Hi Everyone,
Currently trying to diagnose a faulty temp guage. Since I have had the car the temperature guage has been pointing straight up. I have read some threads on here talking about various temp guage issues to see if anyone else has had the same issues. Mine doesn’t seem to match what I have have read about.
The guage points straight up and doesn’t move when the ignition is on or off. I read a thread about simply flicking the needle back to ‘reset’ it’s orientation. However, with the sender connected the needle just rises slowly to 12 o clock and stays there. With the sender disconnected (bugger to get to) the needle (after being pushed back to 100) doesn’t rise. It is therefore the signal from the sender causing it to rise to 12 o clock. I have checked continuity from the sender wire and all ok. I have then jumped the sender wire (to the ground on the block) while not connected to the sender and the needle again rises to 12 o clock and doesn’t return. I have read on other posts that the needle should jump to 12 then return to its rest position when not provided with power.
My thoughts are that the sender might be ok but I might replace for the sake of 17 quid from DGo. I am more worried about the guage although I have read a comforting statement on the forum that someone was yet to see a faulty guage.
Can the guage ‘stick’ to stop it returning to its normal position? Is this something that can be free’d or lubricated from inside the binnacle? I’m yet to go in there but is probably a job that needs to be tackled at some point!
Thanks in advance for any suggestions or valuable insight.
Jon.
You have continuity between the gauge and the bulkhead connector?
Did you see my thread on a temp gauge issue?
(
http://www.deloreans.co.uk/forum/showthr...p?tid=5843)
I used a long wire from the sender to the gauge and this resolved my problem.
Mainly because the brass nut on the circuit board was not providing good connection, hence even though there was continuity from the bulkhead to circuit board, the nut didn’t provide sufficient connection to the gauge to the board……
I did put in a new temp sender too, just to be sure. And as you say for £17, there’s no harm in trying that.
Hi Tristan,
I had read your thread and was impressed with your testing procedure! Your guage wasn’t moving from 100 but mine keeps rising to 12 o clock so I was thinking we had different issues but, seeing as my knowledge on this stuff is starting from zero I will definitely check the things you mention. I will be back in the garage tomorrow so can report back.
Thanks for the quick reply.
Your sender has gone short circuit. Replace your sender.
Quote:Your sender has gone short circuit. Replace your sender.
I wish you would release that bug from behind your screen, gets me everytime.
Yes, that bug has caught my eye many times!
As an update, I thought I would have a look up into the rear of the binnacle at the temp guage just to see what was there. I’ve attached a photo of the back of the temp guage (hopefully). The top most bolt/nut is underneath the circuit board which might not be right? Although I have looked at a few diagrams on the internet and from what I can see the top bolt doesn’t look to do anything and doesn’t run to any of the connectors on the top right of the rear of the binnacle (looking at it from the back).
Is anyone very familiar with the rear of the binnacle and can confirm the above. Or have I got a connection that isn’t, well, connected?
Thanks for any help.
Jon.
[
attachment=1222]
This seems to show that if the sender (183) is open circuit then you'll get full deflection at the voltmeter. So it looks like a break in the wire or a failure of the sensor 183.
That nut looks fine to me, but the PCBs are very fragile so take great care if you go in there!
You have already answered your own problem:
Quote:I have then jumped the sender wire (to the ground on the block) while not connected to the sender and the needle again rises to 12 o clock and doesn’t return
You have shorted the temp gauge wire to ground and maxed out the temp gauge
Quote:With the sender disconnected....the needle......doesn’t rise
You have disconnected the sender and the gauge stays at zero
Therefore the sender is shorted to ground. Replace the the sender.
Your photo is rotated by 90degs to the right.
The actual "top" bolt is actually the bolt to the right in your photograph. The actual "bottom" bolt is the bolt to the left of your photograph. The actual "left" and "right" bolts (left missing a nut) connect on to the same copper trace on the PCB, but i'm not informed enough to say if it is essential that bother are connected to the trace, or if having only one of them connected is enough. That *could* be your open circuit issue.
(12 Oct 2021, 11:49)TristanC Wrote: [ -> ]This may help orientate yourself on the gauge bolts
Thanks Tristan, this makes sense. Not sure what happened to my picture but your diagram is what I can see looking up into the binnacle, the top of the four doesn’t look like it has a connection on the board which matches your picture and looks right.
The update is that I have fitted the new sender and I have the same problem. With the sender connected the guage slowly rises to 12 o’ clock with the ignition turned to second position but engine not running. It then doesn’t return to its start point.
I need to check the continuity from the respective bolts to ground or live but, failing that I’m stumped as to what the issue might be.
Does anyone have experience of the gauges failing?
Ha, I just realised I was looking at the fuel guage connections, not the engine temperature connections. My bad. At least you ignored me trying to send you off on a wild goose chase.
Hi Everyone,
An update on this. I have tested full continuity to from the sender to the guage and all fine. I have 12v on the right hand bolt of the guage (when viewed from the rear) and continuity from the bottom bolt to earth/ground (tested to body of the car). I think, therefore, that all connections to the back of the temp guage are in order so can only be the guage that is faulty.
Unless anyone has any other ideas that I might have missed? I don’t know if these gauges can develop such faults over time. I’ve read plenty of forum posts from people whose gauges stick straight down or fail to move from the 100F point but haven’t come across the same issue as mine where the guage points straight up (past the red area).
Does anyone have any info on whether the Delorean shares the same guage as another car? There is an instrument panel for sale at DMC in the states but this is $150 which seems a bit overkill when the part that may be faulty is likely pretty small.
I was really hoping it would be the sender or a simple faulty earth but doesn’t look like I am in luck.
whereabouts are you based?
Just wondering if there is an owner near you who could pop over with their car and try their
sender in your car to double check things.
I guess if it's reading full scale deflection it must be getting the unadulterated battery voltage through it, not the reduced voltage caused by the variation in the resistance of the temp sender. So that seems to suggest to me that the green wire could be earthing directly somewhere?
My belief is that as the temp goes up the resistance of the sender goes down? So, fully hot, lowest resistance, greatest voltage at the dial, dial reads higher?
So that means that off the scale must mean no resistance at all, suggesting to me that it means the resistance between the green and black is lowest. Or shorted altogether?
The fact that it rises slowly suggests to me that the smoothing capacitor part of the guage is still working. ( I assume they have these!!)
The other source of weird gremlins is usually bad earth connection points of course. Is everything else behaving itself?
Could check for clean connections at the engine wiring harness multi-plugs too?
What happens if you pull the wire off the temp sensor? Does it come back down or stay up?
I've got an idea. Just humour me...
Try shutting your driver's side door?.