Runs Rough after an 1 hour on the road

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Jun 11, 2014
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alberta
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2004 Honda ST1300
My bike starts to runs rough after I have been on the road for about 1 hr. It runs like it got bad fuel or something. I looked in the service manual and it does not talk about a fuel filter anywhere in the system which I find strange but possible. I have not change air filters or spark plugs since I have owned the bike which is getting close to 40,000km ago. I am thinking that is a good place to start but was wondering if they was anything else I should be looking for.:confused:
 
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jfheath

John Heath
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Fuel filter is buried inside the lower tank (under the seat). To get to it, you need to have an empty upper tank and as little fuel as possible in the lower. You need to buy the rubber gasket, new fuel joining pipe between the upper and lower tanks, along with the extremely strong, sprung hose clips. Oh and a new filter. Info is in section 5, page 56 in my workshop manual. Other manuals vary though.

It happens after an hour ? Is that related to the level of the fuel in the tank or not ? Is your coolant OK - replaced recently and topped up - it could be heat related ?

You say you have only ridden for 40 km since you got it ? Is that correct, or is it a typo ? What was done before you got the bike, or is that unknown.


Anyway, if you think its a long time since the plugs and air filter were done, I would start with the plugs and the air filter. Give it a treat and put some good quality fully synth oil (check the rating for your temperature in Alberta) The Honda manuals are inconsistent in what they recommend, but there is a good diagram to show the range for 10W-30 and 10w-40 oils - and a new oil filter (Make sure you follow the guidelines in the owners manual for the spec of the oil). And then run through a couple of tanks with some better quality fuel (preferably not with ethanol - I find it makes the engine knock more readily) and put some fuel injector cleaner in the fuel for a couple of tanks.

Try to have a long run, letting the engine spin up (as a police bike instructor once described it to me) - ie keep the revs up higher than you would normally, and if you can arrange for it to be with 'thick air' - cloud cover, early morning or later evening - that helps too. He told me to ride it in the 4000 to 5000 range for a while. I did this on the way home from spending a 2 day training course with him - after an hour the engine felt loose, easy to rev and responsive.

The pre-2008 models seem to run leaner, or the engine management system isn't as good as the models since 2008. And this is going to sound odd, but it comes from a long time ST1300 rider and senior employee with UK Honda - and it seems to work.
He said that if the bike is happily coasting along and there is very little change in the demand on the engine, then the engine management system seems stop monitoring everything as frequently. To wake it up, it needs some serious input - changes of revs.
Now - whether or not this is true, I do not know, but I had a problem with my A6 which used to seem to stutter after riding on long open roads. Nothing doing much and then I'd want to accelerate away from a corner, and the power wasn't there.
A few hard blips on the throttle and all was OK. In fact I kept the high revs up for a few seconds while pulling the clutch. And the problem would go away. I wondered if this was similar to the diagnostic test mentioned in the manual where it was necessary to run the engine at high-ish revs for a short while before doing a test. I know I have read it , but can't find it at the moment. 10 secs at 4000rpm rings a bell, but I wouldn't rely on that. Someone on here will know for sure.
 

ToddC

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If all the above fails....try cleaning the five way plastic t under the tank and airbox....
Just my 2 cents...

ToddC
 
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mrflexicoil
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I meant 40,000 kms. Just ordered plugs and air filters. I was looking in the service records previous owner had kept and it is time for a change. I will try these items first and see what happens. I don't like trying to many things at once because then you never know what the problem was
 
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mrflexicoil
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I have replaced both the spark plugs and then the air filter and neither one fixed the problem. I now have replaced the fuel pressure regulator valve. Can you explain to me exactly what this does and how it does what it does? There is not much to the valve.
 
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Scooter

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I have replaced both the spark plugs and then the air filter and neither one fixed the problem. I now have replaced the fuel pressure regulator valve. Can you explain to me exactly what this does and how it does what it does? There is not much to the valve.
Why did you replace the pressure regulator valve? I second the previous suggestion and think that your fuel pump heading south. I highly doubt that you've got a clogged fuel filter. First off, there is a pre filter that the gas goes through before it even goes through the fuel pump and through the main filter. Second, if it was the cause, it wouldn't be time sensitive in nature like your problem is.

Read through this thread. It's a little long but it was the original thread describing symptoms that in turn was found to have been caused by a bad fuel pump. See if there is any similar symptoms to what you are experiencing.

BTW, there is no need to spend big money on a Honda replacement assembly. Equivalent pumps can be found on eBay or your local auto parts store.

Another good thread detailing the process of changing the pump can be found here.

Keep us posted...
 
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Before you start throwing money at it I have a couple questions.
Has the FI light come on and thrown any codes?
Like scooters comment, why did you replace the pressure regulator valve?
The first thing(s) I would do, is to replace the plugs and air filter, and replace the vacuum lines and clean the 5 way tee out, and do a TB sync while your in there.
Your Tee may be clogged, and after the bike runs a while, the clog starts breaking up and moving around, possibly causing your issues with the fuel injectors and lines.
Have you tried running a couple ounces of Seafoam and MMO through the bike?
A couple other things you may want to consider that nobody else has brought up, check the condition of your plug wires, caps, and coils? You may be having an electrical issue as it gets hot.
Keep us posted on what you find.
Igofar
 
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mrflexicoil
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The pressure regulator valve was replaced at the suggestion of the tech at the dealer. As I was replacing it it took a quick look at the fuel and vacuum lines and did not see any bad cracks in any of those lines. I have had a 2 blick code come on and go off (which is related to the MAP sensor) but it has not been for a long time and is not currently on. The two blink code does not seem to have anything to do with the bad running because it does not appear at the same time as bad running and has not been on for most of the season and the bad running as been getting worse because now it seems to be doing it on shorter runs. I had it out last night after I put the FPRV in and it did right fine so I need to take it on a longer run to see what happens.
I had it out for two hour ride tonight and it never missed a beat. Rode it through the speed range from just cruising to a bit above the legal limit and all was good. Still not going to say that the FPRV was the issue but we see if it ever returns. If it does the 5 way tee is the next point of attack. I seen that when I was in there to change the FPRV.
I had the bike out last week on what was a 27 Celsius degree day and it started running rough again after 1.5 hours. Burns gas like crazy when it runs like that. Got to where I was going and had to fuel up to make it home. Ran great all the way home again but it had cooled off by then. Lifted the tank to get at the 5 way tee as has been suggested. There is really two 5 way tees under there. One that attaches to the top of the throttle body and one that goes to the EVAP canister from what the parts books shows. I took the one that goes to the throttle body(smaller of the two) out tonight and found nothing in there. No clogs as was suggested I would find. Will take the other one out tomorrow and see what I find there.

Put the bike back together tonight and tried to start it but no luck. Did not even fire. Turns over fine but no life in it. Did get the FI light on now and I counted 5 blinks. One long light and then 5 after that. I check the service manual and 5 blinks does not exist from what I can see but I thought I have seen something on the forum about that but have not found it yet.

Finally got time to get back on the project. I took it all apart to get back at the 5 way tee that I had cleaned and inspected. When I was doing that I had removed the fuel injector power leads and either missed put # 4 on or did not get it on properly. Either way there it was not connected at all which I think explains the 5 blink code that I got. To me 5 blink mean the ECU is really not happy and needs a reset of the ECU. Was able to get it reset which can be a little tricky for first timers but it can be done. That process seem to be timing thing as far as doing everything in just the right time frame. To fast and it does not register too slow same result. Got it reset and put back together and it started like it always does. Still not sure if the problem is solved but I am running out of weather to do any more test runs and I have not found knobbing tire for winter roads.


More update to this problem. I had the bike in to the local college that has a "motorcycle tech" course over the winter and let them have go at it. They pulled the throttle body off and cleaned it all up and check for hose leaks. They did some other repairs like changed tires and new rear brakes and got the rear caliper working properly again. Unfortunality they did not fix the problem that I was hoping to find. It did not take look before the "rough running" showed up again and it seem to show up quicker than before. I finally ordered a new fuel pump assembly from Honda and installed it a couple weeks ago. It had seem to fix the problem but I had not had a chance to take the bike on a long run to prove it for sure.
Well today I finally did get 500 mile run with it and it run fine the whole trip. It was not a overly hot day out so I still have to do a test run on a hot day to confirm the fix completely but I am quite sure I have got it solved. I ordered the assembly from Honda because I don't have time to chase around for a "Will fit/might fit" pump. This way I also get the intake filter and fuel filter at the same time.

Just a couple notes that you might find interesting. Before I started on the pump replacement I run my fuel down to where the FCD did not read anymore at all so I should have been on fumes. I still had at least a litre/quart of fuel left in the bottom of the lower tank so when the FCD says you are "out" you might be surprised at how far you might go with that. Second little piece of information I learned was in the service manual it tells you to remove the lower tank to install the new fuel pump. I did not like the look of that work so I opted out of that. Unfortunely that did not work out well for me because I did not get the pump in place properly and ended up with a massive fuel leak from the upper tank that I did not discover until after I had fueled up completely and then I had to drive home and do it again. I still did not like the complete removal of the lower tank. I did take out the 4 mounting bolts and this allowed the lower tank to move just enough for the pump to fall in place properly. It definitly felt different when the fuel pump dropped into place this time and that fixed the fuel leak problem.
When I was ordering the fuel pump kit the guy at the parts counter did say they don't see very many bikes with 195,000 KMS on them so maybe it was just due because of the high mileage on it. I was talking to another Honda tech that has friend that has over 500,000 KMS on his ST and he had to replace one as well but his failed with even more KMS on it. I was wondering if maybe the Fuel stabilzer I put in for winter storage may be a contributing factor in the pump failure story. Any thoughts on Fuel Stabilizer Good or Bad?
 
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jfheath

John Heath
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.... the bad running as been getting worse because now it seems to be doing it on shorter runs.
I'd do like Igofar suggested and take a good look at the HT part of the ignition - plugs, plug caps, leads and coils. Electrical faults can start of intermittent, and then get worse - particularly in the High Tension part of the ignition, where the spark is able to jump a gap when the fault first develops.

There are a couple of fairly easy checks that can be made.

1 - Plug caps. Remove them and check the resistance with an ohmmeter. They should be 5k ohms give or take a couple of hundredths. 4.5k is not Ok. Note that the plug cap screws off the lead, it doesn't pull off. The lead is buried about an inch into the end of the cap, and if you attempt to pull it off, it will pull out an inch of the copper core with it.

2 - HT leads. Check for corrosion and / or missing copper core at both ends. Corrosion is an obvious light green 'Verdigris' copper oxide. Missing core comes about as a result of repeatedly removing the leads. The end of the lead is a push fit onto a metal spike deep inside the hole where the HT lead fits. Honda HT leads are quite expensive, but they can be replaced temporarily with a length of standard copper cored stuff from an auto-electrical place for very little money. The lead is a push fit into the green coil body, and it is normally held in place by glued-on grommit on the OEM lead. This can be substituted with a wrap around of string and superglue - just for testing if there is an improvement. If there is, then replace it asap with the Honda replacement. (If you don't it will eventually work out and leave you stranded - and you cannot get at the coil easily at the side of the road).

3 The coil has earth contacts to the chassis, and they can become corroded. Remove a coil and see if there is an issue there.

I have some more detail and photos in a pdf file to download in this link:-> Link

If you can't access the pdf file, post back - it might spur me to convert it to a normal thread post !
 
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The code that it threw indicating the MAP sensor switch was probably telling you that your lines/tee were clogged.
I would return there first and clean the 5 way tee with a pipe cleaner and solvent, and replace the 5 lines to the fittings with new hose, then do a TB sync while your there.
If this does not correct the situation (I believe it will) then start checking the electrical stuff.
Igofar
 

Blrfl

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I have had a 2 blick code come on and go off (which is related to the MAP sensor) but it has not been for a long time and is not currently on.
...
The two blink code does not seem to have anything to do with the bad running because it does not appear at the same time as bad running and has not been on for most of the season and the bad running as been getting worse because now it seems to be doing it on shorter runs.
You don't actually know that. The MAP sensor plays a big role in how the engine is fueled. A sensor far enough out of whack to cause intermittent complaints about a fault may also be far enough out of whack to be providing information within the realm of believable but wrong for actual conditions. If the cause of the problem is mechanical (e.g., crud buildup in the plumbing) rather than electrical, it wouldn't be far-fetched to think the engine temperature could have some effect on it.

Could it be other things, like the fuel pump? Maybe, but the ECM has explicitly told you there's a problem with one of the sensors, and that needs to be addressed first. Anything else, including what the guy at the dealer told you, is guessing and a dynamite way to solve your excess time and cash problems. Take Larry's advice and clean out the MAP plumbing.

--Mark
 

ST Gui

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Blrfl said:
is guessing and a dynamite way to solve your excess time and cash problems.
I was reading a Subaru forum (and I don't remember why since I don't have a Subie) and was struck by a posters comment that the dealer didn't want to replace some pricey component of the A/C system because he couldn't be sure that it would solve the problem. WHW?! Not wanting to 'replace that and see if it fixes the problem'? Was he feeling OK??

Many dealers and others may make some sort of assessment and then start throwing new parts at the problem sometimes in a random manner instead of doing some actual troubleshooting. Boom goes the dynamite!
 
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Try this. It affected me in the past.
When it starts to run rough, open the gas cap and see if there is a whooshing sound from the air equalizing. The gas cap has a vent in it that can sometimes stop venting. In my case, it would affect me after riding for 40+ minutes. If this is it, the problem will cease after you open the cap.
 
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The code that it threw indicating the MAP sensor switch was probably telling you that your lines/tee were clogged.
I would return there first and clean the 5 way tee with a pipe cleaner and solvent, and replace the 5 lines to the fittings with new hose, then do a TB sync while your there.
If this does not correct the situation (I believe it will) then start checking the electrical stuff.
Igofar
Plus 1..the reason it does not seem to run "bad" when the light goes on is because the ECM see the fault that is out of its parameter. The ECM then looks at the fuel blocks and substitutes a value for the fault, its best guess. Certain sensor input can not be substituted for example cam and crank position sensors. While your in there replacing parts be sure to check the turn signal fluid level and see if the mufflers need to be rotated.. :think1:
 
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I was having similar issues with my '07, the hotter the day the worse it got. I also noticed when going up in altitude it would barley run until I stopped and shut if off for about 10 seconds, then it would run good until I went up another 500 to 1000 feet. I found nothing helped until I replaced the fuel pump, somewhere on this site is the information on the actual pump number available at most auto parts stores for under $100 US.

Hop this helps!
 
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