G650 XCountry Fuel Delivery

[TRforlife]

Good morning all. Recall, I am working to rescue this G650 XCountry from an abusive relationship as this bike was a storage auction purchase. This bike only has 11,000 miles on it and other wise pretty good shape.

 

Here is the issue. I have been through all the systems. I am getting spark as I have tested both coils and saw spark. The fuel injector was pulled and clean with carb cleaning a cycled a few times to demonstrate atomization.  But, I could not get the bike to fire on its own. I primed the throttle body and it kicked right off. After a few more primes, it would run on its own and pretty well. But, the next day, went to start the bike, and again, only starts with a prime of gas to the throttle body. Clearly not getting enough fuel delivered. Thoughts?  Thanks!

[dirtrider]

21 minutes ago, TRforlife said:

Good morning all. Recall, I am working to rescue this G650 XCountry from an abusive relationship as this bike was a storage auction purchase. This bike only has 11,000 miles on it and other wise pretty good shape.

 

Here is the issue. I have been through all the systems. I am getting spark as I have tested both coils and saw spark. The fuel injector was pulled and clean with carb cleaning a cycled a few times to demonstrate atomization.  But, I could not get the bike to fire on its own. I primed the throttle body and it kicked right off. After a few more primes, it would run on its own and pretty well. But, the next day, went to start the bike, and again, only starts with a prime of gas to the throttle body. Clearly not getting enough fuel delivered. Thoughts?  Thanks!

Morning   TRforlife

 

Lots of thoughts but without testing they are just thoughts.  

 

Low fuel pump pressure, enough fuel pressure would be something that needs to be verified. 

 

Low fuel flow (open circuit), enough fuel flow would be something that needs to be verified.

 

Low fuel pump voltage needs to be looked into. 

 

On the fuel control side, the fueling system needs to know that you are cold starting the engine so engine temperature (oil temp) & air intake air temp  needs to be looked at & be correct for engine starting. 

 

Throttle position input needs to be correct so that is something to verify.

 

Is the compression relief working correctly?  If the compression relief is sticking it might not allow full engine compression after enough RPM's are seen at/after starting attempt. 

 

Is the engine compression OK???? 

 

The fuel pump in the old 650 bikes were not anodized so those could cause issues after long storage with alcohol  containing gasoline. 

 

Check for air leaks in the intake.

 

 

 

 

[TRforlife]

I am not driving the bike as yet. And I tossed the dirty air intake filter. Would not having a air filter cause a lack of fuel issue?

[dirtrider]

39 minutes ago, TRforlife said:

I am not driving the bike as yet. And I tossed the dirty air intake filter. Would not having a air filter cause a lack of fuel issue?

Afternoon TRforlife

 

Not having an air filter element shouldn't make much difference (at least on face value anyhow).

 

Have you tired holding the throttle at about 1/8-1/4 throttle for starting? If that makes a difference then possibly your idle air control device is not functioning properly.  

[TRforlife]

Yes, I did do that as a natural instinct. I did pull the fuel pump out of the tank. I do not have a fuel pressure test gauge but thought that would be a worthwhile investment. So that is coming. This bike sat for quite some time in storage (A few years). And I noticed that the fuel pump mechanism has as a somewhat replaceable fuel filter, Mahle?  So, I did order one of those as I am sure standard ethanol fuel was left in the gas tank for that whole time. Thanks for your suggestions as I work through the investigation/diagnosis process. Much appreciated!

[TRforlife]

What should the fuel pump pressure be?  30-40lbs?  And it should hold that correct. Also, what is the health range for compression test pressure?

 

thanks!

 

Paul

 

[dirtrider]

2 hours ago, TRforlife said:

What should the fuel pump pressure be?  30-40lbs?  And it should hold that correct. Also, what is the health range for compression test pressure?

 

thanks!

 

Paul

 

Afternoon Paul 

 

My BMW manual shows the fuel pressure at 50.7 psi (+/- 2.5 psi).  It will probably start to bleed off a little pressure as soon as the ignition switch is turned off. I can't say how fast but as long as makes the 50.7 psi (+/- 2.5 psi) during engine cranking & engine running you are OK. 

[TRforlife]

Ok, my compression test comes out at 125lbs. The fuel pump tests at 50lbs but drops to 10lbs or less very quickly after stopping the cranking. 

Anything odd about either of these tests?

 

[TRforlife]

Ok, as I continue to play with this fuel pump. I turn the ignition on, the needle on the pressure gauge goes to 12 and drops.  I immediately turn ignition off and back on and the needle goes to 30 and pressure and the begins to drop. I do this a third time and the need goes to 50 and begins to drop despite leaving ignition on. What the heck causes this build in pressure with each switch of the ignition. Could it be the filter is so plugged that it can’t build pressure until the third try?  

[dirtrider]

29 minutes ago, TRforlife said:

Ok, as I continue to play with this fuel pump. I turn the ignition on, the needle on the pressure gauge goes to 12 and drops.  I immediately turn ignition off and back on and the needle goes to 30 and pressure and the begins to drop. I do this a third time and the need goes to 50 and begins to drop despite leaving ignition on. What the heck causes this build in pressure with each switch of the ignition. Could it be the filter is so plugged that it can’t build pressure until the third try?  

Evening  TRforlife

 

That is good question?

 

It does sound like some sort of fuel flow blockage or something wrong with the fuel pump, or even a plugged pump intake screen.

 

Will it start right after the 3rd key-ON at 50 psi?

[TRforlife]

The fuel flow test, I captured about 50mls with three fuel pump cycles. Shouldn’t this be closer to 125ml? 

[dirtrider]

12 hours ago, TRforlife said:

The fuel flow test, I captured about 50mls with three fuel pump cycles. Shouldn’t this be closer to 125ml? 

Morning Paul

 

Darn good question, my BMW service manual doesn't show the liters per hour. (at least that I could easily find) 

 

I do show the 1200GS at 90 to 130 liters per hour. That is a twin cylinder so cut that in half & you end up at 45 to 65 liters per hour.  Kind of a different animal but it still requires X amount of fuel per cylinder per hour.