2004 VFR 800 Trouble Starting

Hey y'all, looking for help here with my '04 non-ABS model. It died on me out of nowhere last week while I was riding and had to be hauled back to the house in my truck. Before it died, the bike showed no sign of any problems and was running and starting normally. Right now, most of the time, it will "start" for a couple of seconds and idle poorly around 800-1000 RPM, and then die. Any touch of the throttle kills it as well.

- Kill switch is good
- Neutral light functions, and it starts the same in neutral or 1st with the clutch pulled in
- No combination of side stand, center stand, gear selection, or clutch changes the problem
- Fuel pump primes for 2-3 seconds when ignition or switch is turned on
- FI light is on during fuel pump priming, but then goes away as normal
- There are no other warning lights present
- I have tried the flooded engine procedure, hasn't helped
- I have drained the fuel tank and added new fuel, no change

The blue connector/green ground wire issue common to some users seems to have been fixed, my blue connect on the left side behind the fairing only has the ground wire on one side. I believe this indicates the warranty work has been completed. All fuses in fuse box are good. Both 30a fuses next to battery are good, and the relay next to the battery appears healthy as well. No signs of overheating, etc. Oil level is good. Battery is fine. There are several relays on the front of the bike behind the windshield/black plastic, I believe one is a fuel shutoff and one is a tip over sensor. I don't know how to test them, but they all appear healthy - wires look good, no melted connections, etc.

Does anyone have any experience with this problem or recommendations on how to proceed? I have the service manual, and will continue to work on it as I am able. It's my daily driver, but I don't have very much time to pour into it right now - I spent most of today reading every forum post I could find, but haven't had any luck so far. Thanks in advance.

 

Wow, excellent write up BV one of the best I've seen, you've covered a lot of good test and checking.

- So if your are hearing the Fuel Pump prime at every switch On, then that means there's no issue with the ESR, FCR and BAS.

- Perhaps a ruptured FPR (fuel pressure regulator) might be a cause. If the diaphragm within the FPR ruptures it will dump excessive fuel into Cylinders 3 and 4 via the FPR's vacuum hose. This will definitely cause terrible running and very bad idle. You can easily check for this by pulling the vac hose off and check for any fuel weepage from the FPR make sure the vac hose appears dry, switch on the ignition for a fuel prime, see if that forces fuel from the FPR vac hose fitting. You could also check the plugs for 3 and 4, see if they are wet, sooty or fouled. Any doubts about plugs Replace them - NGK IMR9B-9H's

- Check the frame Grounds common point, located just rear of the Fuel Tank. Make sure they are clean and tight.

- Are your battery terminals clean and tight?

- Have a Very Close inspection of Main Fuse B 30amp, this fuse powers all your EFI stuff The fuse and its wiring and the single inline connector can all suffer from heat stress, poor high resistance connections causing sometimes intermittent havoc with the EFI. Double check this fuse and it's associated local wiring.

- Is there any chance you've picked up a bad batch of fuel, or have excessive condensation in the tank, especially if using Ethanol blended fuel.

Hope this helps, let's know how you get on.
Cheers.

 

Grum, thanks for the advice. This morning after work I pulled the air box and checked what I believe to be the fuel pressure regulator (one of the attached photos, is that the correct part?). There's no sign of fuel weeping into the vacuum hose, and no fuel spews out of that nipple when the fuel pump is activated.

I also pulled the #4 spark plug (front/right cylinder), and have attached a photo of that too. It looks pretty dirty and smelled like fuel, gap is 0.813mm.

I have changed the fuel out, and it didn't make any difference.

Where exactly is the common ground point behind the tank? I don't see it.

Right now, the motorcycle will "start" and run at 1K rpm for a second or two, then drop below 1K rpm, and then die after a few seconds. Any further help would be appreciated, I'm not at a place financially where I can throw money at parts and am trying to diagnose as best I can before I purchase anything. Thanks again.

 

Yep you've located the FPR.

That No4 plug gap is ok BUT the Plug looks bad, any idea how old the plugs are? I wouldn't hesitate in fitting a new set, then reasses the situation. Plugs can cause some pretty weird running effects. There's a good chance new plugs might hopefully do the trick, they definitely need to be taken out of the equation.
I just checked a set of plugs I removed (from my 2014 8gen) after 60,000k's each one had a light tan coloured insulator with no heavy carbon or soot build up, all 4 are identical in looks, very different to your example.

See attached for Grounds.

Another thing that came to mind is the Fuel Pump itself, you may have a blocked fuel filter, meaning, you might need to run the fuel pressure and flow tests set out in the Service Manual, seems like this is about the only thing you haven't checked, and might be typical of fuel starvation how it runs for a few seconds then dies.
See how you go after first replacing the Spark Plugs.

Good Luck.

 

Thanks for the advice Grum. I just ordered a set of plugs from NGK, while I wait for them to arrive I'll double check the grounds, and run the fuel tests. Will check back in when I've got some more answers.

 

Well, I think I have my answer! I performed the fuel flow inspection as described on page 5-53 of the service manual, and got zero fuel flow. This got me thinking, and since I still had the air filter off from checking the fuel pressure regulator, I attempted to start the bike by spraying starting fluid down the velocity stacks, and it started and runs! I'll still replace the spark plugs when the new ones come in, and will now be pulling the fuel pump and filter assembly. I'm pretty sure the fuel pump itself is fine, and am going to start by bypassing the fuel filter and seeing if I can get it to run.

 

Well, I think I've found the problem. Fuel filter seems fine, but the hose on the dirty side of the filter is split (see photo). Both hoses are very soft, I'm going to head to an auto parts store and pick up some new hose tonight, and try to get everything reassembled!

 

Great News BV. You've certainly found your fault, couple of new short hoses and your done. Your bike will also benifit from the new plugs regardless.

Lets Know how it goes.
Cheers.

 

So for anyone who runs into this in the future, the fuel line inside the tank appears to have been the problem. I wouldn't have suspected a broken/split line would cause such a catastrophic issue (one moment the bike was running down the road, the next it wasn't - no sputtering or anything). However, if you encounter a no-start problem like mine where the bike will start, barely, for a second and appears to be starved of fuel, this may be a good place to check. I wish I'd pulled the fuel system out of the tank *before* I removed all of the plastics and spark plugs, but I learned a lot in the process and the fix ended up being a free scrap piece of fuel line from my local auto parts shop!

 

Nice job finding and fixing that!
As my recently acquired VFR has 63k on the clock, I will put this down as a potential issue in future. Can you tell me what bore pipe is needed - might carry a short length with the tool kit - just in case!
Thanks
Dave

 

There are two pieces of 5/16" fuel hose, one on either side of the fuel filter. They're each about 4" long.

My VFR only has 7,500 miles on it, but I guess 20 years of soaking up gasoline will eventually cause a fuel hose to fail. Keep in mind these are submerged in fuel, inside the tank. You could certainly change them out on the side of the road, but it would be a heckuva job to do in a parking lot!

 

Thanks for that..... I know it's not ideal but if it happens somewhere remote, the worst scenario is dumping most of the fuel - had the pipe blow off the pump in the past on a Guzzi Griso so I think having spare pipe should guarantee it will never happen again....

 

Absolutely - it's one of those things where you need the spare line, and if there's no where open/close then you're out of luck. I was lucky mine quit on me a few minutes from my house, and I have the means to get it home!