Cold start problem

Redback · Jun 27, 2009

ST '05 model with 20,000 klm - I have a problem with cold starts which is most strange. If I park the bike overnight or for say 8hrs during the day on the centre stand, the auto choke (fast idle on cold) 3 in every 5 times it wont cut in causing the engine revs to drop rapidly and it stalls. It will restart but I have to hold the revs up manually or it stalls until the engine reaches full operating temperature. The engine doesn't run rough or cough and spluttter -- BUT, if I park the bike on the side stand I don't experience the problem. I use good quality HO fuel and about every third fill of fuel I add Motul fuel injector cleaner. Once hot, the bike runs even and steady and ticks over at 1,000 revs idle.

I get no 'fail' warnings (blinking) on the EFM F1 dashboard light so my first thoughts are contaminated fuel. I figure maybe that on the upright centre stand the fuel pickup sucks in some rubbish (water or ?) causing the auto choke not to work but on the side stand, the contamination falls to the side of the tank and doesn't get sucked up on starting. Otherwise it may be something buried deep in the electronics or wiring ?? Before I start draining fuel tanks and spending $150 to change fuel filters (what twit put it inside the tank?) has anyone else had this problem or know a likely cause ?

PS: I see an older post that related to loose throttle body clips allowing air in through that seal - could this be it ? but why does have the bike on the side stand have any affect ??

billxp · Jun 27, 2009

I have 87k miles or 140k km on my 2005. I've only experienced a cold start problem a few times over the years. Opening the throttle to clear it out seemed to work for me. It didn't happen often enough to worry me.

Do you have ethanol blended fuel over there? The alcohol in the fuel for the most part has eliminated most of the water in the fuel unless there is a large amount and you get what they call phase separation.

Adding fuel injector cleaner that often may not be to good for your injectors. I've seen on some cars where the cleaner actual removed some of the insulation on the windings in the injector due to over use. I would think at every oil change may be a better interval.

From the service manual fuel system troubleshooting:
Engine Stall Hard Start Rough Idling.
intake air leak
fuel contaminated/deteriorated
pinched or clogged fuel hose
idle speed misadjusted
starter valve synchronization misadjusted

billxp · Jun 27, 2009

Also I would think a clogged fuel filter is going to stay clogged. So it being on the center stand or side stand shouldn't matter.

Redback · Jun 27, 2009

Nope...I am a purest...don't ever use an ethonol fuel only the cleanest 98+ Octane available with no additatives such as you find in Shell fuels.

I only use the Motul specially made for 4 stroke Fuel Injected bikes and all the Honda dealer service areas say to use it about every second tank full but I only may do it every 4 or 5...been adding it since the bike was almost new but my problem only just started about 8 weeks ago.

Blrfl · Jun 27, 2009

I've had the same problem first thing in the morning maybe four times in five years, although I've never noticed if there was a side/center stand connection. (Mine's on the center stand at home and on the side stand at work.)

You may be having a problem with the wax engine that forces high idle when the engine is cold. I'd yank the air box and make sure the mechanicals around the throttle body are clean and move freely. It may be that the wax solidifies differently enough on the center stand that the rod doesn't nudge the starter valves properly.

Just on general principle, I'd cut back on your use of the injector cleaner. I run some through at the beginning and end of the season, and that's more than plenty.

--Mark

billxp · Jun 27, 2009

You are lucky, we do not have that option in some areas of the USA.

Over here all gasoline has cleaner already in it. The name brands are supposed to have more.

If your gasoline doesn't have any cleaners added to them I can then see adding the cleaner at more frequent intervals.
If they do then the dealers are just trying to sell product. IMHO

Wow 98+ octane. I wonder if we use the same method to obtain octane numbers?

Also to high of an octane fuel has been known to cause cold start problems in some cars over here when its not required.

Wonder if you switched to a lower octane but not below what Honda recommends would that clear up your problems? Easier than pulling things apart

Redback · Jun 27, 2009

Yep...I was a bit suss on the use of the injector cleaner so often and as a possible cause I am going to stop using and maybe just at major services. The problem seemed to start as winter set in here with temps dropping from around 22C to 8c in the mornings. I think I will start in the air box/filter and see if there are any obvious foulings or loose clamps. While dirty fuel may be a cause I have to think the filter would get clogged and I'd have a contant problem with poor idling all the time.

Blrfl · Jun 27, 2009

billxp said:
Wow 98+ octane. I wonder if we use the same method to obtain octane numbers?

Australia and most of the rest of the world use the Research Octane Number, which runs higher than ours for the same fuel. The number on our pumps is the average of the RON and another number called the Motor Octanane Number, which describes how the fuel does under load.

--Mark

AZST · Jun 27, 2009

Redback said:
ST '05 model with 20,000 klm - I have a problem with cold starts which is most strange. If I park the bike overnight or for say 8hrs during the day on the centre stand, the auto choke (fast idle on cold) 3 in every 5 times it wont cut in causing the engine revs to drop rapidly and it stalls. It will restart but I have to hold the revs up manually or it stalls until the engine reaches full operating temperature. The engine doesn't run rough or cough and spluttter -- BUT, if I park the bike on the side stand I don't experience the problem. I use good quality HO fuel and about every third fill of fuel I add Motul fuel injector cleaner. Once hot, the bike runs even and steady and ticks over at 1,000 revs idle.

I get no 'fail' warnings (blinking) on the EFM F1 dashboard light so my first thoughts are contaminated fuel. I figure maybe that on the upright centre stand the fuel pickup sucks in some rubbish (water or ?) causing the auto choke not to work but on the side stand, the contamination falls to the side of the tank and doesn't get sucked up on starting. Otherwise it may be something buried deep in the electronics or wiring ?? Before I start draining fuel tanks and spending $150 to change fuel filters (what twit put it inside the tank?) has anyone else had this problem or know a likely cause ?

PS: I see an older post that related to loose throttle body clips allowing air in through that seal - could this be it ? but why does have the bike on the side stand have any affect ??

This is what I am experiencing right now also. Your description fits mine except for the the whole center stand vs. side stand thing. With this I have not noticed a difference. I have never had the bike stall...but the idle labors low until warm up and remains that way until the first few minutes of the ride. It then seems to return to normal idle.

I suspect MAP sensor issue but have been trying other things first before I go under the airbox. I have run Seafoam inject cleaner through twice in the past couple months and have not noticed any difference.

04 ST with 50k miles. I'll keep an eye on this thread with interest.

--Bryan
04ST1300A
:04biker:

Redback · Aug 28, 2009

Think I found the problem....Like all things you get so use to turning that ignition key and punching the starter and you get quicker and quicker at something that routine and more so if you are in a hurry. One morning the F1 light came on and stayed on with the engine coughing and carrying on initially with the poor cold idle raising its ugly head and then it eventually sorted iteself once it got warm but with the F1 light still hard on. Pulled over and turned everything off. Turned the ignition key and waited untill all the dash lights went through their load sequence before hitting the stater. The F1 light didn't come on and everything was fine. Well that got me thinking and pretty nervous that maybe the EFM system had a fault and major $$$$'s went before my eyes. So each time I started the beast cold I would first turn on the ignition and wait until the load sequence completed before hitting the starter button....mainly because I was looking to see if the F1 light came on again and stayed on. Well it didn't and guess what.. from that day on - no cold start problem. So this got me thinking it was all to do with the EFM load sequence

I am pretty convinced that the center stand - side stand conundrum was it seems, a somewhat coincidental but important related issue brought about again by habit. If I parked the bike on the center stand I more often than not jumped on, turned the ignition on and hit the starter straight off waiting for the engine to warm, retract the side stand, fiddle with gloves etc before jumping it off the centre stand. If the bike was on the side stand I tended to turn the ignition on, pull the bike upright, settle bum, gloves etc, retract side stand an then hit the starter. So, if on the center stand it was more likely that I hit the starter too soon before the EFM had time to do its thing whereas on the side stand my delayed hitting the starter meant the EFM had completed its load sequence.

Since this revalation I now wait until the dashboard lights complete their load sequence and then hit the starter. Haven't had a problem with cold starts since on either center or side stand - fingers crossed.

Blrfl · Aug 29, 2009

The FI indicator doesn't go off until the fuel pump has been running for a certain amount of time and the fuel rail is presumed fully pressurized (there's no sensor). The fuel pump was designed to maintain pressure in a running system where the injectors are being opened or bring an idle one up to operating pressure. It can't do both, and by starting early, you're running the injectors at low pressure until the fuel pump can get caught up.

...Which is why the owner's manual says to wait for the FI indicator goes off before starting.

--Mark

Redback · Sep 7, 2009

All sounds very plausible...my manual isn't that specific on the F1/dash lights other than to say to check it does go out ...not when and that it is to be before you hit the starter ... I am a bit surprised given that if one does hit the starter too early (pretty easy to fall into the habit) that there isn't some mention of this in either the owner manual or the workshop manual of the likely implications for the idling when cold. Doesn't even mention it under troubleshooting either. Just another little St1300 quirk ...once you know its a no brainer..happy motoring and stay upright.

Bama Phil · Jul 7, 2014

Redback said:
Think I found the problem....Like all things you get so use to turning that ignition key and punching the starter and you get quicker and quicker at something that routine and more so if you are in a hurry. One morning the F1 light came on and stayed on with the engine coughing and carrying on initially with the poor cold idle raising its ugly head and then it eventually sorted iteself once it got warm but with the F1 light still hard on. Pulled over and turned everything off. Turned the ignition key and waited untill all the dash lights went through their load sequence before hitting the stater. The F1 light didn't come on and everything was fine. Well that got me thinking and pretty nervous that maybe the EFM system had a fault and major $$$$'s went before my eyes. So each time I started the beast cold I would first turn on the ignition and wait until the load sequence completed before hitting the starter button....mainly because I was looking to see if the F1 light came on again and stayed on. Well it didn't and guess what.. from that day on - no cold start problem. So this got me thinking it was all to do with the EFM load sequence

I am pretty convinced that the center stand - side stand conundrum was it seems, a somewhat coincidental but important related issue brought about again by habit. If I parked the bike on the center stand I more often than not jumped on, turned the ignition on and hit the starter straight off waiting for the engine to warm, retract the side stand, fiddle with gloves etc before jumping it off the centre stand. If the bike was on the side stand I tended to turn the ignition on, pull the bike upright, settle bum, gloves etc, retract side stand an then hit the starter. So, if on the center stand it was more likely that I hit the starter too soon before the EFM had time to do its thing whereas on the side stand my delayed hitting the starter meant the EFM had completed its load sequence.

Since this revalation I now wait until the dashboard lights complete their load sequence and then hit the starter. Haven't had a problem with cold starts since on either center or side stand - fingers crossed.

Had this problem yesterday.....I am used to the GW starting and holding. The Nighthawk has a choke, so this was a little new to me. Kinda panicked when my new ST was acting like I needed to choke it. So glad I came across this thread. Thought maybe some other Newbies were having the same problem.

Igofar · Jul 7, 2014

pull the 5 way tee, clean it and replace the lines.
.02

Blrfl · Jul 7, 2014

Redback said:
my manual isn't that specific on the F1/dash lights other than to say to check it does go out ...not when and that it is to be before you hit the starter

Check the Starting The Engine section of the owner's manual:

Always follow the proper starting procedure described below.
...
Before starting, insert the key, turn the ignition switch ON and confirm the following:
...
The PGM-FI malfunction indicator lamp is OFF.

I am a bit surprised given that if one does hit the starter too early (pretty easy to fall into the habit) that there isn't some mention of this in either the owner manual or the workshop manual of the likely implications for the idling when cold.

The manual is written with the assumption is that the directions will be followed. If they had to get into all of the eventualities, there's be 60 pages of admonitions like "do not start the engine with a wrench shorting the battery terminals" and "do no operate the bike with potatoes in the exhaust pipes." (Although to be fair, the manuals for most cars sold in the U.S. have a lot of that kind of material. I guess we get off easy.)

If you hit the starter too early, the fuel rails won't have reached full pressure before the ECM starts opening the injectors and it takes time for the fuel pump to get caught up. You can get away with hitting the starter early when the bike is warm because the fuel rails won't have bled down to nothing.

--Mark

Cold start problem

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