Intermittent starting problem with VR (yes another thread!)

[Ginny11]

Hey guys,

I know there is already a fair few posts on starting problems but mine seems a bit different so any help would be appreciated.

Ok I have a 1993 VR auto executive and a couple of months ago it wouldnt start, it was cranking but not firing and has continued to do this on and off, i.e I could start and drive it over a week with no problems and then all of a sudden it wouldnt start for a week (continually trying to start it) and then it would suddenly start again. Always when it doesnt start it does the same thing, goes to start then just cranks, then afterwards will just crank without firing up.

There has been no pattern as to when it would/wouldnt start, i.e it has started when its been hot and cold and failed to start when its been hot and cold (both the car and the weather), I tjhink this would mean I could rule out the crank angle sensor (have also tried pouring cold water on it). Yes the red security light is going off. The central locking works (excepts for one of the doors, not sure if thats realated or just the lock sticking), so does that rule out problems with the key battery? Have also made sure there is contact between the key and metal around ignition. Also have checked fuel things which all seem fine (pressure, filter, pump, etc.). Have checked the fault codes and have gotten code 31 theft detterent signal missing when it refuses to start, and I have only gotten code 12 when after car starts, disconnect battery, start the car again and check codes.

Now today we checked the ECU as previously noted in another thread referring to code 31 and one of the terminals was a bit corroded so we cleaned it up. Also looked at the BCM, basically just unplugged/plugged in connectors. And the car started. But because of the randomness of the starting/not starting I am still concerned that it was just a fluke that it started, so I was wondering if anyone had any ideas how I could check for sure that its fixed? Also it seems that when its not firing up just cranking the injectors arent going (supposedly you can hear them when they engage, which we did when car started)? Ive also seen it mentioned that the DFI could be playing up? How could I check that?


By the way, car runs absolutely fine when it starts, it has never stopped while running or anything.

Any advice would be much appreciated!!!

 

[dwayno80]

have ya checked ya coil pack? just a thought.

 

[Ginny11]

Yeah, a mate checked to see if they had spark(?) and said they were fine.

 

[dwayno80]

yeh id probly check n spray some rp7 in all ya plugs... eg battery, alternator, plug leads n even ya main plug to coil pack... it seems odd.. see how it goes..

 

[Ginny11]

Rito thanks, will give it a shot.

 

[89vn_Jai]

First up. Replace your ignition and starting relays. Seen intermittent starting problems with other Commodores that have been this. This is one of of the first things we check at my work for this sort of problem

 

[aussie4life]

does the remote locking button on ur key work? could be that the bcm isnt getting enough voltage or that you have a stuffed relay/fuse somewhere

 

[Ginny11]

Yep remote locking button works on key. How much would I be looking at to replace ignition and starting relays? Is there any way I can check this is the problem?
We have looked at most of the fuses and they all seem fine, though I suppose there could be some sneaky ones we have missed, wouldnt suprise me.

 

[aussie4life]

there are fuses under the bonnet with the relays. easiest way to test the relays is to take it out and either swap it for one that you know is working or use a bit of wire to bridge the 2 connections. have a look on the side of the relay and youll see a wiring diagram. usually if its a 4 pin relay there will be 2 tabs (85 and 86 i think)that activate the relay and the other 2 (35 and 87 thinking again) that allow the power thru. check your main relays under the bonnet, fuel pump, ignition, engine, and your fuses and fusable links that are there. also check your earths. there should be at least 2. one on the drivers side quarter pannel next to the battery and another one in between the alternator and the ac compresser on the passanger sid front of the engine block. make sure these are clean.

 

[Ginny11]

Ok thanks we will check these out, its just bloody difficult cause there seems to so many things that can be going wrong and everyone has different ideas. Im just glad I have mechanical minded mates cause most of this stuff goes straight over my head.