2007 vfr 800 vtec - cold start not working.

I have the bike all opened up. Upon inspection, there is no way that I can see removing the wax idle unit with out taking the throttle body out. Did you ever synced the cold start valve?

The fuel pressure relief valve is working. No leaks.
I'm waiting for spark plugs and k&n air filter to come in. The stock filters are pretty dirty. On the other hand my wax idle unit looks like it's very loose. The adjustment bolt don't even show any threads thru it. I've syced the cold start valve.
Then gave the wax idle unit adjustment nut a full turn. Park the bike out this morning around 55 f
It started right up to 2k rpm and slowing dropped back to 1200. Never done that since I bought it. I'm a happy camper.
I think they didn't do anything on the assembly line. Arghhh Honda

 

Great to hear that you've sorted that one Puig!

 

Thanks, Pulg and everyone else who posted to this thread.
My '07 started doing the same thing in the last month or so - wasnt so bad till this morning when it was 17F outside. She fired up, idle sank and bike died... took a while to get her running. I will adjust the wax unit tonight and see if she's ok tomorrow morning...
Ive done a full PAIR mod with plates and everything so I really dont want to have to put all that stuff back on!

 

I didnt put the pair stuff back but replaced spark plugs , air filter and balanced the throttle.
Also replaced a 4 yrs old yuasa battery with a shorai lithium. Its fires right up with just a press on tge ignition button. Compare to the pass when it took a few cranks.
Good luck keep us updated.

 

<this is a repeat post I've put in other related threads>

Well, I'm going to tentatively say....I've fixed mine. After 3 years of head scratching and getting nowhere I realised I'd never actually gone to the trouble of lifting the throttle bodies off completely. Anyhoo, whilst mulling this over it curiosity led me to think about the throttle body boot clamps. There are eight in total, four lower and four upper. Would you Adam and Eve it; all eight were loose enough to spin by fingers alone! Tightened them up and straight away the difference was marked. Took it out for a test ride and it felt like the bike had a new lease of life! Much smoother, engine braking changed, no more grumpiness at lower speeds/revs and just generally much more responsive.

It's been two weeks now and I commute every day on my VFR and she starts up straight away at 2k rpm no hesitation or bogging at all, every time. And what's more my mpg has gone up to 'normal' figures (I've had all the way down to 27mpg, that's UK gallons so for you yanks that'd be..err..23mpg!)

The startup issues will have been that the 'leaks' in the boots will have caused the MAP sensor to go wibbly and throw it off, hence why if I disconnected the MAP sensor electrically it would start up fine albeit in Alpha-N mode.

Needless to say I am delighted to put a long running mystery to bed.

 

AdsroxOr, thanks for the update, at the least this thread will guild the members who search for this problem of what to look for.
Glad you got it sorted. Mines been running great since 2015 post, but will take a look at the throttle body clamps just for good measure. Did you buy your vfr new?

 

People not updating problem threads with the results is one of my major irritations on the interwebs, nothing worse than finding someone who had the same problem but they never came back to say if/how they fixed it!

Anyhoo, no I bought her second hand and she's had one or two gentle drops by previous owners which always led me to believe something in that was connected to the issue.

If I was to give a prognosis I would EITHER say someone had the throttle bodies off and never tightened them up (fnd that hard to believe) OR, and this is my theory that they've vibrated loose. When you tighten the clamps you can feel the bolt 'spring' back slightly and they could really do with a dab of threadlock on to keep them held in place.