VL Injectors

[Simba355]

I'm wondering if the regulator is part issue? Gave the reg a tap and it now faintly try's to fire up on 1 or 2 cylinders if that.

 

[Simba355]

That to me sounds like the pump?

Definitely has fuel at the top end and plenty of it.

 

[vc commodore]

Here's a simple way at home to clean injectors...It's at the 5 minute mark

 

[Simba355]

I checked resistance as per the second video and all at 3.8 ohms. Not sure what the specs should be

 

[chrisp]

You might be able to hear or feel if the injectors are clicking. If they aren’t making any noise at all, then look for an electrical issue. If they are making a noise, then check for a fuel issue.

 

[Skylarking]

There is fuel in the rail, a noid light shows the ecu is firing the injectors and the spark plugs are dry after a long crank so it really seems like the injectors are blocked.

And we now know the injector resistance is 3.I ohms which also seems a little on the low side though I’m not sure whether the VL is low or high impedance injectors…

So we must remember that the injector impedance must match that required by the ecu else they may not fire correctly if at all. May be something to consider?

 

[Simba355]

There is fuel in the rail, a noid light shows the ecu is firing the injectors and the spark plugs are dry after a long crank so it really seems like the injectors are blocked.

And we now know the injector resistance is 3.I ohms which also seems a little on the low side though I’m not sure whether the VL is low or high impedance injectors…

So we must remember that the injector impedance must match that required by the ecu else they may not fire correctly if at all. May be something to consider?

The injectors have 12v on either side and 3.8ohms on the injectors but not sure if within spec. The vl injector is low impedance.
Noid light flashes when cranking. After giving the reg a tap it will stumble when turning over now.

The other thing I wasn't 100% sure of when doing away with the external fuel pump is what looks like a reg on the feed side of the old external pump? I left it in and just ran the new fuel line through it.

 

[Skylarking]

The injectors have 12v on either side and 3.8ohms on the injectors

That’s normal to have 12 volts on either side of the injector with the ignition on when the engine isn’t running. It’s only when the engine is running that the ECU grounds the injector (with a varying pulse width) which causes the current to flow (varying pulse) and thus turn the injector on and off for the required time to get fuel into the combustion chamber.

As long as the injectors and the ECU are the same as when the car last ran, it’d likely be ok as getting 6 injectors failing at the same time is highly improbable meaning the 3.8 ohms is probably correct.

After giving the reg a tap it will stumble when turning over now.

For fuel to actually be injected into the cylinder requires the injectors to be earthed by the ECU appropriately timed causing current to flow through the injectors and thus energise the coil within which pulls the internal pin(?) and thus opens the injector (that’s the clicking sound we can hear).

But if fuel isn’t at the correct pressure within the fuel rail and/or can’t be kept at the correct pressure with the injectors firing, then the correct amount of fuel won’t flow into the combustion chamber and the engine can’t run correctly.

if the injectors are blocked internally, then the correct amount of fuel can’t be injected into the combustion chamber and the engine can’t run correctly.

May be it’s a combination of (partially?) blocked injectors and/or fuel pressure issues.

The other thing I wasn't 100% sure of when doing away with the external fuel pump is what looks like a reg on the feed side of the old external pump? I left it in and just ran the new fuel line through it.

Im not familiar with the VL as it’s been such a long time since I’ve played with one. But if upgrading the fuel delivery system, you need to know what the standard VL expects in terms of fuel rail pressure, whether the pressure regulator is vacuum controlled and whether it has a return line (i strongly suspect it doesn’t for the return line).

Then you just need to check that all is as expected after the upgrade.

A search for VL workshop manual wouldn’t go astray either as such would define the injector and fuel pressure specs as well as describe how it should all work. May be some forum member has a snippet of such info they can post?

I don’t think using a 9 volt battery would be an issue with low impedance injectors but better to pulse the 9V battery rather than hold the power for too long a time. So I’d simply cleam them with some isopropyl alcohol and carb cleaner and see how that goes.

Then I’d look at what fuel pressures are within the fuel rail, whether fuel pump flow is adequate and such issues once you know the injectors are ok.

 

[07GTS]

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

 

[lmoengnr]

Here's another simple thing to try. Fully advance the distributor to the limit of the slot and try and start it.
If it doesn't start, try fully retarding it and try again.
Will only take a few minutes of your time.