On my 98 Disco LE my new ultra gage says it finds protocol 9141 and uses the MAF sensor to calculate fuel usage when the MPG sensor setting is "Auto". However, the MPG displayed while driving, both average and instantaneous, is wildly high - like 1800 miles per gallon. The DTE is also off the chart, like 36,000 miles, until I stop moving and then it is 442 sitting still. This is with a full tank of 91 octane 100% gas with the UG reset to full tank.

Is 9141 the protocol you guys are using? Are you getting accurate MPG readings? I watched the ultra gage MPH which was running 5 less than the speedo and 2 to 3 less than my GPS and adjusted the mileage calibration to 1.036 to make the UG match the GPS, but the fuel calibration said it couldn't be changed. I assume the VSS is OK as the speedo is steady and the UG MPH is steady, so is there another sensor for fuel usage that could be screwing up the MPG?

BTW, if I set the "force MPG sensor setting" to either MAF or MAP, the MPG gages all disappear from the gage pages and from the gage list. The only code being set now and then is P1314.

 

there is no map sensor( manifold absolute pressure) just maf


did you try contacting the company? I don't personally use the mpg

 

I did and tried what they suggested and replied as follows. Their suggestions are in quotes:
My reply:
"Does your vehicle actually have a MAF sensor?" Yes it does

"Let's to a global reset and start over." Done

"Once reset, watch the MPH and MAF1 gauges for abnormal readings. Since the MPG readings were crazy high, either the MPH is reading very high, or the MAF is reading very, very low."

The UG MPH was close before; about 45 at 50 indicated on the speedo and the speedo seems to be 2 to 3 high compared to my GPS. After restoring all defaults, optimizing the 9141 protocol (optimized setting 43) and adding MPH, MPG, MAF1, and MAF2 to gage page 1, I started the engine and MAF1 and MAF2 were .10 at idle and .17 to .18 at 2000 RPM. The UG manual says the MAF1 range should be 0 to 655.35 so these readings are very low. Does this indicate a malfunction of the MAF, or is a different protocol needed for a 1998 Land Rover Discovery?


So...can someone tell me what MAF numbers you are getting on your ultragage? It was too late to go for a drive to see what the MPG numbers are now, but I suspect they will be wildly high again if the MAF readings are so low VS the expected range of 0 to 665.

 

UG replied:

"Its more likely that the MAF is good and that the ECU is not providing the output correctly. However, there is another possibility.
Can you run the following:

MENU --> Ultragauge Setup.. --> Factory test.
The ignition must be in the RUN position (engine off)

When the test finishes, please take a picture of the screen and attach it to this ticket. Best regards, UltraGauge Support"

The UG manual says the factory test is normally only used at the factory with no explanation of what the numbers mean. I hope this helps UG determine what is going on with mine.

 

UG responded:

"Some ECUs scale the MAF output. However, based on the factory test results, your ECU does not, or at least the ECU is not reporting that it is scaling the output. If the ECU is scaling the output, running the Fuel calibration will solve the issue. However, as we have never heard this issue from any other Discovery owner....we suspect there is an issue with your vehicle. Check with the service department of your local dealership to see if there is a general firmware update available for your vehicle. In general dealers are resistant to helping when there is nothing in it for them. So it is generally best to speak in terms of getting the update just to make sure you have any safety and emissions updates.

Alternatively, check with a Discovery specific forum to see if others have had this issue with the MAF output."

So...Any of you guys with UltraGages able to report what MAF1 or MAF2 readings you are getting?

I followed up with UG:
So...are you saying the ECU uses unscaled data and the reporting function is separate from the calculations used for the engine management? Any chance the UG EM Plus treats MAF and MPG differently than earlier models? Is 9141 the correct protocol for my 98 Discovery 1?
and they replied:
"UG has not changed its core MAF/MPG function in years. The ECU continuously reads the MAF sensor. It uses the data to control the air/fuel mixture. The OBDII specifies the details of reading the MAF sensor via the OBDII. The Manufacturer has the option of providing the data as per the standard or scaling the data. Ultimately its still the same data. For example: if the MAF output is 20g/s, the ECU can report 20g/s via the OBDII, or it could report 200 and mark the parameter as scaled by 10. So to use the parameter the g/s = value/10. In this case g/s =200/10 =20. So the result is the same. Your vehicle is not reporting scaling. Hence the value should be the actual output of the MAF sensor in g/s. Since it is near zero, something is wrong. I doubt the MAF sensor is bad, otherwise the Check engine light would be on and the vehicle would not run well, or perhaps at all. When you display the MAF gauge, you are looking at the unaltered value directly from the ECU. Best regards, UltraGauge Support"