FI Fuse pops when turning the bike on (VFR800 05')

Another fuel pump problem I'm afraid. I would love your input.

I woke up one day and noticed my VFR800 05' didn't start as easily as it usually does, however ran fine once started. I went to a HD event and on my way home (bike still didn't start as easily), the ABS light started flashing. About 15 minutes later, the motor died when accelerating onto the highway, but the ignition was still fine. It wouldn't start, fuel pump wouldn't prime and I found that the FI fuse had blown. I replaced the fuse, twisted the key and heard the fuel pump for about 0.5 sec before the fuse popped, again. This was repeated a couple of times later after cleaning some dirty connectors.

The battery is fine, and I would think the problem was the fuel pump, but the ABS light coming on moments before disaster makes me believe it could be another electrical issue.

I would love to hear if you know any better than me. I got the bike this season so I haven't had time to familiarize myself with the bike yet.

 

Hi and Welcome to the MadHouse!

Given the circumstances I fear you may have symptoms of the classic Regulator Rectifier fault - whether other components have been damaged is unclear but a risk..

Basically depending on what diode fails inside the RR it may have different impacts on the motorbikes charging system. If a regulator diode fails then your charging system could receive no power or up to 60 Volts which is not good for a system designed for a nominal 12 and fuses may indeed pop. If a diode in the rectifier bridge fails it could again deliver no power or send AC into a system designed for DC - again not good.

You mention a light flashing - whilst the ABS might light during heavy braking it seems unlikely and instead it may have been the PGMFI fault - please have a look at Kaldeks' you tube video just in case it was actually a PGMFI fault code warning - which if present you can read following the steps Kaldek mentions.



If you have an RR problem then you need to work through "the drill" see this thread. As you can see you will not be the first...

https://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

When you get time please swing by the Introductions forum and say Hi to the rest of the folks on here - tell us a bit about your riding history and always add a photo of your VFR - it is easy - click the "upload a file" link - follow the prompts to select and upload a photo from your computer, use the "More options" to decide how you want the image displayed.

I hope you get the problem resolved - Let us know how you get on.



SkiMad

 

Assume you are blowing Main Fuse B 30amp? This fuse also feeds the ABS.

Seeing you can replicate the situation at every switch on and you're suspecting the Fuel Pump, try just unplugging its 2P connector, does the Fuse blow with Ignition Switch On?
If it still blows move to the ABS and remove its fuses, try again.

Seeing the fuse blows Only when the Ignition is turned On and prior to starting the engine, then it seems unlikely to be the R/R. However, once running Verify your charging system voltage.

 

Cannot believe I didn't try that.
I will check the pump, ABS and RR this weekend and keep you updated.

 

I didn't get further than the RR. Testing the diodes with a multimeter I get no reading through the green wires, regardless of the direction or diode pin, which is bad if I'm not entirely mistaken. This is a shame because, based on the pristine plastic on the connectors, it looks like the RR was replaced not too long ago.

I apologize for the boring reason. It looks like I will have to work through "The Drill" earlier in my VFR career than desired.

 

Mate. If you are saying Main Fuse B 30amp ONLY blows when turning On the Ignition, then you are wasting time checking the R/R at this stage.
The R/R output is connected directly to Main Fuse B and if the R/R was causing the short blowing the fuse, it wouldn't need the Ignition Switch to be On.

Are you working with a wiring diagram of your bike? Be good if you could at least confirm if you are blowing Main Fuse B 30amp!

You can simply isolate the R/R if you needed to for fault finding by just unplugging its output connector.

 

Take your time with this stuff as it is easy to jump to the wrong conclusion and end up replacing stuff which was still OK.

I know it is a convention on most fora to keep posts short but do not let that worry you here. You are the olther side of the planet and we need yiou to tell us what you find and what you have deduced - if we are able to offer pertinent advice.

Hence I guess you have already done some or all of the checks suggested by Grum - and concluded they did not help identify the fault(s) sdaly whilst you know that, we do not.

So did you isolate the fuel pump and find the fuse popped when the ignition was turned on?
Did you move on and check if it was the ABS?

if the folks on here are best able to advise we really need you to tell us what you have ruled out. As they say a picture can save a thousand words so do not hestitate to add a photo/video if relevant.

As for the drill with hindsight I can see the steps are ample for someone already familiar with motorbike electrics but possibly quite bewildering for a total novice - with even questions like what wire to connect where on a multi-meter. if you plough through that thread linked above you will see RR problems can affect almost all VFRs as they only fitted decent electrics to the 7th and 8th Gen models.

 

Yes, it's the 30 amp main fuse B that pops. I disconnected the fuel pump, ABS fuses and RR, but it still pops when I flip the engine kill switch. I'm making my way through the wiring diagram to see what could be the cause, but I ran out of fuses for now. I'm finishing my master's thesis, so I have limited time available at the moment, but I'll keep you updated if something comes up.

 

If you have a multimeter you could measure the load side of the fuse to ground with the fuse removed, you should measure the short as very low ohms.
Otherwise just continue wirh a few more fuses!
- Does your bike have any non standard wiring or accessories?
- Next try removing the ESR Engine Stop Relay,
- If the Fuse doesn't blow, and with the relay still removed, use your multimeter, see if you can probe the Black/White wire of the Relay connector. Do you measure a short to Ground?

 

Will do.
As for non-standard wiring, there has been a lot of "tinkering" previously with the headlight wiring, and definitely some non-standard wiring there. But as the headlights work without popping the fuse, I don't think that's the issue.
The bike also has traces of heated grips that were disconnected.
I'll send some pictures when I'm back at the workshop.

 

I am now confused as to what configuration of controls is blowing the fuse.

Initially you seemed to imply the fuse popped almost as soon as you "twisted the key" (can we assume the kill switch was set to run)>

Now you report the fuse only blowing when you "flip the engine Kill Switch" - do you mean the fuse is happy with the key set to ignition on but with the kill switch set to OFF but blows when you move the kill switch to RUN?

Or is the fuse allowing the fuel pump to prime and only blowing when you actually press the starter button?

This is starting to suggest you may have some sort of switch failure or loom damage on cables feeding the kill switch creating an intermittent short.
It might be worth taking a close look at the kill switch and cabling and circuit testing to check for something shorting to earth.

 

Yeah, I just discovered this yesterday. The fuse does not pop when turning the ignition on with the kill switch switch turned to OFF, but blows when set to RUN. Likewise, the fuse blows immediately if the ignition is turned on with the kill switch set to run. The fuel pump is not allowed to prime.

 

The Kill Switch controls the 12v to the ESR coil via the Black wire. Activate the Kill Switch and the ESR is de-energised, the EFI system is totally unpowered = Dead Engine, it also kills power to the Starter Relay coil = No Cranking.

So your short is either a fault with the ESR or beyond, and the reason for suggesting to remove the ESR and measure for a short on the all important EFI system 12v supply, being the Black/White wire.

Info - Kill Switch 12v to control the ESR, comes from Fuse F 10amp being the Starter/Bank Angle Sensor Fuse (or Fuse C on non ABS Model). Any shorts within the Kill Switch would blow that 10amp fuse. You are not blowing that fuse.