Another Cold Start Issue

[adsrox0r]

So my 2008 VTEC is problematic at ambient temps under 5 degrees celcius. Seems to be the opposite of the common enough high idle.

It'll crack over but revs are very low to the point everything coughs to a stall. If you crack the throttle and hold it she'll fire up and hold, then once warm enough you can risk letting go and see if she'll hold. Fast idle works fine normally, kicks up to a few thousand until dash reads out a coolant temp then returns to normal. Fast idle will also take over once you've held the throttle.

I'm thinking wax idle might be stuck in the 'warm' position? In other words it won't make a difference being stuck when ambient is warm but at cold temps it's not doing its job at all?

I need to get the throttle body open and get the starter valves balanced but money and time is tight at the moment, my wife's car just had a grand thrown at it for....cold start issues!

Wax idle unit is quite expensive to buy here in the UK

Thoughts?

[gilkeyb]

Hi,

Unfortunately, I can't be much help to you except to say that I am experiencing the same thing.

http://vfrworld.com/forums/showthread.php/41493-2007-vfr-800-vtec-cold-start-not-working?p=436584&highlight=#post436584

The thread above, from VFRworld details someone fighting the same issue.

I did speak to someone who had their injectors cleaned and they felt that improved the cold-start issue. I haven't tried that myself.

Im suspicious that it is ignition related. I think when the bike starts and starts idling rough is is running on less than 4 cylinders (sometimes I think my bike is running on 2). Once you hold the idle up long enough (usually 5 seconds or so for me) the rest of the cylinders start firing and the bike starts operating normally. This is all speculation of course.

I also noticed that when I experienced this behavior and took the bike apart, the airbox had some fuel residue inside.

[adsrox0r]

Had the airbox off this afternoon to give the wax unit a visual inspection; looks fine but being a sealed unit there's not much to see. Gave it all a good wiggle and squirted a dab of WD40 on the linkages and wax unit piston but I'm not holding my breath. I did think about giving the wax idle adjuster nut a turn while there but I'll see how we go next time it gets a bit nippy. If it'll start and run holding the throttle I'm not urgently bothered, I'm only really concerned about flooding it when she starts coughing and dying.

To be fair to her it was zero degrees celcius ambient this morning!

I don't actually own a carb balancer so I'll need to invest in one to get that job done some other time. I know you can make them DIY style but with a toddler running round I barely get time to wipe my own arse let alone jerry-rig a fandangled contraption together. £60 buys you a decent mercury affair rather than the old wibbly needle job.

[spud786]

So my 2008 VTEC is problematic at ambient temps under 5 degrees celcius. Seems to be the opposite of the common enough high idle.

It'll crack over but revs are very low to the point everything coughs to a stall. If you crack the throttle and hold it she'll fire up and hold, then once warm enough you can risk letting go and see if she'll hold. Fast idle works fine normally, kicks up to a few thousand until dash reads out a coolant temp then returns to normal. Fast idle will also take over once you've held the throttle.

I'm thinking wax idle might be stuck in the 'warm' position? In other words it won't make a difference being stuck when ambient is warm but at cold temps it's not doing its job at all?

I need to get the throttle body open and get the starter valves balanced but money and time is tight at the moment, my wife's car just had a grand thrown at it for....cold start issues!

Wax idle unit is quite expensive to buy here in the UK

Thoughts?

What is your normal idle rpm at warm?

Ive seen those wax units correct themselves with mileage(usually in the first couple thousand miles of use) and some never work at all and normally requires the rider to wing the throttle trying to warm it up. It sounds like you have the latter, yours doesn't work at all.

[MarkDetroit]

Had the airbox off this afternoon to give the wax unit a visual inspection; looks fine but being a sealed unit there's not much to see. Gave it all a good wiggle and squirted a dab of WD40 on the linkages and wax unit piston but I'm not holding my breath. I did think about giving the wax idle adjuster nut a turn while there but I'll see how we go next time it gets a bit nippy. If it'll start and run holding the throttle I'm not urgently bothered, I'm only really concerned about flooding it when she starts coughing and dying.

From my history I'd say you have nothing to loose by doing an adjustment to the wax idle nut. The nut on my 2006 was very loose when i bought the bike last year and there was no cold idle rpm bump at all. I made a 3/4 revolution nut adjustment and it made a noticeable improvement but it's not right yet. I'm going to give it another 1/2 rev turn when i take the filter housing off next time.

Good luck!

[KevCarver]

On the ST1300 forum they say to take off the "5 way T" and clean it out. They have a vacuum hose from each throttle body that meets up at a common connector and then it goes to a sensor. MAP? I forget. Anyway, they say to clean that out and the fast idle comes back on startup. I don't personally understand why that would work, but it seems to. Also not sure if that is on the VFR. It's under the air box, so not a quick look unfortunately.

[Matthewj85]

...Wax idle unit is quite expensive to buy here in the UK

Thoughts?

I have the seemingly common high idle problem while cold at the moment, and trying to find a new wax unit is proving difficult. Where did you find one?