Fuel Injection Experts Required........ Please

[Ginger Bear]

Right then, had a bit of trouble with the 'Snotter' (GPz1100A2) on the way home from the Ace this Sunday. (Had a bit of trouble on the way there, but that's another story!)
The bike got very hot, stuck in traffic on the north circular, I stopped for some oil, just before I got on the A4/M4 (That's the other story!). I don't know if getting hot is connected or not.
Got on the M4, elevated section no problem (40MPH), then got to the end of that & wound the bike up to about 75, all was well for a while, then the bike started to die, just like it would as if it had ran out of fuel. I switched to reserve, but no difference, I had a tank full of fuel, but thought the main feed may be blocked. I also opened the fuel cap incase it was a breather problem, but it wasn't.
I ended up travelling back at 60MPH, on a very partial trotttle opening, try any more for any length of time & it would just die. I am convinced it is a fuel starvation problem. A couple of hours after getting home, I went to have a look. The fuel pump seemed to make a very 'dry' noise, & the fuel filter was only half full. I have been back out tonight & hey presto, all back to normal
I think the problem lies with the fuel pump, or maybe the fuel regulator. But any input would be gratefully received.

[Pigford]

Sure its not just crud in the fuel tank/tap/line/filter

[Ginger Bear]

Deffo, sure. Tank is spotless (see 'Snotter' thread), fuel tap has been ultrasonically cleaned & is spotless. I did think sat on the M4 it might be filter, but they are clear & doesn't look too bad.

[paul doran]

fuel starvation is the problem

how low did you let the tank get

[Pasc]

Bear, when you say you went back out and it was normal do you mean you took the bike out and up to the same speeds you had trouble at and all was ok? Also, when the fault arises does the bike die completely or does the engine pick up at all when you reduce throttle ?

[Ginger Bear]

Pasc,
when I said all was back to normal, it was stationary. The fuel pump sounded normal & the fuel filter was full. I removed the return pipe to the fuel tank & it would flow fuel very well for about 6 seconds, then switch off. I guess the regulator controls this. This is how it all worked before the problem. I am wondering if the pump had problems because of the heat, or the regulator is at fault, again because of the heat.

[kano]

i haven't run injection for yrs but i used to pop off air filter and push open the flap in the air temp sensor and if i heard the fuel pump wiring as normal all was good there.
there are 2 lights on the left side of the throttle body the mean something check your manual.
last thought do you think your coils got too hot?

[Pasc]

It doesn't matter if the fuel filter is only half full. I've had several 750 Turbos and whilst the DFI system is very similar it's not identical but fuel level in the filter will fluctuate.
The pump will run for a few seconds when you turn on the ignition to prime the system but will run pretty much constantly when the engine is running.
If you think it feels like fuel starvation try dissasembling the fuel cap. There is a channel running through the alloy casting that fastens to the cap outer which can become corroded and block up.
One other thing to check out easily is the ecu under the tailpiece. I'm certain it is a similar unit to the 750. Remove the seat and next to the large harness connector there should be a small LED. While watching the led switch on the ignition (no need to start the engine). The led should blink once which is basically an ECU self test. If it flashes more than once then its a DFI fault code which you can diagnose with the manual.
Does the bike just die like it was running out of juice or does different throttle positions improve it ?

[Ginger Bear]

Tried running with the fuel cap undone.... No change
Had read about the ECU diagnostic LED & it only blinks once when ignition is switched on.
Bike does die, like it's running out of juice & different throttle positions didn't seem to make much difference (except closed). The annoying thing is, it probably won't happen again till the bike is really hot/miles from home.
The fuel pump sounded like it was struggling/full of air when I got back. This leads me to suspect the pump, or the supply to it. I will replace the filter & the fuel lines, maybe one has collapsed when hot? That would be a simple fix.
I also have spare parts I can substitute. I may try another pump.
Thanks for your help so far!

[ARCHIE]

Hello mate i had something similar with my H and i don't know how close to my bike is to yours but my engine temp sensor had a dodgy connection which would make the bike run as if it was cold all the time and also took apart the air flow regulator and re-sealed it. Checked for any connections that needed replacing and also ran some Redex through the injection system.
Hope this is some help, Archie