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Author Topic: 1.6 and oil  (Read 559 times)
Morne
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« on: June 08, 2019, 10:26:18 pm »

The oil warning light in my 1.6 never comes on, as a result I am going through the system to find the fault/s. So far a few questions:

a) As per the photo, are these the min and max marks on the electronic dipstick?


b) On the 1.6 I saw a diagram indicacting that the oil pressure sensor and the low oil pressure switch are located together. However on mine it appears that there is no low oil pressure switch, and only the sensor for the guage on the dash. Where there versions which did not have the switch fitted?

c) As the oil light never comes, I suspect the control unit. I took it out and took it appart. It appears that somebody has alredy been in there. Please see the photo, and the red where I suspect a component has been removed. Are the any circuit diagram for this unit? Do anybody have a photo of the inside of the units?
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Anders Dinsen
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« Reply #1 on: June 09, 2019, 10:32:32 am »

Here's a photo of an oil level sensor unit. As you can see there's roughly the same components, but they're located differently on the PCB. I wonder why? Could there be a difference between the units for the 1.6 and the 2.2? I would think not, but perhaps? This is from a 2.2. The SN96525N is an anlogue IC for this special application, if you can find the data sheet, I'm pretty sure the diagram is from an application note.
« Last Edit: June 09, 2019, 10:41:37 am by Anders Dinsen » Logged

'82 Murena 2.2 prep 142
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suffolkpete
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« Reply #2 on: June 10, 2019, 11:31:57 am »

The oil warning light, by which I assume you mean the one in the cluster of four next to the clock, only signals a low level, which it does by measuring the resistance of the thermistor in the dipstick.  There should be an ignition feed to the lamp and the lamp is lit when a ground signal is applied from connector 3 on the control unit.  Connectors 1 & 2 are connected to the dipstick, 4 is an ignition live feed and 5 a ground.  If everything is working correctly and there is sufficient oil, the lamp should flash once when you turn the ignition on.  The max and min marks on the dipstick are as you say.
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Morne
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« Reply #3 on: June 10, 2019, 09:39:33 pm »

Thank you for all the information.

Question 1 solved : the correct reading of the oil level on the dipstick  Smiley

Question 2 & 3 : As per the attached figure 1, the pinout provide above of the connector for the oil level unit makes sense. I will check all the wiring from the dipstick to the unit, and then pull pin 3 to ground to check the connection from the unit to the indicator light. Unfortunately it is tricky to find a datasheet for the IC on the PCB. A few quick searches did not provide any results.

The reason I am also looking for the oil under pressure switch, is per figure 2 attached. This is from the Murena service manual, and show two paths by which the oil level warning light in the dash centre can be switched on. One is via the electronics dipstick and the electronic circuit(as per above), and the second via a low oil pressure switch on the engine. Where is this switch located?
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Morne
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« Reply #4 on: June 10, 2019, 09:53:09 pm »

The low oil pressure switch as per attached, appears to be located together with the sensor for the oil pressure guage. However as per my earlier photo, mine seems to be blanked off. Is it located at a different place on a 1.6 Murena?

This is where the drawing comes from:
https://www.ebay.fr/itm/Manocontact-de-pression-dhuile-Matra-Murena-1-6-et-2-2-L-Bagheera-Rancho-1979/191988798966?hash=item2cb36c95f6:g:PTMAAOSw9GhYk3ZT
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suffolkpete
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« Reply #5 on: June 11, 2019, 10:13:39 am »

The switch is shown in the official parts list, but on both the 1.6 engines I have it is blanked off as in your photo and there does not appear to be any wiring for it in the engine bay.  I think it must have been deleted as unnecessary, as has the low vacuum warning.  I wouldn't worry, its absence hasn't caused any problems in the 11 years I've owned the car and it is not necessary for the correct function of the oil level indicator.
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roy4matra
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« Reply #6 on: June 21, 2019, 10:48:12 pm »

The low oil pressure switch as per attached, appears to be located together with the sensor for the oil pressure guage. However as per my earlier photo, mine seems to be blanked off. Is it located at a different place on a 1.6 Murena?

This is where the drawing comes from:
https://www.ebay.fr/itm/Manocontact-de-pression-dhuile-Matra-Murena-1-6-et-2-2-L-Bagheera-Rancho-1979/191988798966?hash=item2cb36c95f6:g:PTMAAOSw9GhYk3ZT

On some Chrysler Simca Talbot models (the Tagora 2.2 was one) they did actually have a separate low oil pressure warning light in the instrument panel, and the low oil pressure switch was wired up and used.

However on the Bagheera and Rancho they often had a low oil pressure switch fitted but never wired up and the cars never had a low oil pressure warning, only a low oil level warning.  One reason the oil switch remained fitted was it had the correct thread to screw into the block whilst the oil pressure sender did not!  So the oil switch was simply holding the tee-piece into which the oil pressure sender was fitted.  This often happens in large organisations where something that has been done for a long time, doesn't change unless someone takes a close look at things. (usually to do with cost cutting!)

When they got to the Murena, someone did decided it was a waste of money to keep fitting a switch which was never being used, and so they finally fitted a banjo bolt to hold the tee-piece in place.  Ideally they should have changed either the oil pressure switch or the thread in the block so they matched and then they could have fitted the oil pressure sender directly into the block.  But it was probably decided at the time that to change either was not as cost effective as simply using a banjo bolt.

The Murena, both 1,6 and 2.2, never had a low oil pressure switch.  However, with a low level warning and an oil pressure gauge it really is not necessary.

Roy
« Last Edit: June 21, 2019, 10:53:41 pm by roy4matra » Logged

Morne
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« Reply #7 on: June 30, 2019, 01:25:09 pm »

Thank you for the information provided.

It appears to me that the electonics circuit which operates the electronic oil level measurement has died.
As a result I was checking if there is a "backup" in the sense of the low oil pressure switch. From the above I gather this is not the case, so really I need to see if I can get te electonic circuit going again.


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suffolkpete
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« Reply #8 on: July 01, 2019, 11:59:28 am »

Before you bin the electronic module, check the edge connectors, they are the same as on the fuseboard and often crack.  I was interested to note that your illustration shows six connectors, whereas Roy Gillard's circuit diagram shows five. The official manual shows six, motivating me to delve under the dashboard of my car and check and it indeed has six, so ignition feed and ground are 5 and 6, with 4 unconnected, not as I stated earlier.  Your best bet is to try and find a second hand module, I don't think they often give trouble, so it should be possible to find one.
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roy4matra
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« Reply #9 on: July 04, 2019, 10:26:18 pm »

Before you bin the electronic module, check the edge connectors, they are the same as on the fuseboard and often crack.  I was interested to note that your illustration shows six connectors, whereas Roy Gillard's circuit diagram shows five. The official manual shows six, motivating me to delve under the dashboard of my car and check and it indeed has six, so ignition feed and ground are 5 and 6, with 4 unconnected, not as I stated earlier.  Your best bet is to try and find a second hand module, I don't think they often give trouble, so it should be possible to find one.

Thanks for pointing out the slight inaccuracy in my earlier wiring diagrams, Peter.  I have been constantly checking and updating them over the years, and adding subtle extras, so they do change with time and hopefully get better.

So there are things like the 1.6 amplifier module wiring connections and plug are now shown; as is the plug layout to the distributor; and the horn now has an earth (it earths through its mounting bracket).  The wiper switch to motor is now more correct with the park connection wiring; and yes the oil level control module has the 6 pins where it previously had 5, so the unused pin 4 is shown.

Anyone wanting an updated graphic file can email me directly - not here, as I'll need some details because every file is now unique to the car including its chassis number.

Roy
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roy4matra
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« Reply #10 on: August 01, 2019, 08:16:22 pm »

Before you bin the electronic module, check the edge connectors, they are the same as on the fuseboard and often crack.  I was interested to note that your illustration shows six connectors, whereas Roy Gillard's circuit diagram shows five. The official manual shows six, motivating me to delve under the dashboard of my car and check and it indeed has six, so ignition feed and ground are 5 and 6, with 4 unconnected, not as I stated earlier.  Your best bet is to try and find a second hand module, I don't think they often give trouble, so it should be possible to find one.

PLEASE NOTE THERE ARE TWO OIL LEVEL CONTROL MODULES.

To clarify the situation, I have rechecked my own cars which are 1982 and 1983 builds, and can confirm that the oil level module in these has only 5 pins.  If you check the parts manual, you will see that there is a different module for pre-1982 Murena and these obviously had six connection points but only 5 were used, leaving pin 4 unused.

The later oil level control module has only 5 pins and all are used.  The official Matra wiring diagram was for the original 1981 model year cars built from September 1980, and since they did not produce any updated diagrams, I had used my original 1982 car to correct some of the mistakes, unknowing at the time that there were differences in the number of pins between the early and later cars.

So please be aware if you have a 1980/81 build Murena the oil level control will probably have a 6-pin module (with pin 4 unused) but if you have a 1982 or later Murena it will have the 5-pin module with all of them being used.  So my diagrams for any 1982 model or later should still be correct.  I can provide an updated diagram showing a 6-pin module for 1980/81 builds if you need one.

Roy
« Last Edit: August 01, 2019, 08:22:07 pm by roy4matra » Logged

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