Fueling Issue Poll

[rmcobb]

OK, so I've been trying to resolve a fueling issue for a year now. The intermittent, although has gotten progressively worse, stumble/hesitation/cough coming off 0% throttle. Once you get to about 20-30% all is good. I'm plugging away at the various causes, but haven't found the cure yet..........SO, what is the consensus for the next step?

2008 bike with 51K miles. Still rides fine other than this annoyance.

Things I've done so far.
Numerous treatments of Seafoam over the past year
New Air Filter
New Plugs
New Battery
Throttle Body Synch
New Throttle Position Sensor (really thought this would be the cure after seeing so many posts about the same issue being solved by new TPS)

At this point I'm thinking fuel injector related, or fuel pump related.

So, what is the consensus from the collective as to which one to attempt?

1. Remove injectors and send them out for professional testing/cleaning
2. R&R fuel pump...probably with a used one off ebay.

Don't want to throw a ton of money at this, will probably be selling the bike in the next year.........maybe sooner than later.

Thanks
Randy

 

[RossKean]

Snatchy throttle a common issue on early Gen II although it sounds like it is getting worse for yours.
I think I would do the fuel injector clean before fuel pump although a pressure check of the fuel system could rule the pump out as a potential problem.
Sometimes, setting the idle up to 1150 or so can be helpful.
Check your plug wires. Unscrew the caps from the wires and maybe trim 1/4" from the ends. (Not much, there is little to spare!)
If all else fails, a Power Commander might richen up the lower rpm range to improve throttle response.

Might want to check compression although it should be good at only 51 K miles.

 

[saread]

Check idle RPM. Set to 1100 or so. Snatchy throttle issue was fixed in 2008. Low idle is a known issue. 2008 bike should not need a Power Commander.

 

[Mr. BR]

Wouldn't hurt to pull the fuel pump, check the filter. Replacement filters can be found on Ebay, AliExpress etc. Here's how I checked the fuel pressure on my '05: Ebay used fuel line + common T-fitting + crappy old pressure guage I had laying around.
Regards,
Mr. BR

 

[Whooshka]

How about the vacuum hoses? A clogged/dirty MAF sensor hose might cause a stumble.

 

[RossKean]

A clogged/dirty MAF sensor hose might cause a stumble.

Yes, but usually generates a fault 14 code. Still doesn't hurt to check.
https://www.fjrforum.com/threads/fault-code-14-gen-ii-solved.170314/

Snatchy throttle issue was fixed in 2008.

Not entirely although much improved over '06-'07. A PC might still help although it would be masking the root problem, not fixing it.

 

[Coachpilot]

Does it happen more often when it's warmed up? I've had fuel lines that look good when cold but when they warm up from engine heat they start to kink from any small amount of force on them. Vent hoses too. Hopefully it's something easy before throwing more $$ at it. Keep us posted.

 

[SFZX]

I just solved a problem like this about a year ago, I sold the bike after the repair. but the fuel injectors cleaned professionally made a world of difference. Look at the fuel filter first it. Sounds like the pump motor is still ok or it would be worse at highest rpm. Mine would fall flat on its face if full throttled, and almost die. literally stop running. I replaced it with a brand new fuel pump and then put in those cleaned balanced injectors, that bike never even when new, ran as well as it did after that. You can attempt to clean injectors yourself making a fuel injector cleaner solution tool to spray into the injector. Injectors will fire with a 9 volt battery. Using a tire valve stem and one of those little red straws that come with spray carb cleaner you can make an injector feeder for the cleaning solution. Look it up on you tube. I managed to get the one I played with from below 10%(guessing here) but it was barely working flow to 85% according to the guys at Injector Rx of Houston, one was at 20% one was at 50% and one at 60% at first testing. The one I worked on would hardly squirt when I started and they said it tested 85% before they worked on them. I can't say enough good about Injector Rx of Houston the flow charts they will send you will tell the whole story in a glance. They were very helpful and the tech even spoke with me on the phone I think it cost me $115 for the cleaning and parts replacements they did on the injectors, but thats by memory LOL My bike was 2008 with only 35,000 miles on it, if your over 50,000 they will need cleaning for sure.

 

[Mcarver351]

I didn't see any mention of a valve adjustment and it's way past due. A tight valve could cause your problem.

 

[vzhq16]

Before throwing more parts at the problem, due diligence might save you some $$ as well as time. Making sure the idle speed is set correctly, looking for clogged MAF sensor hose, kinked vent line (pretty common), and a TPS that is properly set. If you replace the TPS, using an OBDII reader, connect the reader, turn on the bike (don't start it) and write down the number at idle and at full throttle. That's the range your particular reader recognizes. When you install the new TPS, rotate it to get as close as you can to those numbers before tightening it down. If you're not replacing the TPS, you can also try to do it by ear. You can hear the pitch change as you rotate the TPS with the bike running. Rotate too far clockwise and the pitch will drop sharply and generate a low voltage error code. To do a rough low range adjustment, just rotate it counter-clockwise a small amount, then tighten it back down. You just want the prongs in the TPS off of the worn spot, or if it was set too low at the factory.

Another option might be to send the ECU to Ivan for a tune. His tune kills the programming to cut fuel delivery on decel. It smooths out the transition from closed throttle.

 

[RossKean]

I didn't see any mention of a valve adjustment and it's way past due. A tight valve could cause your problem.

Rarely a problem on FJRs at just 51,000 miles, but I agree that it should be checked; especially if it hasn't been done before. On my '07, all of the intake valves were close to minimum clearance at the first check but I didn't have to make any adjustments until nearly 100,000 miles.

 

[Rocnsanman]

A long shot but ... Is your bike a California model with charcoal canister?

 

[rmcobb]

A long shot but ... Is your bike a California model with charcoal canister?

Yes, it is.

 

[rmcobb]

OK, so, a lot of suggestions here.....Thanks everyone. To answer some of the questions posed in the various replies

-Valve check was last performed at 36K. No issues or adjustments were necessary.

-Doesn't seem to matter warm or cold. It's intermittent but is happening more frequently since it started 10 months ago. When I first noticed it, it was a month or so before it happened again, then the times in between just kept getting shorter, now its happening on every ride.

-Idle may be a tad low, right how its at 1050 to 1100. I might raise it a bit more to see if that has any affect. I kind of doubt it.

-Code 14........Hmmm, I received this about a couple years back....prior to having this issue. I cleaned out Hose #12 at the time....didn't find anything, but it hasn't come back since I cleared it. I may go ahead and clean out all the hoses and see if that does anything.

-TPS swap and calibration. All that went OK except for the calibration was weird in that I was using both the voltage measurements as well as the settings in the diagnostics. I couldn't get the voltage within the stated range (.63-.73) without the diag panel showing 14 (range is supposed to be 15-17). So setting it via the diag panel to 15 got me .60 voltage reading. Bike runs fine......just like it used to with this current problem.

Question....I see references to MAF, and MAP, are these the same? And are we talking about the Air Intake Pressure Sensor (Item #17 in the schematic)?

 

[Prosolar]

+1 on checking you spark plug wires and resistor caps, remove the caps from the wire and use a DVOM to measure resistance, they should all roughly be the same probably like 5k or so. Also look on the inside of the caps with a flashlight looking for arcing...

 

[RossKean]

Question....I see references to MAF, and MAP, are these the same? And are we talking about the Air Intake Pressure Sensor (Item #17 in the schematic)?

All the same.

 

[Rocnsanman]

Yes, it is.

Cali models with the charcoal canisters are notorious for exhibiting the symptoms you describe. Removal of the canister and tying the overflow and vent lines at the rear of the fuel tank should help to resolve your problem. The fuel vapor is routed through the charcoal canister and directed to the throttle bodies and into the engine. An over rich condition and hard starting/ stumbling off idle results.. I've had to do this mod to two Cali bikes. Hope this helps.

 

[RossKean]

Cali models with the charcoal canisters are notorious for exhibiting the symptoms you describe. Removal of the canister and tying the overflow and vent lines at the rear of the fuel tank should help to resolve your problem. The fuel vapor is routed through the charcoal canister and directed to the throttle bodies and into the engine. An over rich condition and hard starting/ stumbling off idle results.. I've had to do this mod to two Cali bikes. Hope this helps.

The usual issue with the canister is starting starting the bike when it has been sitting in the hot sun for a time. Fuel vapor saturates the charcoal and the engine runs like crap (extremely rich) for five minutes or so until the canister is purged by intake air being drawn through it. There have been reports of problems with the canister getting plugged over time and that could lead to a permanent running issue. Not hard to bypass the canister (compare parts fiche for Cali models to 49 state models), but I would try simply disconnecting it first to see if that makes a difference.

 

[Nazgul]

I had the exact, same problem with my Cali 2012 until I stopped my (really bad) habit of "topping off" the tank, which send raw fuel into the vapor recovery system. On hot summer days it ran so bad on cold start up I thought my baby was broken for sure. Now I leave an inch or so below the top, and the problem went away.

 

[SkooterG]

I would definitely start with the CA evap system. However, I am not convinced that is your problem.

In one of the other FJR sandboxes there has been a years long effort to fix a surging 2013 FJR. Recent success came with replacing the fuel pressure regulator located in the fuel pump.

Read all about it here: Clicky Thingy