Crank but no start Monaro VXR
Discussion
Having completed some work on the car i am at a point where it cranks but doesn't fire. At this point I am going to have to own up to being a complete and utter numpty 
I had been refitting the steering rack and reconnecting the steering column which required the ignition key in place to release steering lock, working with the battery out of the car I forgot to take the key out of the ignition, and yes, you guessed it, the following day replaced the battery and reconnected terminal connections at which point the air turned blue with a series of expletives i won't repeat here.
I have connected GM Tech2 to the car and run the diagnostic feature ( I am very new to Tech2 ) it appears to show no communication with the ECU, have I fried it, is it likely that connecting the battery with the ignition switched to on, caused a power surge and damaged the ECU ? Any abuse coming my way will be taken well I promise
I had been refitting the steering rack and reconnecting the steering column which required the ignition key in place to release steering lock, working with the battery out of the car I forgot to take the key out of the ignition, and yes, you guessed it, the following day replaced the battery and reconnected terminal connections at which point the air turned blue with a series of expletives i won't repeat here.I have connected GM Tech2 to the car and run the diagnostic feature ( I am very new to Tech2 ) it appears to show no communication with the ECU, have I fried it, is it likely that connecting the battery with the ignition switched to on, caused a power surge and damaged the ECU ? Any abuse coming my way will be taken well I promise
L2VXR said:
Also I hope you've not uncentered the wheel or you could also damage the clock spring for the air bag.
Only a minimal amount of movement with the steering wheel whilst disconected from the rack, just enough to allow the end of the column to drop into the socket on the rack, so hopefully all good there.L2VXR said:
Have you connected the candi module to the tech2 as you'll need too on a small boot VZ
I will have a look at this as not using a candi module, i am using Tech2Win software on a laptop via VXDIAG VCX NANO GM GDS2 obd interface and USB cable. I am new to the software and interface, so will do some more research and have another look tomorrow, thanks for the feedback 
stevieturbo said:
It would be extremely unlikely that could cause any damage, if that is genuinely all you did.
Does anything in the car power on ? Does the fuel pump prime on key on ?
Thanks for the reply, dash lights up as normal, engine turns over but doesn't fire, 1st thing I noticed when I first tried to start her up was that I didn't hear the fuel pump prime the system, and thought the immobilizer might be preventing the car firing. More investigation required this end.Does anything in the car power on ? Does the fuel pump prime on key on ?
Hearing that it's unlikely i've fried the ECU makes thing easier, it's looking more like the diagnostic tools i'm using aren't communicatiing with the ECU at present.
LS2Noir said:
L2VXR said:
On the crank but no start, is the red immobiliser light flashing on the dash or dose it go out when the ignition is on
I'm away from the car at the moment, will drop you a reply on this at some point tomorrow, thanks again for your responses.SturdyHSV said:
My Tech2win also says those 3 modules don't communicate. The car runs fine, and it absolutely would not without those modules communicating, so I wouldn't worry about that bit!
Have you got the VZClusterMod software? If you do, log the output from that and post it, I can confirm that the modules are communicating from that (they all send a heartbeat type check in response constantly)
Feel free to PM me if easier, I'm off work tomorrow so can check stuff on the car if you need.
There's a schrader valve on the fuel rail, with ignition on the fuel rails should be at 56psi or so. Put a cloth around that schrader valve and give it a jab, 56psi should mean you get a pretty obvious spray of fuel if there's pressure.
The fact it's cranking means the modules are communicating I'm pretty sure, as the crank signal isn't from the key turn, it's a deliberate signal from the BCM (or one of the modules anyway) that's sent once all the others have responded properly.
Hi SturdyHSV,Have you got the VZClusterMod software? If you do, log the output from that and post it, I can confirm that the modules are communicating from that (they all send a heartbeat type check in response constantly)
Feel free to PM me if easier, I'm off work tomorrow so can check stuff on the car if you need.
There's a schrader valve on the fuel rail, with ignition on the fuel rails should be at 56psi or so. Put a cloth around that schrader valve and give it a jab, 56psi should mean you get a pretty obvious spray of fuel if there's pressure.
The fact it's cranking means the modules are communicating I'm pretty sure, as the crank signal isn't from the key turn, it's a deliberate signal from the BCM (or one of the modules anyway) that's sent once all the others have responded properly.
Thanks for responding, no unfortunately I don't have the clustermod software at present, just had a read up on using the software, useful tool by the looks of it, are you using the clustermod software with the connection cable advertised with the software or the OBD interface and cable you would use with Tech2Win software.
Gave the shrader valve a prod, very little pressure on 1st prod, no pressure on second prod, that was the first thing I noticed when I tried starting the old girl, no sound of the fuel pump priming.
KIWIRS said:
If you have no luck locally, I can recommend emailing Wayne at Pro-Tune here in New Zealand, he has worked on and tuned literally tens of thousands of GMH V8 product is renowned in the LS world. He studied in America and does maps for cars all over the world, including Australia so that says something.
I only recommend him because I know he is a hell of a nice guy, very knowledgeable and passionate and a hell of a peddler in a Rally car.
sales@protune.co.nz
Thanks for responding KIWIRS, I am going to persevere here with some more research and getting my head around the Tech2Win tool, hopefully get the problem solved, and will keep your advice in mind, cheers. I only recommend him because I know he is a hell of a nice guy, very knowledgeable and passionate and a hell of a peddler in a Rally car.
sales@protune.co.nz
L2VXR said:
Have you connected the candi module to the tech2 as you'll need too on a small boot VZ
New to the Tech2Win and learning as I go, as far as I can tell the software I'm using must emulate the CANdi Module as it shows the module present on start-up will keep playing with it and see how I get on.fred bloggs said:
LS2Noir said:
1st thing I noticed when I first tried to start her up was that I didn't hear the fuel pump prime the system,
Tried swapping the fuel pump relay with the one next to it ? Think its headlamp or fan. I did have a fuel pump relay fail years ago. Lincsls1 said:
Any progress on this OP?
Its important to conclude threads like this to help others in the future keep these rare cars going.
Hi Lincsls1,Its important to conclude threads like this to help others in the future keep these rare cars going.
Currently finding it difficult to get time in the garage due to work and family commitments, I am currently looking at the possibility that the crank position sensor or its wiring loom have been disturbed whilst refitting the starter motor, so the car will be going back up on the axle stands for a closer look at he sensor and wiring.
will keep the post updated as go, may be a slow process though.
Secret lemonade drinker said:
Bet you’ve snagged the crank sensor
Secret lemonade, thanks for the suggestion, looks like you could be on to something, will be putting the car back up on the axle stands for an inspection of the Crank Sensor and wiring. When you say "snagged the crank sensor" are you speaking from experience ? if you are, what issue did you find, any feedback would be greatly appreciated. When I ran the Tech2win software initially a DTC showed for the crank sensor, that was the only DTC showing, I cleared the code and since then have cranked the engine over and the same code has shown again.
(he says with a whistling vacuum on the mini)
I do try to be careful, I can't see any damage to the sensor itself, so now looking to test the cabling.Secret lemonade drinker said:
How did the bank holiday troubleshoot go?
Have done some testing at the connector (sensor end ) and found some results that I wasn't expecting, looking at the wiring diagram I was expecting to find a 5v reading on my multimeter on both the Light Blue and Light Blue with White Stripe pins when tested individually. When tested, I read 0v on the Light Blue and 11.8v on the Light Blue with White Stripe.Unexpected results could be down to problems in the loom or faulty PCM, due to the design of the multipin connector it is very dificult to back probe off the pins, so can only really test loom with the multipin connector diconnected from the PCM. I have checked for any resistance between the pin at the multiconnector showing higher voltage than expected (11.8v) and all other pins on the same connector looking for shorts in the loom, that test passed ok and will do the same with the second multipin PCM connector ( the engine to PCM loom is split over 2 x connectors ) when I next get a chance. Not firing the parts cannon just yet.
Edited by LS2Noir on Thursday 30th May 23:34
L2VXR said:
I assume you have the factory manual from your wire diagram pic ...under section 6C3-2 -108 Powertrain management there's a diagnostic check list/procedure for P0335 if it helps
In the holden manual following the P0335 checklist it gives a value as B+
In the Pontiac GTO manual the same checklist gives the value 11.8v
Hi L2VXR, thanks for responding, since my last post yes confirmed that the 11.8v I was seeing is correct, and not 5v I was expecting. In the holden manual following the P0335 checklist it gives a value as B+
In the Pontiac GTO manual the same checklist gives the value 11.8v
Edited by L2VXR on Friday 31st May 13:56
Edited by L2VXR on Friday 31st May 13:57
This evening I have had a chance to do some more checking of the wiring loom, with the multimeter on the sensor connector pin reading 11.8v and checking this remains constant whilst I move the loom around and giving the connector a good wiggle, this seemed ok with reading staying constant.
Thanks for pointing me in the direction of the diagnostic checklists for P0335, I will be having a read through and will update thread as I go.
stevieturbo said:
12v powered cam/crank/hall sensors are not uncommon.
Scope it's output to see if the signal makes sense.
https://www.youtube.com/watch?v=TXKf96wqaoU
crude version
https://www.youtube.com/watch?v=nbOHDk21IxQ
stevieturbo, thanks for the video links, unfortunately I have the starter motor out of position at the moment as I need access to the sensor and connector, so can't crank her at present, had a look at the videos, very useful, thanks again.Scope it's output to see if the signal makes sense.
https://www.youtube.com/watch?v=TXKf96wqaoU
crude version
https://www.youtube.com/watch?v=nbOHDk21IxQ
stevieturbo said:
Or just testing to prove it is fine ?
I have a new sensor and connector with pig tail, both genuine GM from RockAuto which i am fitting, at the same time re-routing the wiring as I was not happy with how close the existing route was to the new headers, will update the thread when finished Gassing Station | HSV & Monaro | Top of Page | What's New | My Stuff