v6 hard to start - doing my head in

[vnss_1]

hey guys.
got a stock VT series1 V6

just the other week every now and then when i started it in mornings it would sometimes idle rough for few seconds then it would smooth out.
fuel pump was getting noisy too.
just the other day it cranked for a lot longer when starting (normaly starts straight away).
when started it was fine.

now everytime i start it it cranks for longer then usual before it fires. when it going its perfect tho.

i put a new fuel pump and a filter in as it was really noisy. still hard to start tho.

i can get it to start normally if i prime the pump a few times by turning ign on anf off a few times then starts straight away.

i also replaced leads and plugs.

no error codes come up.

any ideas?

[Ozzie]

Check your IAC valve isn't sticking.

You should prime a VT v6 everytime you start one. (alot of people don't) But you should only have to prime it once.

[vnss_1]

yeah i normally do let it prime. but if i want it to start normally now i need to prime it 3-4 times. i was gonna pull throttle body off this weekend and clean it up

[BOGANV8]

Could poss be the fuel pressure reg not hold pressure and letting fuel pressure drop overnight or between starts...

[vnss_1]

yeah thought about fuel pressure reg. a mate said to me tho, if fuel reg wasnt holding pressure then it would lack power higher in revs as fuel pressure drops. what ya reckon?
but it does sound like low fuel pressure on start up

[jazza15]

I'm pretty sure I have exactly the same problem. Had it since I got the car, so dunno about that initial rough idling problem.
I took it to a mechanic once where he charged me $200 to change the fuel filter which was something seperate that i wanted done and "fix" this starting problem. He cleaned out the throttle body and the idle control motor. All it did was smooth out my idle and acceleration. He also did some other useless things that I could have also done myself. the sad thing was he was certain that it had fixed it.
So anyway, my mate who used to work at that mechanic showed me a service hint in the VT workshop where it described this (our) symptom the most accurately out of anything that I have tried.
I went into detail about it in a post i recently did in this section, no one has replied. It is on page 2 of the VT/VX section by now. I've been insulating and cleaning ports of wires a lot lately, but am unsure as to where exactly I should be directing most of my attention to.
So as for me, I was leaning towards fuel pressure regulator for a while, even got one from the wreckers, but they are bloody hard to change and in the end I had the same conclusion as you have come to. Fuel injectors also came up, but performance would be down. You changed the fuel pump and as i thought, if there was a problem with mine that was causing this, it would have gone by now.
So yeah, VT's do have some weird electric problems and i guess this seems to be one of them.
Do you have an aftermarket stereo installed as well?

[vnss_1]

yeah its pissing me off. because the car runs perfectly normal its hard to diagnose.
i think the rough idle i had on a few occasions was something separate from this.
i was thinking possibly body control module but i haven't looked into what exactly they control yet. i thinking BCM as a few time recently its done some wierd things when unlicking the doors etc so could be something to do with the key and BCM maybe? i dunno im over it.

[jazza15]

yeah i'd doubt that the rough idle is/was related.
It is most likely something in between the BCM and the ignition key reader. if you can find what exactly it is, then that would be freakin great, as i'm having a hard time trying to find what exactly Australian Arrow are talking about (as per my thread I told you about).

[greenacc]

if priming it a few times 'solves' it, i'd say you should keep the focus on the fuel system, fuel line and injectors. The only thing that priming will do is boost fuel pressure isn't it ?
Tried any injector cleaner ?

[TrEnNaVY]

I used to do the same thing (priming) and the improvement was minimal if no co-incidental. Fuel injector cleaner did nothing for me, howvere I have just bough fuel syustem cleaner just in case, howvere i'm not getting my hopes up...

[jazza15]

I used to do the same thing (priming) and the improvement was minimal if no co-incidental. Fuel injector cleaner did nothing for me, howvere I have just bough fuel syustem cleaner just in case, howvere i'm not getting my hopes up...

[gunk81]

My car (VT Series 1) has just started having this trouble as well, until recently it would start fine then one day it just started having this issue.

I think it's something to do with fuel pressure but I'll see what happens when I replace the fuel filter because before it happened I had been running the tank near dry alot.

[jazza15]

My car (VT Series 1) has just started having this trouble as well, until recently it would start fine then one day it just started having this issue.

I think it's something to do with fuel pressure but I'll see what happens when I replace the fuel filter because before it happened I had been running the tank near dry alot.

Try putting some fuel system (not fuel injector) cleaner in as well. it's about $20 from repco. let us know how you go with that and i'll do it with mine as well when I get back on the road. if it does basically nothing, then we will definetely know it's not fuel system related.

I keep leaning towards fuel system causing it, but with no other symptoms it is pointing more to electrical.

[smokin_vx]

Most likelyl culprit is Fuel Pressure Regulator, Crank Angle Sensor or Fuel Pump / Fuel Filter.

I have the same problem currently and have decied its the CAS.. Starts up fine sometimes but then fires then shuts down straight away, next crank after that takes a while.. Pain in the Ass. Will get round to replacing that and might do the fuel rail / regulator at the saem time.

Best of luck and let us know how you get on

[vnss_1]

thanks for input guys. i looked at it on weekend and found my coolant temp sensor was buggered so i replaced that but still have prob. also cleaned throttle and sensors as needed doing anyway. put some fuel cleaner through it. done about 200km now and no change. i gonna test fuel pressure on thursday. got a feeling fuel reg is letting fuel bleed back to tank

[gunk81]

Managed to get hold of a Holden service manual and found that the fuel pressure regulator isn't the only way fuel can get back in to the tank.

The fuel pump has a check valve to maintain pressure at the fuel rail after the pump stops running. The check valve plays an important part in the fuel delivery system: to keep the fuel rail "charged" with fuel after the pumps shuts off. When the engine begins cranking to start, there is no delay before fuel injection begins, and quick starting is ensured. The check valve is inside the fuel pump, and is not serviceable.

[jazza15]

gee, I hope it isn't the check valve then, cbf'ed changing the fuel pump. Very good and accurate suggestion though, cheers.
I seem to be hijacking/taking over this thread a bit :P

[gunk81]

I would highly recommend downloading this. Don't worry about installing it, just burn it to a CD or mount the iso and make sure you have acrobat reader installed then open "main.pdf"

http://rapidshare.com/files/13336850...h_CD.part1.rar
http://rapidshare.com/files/13336850...h_CD.part2.rar
http://rapidshare.com/files/13336736...h_CD.part3.rar
http://rapidshare.com/files/13336736...h_CD.part4.rar
http://rapidshare.com/files/13336096...h_CD.part5.rar
http://rapidshare.com/files/13336097...h_CD.part6.rar

[vnss_1]

ive replaced pump in mine, i've ruled out fuel pressure now and i am certain it is an electrical prob. possibly crank angle sensor. but unsure. just gonna have to keep looking and rule out each thing as i look.

[jazza15]

I'm pretty sure my pump has been replaced as well, it has to have been at 230k km's.
Did you end up doing that fuel pressure test? or do you think it is firing fine (before starting)

[vnss_1]

i didnt do the pressure test, my mate who is a mechanic came round and we both agreed that its to intermitent to be low fuel pressure. alot of the time it starts perfect then turn it off and back on and it takes a bit to start. im leaning towards crank angle sensor now. gonna do a few tests on monday after work and see if i can nail it out

[jazza15]

Yeah fuel pressure reg is a convenient solution, but I don't think it's right.
People have suggested CAS to me before, but if that is not workin properly, wouldn't you be getting mis firing and all that bad stuff as well? not just an inconsistent hard start
Best of luck to you in finding out what it is though, I hope one of us gets it soon.

Cheers mate (below post)

[wrx884]

2 test the CAS pour some hot water on the sensor n if it starts straight away that could b ya problem.

[vnss_1]

ok. replaced CAS today just to rule it out and no different still doing it. so im stumped. mate bought a scanner home from his work com up with EGR pos fault. anyone know much about the egr?

[anarklov3r]

what kind of "hard to start" are you getting? Does it crank fast but just wont kick over? Or is it a slow sluggish crank that isnt going to any real rythm?

I just replaced my 450CCA battery with a 550CCA battery and my engine starts almost instantly compared to the 1-2seconds it was before. Try hooking up a battery charged to your battery THEN starting your car.