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Discussion Starter #1
i Guys,
long story short, 99 FI BB with 30k km (one owner only before me), worked quite good for a thousand km, i've made an Oil/Filters/Plugs change during the line, and also CCT.


After 600km form service started to stutter and can't hold idle, initially it was also difficult to start when cold, probably for the wet plugs.
Battery 12,7-12,8v cold, 13,8-14v idle and 14,3v over 2k (and also 14,4 at 5k).


All sparks (600km use) badly fouled, and after some test found fuel dripping from the air port of fuel pressure regulator.
Changed plugs with old good one and new OEM FPR from cms, same problem.


It goes quite good when cold, after warm up it start to run bad, for my understanding one cylinder stop from firing, from the smell for me is too much fuel, but could be something else.
Checked ECT (1,6kohm at 30°C), strange thing is when warm couldn't measure any readings....will try better tomorrow
Injectors impedance 14,8kohm all around, tested for spark between every coil and a bolt on the engine and every cylinder show spark, not sure if this is enough to say coils and wires are good.


No error in the diagnostic memory. Fuel pump prime ok, measured fuel from return line (after new FPR) as per service manual , its around 300ml in ten seconds (manual say 220cm3 al least).




https://www.youtube.com/watch?v=qVWatDcyt1Y


A bit lost right now, any help appreciated

Cheers
Adriano
 

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If you have changed to second design FPR your rail pressure has increased by 5 lbs. Check the FPR vacuum port for wetness again. Not very likely but the diaphragm may have ruptured again. Also check your oil for fuel to be safe.
When you say ECT what do you mean?
 

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Discussion Starter #3
HI,
yes it's the new design (part number 16740-MAT-E02) so my base pressure is increased and my ecu doesn't know nothing about it.....should i have to switch to old fpr 16740-MAT-E01?
ECT, Engine coolant temperature sensor, and yes i could definitely smell fuel in engine oil.

Possible that i had a faulty fpr and now a fpr with 0,5bar more pressure that false my carbuation?
 

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Discussion Starter #6
not yet,
i'm an not a professional, just an amateur that like fiddling with things, fact is: ECT from cold (28-30°C right now) is 1,6kohm between pink pin and green wire, i'll double check today but should be around 4-600ohm from pink to sensor ground. When hot multimeter gives me just "1" that means what? no resistance or too much?
And yes i'll definitely change if reading are confirmed
 

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1 should mean a short. And depending on the fuel table cross it may be causing it to go rich. You need to go through the manual steps again. Any reading other than the spec means it's bad. The system relies heavily on that temp input to pulse the injector correctly.
 

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Blitz
Also it doesn't take much to fuel foul the plugs. You may have to replace them again. Note too did you change out the oil and filter after the failure of the FPR. If not then DO NOT run it again until you do.
 

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Discussion Starter #9
First i will remove ect and test as service manual say, after that if it's broken will buy another one, with new plugs and fresh oil change.
Interesting about FPR, original part is 16740MATE01, superseded part is
16740MATE02 (the one i bought) which is the same for '01 BB, i've ask cms if this parts have different base fuel pressure because after '99 SM report that:

Dear Adriano,


The part ordered is an superseded part by Honda. Supersede part are functionally the same.
Please read more about superseded parts at FAQ on our website.



My conclusion is that ordered and replaced parts are not the cause of your problem and you will have to search further for the cause to solve your problem.





I will try to test this just to be sure.







 

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Discussion Starter #10
Just a followup, new ect sensor, a bit better but same problem. Is always cyl1 to have intermittent starting problem.

Changed plug, swap spark wires to see if problem was this, swap left coil with right coil, i'ts always cyl1 to stay cold (measured 100 degree less than others).

Will continue with other test, if you have any idea you are welcome.
 

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Discussion Starter #12
beestoys thanks for your time and help!

Found the arcane, after testing everything else and changed also ect sensor, was told to to clean injectors....and it was the solution!


Cleaned with ultrasonic wash and bam! working perfectly! Notice before clean they were tested and they was pretty good apart from one flowing a little bit less.


Now Idle like a champ and no more problem when hot, i don't understand why a clogged or dirty injector could make this mess only when hot, but fixed problem this way.

So guys if your bird is going crazy check and clean injectors, they are 20 years old now.


Back on the beast and happy as a child!
 

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Your very welcome sir
Glad you have it sorted out now. Got larry's bike back up and running his was a coil issue. Non stock replacements caused a phase issue and missfire. Replaced the stock coils and she is happy again.
 

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there appears to be quite a lot of faults around the injection system
is there a general write up on the sequencing of the faults by probablility and symptom to help the members?
 
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