The Honda PCX / Forza / ADV150 / SH Forums

Hi All,

Long time lurker, first time poster in dire need of assistance!!

I've read just about every stall thread on this forum but still it's getting the better of me.

The problem is VERY intermittent, but it happens when I come to a light or go slow enough for the clutch to disengage. The idle may or may not hold but then gradually die. Again, it's very intermittent. I can save it by giving it some gas and this is a U.S. model so no idle-stop.

Here are the things I've fixed based on the other threads:
1) Changed Air Filter
2) Changed IACV and gasket
3) Fresh Gas and Oil
4) Fuel Stabilizer
5) purchased and read the manual, but it's no help because I don't have the MCS (motorcycle comm system).

Here are some possible leads that I could try:
1) Fuel System or Fuel line kinked
2) IAT Sensor
3) Burn the bike...

I'm really truly getting fed up with this, so any help would be greatly appreciated, thanks all!

Is the idle set too low, is the spark plug ok?
Does the manual mention a throttle sensor reset procedure?
If it does give that a go.

The 2 sensors I would immediately look at would be the ISC or IAC as some refer to it, and then check your Throttle position sensor. I am not sure if these sensors are on this engine as I am on the road traveling, but do as GNC said above and then do a code check if possible . See if any faults are in history or active. (check engine light ). Did you check for water in the fuel or stale fuel. Sometimes you can get a bad batch of gasoline from the filling station so change that as well.Spark plugs need to be checked as well as a fuel injector cleaning, but if your issue is intermittent that would be a lesser possibility I would think.Any work done lately on the engine by anyone ??

One of the die-out threads we had on here some time ago found valve adjustment as the culprit. I'm assuming there's no MIL illuminated on the dash? How many miles on the bike and does the motor keep running once it reaches normal operating temperature? The symptoms of the valve lash trouble were that it ran for a short while and died out at stops. It would restart and once it was fully warmed up it kept running.

Thanks so much for all the input guys. Last night, I got really fed up after tearing the entire bike down and realizing it's not going to be an easy fix.

The last remaining things for me to check are valve adjustment, TP sensor, but rather than do all that, I think I'm just going to see if the dealership will take it back for me to trade into a Forza.

The goal of owning a scooter is convenience, and the PCX has not been very convenient lately. :X

Mr.Scooty wrote:Thanks so much for all the input guys. Last night, I got really fed up after tearing the entire bike down and realizing it's not going to be an easy fix.

The last remaining things for me to check are valve adjustment, TP sensor, but rather than do all that, I think I'm just going to see if the dealership will take it back for me to trade into a Forza.

The goal of owning a scooter is convenience, and the PCX has not been very convenient lately. :X

Welp as I mentioned in my for sale thread which is now significantly shorter, I'll be keeping the PCX after all. Dealership only offered me $1300 for it which was pathetic. At that rate, I won't bother buying a forza and instead keep the PCX for a sunny day!

Just need to do the work on it now. :Sigh: thanks all for the suggestions, I'll get back to u all after I do the valve adjustment

Going to try spark plugs.

bad news guys - new spark plug wasn't the answer.

gonna try valve adjustment now.

It might be time to bite the bullet and get a mechanic to look at it. It might have been cheaper in the long run.


Sent from my iPad

Are you out of warranty?

GatorGreg wrote:Are you out of warranty?

I probably should have started with this, because it's a 2015 and it's only 2016!

In any case, I've got my fingers crossed that the valve adjustment I performed this weekend will keep the CEL from coming on. I'm not exactly sure how it could be related, but my short 3 mile commute to work after I did a soft reset did not result in the usual code 29 IACV error that I normally get.

The valves were tight by just one feeler gauge so I'm not sure that could actually be the case.

If it comes back after this, I'm going to send it along to the dealer because I have no idea what else to look at after this.

Update:
The valve adjustment didn't help.

The bike is still under warranty for 2 months, PHEW! I'm bringing it in after I've had a chance to remove the sliders - just so they can't say that I broke it.

Let us know what they found at the dealer. I haven't heard of a pcx having this much trouble. I have two 2013s but their engines are the same as that of the 2015, with only a gearing change. I don't know where you live, area wise, so I can't say if you have something extra that I don't have on mine, such as a Start/Stop circuit.

There was a problem a few years ago on one, as I recall, and it turned out to be a wire on the side stand switch, but if yours has a computer code then I am sure that it is something else.

Did you check the TPS.. If the TPS is loose or defective the ISC valve will not function correctly.Check for tight connections at the computer and see if any water has gotten into the computer or plugs.

Hi Mr.Scooty,
although I got not pcx150 but S-Wing 150, i got the same problem on a same engine.

it stalls either the engine die on stops, or during ride the revs just got 'killed' by 1000-1500, but then it catches up and i can ride on.
problem is VERY intermittent, but it happens when I come to a light. It happens even when the engine gets to operating temp, normal temperature right, and it just switch off engine.
I can restart it immediatelly and it is running fine.
I bet it is some sort of shortcut somewhere inside, because it started after i left my bike outside for winter. Understand english winter in UK (which is no snow and freezing temps max 5 days in a year)

Replaced sparks,
air filter,
cleaned air pipes,
mechanics have taken it apart and cleaned the fuel filter which was in the fuel tank (2h work for dismantling and assembling)

could not find andy normal reason for this yet.

Any more suggestions appreciated.

It could be an issue with the emissions system, specifically your gas cap or evap system. Next time it happens, open the gas cap and see if it sucks air hard when you do.

Hey All, just wanted to do a quick update on this!

I found out my PCX had 2 months of warranty left, so I brought it in and they discovered it may have been not the IACV itself, but the connector inside that was a little corroded so they took it out and cleaned it. They also mentioned they reset the ECU and it's been fine for the last few weeks (or since I last posted up).

Although the cause was fairly benign and seemed like a simple fix, I'm a little bit wary now of future problems that could arise that I won't be able to fix myself since everything is proprietary and digitized now. The honda manual references using the honda scan tool that only dealerships have, and the simpler days of the past of DIYing everything are gone.

As such, I've jumped on the opportunity before my 1-year warranty ends to extend it out to 4 years just for peace of mind. Percentage-wise, It's a little hefty of a price tag $350 for 4 years, but I figure if something else breaks that I can't diagnose or even fix myself, it'll be worth it since the labor and fees for this time would have probably been just as much on the first go-around - not to mention any future occurrences.

Normally I am very ANTI extended warranty as my friend used to work in finance at a dealership and would tell me about all the suckers, but in this case it's one of the first times a vehicle that I've owned has legitimately had a serious problem within the first few months of ownership, that I've felt completely helpless with. $350 is reasonable for the duration of coverage and honestly, I ride this thing pretty hard sometimes even though I do take care of the maintenance. At the end of the day, I know the PCX is a quality product, but I don't want to take any additional risks and will pay for the warranty up front.

I may be writing this just to make myself feel better about buying the warranty, but in any case, the stalling issue is finally in the past and I'm covered for the next 4 years from freak occurrences like this.

/case closed.

My scoot is still apart, I've cleaned again every connector that I could find inside with Halfords contact cleaner now.
I tried then to start the engine and running it for about 10min till it warmed up. The revs kept steady at 1500, which was not the case before.
Have to put it all together now and do a test run. Hope no rain today in Preston.

Thanks Mr.Scooty for the update. I am not loosing faith now that it might be caused by some connection and I don't have to buy a new fuel pump or ECU(very expensive) , which was suggested by some mechanics around my location.

Fingers crossed it will go well.
I am off next week for Spain, will update results after that.

funtomino wrote:My scoot is still apart, I've cleaned again every connector that I could find inside with Halfords contact cleaner now.
I tried then to start the engine and running it for about 10min till it warmed up. The revs kept steady at 1500, which was not the case before.
Have to put it all together now and do a test run. Hope no rain today in Preston.

Thanks Mr.Scooty for the update. I am not loosing faith now that it might be caused by some connection and I don't have to buy a new fuel pump or ECU(very expensive) , which was suggested by some mechanics around my location.

Fingers crossed it will go well.
I am off next week for Spain, will update results after that.

Funtomino, I know your frustration all too well. I certainly hope cleaning it will suffice and let that be the end of it. I know that there was another member who needed to have his ECU reset. If it gets that far, depending on if you have warranty or how much the dealer will charge to get that done, you may or may not just buy the parts. But my fingers are crossed for you. Hopefully it doesn't get that far.

Hey, got finaly time to run the scoot, and it worked like new.
NO more stuttering or stalling at all. Made about 10km, with pride. ☺No ecu reset necessary.
My Honda runs like new!!! Wow.
Thanks a lot for your support.
Next are rollers and belt. But that is another story.