The Honda PCX / Forza / ADV150 / SH Forums

My first instinct would be a weak battery, but you say it starts fine after warming a bit. I would then think it would be a PCM problem. The on board computer is failing to complete it's engine sensor checks and cannot get any feedback to start the engine. Because this event only takes place when freezing temps are incurred, I am thinking that water/ moisture is present and is turning to ice somewhere inside a plug or connection , or the main relay, PCM, that will not permit a solid connection . If it were me I would pull apart every plug, connection, etc going to the computer, spray contact spray inside and dry out and then reconnect every connection. Make sure they are all tight and very clean. Use fresh strong battery and go from there. Good luck

I'll keep in mind pricing out a new battery just in case.

Started fine this morning and it was even colder, but dryer. The mini-blizzard Tuesday came in sideways, melted completely, then refroze, then snowed again Wednesday, then dried overnight.

I'd love to have a garage to work on it, but I'm run and gun. Has to be dry outside to take anything apart. My particular advantage will be that the PCX is low cost to begin with.....these storms are going to emaciate me though. The motorcycle cover is going to be my constant friend.

I'd say my greatest mistake is possibly not even a mistake. The weather report was completely off and by the time I had a chance to react, we were already encased in deep waterfall frost.

If you can jump start the bike it will more than likely be a failing battery. Once the battery starts failing it becomes unpredictable and could work at one point and not the next. It would really be strained if you had the stop-start circuit engaged. Even charging it up would not solve the problem permanently. Batteries are interesting items, and if you studied them like I did when i was in the military, you would see that the lead-acid ones have been around a long time, so most of their quirks have been discovered already, but any variation can add new problems, such as those that are gel-celled and sealed.. Now we are seeing Ni-cad, and Lithium batteries. Those have their own set of problems.

Pull the plastic wrap from the Computer and check the black connector ..clean with contact cleaner..Reinsert ..See what happens.. Let us know and we can go from there.

foggyhelmet wrote:I'll keep in mind pricing out a new battery just in case.

Started fine this morning and it was even colder, but dryer. The mini-blizzard Tuesday came in sideways, melted completely, then refroze, then snowed again Wednesday, then dried overnight.

I'd love to have a garage to work on it, but I'm run and gun. Has to be dry outside to take anything apart. My particular advantage will be that the PCX is low cost to begin with.....these storms are going to emaciate me though. The motorcycle cover is going to be my constant friend.

I'd say my greatest mistake is possibly not even a mistake. The weather report was completely off and by the time I had a chance to react, we were already encased in deep waterfall frost.

Stop thinking and listening. New good quality battery

Just had this problem had to take battery out and warm it up under my armpit! It worked anyway and saved me a 30 mile walk home pushing a pcx! Time for a 3rd battry in 3 years. Btw i dont use idle stop and my commute is a 60 mile round trip with little trafic. Might spend a little extra and try a lithium this time.

Not starting in the cold is almost always a battery issue. I know I'm beating a dead horse with how many people have said that, but I have experienced it firsthand with a couple of my cars, won't start at 0700, but will start fine at 1700 after work when it's 20F warmer.

My new Lifep04 battery+charger has arrived. I have installed it and i'm still having the same issue, in fact it seems to be getting worse, now my scoot will only start after sunbathing for an hour and after its started once, if i turn the engine off it refuses to start again untill its been stood for at least an hour, so basically the light on the dash that comes on when turning the key does not light up and this prevents being able to start the scoot. on the occasions the light comes on and the scoot starts, it runs fine and i have even checked stop start and that works fine. I have stripped all the bodywork off and spent hours wire wiggling but have been unable to diagnose the cause.
Any idea's anyone i'm close to booking it into honda but would rather avoid their hefty labour costs and lengthy journey.
Cheers

Buddy, If, as you say, the battery has been changed multiple times and the problem persists, your problem is somewhere in the electrical system, unless you leave the vehicle unused for months at a time and the battery sits without charging. now that we're into the warmer months in the northern hemisphere, there should be no point at which your battery would have the need for "cold cranking." If indeed you haven't left the scoot disused for long periods of time off a charger, I'd suspect either a corroded connector somewhere or possibly an issue with the charging system. If you aren't familiar with the use of a multimeter, you'll want to have someone who is do a voltage test on the stator and diode test on the regulator/rectifier. If these check out fine, then Something else in your wiring harness is ferhutzed.

Hi Honkerman thanks for your response,

I think i'm gonna call a few auto electricians tomorrow while i have all the tupperware off and see if they'll be able to come to the scoot rather than taking it to a honda dealer and having to remortgage to pay the bill!

With a multimeter check for a parasitic drain on the battery - something is on (stuck switch?) that is drawing down the battery.

Also check the ECU connector. Others have had issues with corrosion in that causing similar problems.

Good luck!

Picked up a 2nd hand wiring harness with all relays + fuses etc swapped them and still same issue. Im gonna swap out the sub harness next Hopefully that will be the problem otherwise the blame may be on the ecu. I have checked all connectors and they are all clean and free from corrosion. I'll update when sub harness arrives from the us.

Flog it on a warm day and buy a new one.

you you wrote:Flog it on a warm day and buy a new one.

haha the thought had crossed my mind

2nd hand ecu turned up. Plugged it in and problem resolved. Now just the job of putting all that tupperware back on!

Great news. Glad you got it sorted; I know that wasn't much fun for a while there. Plug 'n Play wins again! Sorry about that tupperware thing. They say after you do it a couple of times it gets easier. Schedule some more for next week, or no?

Johnny

montliz44 wrote:Great news. Glad you got it sorted; I know that wasn't much fun for a while there. Plug 'n Play wins again! Sorry about that tupperware thing. They say after you do it a couple of times it gets easier. Schedule some more for next week, or no?

Johnny

Thanks and yeah it had me stumped for a while, I always thought it might of been the cdi but after browsing the prices Honda charge in the uk for these units https://www.fowlersparts.co.uk/parts/view/30400-KWN-783 I thought I'd start by ruling other suspect parts out 1st(wiring etc) I'm glad I did because a used one popped up on eBay for a measly £30 so I put a £20 sneaky offer in that got accepted and this resolved my issue!
Putting it back together was easier than taking it apart. One thing that I was surprised with was the fact I had 0 screws nuts or bolts left over either so after a month of having to commute using unreliable public transport I'm finally back on the road!