Fuel Gauge

[exec406]

Hi

I have a 2003 Exec 406 Hdi.

I've been having issues with the fuel gauge after a new in tank pump was fitted. From a cold start sometimes it would take 5-10 minutes for the fuel gauge to register showing any fuel each day, and after a wiring repair I'm now getting 'fuel level low' appearing on the dash when there's plenty of fuel. The needle is now constantly showing empty but the fuel computer is working.

I've heard you need to go to a Peugeot main dealer to get the fuel gauge calibrated in this situation, it needs hooked up to their Diag equipment. Is that the case?

Thanks

[PeterN]

Try doing a BSI reset.

Peter

[frog]

To me it seems that the the float arm (which is assembed with with the tank pump) is not free to move and stuck in its lowest position. Maybe give it a good thump?

Did you refit the tank pump fitted yourself or have a local garage / professional do it for you? Maybe you can go back and ask them to check?

The float arm is a pretty low-tech sensor in the form of a variable electrical resistor that varies with the height of the float axis. The BSI reads it and does some filtering / post-processing, but i don't think it needs any kind of calibration.

I added some prints from the HDI system book. You might want to check if your resistance values are as expected.

[frog]

Just came across this post that suggests it might be in your instrument cluster:

http://www.honestjohn.co.uk/forum/post/ ... tm?t=42091

Quote:
"The later 406s do suffer from a lose earth screw on the back of the instrument cluster pcb that will cause the fuel gauge to read incorectly when it starts to work lose, Also cause the cluster to stick warning lights on for no reason too.

A simple tighten up with a screwdriver fixes it for good."

[exec406]

Try doing a BSI reset.

Peter

Thanks, I tried the BSI reset but no joy. I'm getting the following 'P' code when hooked up to an OBII scanner (among others, but this does look fuel gauge related)

P0461 Fuel Level Sensor A Circuit Range/Performance

May need to get the in tank pump checked out (the pump is less than two years since fitted from new).

On another note, I have a separate Eolys liquid tank, does the Eolys fluid get injected when system knows fuel cap is off (i.e. filling up) or is it fuel gauge / amount of fuel related?

Thanks

[exec406]

To me it seems that the the float arm (which is assembed with with the tank pump) is not free to move and stuck in its lowest position. Maybe give it a good thump?

Did you refit the tank pump fitted yourself or have a local garage / professional do it for you? Maybe you can go back and ask them to check?

The float arm is a pretty low-tech sensor in the form of a variable electrical resistor that varies with the height of the float axis. The BSI reads it and does some filtering / post-processing, but i don't think it needs any kind of calibration.

I added some prints from the HDI system book (it's from the version with DPF but that makes no difference). You might want to check if your resistance values are as expected.

Hi

Thanks for the info. Looking at the prints you posted from the HDI system book, does that mean the in tank fuel pump / sender then controls the amount of Eolys additive being injected? I can see the DPF filter clogging quite quickly if I don't get this fixed somehow.

[frog]

Looking at the prints you posted from the HDI system book, does that mean the in tank fuel pump / sender then controls the amount of Eolys additive being injected? I can see the DPF filter clogging quite quickly if I don't get this fixed somehow.

Yes, it is stated in the prints. Other sources talk about a fixed amount per tank filling session. See e.g. http://406oc.co.uk/viewtopic.php?f=5&t= ... =0#p242924 which says: "Every time you remove the fuel cap the fuel tank is dosed with a fixed amount of additive". But then again, http://www.honestjohn.co.uk/forum/post/ ... tm?t=83830 says: "It then looks at the fuel level before & after re-fueling & injects the correct amount of Eolys ( addative Gasoil ) into the fuel tank."

I don't know how the dosage is calculated. I don't have experience with DPF systems; my 2003 HDI does not have one.

[8Jb9]

If you don't trust your gauge you can always just measure on the float's pins on at the pump. It's just a variable resistor. When my pump failed I first suspected a bad connection somewhere, but measuring on the pump proved that the problem was located within the tank.

I don't have the nominal full/mid/empty resistance-values right here, but they were easy to find online.