VZ/WL Fuel guage woes - SOLVED

[Gareth]

The wiring between the tank and PCM is fine also, no shorts to earth or each other.

[Tazzi]

The wiring between the tank and PCM is fine also, no shorts to earth or each other.

What does the PCM show in live data for the fuel ohms when doing the tests?

The infamous "fuel gauge error" problems are common on the VZ's when the ecu starts giving out, although you tend to get other problems happen when that occurs.

[Gareth]

That’s with no sender plugged in

[Gareth]

With the sender plugged in and set to empty it’s 0.69v, with the sender at full it’s 2.39v

Soooo, based on that it isn’t the PCM is ok. So that leaves PIM and BCM…

[The1]

So is the cluster bricked? Have you tried with another yet?

[Gareth]

Yeah, as per previous posts, replacement cluster cloned and installed, exactly the same.

I understand this system to be sender to PCM to PIM to BCM to cluster. First things I’m going to revisit tomorrow will be what the PIM and BCM are reporting.

[Tazzi]

My understanding was ECU to PIM then PIM to cluster.

Since the PIM is basically there to translate the data from the ECU to ALDL format.

Failing PIMs typically cause no start conditions, so I wouldn't believe its causing the fuel gauge problem.

hmmmm... really odd! I believe the instrument clusters engineering menu (hold mode and set) will also show the fuel voltage (I think?) so you could see what the cluster says and also the ECU and compare. If they are different, then there has the be some sort of firmware issue from ECU or cluster.

[Gareth]

[attachment=0]EA3FE767-6ED1-4BC7-BB5B-CED4617BA607.jpeg[/attachment]
A35=PCM, A226=PIM, A11=BCM, A5=IPC

So there is no live data with tech2 for fuel level in either PIM or BCM so that fucks that.

But, whilst sitting there fucking about I noticed that the guage had responded to empty with the sender set to full after a good 5min, I set the sender to empty and waited 5min and it showed full.
Using Tazzi's software I reversed the guage but the dash still responds the same ways, the changes stuck to the cluster as I can read them out and they are correct.

My experience tells me to search out aftermarket or non factory items connected to the vehicle, There is nothing as far as aftermarket connected to this car that I'm aware of with exception of the PCM being HPT...

This car WAS on LPG a long time ago but has been removed, It was a parnell injection system that was fitted by parnell. The LPG level was displayed via the LPG switch - no guage interface.

[Tazzi]

Honestly sounds like making sure the ECM and IPC are up to date with the latest calibrations would be the starting point, since the newest updates addressed a fuel gauge related issue.

I don't believe VZ's ever got LPG from factory, their fuel configurations in the instrument cluster never had LPG either. So unless some wacky wiring has been done at the fuel sender wires to switch between after market LPG and Petrol, and this was never properly removed or fixed?

[Gareth]

Honestly sounds like making sure the ECM and IPC are up to date with the latest calibrations would be the starting point, since the newest updates addressed a fuel gauge related issue.

I don't believe VZ's ever got LPG from factory, their fuel configurations in the instrument cluster never had LPG either. So unless some wacky wiring has been done at the fuel sender wires to switch between after market LPG and Petrol, and this was never properly removed or fixed?

There is one of the issues I can't resolve - The PCM I cannot update as SPS says no...