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1998 honda vfr 800 fi cylinder three cold


lawnmowerman

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so it seems i have had many problems started out cylinder 3 was cold and not firing too much fuel so i checked the fuel injectors and all seem to work when bench tested then i went to check my oil and it was half oil and gas , so i changed my oil, so then i replaced my pressure regulator.  then when i went to start the bike cylinder 3 was still cold, so i did the flooded thing where you hold the throttle open and it finally started to fire on that cylinder then when i was still clearing it out i noticed smoke  and it smelled like oil, after looking for the smoke i see the smoke coming off the exhaust  running down the top of the exhaust  but bike is still clearing out . had to close the garage door  because of the fumes . I  have not had a chance to run the bike for long period of time and wont for a few days. my question is what could cause this?

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So what about your bike's 23-year-old Fuel Pressure Regulator?

 

When I purchased my two 5th Gen VFRs (one is a '99 and the other is a '01) I replaced the fuel pressure regulators, because they were about 20 years old.

 

Because I replaced the Fuel Pressure Regulators on my VFR800s immediately after taking possession of the bikes (as part of my "new owner" maintenance efforts) I haven't had to deal with the problems/symptoms that a failing Fuel Pressure Regulator might cause, but the odd conditions you've described could be FPR related. 

 

So this is just a thought: I wonder which one of the engine's 4 cylinders would be most affected if the Fuel Pressure Regulator was allowing gas to pass into its vacuum line?  Cylinder #3 maybe?

 

But even if your bike's FPR hasn't begun to fail it's still 23 years old, you should go ahead and replace it.  I'm pretty certain the Honda engineers viewed the bike's FPR as a "consumable item".

 

Good luck with the problem.

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I think he's already changed FPR?

 

measure impedance of all injectors

switch injectors and see if issue moves with injector to new cylinder.

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When you changed your oil did you change the oil filter? It may be as simple as oil from the filter change that has dripped onto the exhaust.

 

I've had this numerous times and it will just burn off.

 

Make sure your oil filter is not leaking and that the rubber seal of the old filter came off with it.

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6 hours ago, GreginDenver said:

So this is just a thought: I wonder which one of the engine's 4 cylinders would be most affected if the Fuel Pressure Regulator was allowing gas to pass into its vacuum line?  Cylinder #3 maybe?

Hi Greg. Vacuum for the FPR is tee'd off cylinders 3 and 4 so only those two can be affected by the ruptured diaphragm.

Cylinder 3 seems to be the most affected for some reason.

Cheers.

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10 hours ago, Grum said:

When you changed your oil did you change the oil filter? It may be as simple as oil from the filter change that has dripped onto the exhaust.

 

I've had this numerous times and it will just burn off.

 

Make sure your oil filter is not leaking and that the rubber seal of the old filter came off with it.

thanks for the picture , that is a nice clear picture , no i did not change the oil filter, but i will when i get it running right.  oil seems to be coming out of #1 and # 3 exhaust under the seat so it seems. but now that i changed the FPR it is clearing out  and burning out the oil and im thinking it might be gas mixed with oil.

 

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Just wanted to let you all know the fix for my problem  was a fuel pressure regulator and doing the flooded procedure.   Thanks you guys rock

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