Possible Injector issue?

[tomek]

So, it is referenced FPR.

 Vacuum leak will effect fuel pressure and consequently fuel to air ration. 

[SwampNut]

17 hours ago, fizzy said:

As stated, line must be dry. 

 

I forgot to add a note on this, to be more clear.  Any fuel that leaks out of the FPR goes into the line into the carb, and enrichens it or floods it.  A small leak would then be a slight hiccup in a single cylinder, but the bike would still run.  With a major leak the bike won't run at all, no fuel pressure.  FPR failures don't leak visibly, just through that one line.  I don't know if there's an FPR failure where it does NOT leak, but have never heard of one.  It seems like anything that could go wrong would cause leakage/flooding.

 

[tomek]

3 hours ago, SwampNut said:

 

I forgot to add a note on this, to be more clear.  Any fuel that leaks out of the FPR goes into the line into the carb, and enrichens it or floods it. 

 

Carb? WTF? 

[bryanhes]

On 9/26/2026 at 10:52 AM, SwampNut said:

 

Yeah this, and a piece of 2x4 or 4x4 will help hold the tank area open.  I've done this a lot.  I got my FPR from Partzilla, at the time it was the last one in the country.  There are third party versions on eBay.  I made a bunch of calls and it really was the only one in the country.  I was surprised to see how every dealer now has access to every other dealer's inventory.  Hopefully they've restocked?

 

I had to look, back in stock:  https://www.partzilla.com/product/honda/16740-MAT-E22?ref=7cc2d06c61c94b967b14df385071e26be34292df

 

I lifted the tank (was sure to pop loose the button tabs from the filler plastics on the side of the tank beforehand) and puled the vacuum line off the FPR after running it for a couple minutes. Bone dry. Unless I need to take it for a run longer than a minute or two of running to see any fuel there? I did notice more on my ride the other day that it did smell like she was running a little rich.

 

Guess I'll pull the tank and check all the vacuum hoses and check the boots. May as well replace the hoses as they are old. Any good source for the correct size quality vacuum hose? May go ahead and run this tank of fuel through it with the Techron to see if I notice a difference. I'll try to take it for a ride with my 360 camera mounted near the exhaust and upload a video of what it is doing in the next couple days. 

 

It does have a PCII on it along with a Micron 4-1 header, micron exhaust and a K&N filter. 

Edited September 28 by bryanhes

[tomek]

have you checked voltage at battery with motor running thru rpm range?

[bryanhes]

1 hour ago, tomek said:

have you checked voltage at battery with motor running thru rpm range?

No, I have not. My thinking hadn't gone there as the battery seems to have plenty of juice and it fires right up even after sitting for a couple weeks. What are you thinking?

[tomek]

what am I thinking? Cover the basics first. don't overthink. It takes couple seconds to check voltage with engine running once the seat it off. 

[SwampNut]

46 minutes ago, bryanhes said:

What are you thinking?

 

You may be giving too much credit there.  I can only assume it's along the lines of insufficient power to run the EFI and/or ignition.  A failure mode I've never heard of, I ran mine down to a really dead battery after a stator failure before it quit.

 

13 hours ago, bryanhes said:

Unless I need to take it for a run longer than a minute or two of running to see any fuel there?

 

Pretty sure no, again every failure I've read of flowed fuel right away.

 

13 hours ago, bryanhes said:

I did notice more on my ride the other day that it did smell like she was running a little rich.

 

Odd, I would expect a clogged injector or other common issues that are not the FPR to make it run lean.  Could it just be imagination, or other variables?

 

 

[fizzy]

1. How many miles to the tank? Fill up to warning light on, normal riding.

 

2. After a cold start with high idle speed,, does the idle speed go down to 1100rpm once warmed up? 

 

 

[bryanhes]

1 hour ago, tomek said:

what am I thinking? Cover the basics first. don't overthink. It takes couple seconds to check voltage with engine running once the seat it off. 

Meaning, are you thinking regulator/ rectifier issue at low RPM and not high? I'll check the voltage through the range and report back. 

Edited September 28 by bryanhes

[bryanhes]

1 hour ago, SwampNut said:

 

You may be giving too much credit there.  I can only assume it's along the lines of insufficient power to run the EFI and/or ignition.  A failure mode I've never heard of, I ran mine down to a really dead battery after a stator failure before it quit.

 

I'll check voltage across the range later today.

1 hour ago, SwampNut said:

 

Pretty sure no, again every failure I've read of flowed fuel right away.

 

Got it. It was totally dry. 

1 hour ago, SwampNut said:

 

Odd, I would expect a clogged injector or other common issues that are not the FPR to make it run lean.  Could it just be imagination, or other variables?

 

I am still thinking injector not spraying correctly but willing to check simpler possibilities first. The smell of unburnt fuel, like an old car you are behind that you can tell is running rich or you can smell the richness of the exhaust on your clothes. My son was riding behind me and could smell it occasionally as well. 

1 hour ago, SwampNut said:

 

 

[bryanhes]

21 minutes ago, fizzy said:

1. How many miles to the tank? Fill up to warning light on, normal riding.

 

2. After a cold start with high idle speed,, does the idle speed go down to 1100rpm once warmed up? 

 

 

 

1. I have no idea yet, I purchased it a couple moths ago and have not run a tank through it yet between vacation and other projects etc. 

 

2. Idle drops down to a normal rage but will increase by 100 RPM or so sporadically as it is idling. 

[SwampNut]

Your short experience with it leads me to ask...did it EVER run well when you've owned it?  Or did you get it with the problem?  If the latter, I would suspect some programming issue with all the aftermarket stuff.

[CBR-RR-XX-CESS]

^^^^ thinking a flakey PCII, easly bypassed?

[bryanhes]

47 minutes ago, SwampNut said:

Your short experience with it leads me to ask...did it EVER run well when you've owned it?  Or did you get it with the problem?  If the latter, I would suspect some programming issue with all the aftermarket stuff.

 

That is correct, it has had this issue since purchasing. I thought I would check some of the other common issues before unplugging the PCII and bypassing it. I am sure that if I bypass the PCII it will have another effect on running due to the 4-1 Micron system along with the K&N filter. 

[bryanhes]

48 minutes ago, CBR-RR-XX-CESS said:

^^^^ thinking a flakey PCII, easly bypassed?

I have thought about this as well and taking it out of the loop. I am sure there will be some other run issue due to the 4-1 Micron full exhaust and the K&N. But at the same time I have thought about changing it back over to the OE exhaust and header as I have them. But the Micron sure sounds good!

[SwampNut]

1 hour ago, bryanhes said:

 

That is correct, it has had this issue since purchasing. I thought I would check some of the other common issues before unplugging the PCII and bypassing it. I am sure that if I bypass the PCII it will have another effect on running due to the 4-1 Micron system along with the K&N filter. 

 

Ignore everything I said before.  I thought this was a NEW problem.  It's 98% likely to be the mods.  Clean the filter, and lightly re-oil it properly (K&Ns suck, might even just try running without it for a test).  I don't know anything about the PC, bypass it if you can.

 

At NeXXt I'm constantly nasally assaulted by the various bikes with these mods that run super rich.  Eventually I ride slower to be away from them.

[bryanhes]

1 hour ago, SwampNut said:

 

Ignore everything I said before.  I thought this was a NEW problem.  It's 98% likely to be the mods.  Clean the filter, and lightly re-oil it properly (K&Ns suck, might even just try running without it for a test).  I don't know anything about the PC, bypass it if you can.

 

At NeXXt I'm constantly nasally assaulted by the various bikes with these mods that run super rich.  Eventually I ride slower to be away from them.

 

Yes, been this way since I purchased it from Dennis. Get pass 4000 RPM and she pulls hard like it should, even if you get on it pretty good from low RPM. Its that slower gradual roll on that it is the worst. I know he had not ridden it much in the last few years but would try and start it monthly I think he said. Said he never had this issue and the bike has had the PCIII (not PCII), Micron and K&N set up since 2004. I believe Denis purchased it in 2014 from the original owner. But I know PC's can go bad. I'll do some more checking this afternoon.

Edited September 28 by bryanhes

[tomek]

2 hours ago, bryanhes said:

 

That is correct, it has had this issue since purchasing. I thought I would check some of the other common issues before unplugging the PCII and bypassing it. I am sure that if I bypass the PCII it will have another effect on running due to the 4-1 Micron system along with the K&N filter. 

oh, pc3? When troubleshooting you always should eliminate simple to check things first before digging deeper into it.

KISS. Always. Saves time and aggravation. 

 

BTW, check grounds. Bad ground connections can be responsible weird voodoo shit. And that bike was sitting for awhile. 

Edited September 28 by tomek

[bryanhes]

21 minutes ago, tomek said:

oh, pc3? When troubleshooting you always should eliminate simple to check things first before digging deeper into it.

KISS. Always. Saves time and aggravation. 

 

BTW, check grounds. Bad ground connections can be responsible weird voodoo shit. And that bike was sitting for awhile. 

 

Yes, I was thinking PCII but upon looking again it's a PCIII. Dennis didn't ride it much over the last three years or so I think. But he would swap out the fuel every year and run it. But as we know running at idle for a few minutes isn't letting them stretch their legs. 

[tomek]

 Well, I don't think it is fuel injector(s) issue. Fuel flow is metered by the length of their opening. Pressure in the rail stays more or less the same thru the rpm/load range.  Referenced FPR can change the pressure it by some but the change is small vs. typical 3-4 bars in the rail. So, if injector is clogged it won't act like it does not flow at small load but flows OK at heavy. 

 Carbs are different in that area because they have separate circuits, like idle system that controls, well, idle but also small throttle opening and light load is completely independent in operation from main jet, etc.  So, in carbed bike if idle circuit is clogged engine will run like shit or won't run at all at low rpm and load/idle but can be perfectly fine at WOT. 

 That's why I never suggested injector cleaning based on your symptoms. Also, it is simply impossible for them to get clogged at the same time, all of them. 

 

 Always take care of simple and not time consuming things before getting deeper. 

Open air box as well, there could be mouse nest in it.😁

 PC3 directly plugs in between bike ECU and injector leads, and alters duration of the signal or opening of injectors.

 PC2 would change input data to ECU to alter duration. Like it would tell outside temperature was lower and change the mixture that way. 

 Either way, unplug it and see it is runs better. 

[bryanhes]

I finally had a chance to ride it today for about 15 miles after removing the PCIII from the equation. No change. I did pay closer attention to my RPM's relative to the issue in all gears. Doesn't matter which gear you are in it still sputters in the 2-3000rpm range. Almost like a miss, not firing or fuel shortage. Above 3k it runs fine and pulls like a train. That part didn't seem to matter even with the factory ECU, which I was surprised given the 4-1 Micron and K&N.

 

I checked voltage from idle to 5000rpm. It was 12.35v at idle up to 14.14v at 5000rpm.

 

Pulled vacuum line off of FPR again after about a 15 mile ride. Still bone dry.

 

I'll pull the tank this weekend and remove the K&N filter along with check all vacuum hoses and boots for cracks.

[tomek]

 I'd say 12.35 V at idle is too low. It probably momentarily reads even lower when you get on gas (because injectors draw more current at load vs. light load), and before rpm hit your magic 3000 rpm mark. 

 I don't have XX any longer but my FI Honda VFR 1200f reads around 13.8 at idle. 

Without engine running 12.35 V is pretty much discharged battery. What does it read without engine running? Ignition on, and ignition off?

 If I were you I'd hook up voltmeter the way it would allow you to read it while riding. 

Like get in 3 gear, and start accelerating at around 1500 rpm and see what it shows. 

 

[tomek]

 Also, it might be something as stupid as loose battery connections. 

[bryanhes]

46 minutes ago, tomek said:

 I'd say 12.35 V at idle is too low. It probably momentarily reads even lower when you get on gas (because injectors draw more current at load vs. light load), and before rpm hit your magic 3000 rpm mark. 

 I don't have XX any longer but my FI Honda VFR 1200f reads around 13.8 at idle. 

Without engine running 12.35 V is pretty much discharged battery. What does it read without engine running? Ignition on, and ignition off?

 If I were you I'd hook up voltmeter the way it would allow you to read it while riding. 

Like get in 3 gear, and start accelerating at around 1500 rpm and see what it shows. 

 

 

Kind of interesting, I went back out to the shop to start it up again and check voltage. 12.9v ignition off 12.35 ignition on. Then started it up and it is at 12.70v at idle. 

 

I'll have to see if I can attach some leads to check it while riding.

 

I did loosen and retighten both positive and negative battery leads yesterday.

Edited October 1 by bryanhes