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I know on cars there's a return line from the fuel rail, and these motors are basically car motors. When the fuel pressure gets high the return is the 'purge' to relieve it, sort of. Have you done any troubleshooting of the fuel return line(s)?
How do your spark plugs look? Do they have black soot? All of mine had black on them, I was thinking probably because of the 90 psi and making it run rich, therefore setting off the code "1" on mine. BTW did you order the hds?
Here's my update:
Fuel Pressure Too High Issue ==> 90 PSI, possibly causing my code "1": Went to my local Honda Service and ordered a new Pressure Regulator and Mesh Fuel Filter/o-ring. I figured if I have to take the time and take this apart again, I want new parts in hand to replace with. I consider it a small dollar value vs my time. So, the plan now is to wait till Wednesday when the Pressure Regulator parts are in and replace it then. Stay Tuned........
Now for my Surging Issue at low RPMS: Please note; During startup, if the throttle is left at it lowest point (~700 RPM's) NO problem is apparent. As soon as I increase it slightly to say 900 RPM's it starts to surge between 800-1100 RPM's.
Once again, I thought I had another smoking gun when I opened up my Throttle Body Assy. Evidently the rubber belts below the silencer have a tendency (at least in my case) to shed fragments of rubber belt into the silencer and therefore get sucked into the Throttle Body and then the Intake Air Manifold. I cleaned the associated Throttle Body Assy's (IAC, TP Sensor, IAT, Throttle Valve and orifices etc.) with Carb Cleaner. Once again it did not fix my surging issue, but never the less had to be cleaned up and I can cross it off of the list of potential root causes. FYI:The local Honda Service guy did mention he just fix another guys surging engine doing this.
LP Fuel Filter Bowl Issue Gas level too low: I'll try to splice my clear tube between the LP Fuel filter and Fuel/Water Check bowl tomorrow.
Today's conclusion: Low Idle Surging: I'm thinking some type of air infiltration somewhere into either the Gas Line System or Air Input System. Also, After cleaning the throttle Body Assy the flapper moved very smoothly, so I'll rule out any mechanical binding. But there is still a potential for the Idle Air Control Valve (IAC) gizmo to be Faulty, I need to figure how to test that part or verify functionality.
Regarding IAC, Clymer manual states disconnect both battery cables, unplug IAC motor harness connector, test for 10-13 ohms across its terminals. Now touch the negative probe to engine ground and pos probe to either IAC terminal, should get open circuit OR very high resistance. If either of those tests fails, replace IAC. Clean all electrical connectors when reconnecting.
OK. That is the correct plug. Hope I didn't get you cranked over that post.
I was once told to never try to re-gap an iridium-tipped plug. Perhaps that was bad info.
Anyway, I have known of several cases where an owner walks into a auto parts store, orders NGK IZFR6F11 plugs and is sold the standard ZFR6F11 plugs. Even happened to me once.
BTW - I just noticed yesterday that you can get the NGK IZFR6F11's on Amazon Prime for $7.25 each. That is a heck of a savings from an over-the-counter parts store.
Just be cautious, my co-worker just received his plug order from Amazon for a Buick and he got 4 different plugs for a v6. Check them over carefully.
Regarding IAC, Clymer manual states disconnect both battery cables, unplug IAC motor harness connector, test for 10-13 ohms across its terminals. Now touch the negative probe to engine ground and pos probe to either IAC terminal, should get open circuit OR very high resistance. If either of those tests fails, replace IAC. Clean all electrical connectors when reconnecting.
IAC measures 13 ohms across terminals and no shorts to ground. Check..
Perfect, now you know the IAC is functional. I don't remember if you pulled the IAC assembly off but I think there's a screen/filter under it and Honda recommends replacing the o-rings.
OK, I replaced the Fuel Regulator and also cleaned (with Carburetor Cleaner) the Mesh Screen filter and my fuel pressure is finally within spec ~4x something psi. I didn't replace the replace the mesh screen. Because it did not get delivered and I new the solution was close, so I cleaned the existing one instead.
In addition to the normal fuel pressure the low throttle surging has also gone away, and I didn't get a chance to run it more than 20 minutes but I suspect that my error code "1" may also be gone. I will give a full test run tomorrow.
My suspicion is that the real problem here is the Mesh Screen at output of the pressure regulator is clogged and I wasn't able to determine this by eye the other day. Today when I sprayed it with carburetor cleaner the mesh screen color changed from amber-ish to silver-ish. And the residue on the cloth was amber. Maybe clogged causing the back pressure? or I could have just had a bad Press. Reg..
Just for mind sake; off season I'll swap back the old P.R. and test it.......
Keep in mind I still have that low gas level on the LP filter bowl, but it seemed to run pretty good idling, run up to 2k rpms and also kicking it into gear while tied up in my slip.
Does any of this sound familiar? Skooter......