated by the instrument cluster .
So an ADR engine in a Audi 80 Cabriolet will have a different sender from a ADR engine in an Audi A4.

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Last edited by CCV6 on Thu Dec 15, 2011 10:17 pm; edited 1 time in total 
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CCV6
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PostPosted: Thu Dec 15, 2011 10:09 pm Reply with quote Back to top

skintrade230 wrote:


The fuel gauge does read fuel but just not correctly and it goes down when you go uphill or round corners Sad but I have not taken a look at the screws and I will add some spring washers & see what happens. The contacts seemed to be clean...


The screws dont cause this fuel gauge fluctuation issue, they just cause the temp gauge to read low due to higher resistance.

On mine the voltage regulator caused the fuel gauge and temp gauge to go to zero together. This however could I guess show up as a fluctuation if the connection was intermittent when you went round a corner.

Only other point to remember is the car is an old design from the 1990's and the gauge does fluctuate a bit on slopes.

Hope it helps.

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skintrade230
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PostPosted: Thu Dec 15, 2011 10:39 pm Reply with quote Back to top

Thanks for your response.

So am I right in thinking that despite having only two wires from the loom I could still use a 3 or 4 pin temp sensor?
I would have thought that I would need either 3 or 4 wires from the loom?

I definately have only two...and I also need to know if it should be either a square or oval cap for my car.
 
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skintrade230
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PostPosted: Thu Dec 15, 2011 10:42 pm Reply with quote Back to top

Oh by the way the instrument cluster I have for my car is a Hella 8AO/893 919 067 D.
 
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CCV6
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PostPosted: Fri Dec 16, 2011 5:37 pm Reply with quote Back to top

skintrade230 wrote:
Thanks for your response.

So am I right in thinking that despite having only two wires from the loom I could still use a 3 or 4 pin temp sensor?
I would have thought that I would need either 3 or 4 wires from the loom?

I definately have only two...and I also need to know if it should be either a square or oval cap for my car.


Oddly the ADR engine sensors for cooling do not show up in my version of the Audi parts software. Someone else might be able to get it with a newer version of the software.

For what its worth the F76 thermoswitch with four pin temp sensor has 1) +12v supply and 2) the resistance output to the gauge in the dash. The other wires are for the air conditioning safety cut out and a signal to the overheating warning lamp. The F76 switch is usually used on the V6 2.8 and 2.6 engines. (it could be others...)

There does seem to be a right mix of sensors. 3 pin and 2 pin. Some of the 2 pin being for the engine management and others 2 pins being one for the over heating lamp and one to actuate the temp gauge.

So no real help....

Anyway the sensors are fitted to your engine - I would just test them with an ohm meter to see if the resistance is in spec. 37ohms hot and 660ohms cold. This spec does not appear to change with the engine type.

Worth a try...

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oxfordpaul
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PostPosted: Sat Dec 17, 2011 10:28 pm Reply with quote Back to top

Hi, probably not this but on my Corrado I had a fuel gauge that was all over the place and it turned out it the fuel pump/sender assembly was floating around in the fuel tank intsead of being screwed tightly to the floor! I'm not sure if Audi's have a similar set up but just a thought.
 
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Marvin
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PostPosted: Wed Dec 21, 2011 10:45 pm Reply with quote Back to top

This may help...

http://www.audifans.net/ftopict-17733-.html

My water temp gauge issue was due to a broken printed circuit board track. All was fine when the lights were on. The heat from the bulbs would cause the board to expand and so make the joint!

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andrewaudi
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PostPosted: Mon Dec 26, 2011 5:59 pm Reply with quote Back to top

The terminals on the back of the temp and fuel gauges are a nightmare, I have soldered mine and the joint still breaks! I never saw the spring washers before, that's what I'm trying next! It really is a poor bit of design.

My petrol gauge works fine, until the temp gauge drops off, then the petrol gauge drops too, I imagine this must be to do with voltage regulation, because when my temp comes back up, the fuel does too.

The fuel gauge also goes down uphill and up downhill, the sender must be positioned towards the front of the tank! Smile
 
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andrewaudi
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PostPosted: Wed Dec 28, 2011 12:07 pm Reply with quote Back to top

Maybe make this one a sticky? It's a problem that keeps popping up on this forum...
 
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andrewaudi
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PostPosted: Wed Jan 11, 2012 2:13 pm Reply with quote Back to top

I can confirm that my temperature gauge problems look like they are finally solved with the spring washers. Got a heap of them in a little box for about 3 quid from Maplin!
 
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CCV6
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PostPosted: Wed Jan 11, 2012 6:49 pm Reply with quote Back to top

Cool. Was it the temp gauge screws or the voltage regulator screw?

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andrewaudi
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PostPosted: Thu Jan 12, 2012 6:39 am Reply with quote Back to top

Just the temp gauge screws, since I put in the spring washer, it's actually reading a slightly higher temperature than it did before, just sitting slightly below 100, covering the right side of the 0 in 90.

I think I have every possible problem with my coolant system, now I have a slightly musty smell when I put the heating on, my windows fog up slightly as the car heats up. I suspect the eater matrix, going to wedge some K seal in it, easier and lazier than dash out, but after a wee search on here, the heater matrix is a fairly common suspect. Sad

The joys of a 15 year old car...
 
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CCV6
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PostPosted: Thu Jan 12, 2012 5:33 pm Reply with quote Back to top

Check the expansion tank as the pipe on mine had a slight crack that was giving out wisps of anti-freeze smell that were getting sucked in to the vent system

.

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andrewaudi
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PostPosted: Thu Jan 12, 2012 5:50 pm Reply with quote Back to top

How much was a replacement?

I stuck in k seal today, I am going to flush it out next week, if my tank is all brown it'll be getting replaced anyway, I hate to see a brown tank on a car...

Usually you only get that when some cheap a.... has used rad weld or k seal in their car! Smile
 
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smokie
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PostPosted: Fri Sep 14, 2012 11:30 am Reply with quote Back to top

Had a small problem with my temp gaugue on dash board so took it out and also just cleaned up the washers on mother board and made sure they was tight as some was not, put it back together and my temp gaugue is working perfect now

Smokie
 
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audioc
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PostPosted: Fri Sep 14, 2012 4:46 pm Reply with quote Back to top

the expansion bottles aren't that much- less than 30 from a dealers, if memory serves- and that's a common fault on a lot of the "older" Audi's...

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