3.0R choking on startup

[SegR]

My poor 3.0R has been having problems starting for the last month or two. If I had to describe the sound, I'd say it sounds like this:



If I had to use words, I'd say it sounds like it's being starved of one of the three critical elements while cranking. Strangely, about 60% of the time the car starts fine without doing this. The remaining 40% of the time it has two cracks at starting as in the video (I was holding the key to 'start' the entire time) or just cranks in a single sequence for a couple of seconds longer than it should before starting. Either way, when doing this it always sounds like it's about to stall just before starting.

I can't find a pattern to it either - hot weather, cold weather, high/low fuel level, high/low humidity, recent vehicle use (whether I've driven it multiple times recently or it's been sitting in the garage for a week) - doesn't seem to make a difference.

Any idea what may be causing this?

I suspected my battery at first but since it was under warranty (the previous owner had one installed by RACQ) I had RACQ test it and they said it was fine... voltage was around 13V and 10.5V when starting. This sounded a little low to me though and I'm not 100% convinced they weren't just trying to avoid a warranty job on a 2.9 year old battery.

[SH30RB]

have you thought about getting someone else test the battery?

my first thoughts would have been the battery too

[HyRax]

Old spark plugs not firing? Coil pack not zapping properly? Pre-fuel from pump not occurring when ACC engaged?

[SegR]

Shouldn't be the plugs; had them changed about a month ago and it was doing it before & after.

Not sure about how to test the coil pack or pump.

My multimeter shat itself; need to buy a new one so I can check the battery for myself. Just dropped a ctek charger on it so will see if that makes a difference.

[champ]

check condition of the starter motor too.

[Deep Heat]

My guess is the fuel pump.

[666]

I also think it's the fuel pump, only because the fuel pump went on my Impreza last week and it sounded and behaved just like what you've posted. Only difference was that mine went without warning but it did sound like yours did just before it went.

Rob.

[west_minist]

Sounds like fueling issues, timing out or coil related.

When it does start, what happens?

[Robbks]

do you wait for the fuel pump to prime fully before cranking? (and don;t touch the throttle)
i usually wait for the gauges to finish dancing before i crank mine over, starts easier.

Next test is to start it with the throttle flat to the floor (after waiting for fuel pump to prime)

yours is a bad start i'll give it that, but knowing those two things will help to know if it's getting enough or too much fuel.

test that and get back to me

could be a dying/ dirty crank sensor

[SegR]

Thanks for everyone responding to this.

When it does start, what happens?

On the days when it doesn't have a problem, it starts normally
On the days when it does have a problem, after turning over the starter, ignition happens, the engine 'chokes' a little (sounds like it's not getting enough fuel or air, or idling too low) for 0.5-1sec, then goes into normal idle and is fine.

do you wait for the fuel pump to prime fully before cranking? (and don;t touch the throttle)
i usually wait for the gauges to finish dancing before i crank mine over, starts easier.

Next test is to start it with the throttle flat to the floor (after waiting for fuel pump to prime)

yours is a bad start i'll give it that, but knowing those two things will help to know if it's getting enough or too much fuel.

test that and get back to me

could be a dying/ dirty crank sensor

No I don't wait for the pump to prime; I usually insert the key and turn it. I will try those things. Unfortunately because the problem doesn't always happen, it's a bugger to troubleshoot.

[SegR]

Well, starts have improved since I've been giving the fuel pump 3-4 seconds to do its thing before cranking. (that said, since it's random, that may simply have been good luck.) Today though, the starts have been crap regardless (though not as bad as in the vid).

Haven't tried the foot-flat test yet though will be booking her in for a look-over later this week anyway.

[d-chang]

Yeah I have posted a similar thing as yours there mate, but mine is not as bad... it's generally in the mornings that this happens for me.

viewtopic.php?f=45&t=16126

I think this is a common issue with Liberty's that may be still on their original internals in the engine bay if your car is over a certain age. Mine is a 2.0R from 2006.

But as from the thread I posted above, some people have maybe narrowed it down to the type of fuel that is also used..

Please let us know what your mechanic says, will shed a lot of light on the issue.

[Tradewind]

Once upon a time choking on start up was necessary to get an engine running!!

That might be a touch far back for some of you

[SegR]

Yeah I did consider my poor choice of words after I posted the thread. Not that I'm old enough to know what you're talking about of course.

[SegR]

Update on this...

Handed over the vehicle to my regular mechanic for a day.
Of course he couldn't reproduce the problem, despite the fact it had been having starting issues more frequently recently! I knew that would happen.
Pump and bracket were removed and reinstalled; no visible problems.
Fuel flow checks showed nothing as the problem wasn't happening at the time.
No Diagnostic Trouble Codes (past or present)
Battery and alternator voltages OK

As of the last few weeks it's been pretty reliable when priming line twice before starting. When not doing so it's been fairly bad. Since I got the car back though I havent had an issue... will see what happens over the next month. Maybe reseating everything will make it happier, or maybe the pump is just on its way out. The fact that priming the line twice was making a difference seems to indicate to me that it's not an electrical issue though.