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V6 Engine will not crank over but will start if I bypass the starter relay.

OlderVZDude

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Hello All
I have a 2004 VZ which will not crank over however if I remove the starter relay & short circuit the battery to the starter motor it will start & run. I can then stop & start the car with the relay for the rest of the day. If I do not restart the car for 3 or 4 hours then I have to bypass the relay again. The local Holden dealer wants to replace the Engine Control Module ($1,300.00).
I would appreciate any suggestions or experience regards this problem that I have.

Thanks
OlderVZDude
 

db_notso

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vt v6, mods(susp brakesetc...)
does sound like a sticking switch

have you tried swapping the relay with another could be a worn relay not letting enough current through so you jump it and woolah!
then car is hot on restart requiring less current to signal starter

there are MICRO SWITCHES in the ecm that have control over the ignition circuits if these fail it wont crank
normally it wont crank at all

also try jump starting the car when it WONT start before you bridge it
sometimes low battery voltage (especially after long sitting time) can cause only certain circuits too malfunction

good luck
 

OlderVZDude

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db_notso
Thank you for your thoughts.
I have tried both keys, replaced the relay, replaced the ECM fuse & NRMA have tried to jumper start the car.
I have Temporarily connected the relay & connected an earth to the ECM leg of the relay & it started fine.
The ECM appears to not be supplying an earth for the starter relay.

Still looking for the answer.

Regards
OlderVZDude
 
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db_notso

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vt v6, mods(susp brakesetc...)
this works then here is the diagram you need

so depending on which leg of the relay your connecting an earth too....
pin x1_86 is earthed inside the ecm PERMANANTLY so if no other fault i would just earth that wire
if it didnt cause engine light and all worked just earth it

from what youve described to me
x1_87
x1_30
x1_85
is good circuit all except x1_86

so if circuit between x1_86 (pin 86 on relay) and pin x2_35 (on ecu) is not open circuit or high resistance
and its an auto or if manual the clutch switch is operrating correctly (disengages cruise control? or get it checked with scantool)
then the fault is inside the ecm

http://forums.justcommodores.com.au...ed-picture108389-x1-x2-04vz-ecmconnectors.png

theres the ecm connectors good luck man~!
 
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OlderVZDude

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Hello db_notso
Thank you for the diagrams.
I have proved continuity from relay leg quick connect socket (86) to pin x2-35 with a digital multimeter.
The car is an Auto & I have held the key to the start position & shuffled the shifter between park & neutral without success.
It was ECM leg (86) that I connected the earth from the battery to & the engine started.
I have also looked for an earth from the ECM at relay socket quick connect 86 with key to start position using the meter & did not get any earth.
I have noticed warnings like ESP failure, low fuel level,ABS failure & fuel guage error & service vehicle soon with the spanner symbol when I try to start engine initialy
& after bypassing the relay but are not present when I start the car with the relay after the initial bypass start.
I am interested in what the key start connects to within the ECM as this must activate something perhaps even supply the earth to the starter relay coil via leg 86.

Regards
OlderVZDude
 

bigdaddycool

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Have someone fix/look at your ignition barrel, had this issue before. The problem lies at the bottom of it.
 

db_notso

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vt v6, mods(susp brakesetc...)
yes thats correct this is all assuming you have a on/crank signal to pin x35_85 on the R1 igniton cont relay

check with a multimeter that when key is in run (or) crank position there is voltage supplied to that pin
also should be voltage at x2_31 on the ecu in crank position
x2_31 this one is the signal to ecu that key is in crank position then the ecm internally earths the starter relay signal side that you have been earthing out manually

if either of these fail then fault is in the ignition switch on the end of the ignition barrel (left side under steering coloumn covers)
they stick and then fail to provide a sgnal to the ecu they also get brittle with age

if the signal to these towo pins is good it needs an ecm module

hope this helps ...
 

papj

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i'm interested in how you got on with your problem as i'm haveing the same problem with my ute in every detail
 

db_notso

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vt v6, mods(susp brakesetc...)
well now if you read above hes got it narrowed down to either an ecu OR ignition switch
the switch is more likely though
 

OlderVZDude

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Hello db-notso & bigdaddy cool,
Thank you both for your suggestions, I have had the opportunity to test some of them.
When I turned the key to the ON position, I felt the engine control relay operate.
Disconnected the x2 ECM connector from the ECM & used a pin & multimeter to measure 12v successfully at x2-24 which is permanently supplied via the engine fuse to the engine control relay coil & leaves on relay leg (86) looking for an earth from the ECM to operate the relay.
I then used the pin & multimeter at x2-31 to look for 12v being supplied from the key in the START position & watched it the go from 0v up to 12v when I turned the key to & from START position.
Lastly I reconnected the x2 ECM connector & set the multimeter for continuity & looked for the earth at starter relay leg socket (86) which should have supplied the earth from the ECM to for the starter relay coil when I turned the key to START but I did not get the earth.
Based on these tests I believe that the key barrel switches are O.K. & the ECM is not able to supply the earth to allow the starter relay coil to power up & therefore not operate the relay to pass power to the starter motor.
I think the ECM needs to be replaced.
Hi papj , I hope the information supplied by db_notso & bigdaddycool is as helpful to you as it has been to me & maybe there is some benefit to you from what I have done.
I look forward to any further thoughts before I book it in at the dealership.
Regards
OlderVZDude
 
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