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Discussion Starter · #1 ·
whats the easiest way to locate the map sensor on the 919? ive had this rough idle issue and im swapping out the map sensor but dont want to tear haif the bike apart to get to it? i looked it up and seemed fairly easy to acess but was wonering who has done it already? ive already replaced the battery my FPR, the spark plugs witch were wet.... and put an OEM filter back in... i had a battery tender lithium battery in and had it tested but seems its near the end of its cycle... maybe causing the rough idle and plugs being wet?
 

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McTavish
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whats the easiest way to locate the map sensor on the 919? ive had this rough idle issue and im swapping out the map sensor but dont want to tear haif the bike apart to get to it? i looked it up and seemed fairly easy to acess but was wonering who has done it already? ive already replaced the battery my FPR, the spark plugs witch were wet.... and put an OEM filter back in... i had a battery tender lithium battery in and had it tested but seems its near the end of its cycle... maybe causing the rough idle and plugs being wet?
In terms of the rough idle and wet plugs vis a vis the battery, I some comments.
1
Correct or otherwise, I was under the impression that cold start and warmup idle was OK and the problem was only after fully warmup.
Please correct or confirm.

2
Your battery is suspect, correct?
And you keep it on a tender when not riding?
How was the battery "tested", just by tender indication or by proper volt meter?
It's possible the idling voltage is low and reducing spark energy.
Keep in mind the alternator output is low at idle, in terms of wattage and voltage.
2E results might indicate Regulator/Rectifier involvement or co-involvement.

3
A-Suggest you do a battery voltage check before a cold start.
B-Suggest you do a voltage (drop) check during the cold start.
C-Suggest you do a system voltage check when cold idling.
D-Suggest you do a system voltage check when warmed up idling.
E-Suggest you do a system voltage check @ 5,000 RPM and it should be 15.5 v.
There may be multiple things at play, MAP sensor included.

The voltage checks would be of good insight towards how wide a field of possibilities there might, or might not be.

Hope this helps at least some.
 

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Discussion Starter · #4 ·
In terms of the rough idle and wet plugs vis a vis the battery, I some comments.
1
Correct or otherwise, I was under the impression that cold start and warmup idle was OK and the problem was only after fully warmup.
Please correct or confirm.

2
Your battery is suspect, correct?
And you keep it on a tender when not riding?
How was the battery "tested", just by tender indication or by proper volt meter?
It's possible the idling voltage is low and reducing spark energy.
Keep in mind the alternator output is low at idle, in terms of wattage and voltage.
2E results might indicate Regulator/Rectifier involvement or co-involvement.

3
A-Suggest you do a battery voltage check before a cold start.
B-Suggest you do a voltage (drop) check during the cold start.
C-Suggest you do a system voltage check when cold idling.
D-Suggest you do a system voltage check when warmed up idling.
E-Suggest you do a system voltage check @ 5,000 RPM and it should be 15.5 v.
There may be multiple things at play, MAP sensor included.

The voltage checks would be of good insight towards how wide a field of possibilities there might, or might not be.

Hope this helps at least some.
[/QUOT i had the battery tested at a battery store and seemed it was at the end of its life soon. so i bought another one. i replaced with spark plugs. took another ride on it and when its warmed up while riding about 15-20 mph i lug on the throttle and it hiccups... in 2nd gear i let it fully warm up and did this around a parking lot. ride it in 2nd and 3rd gear at low rpm below 3k and i lug on the throttle and thats when it burps and sputters... only thing i havent done yet was chnage the map sensor... this is getting very frustating to say the least...
 

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McTavish
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Hmmm, so the problem is, more correctly still is, isolated to a fully warmed up situation only.
All the sensor related hoses are good and correctly connected.
Plus you now have a new battery in it.
I can just imagine how much hair is getting yanked on hard!

You have the MAP Sensor, correct?
Might as well put it in and hope that it solves the problem.

To be frank though, my guess is that it won't solve the problem - although I hope it does.
Where does your coolant temp gauge needle range between with all this?
I'm a wee bit suspicious about the ECT Sensor.
IF it was sending a false "hot", the ECU responds by incrementally adding more fuel with increasingly abnormally hot temp signals from the ECT. BUT I don't at all know if the ECU only does that in higher power modes (per %TP x RPM).

Hopefully the MAP Sensor fixes it.

HEY, is your PAIRS still intact?

I'm grasping at straws.................
 

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Discussion Starter · #6 ·
Hmmm, so the problem is, more correctly still is, isolated to a fully warmed up situation only.
All the sensor related hoses are good and correctly connected.
Plus you now have a new battery in it.
I can just imagine how much hair is getting yanked on hard!

You have the MAP Sensor, correct?
Might as well put it in and hope that it solves the problem.

To be frank though, my guess is that it won't solve the problem - although I hope it does.
Where does your coolant temp gauge needle range between with all this?
I'm a wee bit suspicious about the ECT Sensor.
IF it was sending a false "hot", the ECU responds by incrementally adding more fuel with increasingly abnormally hot temp signals from the ECT. BUT I don't at all know if the ECU only does that in higher power modes (per %TP x RPM).

Hopefully the MAP Sensor fixes it.

HEY, is your PAIRS still intact?

I'm grasping at straws.................
so i pulled the tank off and replace the map sensor and looking over the spark plug wires i noticed a slight tear in the boot cover for the spark plugs... it was the PIA checking that plug. once i removed the red boot cover is when i noticed it had a little tear... not sure if its the whole way threw though... wonder if that could be the issue?? still doesnt seem right because you would think the bike would missfire all the time..
 

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McTavish
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A tear in the actual plug boot area could do it, or be part of it.
It shouldn't if the tear is on the cap at the periphery.
In the good ole days before deep spark plug wells and capped boots, one could go into a dark garage and let the bike (or car) run, while looking for a light show, as in nice blue small lightning show.
Where exactly is the tear?
Can you take a picture of it and post it for all to see?
 

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McTavish
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6,309 Posts
A tear in the actual plug boot area could do it, or be part of it.
It shouldn't if the tear is on the cap at the periphery.
In the good ole days before deep spark plug wells and capped boots, one could go into a dark garage and let the bike (or car) run, while looking for a light show, as in nice blue small lightning show.
Where exactly is the tear?
Can you take a picture of it and post it for all to see?
Depending on where the tear is, perhaps some dielectric grease could be tried to see if it changes anything.
 

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Discussion Starter · #9 ·
A tear in the actual plug boot area could do it, or be part of it.
It shouldn't if the tear is on the cap at the periphery.
In the good ole days before deep spark plug wells and capped boots, one could go into a dark garage and let the bike (or car) run, while looking for a light show, as in nice blue small lightning show.
Where exactly is the tear?
Can you take a picture of it and post it for all to see?
158218
 

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