low rpm misfire

9327 Views 15 Replies 8 Participants Last post by Hasannafea, 3 mo ago

renais

Discussion Starter · May 22, 2016

brief history:

bought bike last December with less than 2.5K miles, guy did less than 50 miles in the year before I bought it

After about 1K miles trouble free, fitted de cat link pipe and Pipe Werx can, fitted servo buddy from my gen3, it worked ok so I left it fitted for a while

After about 200 miles misfire developed below about 3K rpm. Bike pulled like a train after that with no problems

Difficult to negotiate junctions and roundabouts without slipping clutch

replaced servo buddy with oem motor (cables disconnected)

refitted oem exhaust with cat, still got misfire

with such low mileage (sub 4K) I cant believe it would be the plugs, but IDK

other possibilities are 1) damaged ECU due to wrong servo buddy, (but I really doubt this one) 2) stick coils 3) Lambda/02 sensor 4)fuel pump

No F1 light or other signs, idles on 1 bar but jumps to 2, slightly rough idle

Any input appreciated...:|

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SkyDork

· #2 · May 22, 2016

The G4 uses an idle control valve to monitor and maintain the idle speed. I would be looking there to see if there's any issues with the operation of that or the air lines with the throttlebodies.

What mods are done to the bike? Does it sit outside? It may be water or crap in the fuel that needs to removed. And how do you know that it's misfiring instead of stumbling at low RPM like that? Poor running due to a fueling issue may feel and sound like an ignition misfire, but it's just a general stumble in the motor.

renais

Discussion Starter · #3 · May 22, 2016

Thanks Sky for response

idle control valve may affect idle speed, but I'm not sure it would cause stuttering at low revs. something to look at though

Bike is stock, no mods

kept in garage, haven't ruled out fueling, its just knowing where to begin

It has obviously spent long periods not being used, 2.5K miles in 5 years ! But it was running perfectly for the first 1000 miles or so after I got it

any thoughts on ECU damage due to possible spiked voltage from DIY servo buddy ?

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SkyDork

· #4 · May 22, 2016

renais said:
Thanks Sky for response

idle control valve may affect idle speed, but I'm not sure it would cause stuttering at low revs. something to look at though

Bike is stock, no mods

kept in garage, haven't ruled out fueling, its just knowing where to begin

It has obviously spent long periods not being used, 2.5K miles in 5 years ! But it was running perfectly for the first 1000 miles or so after I got it

any thoughts on ECU damage due to possible spiked voltage from DIY servo buddy ?

Right you are about the idle valve in the low rpm. The reason I suggested looking into that was because of the idle fluctuation you mention going up to 2000 or so with the second line showing up. If something is wrong with that it may be contributing to the issue.

And no, I can't see how the ECU would be damaged by the servo buddy. Certainly not something that would be a problem only at low speeds. If you damaged the thing it would be causing problems all over the place. I wouldn't give that a second thought myself.

Reactions: 1

scout

· #5 · May 23, 2016 (Edited)

If you rode without changing a thing for 1k miles then did the your listed change we a problem range, so easy to sort. If you can drop that servo, then test. If not the problem then you are running rich so need a commander or just buy the graves as both are probably near the same cost but graves is light years better than whatever you pulled off of whatever to try on this most excellent ride.

renais

Discussion Starter · #6 · May 23, 2016

Appreciate that Scout, but exhaust all put back to stock now bar the servo cables, so should be running as it was originally, but still have misfire at low rpm

I'm going to begin by checking for any bad connections/earth, low battery etc. then a slow process of elimination until I get so pi$$ed off I call in the professionals

clutchcrusader

· #7 · May 23, 2016

I would try the plugs.see how the look.might help point you in the right direction.good luck.

renais

Discussion Starter · #8 · May 29, 2016

OK, so brief update on this..

Tried Motul Fuel Cleaner for 100 miles and no change, took advice from Cornwall Kawasaki who took it for a trial ride and thought, like I did, that it was a faulty plug

Changed plugs (4200 miles) Changed the air filter while I was in there, (but don't think that was anything to do with the problem)

Went for a 50 mile ride today and all good :thumbsup:

Relief :smile2:

gr8shine

· #9 · May 29, 2016

Good to see your problem is fixed, thanks for sharing the inputs.

Reactions: 1

scout

· #10 · May 30, 2016

ok, but if the secondary servo has failed then the plugs will go bad again. The top flies stay closed or whatever. I had this prob on either fz1 or r

renais

Discussion Starter · #11 · May 30, 2016

scout said:
ok, but if the secondary servo has failed then the plugs will go bad again. The top flies stay closed or whatever. I had this prob on either fz1 or r

I'm afraid I cant really follow this...

I dont know what a secondary servo is unless you mean the secondary flies (?)

But I don't see the relevance, the secondary butterflies aren't a problem I'm aware of

dharmon012

· #12 · Jun 1, 2016

im having this exact issue on my '15. ran great until i installed an akra slip on with link pipe. now it stumbles between 1k and 2k at idle like yours

i have a video but i dont know how to embed

Zee1158

· #13 · Jun 1, 2016

I have a couple Idle Actuators if you need one

renais

Discussion Starter · #14 · Jun 1, 2016

dharmon012 said:
im having this exact issue on my '15. ran great until i installed an akra slip on with link pipe. now it stumbles between 1k and 2k at idle like yours

i have a video but i dont know how to embed

Did you get the problem straight away after installing new exhaust?

My bike was OK for about 200 miles, then I experienced rough idle and misfire

If you got the problem right after the instal then I suspect the fueling is badly out. I think the link pipe with Akra would lean out the mixture a lot

I'm sure my AFR was too lean also and may have contributed to plug damage, but IDK

I'm happy with the OEM exhaust on there, performance feels good and although others might disagree, it feels more responsive with the servo cables removed

If you dont have a misfire, but just a rough idle, then you prob just need to adjust fueling with PC or whatever. I didn't want to go down that road right now

sorry, cant help with the vid

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dharmon012

· #15 · Jun 2, 2016

ya it was immediate. i thought about fueling and needing a remap but my buddy just got a graves and doesnt have any issue which is why im scratching my head

Hasannafea

· #16 · 3 mo ago

Hi guys
I have washed my 2008 Zx10r then after that bike started run rough , I have checked the coils they are fine, changed the spark plugs, flashed the fuel, but the bike still runs rough, can anyone tell me what should I do?

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