Air in fuel system? Bright Ideas?
 

So for various reasons I've had the tank, fuel hose, injector rail, and injector off the Tenere. Back together now, but it won't run for more than a few seconds at a time before cutting out.

Can hear the fuel pump running when I turn the key on, so I've managed to plug that in properly.

Only explanation I can come up with is there's still air in the injection system, but I can't really think of a sensible way of getting it out other than to keep trying to start it (or generally rattling the bike around in the hope it finds its way back up through the pump).

Any suggestions? Or any other ideas for what might be the problem?


Something has also set the engine warning light flashing. I think there's a reasonable chance it's just objecting to the battery having got a bit flat with all the cranking over, although it's not gone away this morning with a freshly charged battery. Maybe it needs the engine to run for a while to reset it?

Just in case it is something else, can you actually get at the fault codes through the dash on the Tenere? I can only find instructions for the R/X on here.

Cheers
Dave

I'd first try to find out why the warning light is on. To get at the fault code turn of the key, turn it on again and start counting the flashes of the warning light. Long flashes are tens, short flashes are units.

So 2 long flashes and 3 short flashes make 23.

Cheers for that.

Turns out my guess was right though, coming up with code 46, which is 'low voltage' according to Kev.

The fuel pump is self bleeding, the injector will bleed the air out of the fuel rail & injector.

Why did you strip everything, was there a problem?

Is the fuel pump connect fitted correctly, pins not bent, free of corrosion?

Is the injector connector fitted correctly, is the injector fitted correctly in the fuel rail?

Is the fuel pipe connected to the tank correctly.

Did you strip down the fuel pump, one of of the fuel pump hose may be not connect within the fuel tank or leaking?

Confession of idiocy:

Taken apart because I managed to drop the tank while still connected to the bike by the fuel hose. Had to replace both hose and injector rail. Had unplugged electrical connections to the tank at that point, so shouldn't be any issue with broken wires, etc.



Mechanically, it's all put back together properly, everything plugged back in.

If you reckon it ought to self-bleed, then my suspicion starts to fall on the fuel pump, expecially since the manual basically says "don't drop it". Will get the tank back off and check the pump as suggested in the manual.

What hoses in the tank? Nothing shown on the diagrams in the manual.

Next question, how on earth do you get the fuel pump out? Something doesn't fit through the hole in the tank, and I don't want to pull too hard on it.

It should just pull straight out with a little bit of wiggling. It only just fits through the hole mind you, by a mm or two, but it does fit. Maybe something got broken or came loose in the drop which is catching?

Starting to wonder that. It only seems to be catching by a mm or two as well, but I can't tell what the thing it is catching on is.

How far out can you get it before it gets stuck?

It's catching on the stop for the fuel gauge float arm. Can't see how that might be displaced from where it should be though.

Are you trying to remove the pump with the tank upside down because the float can get stuck in the narrow sides of the tank. I removed mine with the tank upside down (so the float is highest and the arm straightest), then rotated the pump about 90 degrees clockwise so the float arm was effectively pointing at the front of the tank. The nylon clips that hold the float arm to the sender unit are fairly flimsy too. Also the float stop/rest is really very feeble - if that snaps the float will drop much lower and get stuck.

I've got the tank stood on its front end, but I'm sure it's not the arm that's causing the problem, but the stop itself.

Trouble is, that begs the question "how on earth did Yamaha put it together in the first place?"

Can't really suggest anything else really! I got might out, so I can't believe it should be any different?? I suppose its a bit like moving an old sofa out of your living room through a doorway - you know it went in, so it must come out, but you spend hours trying, swearing and kicking things, then the wife comes along, moves it an inch one way and it slips out with ease! My suggestion would be to let someone else have a go, probably someone female...

IT'S ALIVE!

Got the pump out in the end with a bit more wiggling and some *very* gentle bending of the float arm stop with a screwdriver.

I was pretty sure beforehand that the problem was a leak somewhere in the pump assembly. Reasons:

- Since Kev had said the system should be self-priming, then the only other option I could think of was the pump failing to deliver enough fuel to the fuel rail. I could hear the pump working when I turned the key, which suggested it was producing some flow, but that wasn't reaching the injector.

- When I took the tank off, fuel came out of the pump outlet. It wasn't until I started to suspect a problem that I thought to check whether this was supposed to happen (I'd just treated it as annoying before). Turns out the answer is 'no'. More evidence for a leak between pump and outlet.

This was confirmed with the pump out by the fact I could blow in the outlet, and hear air escaping somewhere.

The pump assembly has two main parts, the pump unit itself, and the tank interface/mounting flange. These are both plastic and are just a snap fit together. The output from the pump has to flow from one to the other, and where it does, it is sealed with an O-ring.

When I dropped the tank, it dislodged the pump unit slightly. I actually found this out at the time, clipped them back together without removing the whole pump from the tank, and thought no more about it until today.

With the pump out, I separated the two parts, and found that the drop had also displaced the O-ring, such that it wasn't sealing. When I put it back together properly, and tried again to blow into the outlet, it wasn't possible.

Pump back in tank, tank back on, fuel in, thumbed the button, and it fired within a second or two and settled down into a stable idle.

:thumbsup[1]:


Moral of the story kids:

Don't drop your fuel tank. This particular episode of clumsiness has cost me...

- �63 ish for a new fuel hose
- �80 ish for a complete XTX throttle body from eBay (same fuel rail, so a better option than paying ~�220 for just the fuel rail from Yamaha)
- Two weeks of having to commute in the pickup, which uses over twice as much fuel and wastes at least half an hour a day in traffic.
- Going to the Dragon Rally, by a matter of a few hours. I could technically still go, but even if I left right now (which I can't, because I'd need to finish putting the bike together, not to mention packing) I still wouldn't quite make it there before dark.


On the bright side, I've not had to spend the truly ridiculous �715 :107: that Yamaha want for a new fuel pump.



Thanks to all who have contributed ideas to this thread (and GULGo and tripletom for helping out via PM and phone respectively)

Nice one - a happy ending!

Having a laugh - �715 for a fuel pump!?:smilielol:

Nice work mate.

i had that prob when I put the gilimoto tank on...
that little bit that catchs..push it down it will unclip from the pump
unplug the wires..drop it in the tank..remove the pump..then retreive the
bit in the tank... clip it back on the pump & wires... pump fits in with it on..
Well it did in the Gilimoto tank..

Nice one mate, pleased it's all sorted.