JJ7893 Posted April 12, 2009 Share Posted April 12, 2009 Hi there Im hoping you can help me on this before I spend anymore money on this temp problem I have. The temp did not work when we got the disco so I did a short on the gauge and it rasied to full so I know that works, Well I think it does! so I ordered a new green ring sensor, I fitted and it still dont work. So I did a resistor test when engine was cold and ran it for an hour and the tester did not move once. So is that the sensor faulty or not? I emailed the guy back (Got the part from E bay) and he said that it is very rare for sensors to pack up, So have I done something wrong or is the sensor faulty again? I have got rid of the old sensor so I can't test anything with it. Any ideas please thanks ...JJ Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 12, 2009 Share Posted April 12, 2009 I assume you are testing at the sensor rather than the dash end of the wire. Yes the resistance should change. Don't know the description Green ring but suffice to say the sensor on a 3.9 V8 will go from 9210 Ohms at -15C to 2420 Ohms at 19.5C and 181 Ohms at 100C. You need to know this info to calibrate MegaSquirt. Steve Quote Link to comment Share on other sites More sharing options...
cipx2 Posted April 12, 2009 Share Posted April 12, 2009 For AMR1425 the book says 136 ohm "when the coolant temp is low" and 17 ohm "when the coolant is hot", whatever that means on the Celsius scale. I thought I had some more specific values or a diagram but I cant find them. Quote Link to comment Share on other sites More sharing options...
western Posted April 12, 2009 Share Posted April 12, 2009 might need the black top sender instead of the green top version. Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 12, 2009 Author Share Posted April 12, 2009 Yes Im testing the sensor and not the gauge as I earthed the gauge and it raised to the top, So I guessed that was ok as that is how I tested other temp gauge's etc. I only changed the sensor with a green one as there was a green one there before. I have earthed the body to the neg of battery and tested it nothing, Steve_B the green I was on about is what Cipx2 is showing in his post also the engine is a diesel 300tdi but I dont think testing is any difference as there is no reading at all and yes the tester does work tried it on the battery to make sure Western is there a part number or is there anyway I can find out what colour sensor I should have on the car? It's Discovery ES 1994 300 TDI if that helps. Thanks for your imput so far guys ......JJ Quote Link to comment Share on other sites More sharing options...
cipx2 Posted April 12, 2009 Share Posted April 12, 2009 The part number is the one I already gave you in my previous post and is the only kind of coolant temp sensor fitted to 300tdi Discovery. Take the sensor out, measure its resistance on cold (room temp) then through it in boiling water (80 ... 100C) and measure its resistance again. Quote Link to comment Share on other sites More sharing options...
western Posted April 12, 2009 Share Posted April 12, 2009 Part number for the green as cipx reply above, IIRC the black one is AMR3321. as a green was fitted a new green one should hopefully sort it. Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted April 13, 2009 Share Posted April 13, 2009 Part number for the green as cipx reply above, IIRC the black one is AMR3321.as a green was fitted a new green one should hopefully sort it. Isn't AMR 3321 just fitted to defenders ?? You could do with giving us a clue as to the age of your disco. It may of had the wrong sensor fitted originally and therefore you have fitted another wrong one. Does it look like someone has bodged the wiring at the sensor to make something fit that shouldn't be there ? 200tdi disco1 should have PRC8001 which looks like.. 300tdi disco 1 until 1998 should have ERR2081 which looks like.. Quote Link to comment Share on other sites More sharing options...
cipx2 Posted April 13, 2009 Share Posted April 13, 2009 Yes, AMR3321 (i.e. the black ring temp sensor) is fitted only on Defenders. JJ gave you the clue as of which Disco he has in post # 5. ERR2081 you suggested for 300tdi Discovery is the sensor used by the EGR ecu (or ECM ecu for EDC 300tdis) and has nothing to do with the temperature indicator. Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 13, 2009 Author Share Posted April 13, 2009 Thanks again guys, so the green is for Discovery and black for Defenders etc and I test it again with cold and hot water before I order a new one, jimmy_neutron cheers for the imput I have a 200tdi and hope it was the same but sadly it was not lol. and the blue block one is as cipx2 said is right as I started to thought it was them till I tested the wire, the answer to your question Jimmy is no the connector not been cut and shut and still there in one peice. ......JJ Quote Link to comment Share on other sites More sharing options...
western Posted April 13, 2009 Share Posted April 13, 2009 ERR2081 is also the temp sender for Td5 cooling system, cos I had one here for a experiment. Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted April 14, 2009 Share Posted April 14, 2009 ERR2081 is also the temp sender for Td5 cooling system, cos I had one here for a experiment. Cheers western i thought old age was creeping in If it is a 200tdi and it was mine then i'd be going for PRC8001 as an AMR1425 is for a 300tdi but i aint getting into a handbags at dawn about it Quote Link to comment Share on other sites More sharing options...
western Posted April 14, 2009 Share Posted April 14, 2009 I'd go for the correct item to if it was my Disco, if it still doesn't work with a new sender then the gauge must be at fault. Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 14, 2009 Author Share Posted April 14, 2009 I ordered a genuine item today it will be here tomorrow afternoon so I test that and go from there. I will report my findings .......JJ Quote Link to comment Share on other sites More sharing options...
cipx2 Posted April 15, 2009 Share Posted April 15, 2009 You can also do some other tests: - use a couple of wires to connect the new sensor to the circuit (the sensor's body to the cylinder head and lengthen the wire it normally connects to) - dip the sensor in boiling water, ignition on > the indicator should rise somewhere just bellow or in the middle position (almost horizontal) - if you have a 0-100 C thermometer, dip in the water together with the sensor and note the temps while everything cools down; you should get something like: * bottom (stranded) line: aprox 45 C (40- 50) * bottom end of main temp area : 55 C (50-60) * the needle over the waves in the temp symbol (the symbol is like a thermometer dipped in waves of water): 75C * no matter how much the temp will rise above 75C up to 105C the needle will stay about there, in a horizontal position (that's why the indicator is no good when the engine overheats). - you can connect a 100 ohm potentiometer in place of the sensor and note the values you get for different needle indications; I have some values somewhere to compare to but not handy at the moment; tell me if you're gonna do this and I'll search for the data. One other reason the needle doesn't rise to a middle position is that the engine doesn't heat that much due to a faulty thermostat (stuck open), although it will eventually warm up if you climb up a hill, towing or simply apply an italian tune up (pedal to the metal). Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 15, 2009 Author Share Posted April 15, 2009 I got the sensor today, But it still dead! So I have taken out the gauge out and checked the connections where live & earth both read right. There is no broken wire from the sensor to the gauge so to me that leave the gauge being dead, What do you think? The gauge does not move a wink or anything, is it still worth trying these test cipx2? even with the thermostat stuck it should be able move it a tad or something? ......JJ Quote Link to comment Share on other sites More sharing options...
western Posted April 15, 2009 Share Posted April 15, 2009 with the end of the sender in hot water & suitably connected to the gauge it should work, sounding like a dead temp gauge to me Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted April 15, 2009 Share Posted April 15, 2009 I got the sensor today, But it still dead! So I have taken out the gauge out and checked the connections where live & earth both read right. There is no broken wire from the sensor to the gauge so to me that leave the gauge being dead, What do you think? The gauge does not move a wink or anything, is it still worth trying these test cipx2? even with the thermostat stuck it should be able move it a tad or something? ......JJ I thought you had already tested the guage and it raised to full ??? Which sensor did you buy in the end ?? If your doing the boiling water test then remember to earth the body of the sensor. Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 16, 2009 Author Share Posted April 16, 2009 Yes I did do the gauge test I shorten the sensor wire to earth and it raised to full, I will do the boil test with the sensor or replace the thermostat with a new one I seamed to have bad lucks with the thermostat! I have a wire that will earth the sensor etc, I will post some pictures later so you know I know what I'm doing I'm not all that daft! lol Forgot to say where the sensor came from "Bearmach" it was a silver box with a pic of a landy on it cost over £8 for it!! Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 16, 2009 Share Posted April 16, 2009 PM me your address, I've got 2 or 3 LR temp gauges on a shelf you can have to swap about... Quote Link to comment Share on other sites More sharing options...
JJ7893 Posted April 17, 2009 Author Share Posted April 17, 2009 Hi and thanks Turbocharger I have sent a P/M to you .......JJ Quote Link to comment Share on other sites More sharing options...
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