VL Injectors

[Simba355]

I think I will pull the rail with injectors attached and crank It over and visually have a look.

 

[Simba355]

looks like injector resistance is 2.4 ohms new so the 3.8 may just be an aged set, u could remove the regulator and put fuel direct to the rails only turn on for couple seconds after u know fuel is getting there, then remove pump fuse so dosnt run and over pressure but u can then try and start it and if it fires and runs till it uses up the fuel in rails u know more about what might be going on

I crimped the return line after the regulator and no go. 99% must be injectors?

 

[07GTS]

fuel is getting past the regulator to the injectors ? if so id prob take them to a injector service place to get them checked out and cleaned up, also i think the low impendence injectors use an injector driver to control them so even if ur seeing a pulse it may be too small for the low ohm injectors to fire them so could be a driver issue maby

 

[Skylarking]

Momentarily applying 9V to a low impedance injector shouldn’t cause issues from what I understand but I haven’t found specific VL commodore info from a workshop manual…

Years ago you could buy the factory workshop manuals and supplements but doubt they are still available. Luckily these days there are some supposedly good cheap 3rd party workshop manuals you can buy retail parts stores but I’ve not seen them.

Info is always helpful so I searched for a free VL workshop manual but no luck… Oddly I came across an 80’s Datsun EFI manual (some call the EFI bible), Probably not useful but it could have some useful information (like low impedance injectors back in the day had ainline resistors which may or may not be relevant to VL?). I’ve included the link to it is below just because

http://xenonzcar.com/s130/files/othermanuals/1980%20EFI%20Bible.pdf

The following is more commodore specific but yje page didn’t like my google analytic filters and I couldn’t be faffed turning them off

https://cardiagn.com/holden-commodore-vh-service-manual-supplement/

Maybe between those docs you can gleen some useful info going forward.

 

[Simba355]

No updates just yet gents, still need to pull the rail and check these injectors.

 

[Simba355]

I think I will pull the rail with injectors attached and crank It over and visually have a look.

Can confirm injectors won't fire when cranking over but when I hook my 18v battery from my cordless tools and tap the injector I can now confirm the injectors flow great.

 

[Skylarking]

Can confirm injectors won't fire when cranking over but when I hook my 18v battery from my cordless tools and tap the injector I can now confirm the injectors flow great.

That's odd having to use 18V.. Didn't it work using the cars 12V battery as the trigger source?

In my case, my high impedance injectors would fire using a good 9V battery but not when using an old 9V battery. You'd expect low impedance injectors would pull more current so you'd think would fire easier than high impedance injectors but then it depends on whether the battery can provide the required current.

I'm now uncertain if your injectors deliver fuel when connected to the rail and the engine is cranked as @lmoengnr asked earlier whether the plugs were wet after cranking and you said they were dry.

So try it with 12V direct to an injector (short intermittent bursts) and report back if it fires. Then try it with all the injectors in the fuel rail but out of the intake and inserted in small coke bottles and crank the engine and report back what happens

Doing such should resolve whether an injector will fire with 12V and then also confirm whether all injectors will fire when commanded by ECU (which also confirms whether the fuel rail can provide the required pressure and volume).

Can't really be timing or spark if it fires up with start ya bastard.

May be it's the fuel control wiring side (resistance not correct? doesn't it have an inline resister? was it changed? ...

 

[Simba355]

Running some wires directly from the 12v battery with short bursts works with the fuel rail out and injectors exposed. Crank it over normaly without direct power and nothing.

The strange thing is now I don't have 12v at the injector plugs and noid light not flashing now, strange that I had 12v and noid light was flashing and now nothing.

Double checked relay near the battery and confirmed the negative wire had separated near the resistor so I have since joined that back but still no luck.

I will install the top half of plenum back with injectors and rail and keep searching.

The lack of 12v and noid light not flashing has stumped me now. Did I fix a problem and unearth another now?

 

[chrisp]

I wish that I could remember the VL system better. I did manage to extract the code out of the EPROM at the time, and I know it ran a variant of the 6809 microprocessor, but I can’t remember the injector switching arrangement, whether it was high-side-switching or low-side-switching.

However, the injectors were Japanese made equivalents of a standard Bosch injector, so nothing special nor exotic. However, the relay use in the supply does need to be a specific relay (i think it might have a freewheel diode in it?) so don’t swap it willy-nilly when testing.

 

[Simba355]

I bypassed the reverse polarity diode just down from the relay near the battery.
Injectors are fine and will flow with direct power.
Injectors wont pulse now and can't get 12v on the multimeter on the I jector plug.

Just about giving up now.