Author Topic: engine misfires or dies under 3000rpm  (Read 8461 times)

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wagonweel

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engine misfires or dies under 3000rpm
« on: April 23, 2018, 07:28:56 »
1000, 2008 model, efi, 54000kms, mostly hwy use and very low speed/rpm riding.

A few months ago the trouble started and I thought maybe I got a bad tank of fuel. It started having issues at lower speeds and edpecially coming to a stop, and would die at idle intermittently. When you tried to restart it sometimes itit will sound like a totally flat battery, but then try again and volia. The bike runs when initially started for the day then as it heats up it MAY start misfiring at anything below 3000rpmstart. But it seems to be getting worse and only when the bike is hot. Most of my riding is at low speed/very low revs (sporting events) and then 1-2hrs hwy riding back home. If it starts playing up it will continue after I get off the hwy (runs fine at 80+ kms/hr 3000+rpm).

Numerous refills, tank flush (x2), injector cleaner, service, k&n filter reoiled (x2), new plugs (twice), new battery. No idea what is going on and the honda dealer and 1other shop ( independant mechanic) have been unable to find the problem. Oh, and neither place cleaned the fuel filter just assumeds it was fixed each time as it takes a while before it starts playing up.

In traffic is a nightmare now as I have to keep the revs 3000rpm+ so it doesn't stall.

Is it:
-filter
-Blocked injector/s
-Fuel pump
-Some heat related problem?

That's about all I can thjnk of....any ideas  would be most welcome as I love the bike and normally it's brilliant to ride.

SB

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Re: engine misfires or dies under 3000rpm
« Reply #1 on: April 23, 2018, 09:18:44 »

Early carb models had issues with the fuel pump but the efi models seem to have overcome this.

The fact that it changes with temperature tends to suggest a sensor problem (MAP, IAT, ECT, CAM, TP etc.).

I think we need a bit more information on you bike and the symptoms:

When you say " When you tried to restart it sometimes it will sound like a totally flat battery" do you mean it wont turn over or it turns over but wont fire ?

Does the bike have the O2 sensor fitted in the exhaust ?

When you turn on the ignition when the bike is acting up does the FI lamp come on as normal or does it flash ?

If the FI light flashes (indication of a fault code) please try to describe the sequence.

Thanks
SB



wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #2 on: April 23, 2018, 09:54:13 »
The battery, you know when a battery is just about out of juice and all you can get out is about one turn of the engine, that slow ra ra then nothing ... it won't turn over. Leave it for a second and it will turn the engine over like normal.

Yes O2 sensor it still on the bike (original exhast)

I haven't noticed any flashing of the lamp after a engine stall. I normally don't turn the ignition off after the engine dies, I just restart

In relation to the codes, The Honda shop found no fault codes coming up, but it didn't play up for them either
When it is misfiring nothing on the dash lights up or instrumentation jump around (apart ftom the tachometer)

One other point, thinking about the fuel pump, what noise should the bike make on turning the ignition on? The reason I ask is that from memory just the initial whirring of the fuel pump. But I noticed (and recorded) a strange noise after the pump does it's thing. Best way to describe it as like radio static. Normal? Never noticed it before.

Skye

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Re: engine misfires or dies under 3000rpm
« Reply #3 on: April 23, 2018, 11:06:13 »
Think it is a battery issue. Not charging enough and this will make a misbehaving ignition.
Can be Stator, rectifier issue but try changing battery and seller if the problem continues

wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #4 on: April 23, 2018, 11:59:33 »
Think it is a battery issue. Not charging enough and this will make a misbehaving ignition.
Can be Stator, rectifier issue but try changing battery and seller if the problem continues

Battery was changed. Will get the stator and rectifier looked at and see what comes up. The weekend should make it play up again and can get it checked then and there

zebulon

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Re: engine misfires or dies under 3000rpm
« Reply #5 on: April 23, 2018, 13:05:45 »
We had also on the french forum some fuel pump problem on MK2/3; and it takes months to diagnose it ... if previous elements have no positive result, try this way !  VCIF_ok
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wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #6 on: April 23, 2018, 13:10:49 »
We had also on the french forum some fuel pump problem on MK2/3; and it takes months to diagnose it ... if previous elements have no positive result, try this way !  VCIF_ok

Yes I was wondering about that that possibility

Bruvex

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Re: engine misfires or dies under 3000rpm
« Reply #7 on: April 23, 2018, 21:15:30 »
We had also on the french forum some fuel pump problem on MK2/3; and it takes months to diagnose it ... if previous elements have no positive result, try this way !  VCIF_ok

Yes I was wondering about that that possibility

I had one of the early injected models from 2008 and I had to replace the fuel pump.

The symptom was hesitation from the engine at about 4000rpm from time to time. It became worse and after a week or 2 (I drive every day) it died on me completely while driving before I had managed to make an appointment with my dealer.

In my case it was obvious it wat the fuel pump since it was malfunctioning.
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SB

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Re: engine misfires or dies under 3000rpm
« Reply #8 on: April 23, 2018, 22:02:46 »
Fuel delivery problems normally get worse with higher RPM not better !


The battery, you know when a battery is just about out of juice and all you can get out is about one turn of the engine, that slow ra ra then nothing ... it won't turn over. Leave it for a second and it will turn the engine over like normal.

The problem with the starter would tend to suggest an electrical fault which would also tie in with the the engine struggling at low RPM (low voltage !). It's difficult to see why a battery would be dead one minute and then start with no problems a few seconds later !

If possible, before spending any more money I would try and find a way of measuring the voltage supply to the ECU at 2,000 and 4,000 RPM and with the engine warm when the problem occurs.

wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #9 on: April 23, 2018, 22:56:39 »
Fuel delivery problems normally get worse with higher RPM not better !


The battery, you know when a battery is just about out of juice and all you can get out is about one turn of the engine, that slow ra ra then nothing ... it won't turn over. Leave it for a second and it will turn the engine over like normal.

The problem with the starter would tend to suggest an electrical fault which would also tie in with the the engine struggling at low RPM (low voltage !). It's difficult to see why a battery would be dead one minute and then start with no problems a few seconds later !

If possible, before spending any more money I would try and find a way of measuring the voltage supply to the ECU at 2,000 and 4,000 RPM and with the engine warm when the problem occurs.

The ra ra nothing when starting was the initial symptom. And something I forgot to mention when it would do this with the old battery it would reset the clock and trip meters

SB

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Re: engine misfires or dies under 3000rpm
« Reply #10 on: April 24, 2018, 00:37:05 »
when it would do this with the old battery it would reset the clock and trip meters

That's normally just a sign of a weak battery and the system voltage dropping too low when you try to start the bike.

wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #11 on: April 24, 2018, 01:28:54 »
when it would do this with the old battery it would reset the clock and trip meters

That's normally just a sign of a weak battery and the system voltage dropping too low when you try to start the bike.

Thanks. I have mentioned all this to the honda workshop but they just worked on the fueling.
I'll check the battery voltage with ignition off,  on and then with the engine running and post the details.

Skye

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Re: engine misfires or dies under 3000rpm
« Reply #12 on: April 24, 2018, 08:44:33 »
Try to measure the stator cables (yellow) should be a value between 2-4 ohms. It could also be a shortcut in this wire. If this occurs you not get enough wattage from stator and only getting 2/3 of full effect.

wagonweel

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Re: engine misfires or dies under 3000rpm
« Reply #13 on: April 25, 2018, 04:51:02 »
Try to measure the stator cables (yellow) should be a value between 2-4 ohms. It could also be a shortcut in this wire. If this occurs you not get enough wattage from stator and only getting 2/3 of full effect.

Will try to check that too. Just as soin as I replace my dead multimeter (great timing 🤐)

SB

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Re: engine misfires or dies under 3000rpm
« Reply #14 on: April 25, 2018, 09:29:33 »

Temporarily mounting something like this might tell you a lot ?

https://www.amazon.co.uk/XCSOURCE-Motorcycle-Waterproof-Digital-Voltmeter/dp/B01NAK5ENF

 

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