VR6 not starting, low voltage at fuel injector rail, can anyone help?

[Thom 1]

Thanks for all the replies, ..After dropping the fuse box, bypassing the aftermarket immobiliser and checking all the wiring back from the fuel rail to the fuse box, it turns out that the origin of the problem is ignition and not fuelling after all. When I first checked for a spark, I used an led spark tester between each lead and plug and got a flash, however grounding the plugs (which were wet with fuel incidentally)on the block and cranking gave no spark (seems that my spark tester requires less voltage to work than a plug does!?) Wiring to the coil pack all measures as it should so have ordered a new coilpack.

 

For info, some research found that 4.8v is the voltage for the injectors.

 

Now, if you'll excuse me, I'm going to have a drink

[Dox 23]

Using a jump lead to earth a spark plug to the block makes viewing the spark easy

[Thom 1]

Using a jump lead to earth a spark plug to the block makes viewing the spark easy

 

Handy tip that, cheers

[fendervg 32]

Handy tip that, cheers

 

Using a jump lead to earth a spark plug to the block makes viewing the spark easy

 

Someone showed me that trick a few years back - very useful and means you have your hands free as well!

 

Good info on the 4.8v for the injectors - I stand corrected, my guess at 12v was just some basic Google research - makes sense really as a lot of the more sensitive components use in and around 5v.

 

I did find some stuff that mentioned that poor wiring to and from the battery and starter can cause the voltage to drop to way below what is needed to fire the injectors etc during cranking, so that might be worth bearing in mind for others troubleshooting similar issues.

[Thom 1]

 

I did find some stuff that mentioned that poor wiring to and from the battery and starter can cause the voltage to drop to way below what is needed to fire the injectors etc during cranking, so that might be worth bearing in mind for others troubleshooting similar issues.

 

Some more helpful info,thanks!

 

Yeh it had me stumped about the injector voltages as all the online info for most engines says 12v switched feed and a pulsed ground, so expected it to be the case here.

 

Cheers

[Bush 10]

Is it a permanent 4.8v? Then the ground/0v side is switched to open the injector? Handy having info about what voltages to expect where on the forum for faults like this.

 

Hope your new coil pack gets you up and running again

[Thom 1]

Hi it's ignition switched 4.8v, with the ECU pulsing ground on crank and run. This is my understanding of it anyway. Not gospel, haha

Yeh get the coilpack Wednesday, fingers crossed I'll be back on the road :-)