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Electric Oil Pressure Gauge

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#1
I am having 'silly' problems now with a 52mm electric oil pressure gauge I am trying to install on F4 No 2.
I have wired it exactly as I did for F4 No 1, which works well.
Soon as ignition is switched on needle swings way past the 100 psi mark, even with the wire to the oil pressure sender disconnected.
Have tried a 2nd gauge with same results.
Scan of fitting instructions attached for information.

Any thoughts please?? Thanks.
 

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Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#3
have you connected + via other instruments + ?? If so it'l boink out like this..
Hi reidalpine.
I see where you are coming from.
I have the same set up on F4 No 1. Water Temp; Voltmeter and Oil Pressure and all work perfectly. Common points are a) earth and b) ignition switch. Have totally independent wires to the respective senders. Lighting to instruments is a combined feed and earth system.
I will disconnect water temp & voltmeter and try with just the 2nd oil pressure gauge and see the outcome.
Thanks for your comment.
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#4
I disconnected all other instruments and used the 'spare' oil pressure gauge.
With ignition on needle goes off the scale completely.
No difference with engine running.
More confused now. Any thoughts anybody?? Thanks.
 

laxeian

Enthusiast
Messages
218
Location
Galicia
#5
If there are interchangeable have you tried swapping the sender unit itself over from one van to other?
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#6
If there are interchangeable have you tried swapping the sender unit itself over from one van to other?
Hi laxeian
It is a spare sender that is fitted. So have 2 gauges and 2 senders to play with.
I am still very confused about what is happening.:doh:
Regards
Tom
 
Messages
1,448
#7
Hmm.is the sender-unit itself grounded? remember if you use teflon tape on senders threads you would need to establish separate ground
 

laxeian

Enthusiast
Messages
218
Location
Galicia
#8
Just a thought, angels last reply to your problem with the wiring of the rev counter, that sometimes the coil wires are reversed and this does not affect running, the gauge started working when connected ( diagram wise ) to the wrong side.
Could the original wiring to the coil at some stage been reversed on the van the your having problems with gauges and not on the van where everything is working?
ie. Is it worth a try reversing the coil wires? ( with the rev counter wire remaining connected to wire from points)
 
Last edited:
Messages
300
#9
Does the oil pressure gauge read maximum when the feed from the sender unit is disconnected? It should read zero if the feed from the sender is disconnected; if it doesn't, there's a wiring problem. Another thought is this: does the gauge have a bulb illuminated when the sidelights are on? If it does, are you sure you've not confused the feeds and earths? (No insult to your abilities intended-just worth a second check, just in case....)
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#11
Does the oil pressure gauge read maximum when the feed from the sender unit is disconnected? It should read zero if the feed from the sender is disconnected; if it doesn't, there's a wiring problem. Another thought is this: does the gauge have a bulb illuminated when the sidelights are on? If it does, are you sure you've not confused the feeds and earths? (No insult to your abilities intended-just worth a second check, just in case....)
Yes it does read maximum with feed to sender disconnected. I am always very careful with electrics being a mere civil engineer. With the 'spare' oil gauge only connected it read maximum with sender wire disconnected. Only got earth and ignition wires to worry about then. Additionally the water temperature gauge reads perfectly.
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#12
Just a thought, angels last reply to your problem with the wiring of the rev counter, that sometimes the coil wires are reversed and this does not affect running, the gauge started working when connected ( diagram wise ) to the wrong side.
Could the original wiring to the coil at some stage been reversed on the van the your having problems with gauges and not on the van where everything is working?
ie. Is it worth a try reversing the coil wires? ( with the rev counter wire remaining connected to wire from points)
Maybe I will try reversing the coil wires. Still the fact the water temperature gauge is fine but oil pressure is not is the mystery!!
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#13
Swapped over the wires on the coil as suggested.
Oil pressure still off the dial even with sender wire disconnected.
:whistle::whistle::(
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#14
Stripped panel with 3 gauges out of the car.
Picture of wiring at back of panel attached.
Basically feed and earth to internal lights on separate circuit to that of gauges.
Ignition switch connection is a 3 in 1 as is earth. Single feeds for water temp and oil pressure to senders.

Any comments?
Thanks
 

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Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#15
I was hoping someone was going to say "that does not look right" but no comments at all.
I am still confused that it is not working OK!!
 

laxeian

Enthusiast
Messages
218
Location
Galicia
#16
Afraid short of taking readings with a multi-meter on each wire in working van ignition off, then ignition on then comparing readings with problem van it looks in the photo a mirror of installation diagram, its a puzzler :dontknow:,
 

mojobaby

Enthusiast
Messages
1,196
#17
Hello Tom, forgive the intrusion as I know next to nothing about electrics.

Laxeian asked a few days ago whether you had tried swopping over the unit from the F4 that works, and you said that you were using your 2 spare units. Perhaps you should take his advice just to make sure.

on F4 number 2, the gauge goes to max when its connected. It also goes to max when its not connected. So the unit is obviously not making a difference. Maybe because it's broken?

Murphy's law states that if you have 2 spare units, then both will be faulty:)
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#18
Afraid short of taking readings with a multi-meter on each wire in working van ignition off, then ignition on then comparing readings with problem van it looks in the photo a mirror of installation diagram, its a puzzler :dontknow:,
It has me totally baffled. Rather than stripping out the gauge from F4 No1 I have decided to purchase another gauge and see what develops.
 

Tomcat

Enthusiast
Messages
835
Location
Milton Keynes
#19
Hello Tom, forgive the intrusion as I know next to nothing about electrics.

Laxeian asked a few days ago whether you had tried swopping over the unit from the F4 that works, and you said that you were using your 2 spare units. Perhaps you should take his advice just to make sure.

on F4 number 2, the gauge goes to max when its connected. It also goes to max when its not connected. So the unit is obviously not making a difference. Maybe because it's broken?

Murphy's law states that if you have 2 spare units, then both will be faulty:)
I am purchasing another gauge I think from Mr Murphy!!:clapping::laughing:
 

mojobaby

Enthusiast
Messages
1,196
#20
When I said "unit" I was actually talking about the sender unit. I wasn't suggesting that you buy another gauge, just in case you misunderstood
 
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