engine wont crank

[alloytec sludge]

just installed my rebuilt v6 and auto hooked up all connections and everything. tried to crank it over nothing

 

[diysv6]

Can you get a scan tool or Tech2 on the car? It might give you a starting point.

The early VZ ECUs (2004/2005) are a problem if they are powered down for any period, the ECU sometimes will fail when repowered. Hope yours is not one of them.

A member recently gave the cars "engineering" codes 1-31, the zeros and ones listing which may help pinpoint the failure/trouble point if you can't get a scan done.

http://forums.justcommodores.com.au...5-vz-starting-problem-possible-ecu-issue.html

 

[alloytec sludge]

i hope not too, its a 2004 so it could be. i might have to buy a tech2 scan tool maybe

 

[alloytec sludge]

it also has low fuel warning too

 

[diysv6]

My thanks to a member who offered the schematic diagrams. ( I think they are the Oz alloytec, not too certain. Most of the connectors match up if US alloytec)
I drew them out for ease of finding my faulty ECUs feed points.
They may help when looking for voltages around the engine bay.

 

[alloytec sludge]

yeah thanks for you help

 

[alloytec sludge]

Can get it to crank by bridging terminals 30 87 on relay but no start cant hear fuel pump running

 

[diysv6]

Can get it to crank by bridging terminals 30 87 on relay but no start cant hear fuel pump running

I think the VZ fuel pump doesn't run all the time, as the regulator is built into the pump assembly. It runs up to pressure and waits for the fuel to be used. Over a period of time the pressure bleeds away if the ignition is not left switched on. From memory mine held operational pressure for about 30 minutes before it started to drop back.
A fuel pressure meter is handy.

No responsibility for this following piece.
Saw some person on utube give a careful quick depression of the Schrader valve at the fuel measurement point before the injector fuel rail; it may release fuel if there is pressure behind it with the ignition off. Gloves, goggles, protective cloths etc. and face mask and fire extinguisher etc. if you try it.

This may prove some pressure is present, but it may not be correct as the injectors require the specific pressure to atomize the correct fuel load.

 

[alloytec sludge]

Was swapping relays around and swapped engine control relay with high beam relay and heard pump come on and it started and ran straight away was driving it around all day then tonight went to start it and again dash read out said low fuel level. Faulty fuel gauge see service dealer and no cranking or starting so disconnected battery and swapped relays again finally it started so think it might be a computer problem somewhere

 

[99notout]

Make sure you do have a full tank, the sender unit on the fuel pump assembly is not the best and it can cause similar problems.