I just received a new to me UltraGauge from a forum member (no complaints with the seller) and am disappointed to find that it doesn't track oil pressure (or temp). I got it primarily for coolant temp which it works well for. I guess I just assumed it would work for oil pressure too. My mistake or is there a way to do it that I'm not familiar with? This is on a '03 Disco II "S".

 

I know Ultragauge does not provide oil pressure, oil temp or fuel level info. I would have liked to see these data as well.

I have seen posts on sandwich plate type sensors installed between the engine block and oil filter.

 

I am just getting familiar with it but I think mine will provide fuel level info. Owners manual says it either draws from the tank float level or amount used since last fill up.

 

That is correct, it will not do oil pressure. I know people like the ultra gauge. There are some inexpensive blue tooth adapters for the Torque app on your phone that have some pretty cool statistics, throttle, temps, G force, etc.

If you want oil pressure, i have all the parts you need to install an electronic gauge. I was going to install, just never got around to it.

 

There is a "gauge availabilty estimator" linked from the UltraGauge support page. You enter vehicle info and the estimator returns a list of supported ECU outputs UltraGauge can display. If you scroll down the results list you'll find there are lists based on manufacture date of the vehicle. I haven't compared any of the lists to each other but I'd be surprised if there were any differences at all for DIIs.

The question of why oil pressure isn't displayed prompted me to check RAVE to see if I could find the answer because I have wondered the same thing in the past. I think I found the answer.

UltraGauge only displays outputs from the ECU, but based on RAVE and the electrical circuits diagram the oil pressure warning lamp is illuminated directly by the oil pressure switch. It doesn't get its signal from the ECU, so there's no way for UG to display oil pressure.

The first clue was that RAVE says the DII uses an oil pressure switch. It's not called an oil pressure sending unit. It's an on/off system. An oil pressure reading, of course, would need some sort of variable signal.

The story with the fuel gauge is similar. While there is a fuel level sending unit with continuously variable voltage output to enable the gauge, it is wired directly to the gauge and does not pass through the ECU. The instrument cluster actually sends the low fuel signal to the ECU but that too is an on/off signal.

Because of these two factors no OBDII device is able to display oil pressure and fuel level.

An earlier version of UltraGauge didn't even show voltage.

 

The OBDII "does" see fuel flow and can calculate MPG, because that stuff is encoded into the chip. It seemed to be fairly accurate for me until I put the bigger tires on and screwed up the gear ratio.

I used it primarily to watch coolant temps and intake air temp (since the air intake is in the engine bay, it's also a good gauge of the ambient air around the engine too). Using both the actual coolant temp and the temp. of the air it's seeing, you can more easily judge if your starting to run hot or not.


It's sad that you can't get fuel level (and better estimate MPG) and oil pressure, but that's because those sensors don't exist as OBDII inputs as mentioned above.


Still...it's an invaluable tool, cheap, and plus it can read/reset codes also.


It does everything an expensive OBDII reader or Bluetooth phone adapter does, but it's designed to be left in the car at all times.


I'm thinking of getting more for my other vehicles.

 

Thanks for the input gentlemen, this explains alot.

 

In short the factory oil pressure switch is a simple on/off switch

 

So, if I were to install a REAL gauge, I could put the sending unit where the current switch is? Or would I be better off with a "T" and have both?

 

Based on my read of RAVE and the circuits diagram the only reason to keep the switch is to have the warning light available in addition to the gauge. The oil pressure switch does not connect with the ECU so there shouldn't be any other effect from removing it.

I have no idea whether or not any oil pressure sending unit would be threaded to simply screw right into the front cover in place of the switch but I suppose there would be a step-up or step-down adapter available, perhaps in the plumbing section at your local Lowes or Home Depot.