P38A Gauge Temp Sensor AMR5929 (green)

Hi folks,

just a quickie but do any of you fine folk know whether both the Gems and Thor V8s used the same sensor ?

I’ve read that the gauge is basically a placebo but mine has gone from
Intermittent to dead.

I know that they’re a bugger to get hold of these days but I may have found a donor but just wanted to check before making the trek.

thanks again

Bob

From memory I think they are different,one has a single wire and the other two.

Bugger

tomcat59alan said:

From memory I think they are different,one has a single wire and the other two.

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Was that not the oil burner?

Grrrrrr said:

Was that not the oil burner?

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Not sure, I'm thinking back to the black bastid,4.6 Gems.

GEMS has a sensor for the ECU and another for the gauge, Bosch makes do with one for both.

Marshall8hp said:

GEMS has a sensor for the ECU and another for the gauge, Bosch makes do with one for both.

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I think the question was if they were interchangeable between GEMS and Thor?

Grrrrrr said:

I think the question was if they were interchangeable between GEMS and Thor?

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Well I'm a blind stag. no eyed deer.

tomcat59alan said:

From memory I think they are different,one has a single wire and the other two.

Click to expand...

I think the second wire is only an earth rather than relying on the sensor thread in the block.

There is a single pole version from earlier (AMR1425 or something) and someone else suggested checking some wiring connections under the coolant reservoir.

I did notice on one of the US forums that they recommend Ultraguage -which is basically a ODBII reader which gives an accurate display of engine temp (and other parameters) on a smartphone.

ifnots going to be pricey / impossible to get a replacement sensor for the gauge, maybe that’s the way to go

awkwardbob said:

There is a single pole version from earlier (AMR1425 or something) and someone else suggested checking some wiring connections under the coolant reservoir.

I did notice on one of the US forums that they recommend Ultraguage -which is basically a ODBII reader which gives an accurate display of engine temp (and other parameters) on a smartphone.

ifnots going to be pricey / impossible to get a replacement sensor for the gauge, maybe that’s the way to go

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Hard to believe that it's impossible to get a sensor, the V8 is or has been used in many different cars including specials. Someone must do sensors.
If the sensor does not work, how will an Ultraguage OBD reader get a temperature reading to display?

Is the engine running ok? because I was thinking if it's two sensors in one, one must go to the ECU to control the fuelling according to temp,
and the other just does the gauge, might be worth testing them with a multimeter.

The cheap, readily available ECU sensor is working just fine and it’s that (I believe) which speaks to nanocom / odbII.

The green / gauge one is the tricky bugger and I’ve seen no news of a replacement / alternative / oem option.

I may ask the local main dealer tomorrow for a laugh !

awkwardbob said:

I did notice on one of the US forums that they recommend Ultraguage -which is basically a ODBII reader which gives an accurate display of engine temp (and other parameters) on a smartphone.

Click to expand...

Sounds like Kermies madness

awkwardbob said:

There is a single pole version from earlier (AMR1425 or something) and someone else suggested checking some wiring connections under the coolant reservoir.

I did notice on one of the US forums that they recommend Ultraguage -which is basically a ODBII reader which gives an accurate display of engine temp (and other parameters) on a smartphone.

ifnots going to be pricey / impossible to get a replacement sensor for the gauge, maybe that’s the way to go

Click to expand...

You can use an app called Torque on the v8 engine via you smart phone and a bluetooth dongle and you can see the engine stuff as you drive.

Yip that’s the one Nev uses

awkwardbob said:

The cheap, readily available ECU sensor is working just fine and it’s that (I believe) which speaks to nanocom / odbII.

The green / gauge one is the tricky bugger and I’ve seen no news of a replacement / alternative / oem option.

I may ask the local main dealer tomorrow for a laugh !

Click to expand...

Put an ohm meter across the sensor with it disconnected and engine cold and not the reading, do the same with the engine hot, the reading should be a lot lower. This can be done with the sensor out of the engine using a pan of hot water.

This lot say its been superseeded but the new number doesn't show any fitting to a RR.

alleuro.com: Genuine Land Rover Front Right Engine Coolant Temperature Sensor AMR5929 AMR 5929

Can you see any Bosch numbers on it?

J

awkwardbob said:

The cheap, readily available ECU sensor is working just fine and it’s that (I believe) which speaks to nanocom / odbII.

The green / gauge one is the tricky bugger and I’ve seen no news of a replacement / alternative / oem option.

I may ask the local main dealer tomorrow for a laugh !

Click to expand...

According to Rave, the Thor uses a single unit that, contains both sensors with four wires coming from the plug, two for the ECU and the other two to the BECM to operate the gauge but,
when I had a look for pics of it, appears to only have two terminals

Going to investigate more fully tomorrow when I have more time but it looks like the wiring may be the source of my issue.

It appears a different connector has been spliced onto the end (green and black wires in the loom are both red at the connector) so I think a continuity check is a good place to start.

also the insulation has baked hard and brittle and is breaking away.

my vehicle had a ‘new’ engine about 60,000 miles ago and the evidence points to its predecessor having overheated quite badly ! -so I wonder if that has damaged the insulation.

there are also a couple of multi-connectors under the coolant reservoir which are pretty oily and yucky so a bit of a clean there may help too.

Funnily enough I’d thought about doing the boiling water in a jam jar thing to see if the sensor was ok and also varying the resistance across the wiring to see whether there was any gauge movement.
I’ll yet you know how I get on.

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