Commodore VT sometimes not starting

[hsv_sc]

hi all...

assume this is a batt in need of a charge but thought i'd check..

doors locking / unlocking a bit slower
dash lights look slightly dimmer
indicators look slightly dimmer
ecu not allowing fuel pump to prime or starter to spin
3 beeps from behind dash after 10 seconds

over the past few weeks, when car has turned over but not started properly on first turn of key, i haven't been able to get it to turn over again without leaving it for say 30 mins, then when i go back, the fuel pump primes and starter will spin again.

to me, this suggests the battery recovers slightly from the power drain of first attempt. perhaps the ecu detects the voltage in the batt and won't allow you to start the engine if the voltage is too low?

any thoughts welcome

[bigwheel]

I don't know if your model has a voltmeter on the dash. If it has, ignition on must show a minimum of about 11 volts for the starter motor to spin.
It does appear your battery is finished or needs water topping up.
A lot of car-parts shops can connect their battery analyser that will give a concise report on the state of the battery.

[motomk]

Press Mode and the up arrow on the tripmeter and then put the key in the ignition and try and crank over the engine. It should come up with a voltmeter on the dash, normally called Police mode. You can hit mode and it will scroll through a few other functions. I am assuming you have a 3 windowed dash although I am pretty sure the single windowed ones do it too. No idea if the newer Monaro's do it or not.

[bigwheel]

'05 CV8
Holding Mode and Set, turn on ignition or start gives new menu info including voltage. Scroll through with Arrows. Set button (or Mode, can't remember) exits this menu sequence.

[hsv_sc]

thanks guys, i will put a meter on the batt to check the voltage.

i've got another charged batt to substitute so will do that first.

the car is a 2000 VT (3 window cluster), has 1 mode and 2 arrow buttons (pressing both arrows together is for SET function).

i'll try to get to the additional features you mentioned.

[motomk]

hsv_sc said:

thanks guys, i will put a meter on the batt to check the voltage.

i've got another charged batt to substitute so will do that first.

the car is a 2000 VT (3 window cluster), has 1 mode and 2 arrow buttons (pressing both arrows together is for SET function).

i'll try to get to the additional features you mentioned.

Instructions were for a 2000 VT as that is what I have...I had to go out to the car and test it though as I couldn't remember the combination. Mode and up arrow should work.

[hsv_sc]

thanks moto, i will try that asap.

so the ecu doesnt send power to fuel pump, starter etc if it doesn't see a certain voltage? i.e. 11 volts?

[hsv_sc]

hi all..

ok, have charged batt and fitted..

checked voltage on dash using menu and arrow button.. shows 12.5 v.

so the batt is now ok..

car still won't start:

turn ignition on

no fuel pump or starter

all lights come on and go out apart from the usual batt, oil press and yellow eng warning light

after about 10 seconds, the airbag light comes on and you hear 3 ascending beeps from behind the dash.

i'm guessing something is up with one of the airbags? maybe the low voltage in the batt has screwed something up? is there anything obvious i should check? anyone had this prob before? help! :/

[harrypp]

Don't know what system you have got fitted to the car but "no fuel pump or starter" could be an immobiliser problem.

[marcevo1]

tim

the slow central locking etc does indeed sound like low voltage but the new battery and voltage check should have resolved that (i'm used to 80's italian cars which drained their battery every three days - locking you out of the car!)

so sounds like it may be a dead fuel pump? check the fuses / relays first? then check the pump is getting a supply (dont think you need to drop the tank to get to the wires)

have you been running low of fuel at all? if so it may have killed the pump as they need alot of fuel to cool them and are very sensitive to crap out of the tank - that said i know your tank is clean as a whistle as i've had it out twice.... to fit guess what - a fuel pump... the standard one wasnt up to the job - replaced with a s/h gtsr which packed up 20 miles down the road! ended up fitting the biggets one walbro sell!

pretty certain when the gtsr pump failed it wouldnt turn over without the pump? may be mistaken however

think the airbag light is a red hearing as it wont be able to do the self check without firing up?

[hsv_sc]

hi marc!

hope you are well.. thanks for posting.

i thought about the fuel pump, but discounted it because of the warning beeps which i assume are related to the airbag because the airbag warning light comes on at the same time (after 10 secs)

i've never let the fuel get below 1/4 tank, so i'm fairly sure it's not that.

am not sure but would assume the ecu checks the airbag system as soon as you turn the ignition on? i'm just guessing tho.

one thing i did notice the other day when i first had the problem: when i had no fuel pump, i tapped under the steering column a few times, then on the next try the fuel pump primed and the car started. it may have just been coincidence.

i'm going to get the rac to have a look in the morning.. you never know.

also, i've read that you can clear some error codes from the ecu by bridging 2 of the pins on the diag port under the dash?

[hsv_sc]

think ive found the problem:

code ring on ignition barrel faulty.

if i keep tapping underneath the barrel, then keep turning the key, after a few attempts, the car starts..

strangely, it will then start with no problems until the next day, sometimes a bit longer, then the problem returns.

looks like i will need a new code ring fitted and get the keys reprogrammed?

am assuming i would need to go to a vauxhall dealer to get this done?

[motomk]

Does the spare key behave the same?

[hsv_sc]

yes both keys behave the same, although continually switching between keys when trying to start seems to help....?

[motomk]

Maybe new key time? On my 8 year old, I have recently replaced both keys. Dealer had to do this as they had to program the keys.
Maybe get them to plug the Tech2 into it to see if it is throwing up any codes that might help diagnose it better?
Sorry, Not really helping diagnose the problem here.

[hsv_sc]

hmm.. was this at a normal vauxhall dealer?

the range on both keys is fine, seems more like a problem with the decoder part of the barrel. :/

[marcevo1]

sounds like good news Tim (well sort of) - seems strange that it never happened to me as i drove the car every day....

marc

[hsv_sc]

i know.. think that's part of the reason, car only seems to do this when it's been sitting for a few days.

i'm gonna make a few calls tomorrow and see about getting this decoder replaced..

thanks for your help though.