Hi all, I wired up my oil temp gauge last night after my camper had its 500 mile engine service after the rebuild, We fitted a CSP sump cover, with the angled drain hole, which I put the VDO sender in. I ran a 1.5mm tri rated single (thin multi strand) core cable from the sump sender to the back of the gauge and terminated. Piggy backed the power supply from the oil pressure gauge. Fired up the engine, and have got no response from the gauge. I left it running for a few minutes, but still had no response. I get around 8v to earth on the sender with it connected to the back of the gauge. With is disconnected from the gauge I get 0v so the 8v is being produced at the gauge sender terminal. I left it at that as the misses came home with the kids and it started to rain. I had a quick look online, and the general comments seem to be that with the temp gauge you need to start driving for the temp to rise to register on the gauge, I just assumed that it would start to read at 50 degrees quite quickly, hopefully some experience from you guys may help
To check the circuit short the wire at the sender to the engine case and the needle should go it max I had one of the new angled drain hole plates and was not impressed i found it did not work that well with the sender as the sender does not stick up into the oil as far due to the plate beeing thick also the plate is finned so cools more, i switched back to the normal plate and it read higher and was more reactive
Will give this a shot tonight. I used the csp plate as had read the sensor in the standard plate had clearance issues with the underside of the strainer?
I went through all this recently. You wont get an accurate reading with the csp sump plate. I found that the gauge went up instead of down when you are stationary after a run and it reads on the low side all the time because the sender is not properly in the oil flow. I kept the sump plate but got a new sender that goes in the oil pressure relief plug instead. Theres a guy selling them in the US on ebay selling them for a fraction of the price the usual uk sellers http://item.mobileweb.ebay.com/viewitem?itemId=190640174611&cmd=VIDESC
been out for a spin today, and got no reading at all. shorted the cable to the plate and it went to 150 degrees which is max. plugged back in, nothing, took a piece of wire and went from the sump plate, to the brass case of the sensor, and the needle moved a bit to read actual 50 degrees not under but that's it, could this be an earthing issue (@snotty @zed @Paul Weeding @scote ) @scote where did you put yours, I don't know where oil pressure relief plug is?
Mine's in a fitting in an oil line straight after the pump. I thought it was broken but it takes quite a while to show a reading. I can't see how your switch could have an earthing problem screwed directly to the sump plate, but aparently it judging from your experiment.
it was running before we set off, drove about 25 mins and stopped and it ticked over a bit and still no reading.
If I drive about at 3-40mph it barely registers and in winter doesn't. If I drive 40-50 it shows it's warm Faster and it gets up to temp. Try blasting along at 60 for 10 minutes.
Measure the resistance of your sender to earth, ie the terminal to engine case it should be in the low hundreds of ohms. Cant fibd a pic of the oil pressure relief valve plug on the interwebs at to moment but its near the back and horizontal on one side if that makes sense
Right put this problem to bed the csp sump plate is aluminium thats why it's not earning properly been chasing this problem for 2 years and I have figured out this must be the reason needs to be a steel sump plate for earthing
No reason why an aluminium plate shouldn't earth the sender properly - it's almost as conductive as copper! I think your problem lies elsewhere.
No, what the sender needs is an earth connection. Aluminium is a very good conductor of electricity, but heavy anodizing is not , its a very good insulator (its carborundum, used on silicon chips as an insulator) .. So make sure the outer metal body of the sender has a short circuit to earth. Scratch up anodizing around the sender and around at least one of the sump plate nuts. Either measure 0.0 ohms from the body of the sender to the engine block with the ignition off, or that the voltage between the sender body and the engine block is 0.0 volts with the ignition on, and a voltage like 8 volts or so on the tag of the sender .
Oh god don't spoil the dream of finally figuring out this problem as it happens I am just in the process of fitting the original steel plate ..but there is no way the oil strainer will fit with the temperature sender sticking through the plate do you now hoe every one else has done it...does it need to be a different strainer or angled sump plate thanks
A well powder coated steel sump plate could do the same for you, leaving the sender earth disconnected through the powder coating acting as an insulator. I would assume that different senders may have a different profile above the sump plate . so a plate with an angled sender is a solution, or drill and tap the plate off centre for the sender so it fits under the bell at the end of the pickup, not hitting the pickup tube, and fit a standard M14 plug in the middle.
