VZ Fuel Gauge Error's

[Dylan]

So with this contact dealer problem. More likely a faulty ecu or sender or calibration problem?
To bloody hi tech this late model gear.

[vn5000]

If the car starts and runs fine now ,and all other dash info is good except fuel guage ,checking sender resistance would be good place to start.

[Dylan]

No worries. Might have jumped the gun after all the horror stories of crook ECU's.

[Gareth]

So that ecu wouldn't work in the car but ok on the bench?
Ive heard the alloytec ones are doing that.

Would work on the bench ( never tried, replaced it then moved on to the next broken car...) the last one I kept works fine for testing, the vehicle drove around with the same problems you described for a few weeks, I think that the engine bay environment has a lot to do with the actual issue (heat, vibration, engine running, etc...) bench testing can't do that. Im sure that some sort of shock or indirect impact caused the failures of the last couple.
As far as alloytec failures, we see them at about the ratio of 20 to 1 V8.

No trying to be smart but I doubt that the fuel guage sender is the issue, not impossible but unlikely. The only time we've seen VZ V8 fuel guage issues they have been calibration or ecu problems, not electro mechanical.

[antus]

My mate has a vz crewman, havnt seen problems there and it seems pretty good. It doesnt sound like the wrong cal segment to me, it sounds more like wiring or sender or less likely dash. The VZ got the very first of the E38 and still has a PIM converting pcm canbus to aldl for the dash. Technically you should be able to monitor the ALDL bus and see the fuel level as data from the computer and see if is changing radically or not when the guage swings. This will tell you if its a dash side or pcm/wiring problem. Im not sure but there also might be an OBD2 PID you can read with something like an elm to see if the pcm is reporting wild swings on its input. Unfortunately I dont have the details of the ALDL protocol for that or the OBD2 pids. Best bet would be something like palmer performance scanXL with GM addon, but having said that I dont even know if the PID exists so you'd need to confirm that first. As for number of PCM failures, i'd be slightly suspect of what 'people' say. A lot of people blame PCMs when they just dont understand a fault, which sorta muddys the waters a bit, but perhaps its somewhat true.

[Dylan]

The LS1 VZ was an E38 ECU?
I thought it was still 411

[antus]

Sorry, I saw 6 speed and read it as 6 Liter. What I said was for that version of it. Disregard im too tired.. heh.

[vn5000]

What Antus said still applies to the vz ls1 there are fuel sender level/voltage pids , also although it wont set engine light if there is a fuel sender error it will report codes
P0461
P0462
P0463

[Dylan]

Bit of an update. I brought the car (maybe stupid idea) so i will look into this.
Today driving around all was good. Sitting in driveway cleaning it i had the key on for the radio.
After about 30 minutes the low fuel alarm come on. Then gauge went back up.

I will look into some software as id like to tune it as well.
Does tuning software give you access to the calibration part for the cluster?

[VX L67 Getrag]

Depends on what software, HPT give's you SOME calibration's, EFI Live gives you a better idea & then I believe the best of all is CAT's but don't own it to confirm.

But then it's a matter of knowing what module/calibration's suits what model's!

I believe Antus's program might give some more light on all of this.. but time will tell!