VZ Exec No Start, No fuel pump, Fuel gauge error.

[rambunctious]

Anyway.
The fix.


RAC guy jumped the starter relay.

So weird as.
I pulled all the relays from my VZ and my battery put them in and nothing changed.

This guy jumps the starter relay and replaced the same relay back in and no dramas.

Gremlins

I wonder if it is not getting enough power to the relay due to old wiring/connections.

 

[Fu Manchu]

It could be possible. However this car is the most immaculate VZ many will ever see.
I had a bit of a suss at it and the connections all look new in the fuse box, relay box etc. No corrosion.

I’m guessing the earth on the ignition side of things in the ecu is kaput.

How many volts into the relay am I looking for? Assuming it’s not 12v.

The no start thing has been occasionally intermittent for some time.

 

[delcowizzid]

The ecu is failing very common no crank fuel gauge error etc. If you swap in the other ecu you also need to swap in the bcm pim and key for it to start and it needs to be from the same series of engine as the cam sensor count on the cam sprockets changed. Mine has the wrong sprockets and only runs with the cam sensors unplugged cause the tune is wrong for the trigger count must pull finger and get the correct tune in there haha

 

[Fu Manchu]

Changed the whole computer set. Key, pim, bcm and ECU. Have it the garage. Used to run in my crewman for a while. It’s from a wagon. It’s an easy job. Takes 10 or 15mins.

Interesting about the cam sensors.
I even tried to swap mine over but they are slightly different with a different plug. Cam solenoids are same.

I have had issues with ECM/U on my car before. They are a B.

@wannaeatyourbrains made a good bracket that got the ECM off the engine with no wiring mods.

I guess it’s important to find the cause for sure first before throwing dollars at the ECU. Would have been good for the RAC guy to have plugged the Tech2 in and poke around. Broken earth on the ignition circuit in the ECU is my bet.

 

[delcowizzid]

The sensors work the same but the trigger wheels on the cams have different Teath counts

 

[Fu Manchu]

Yes. There are different Cam sensors on the '04 v the '07 VZ. The shape is different and the plugs are different, so couldn't swap them.

As a development, spoke with a local ECU repair shop. The guy described what was happening to a T. The circuit is affected by low voltage and the ignition part fails. It is not repairable, however there is a work around, and the unit resealed, meaning for this, there's no need for a replacement ECU.

Common after being left with flat batteries, parked for long periods or other issues with the charging system. Not always.

Also can appear intermittently at first.

 

[99notout]

Fu, which ECU repair did you use? You can PM if you wish.

 

[Fu Manchu]

The one on mine was in Melbourne i think. Don't recall who.
That was years ago. Better than new.

There is two places here in Perth. EFI AutoParts and there’s this mob AFI Australia but the last one is only repaired via a third party with an account.

Injectronics work similar via Repco i think.

The extra VZ I have here now hasn't had the ECU repaired... yet. I have to make time to get it to him now if that is what the Father in law wants.

 

[Fu Manchu]

Jump the car by bypassing the relay. Works. Open close the car. Start the car. However, after 15-30mins. No start again.

Update:
RAC paid a second visit, and started the car same way.
“Technician” did not use a diagnostic tool. Which if connected, would verify the diagnosis as per Holden’s tech guides.
Diagnosed it as a key problem and did a sales spin on getting a new key from RAC preferred places.

Still can’t get my head around this diagnosis because the car locks and unlocks fine. Two different keys.

Same fault with two keys.

Says the new key needs to be programmed to the BCM. And dollars are getting verbally dropped on the fault.

So we jump the car and drive it a bit.

Next day, starts fine. Drive it somewhere. Park it. Hours later, it starts without a hiccup.

Problem gone.
Go figure.

*This guess work is what I expect from me without diagnostic tools or formal training.
This sort of guess work is the sort of shite that gives me more confidence in my self trained experience, informed with factory information, than that of an industry that half arses things. People open wallets for nothing. It’s crap.

Lift ya game auto industry.

 

[Fu Manchu]

... aaaaand, its back.

I highly doubt that the BCM is not registering the key "intermittently". Therefore IMO reprogramming a new key with the BCM will achieve much other than waste money and time only to see the same under lying cause return.

Of note again, connecting a diagnostic interface tool (Tech2) will tell the service technician this info easily. It has not been used by two technicians on two occasions.

Also, further to my comments earlier about the swapped computer set I used into the car, (this is an early VZ '04.)
Source: https://forums.justcommodores.com.au/threads/pre-ve-6-speed-auto-conversion.267342/

Looks like I may just have the only model that this could work with. The later VZ's fitted with the Gen 4 V8's use a CAN Bus system which is what the GM A6 transmissions use and the 4 speed auto trans module also communicates to the ECM via CAN. Late model VZ's use the E38 ECM, also used in VE and non supercharged VF models.

This set came from a late VZ and has been used in another late VZ fine.
Did not start the early VZ but most functions worked fine.
Has different cam timing that might also play a part.