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Old 10-14-2012, 01:30 PM   #5982
DirtJack's Avatar
Joined: Aug 2007
Location: San Antonio, Texas
Oddometer: 1,607
Originally Posted by nippybit View Post
Dave and I just spoke and he confirmed what I thought which is that the armature is turning at one speed. Power goes to the pump through the brushes and then to the commutator which causes the armature to rotate thereby driving the pump. Given this, it is not like the armature has to struggle to deal with various loads, it simply turns at a consistent speed. We are studying the pressure regulator which we believe has a mechanical mechanism and is connected to the ECU so that the ECU can see if it is regulating pressure, however the ECU does not provide power to it. More to come on this.

While my new pump has seemingly fixed the problem it may occur again. As you know, a number of posters here have had multiple pumps, which is frightening as you don't know if you can trust your ride off-road, it is damn expensive, and it shouldn't be happening. I had a 2005 BMW GS (FI with a submersible pump and filter) and I put about 28,000 miles on it without even the hint of a problem. I am hopeful that we find something other than the pump as the cause of the problem.

Sorry for the delayed response as I was riding in the Lincoln National forest (NM) last week. I had one of the early threads about the 690 fuel pump issues. My my fuel pump problem seems to have been solved by installing a CA Cycleworks pump. My fuel pump stoppages occurred at all temperatures and altitudes and were very intermittent, sometimes running perfectly for more than 500 miles. It never left me stranded and would always eventually start running again. The first time it happened, I nearly ran down the battery trying to restart. I later learned that it would not start until the fuel pump prime sequence occurs (which you can hear when you turn the key on). Just wait till you hear the prime, then it would start. The pressure regulator is a passive pressure relief valve which is not connected to the ECU. It returns excess fuel to the plastic pump housing for cooling purposes. There is (from the 690 wiring diagrams) one connection of fuel pump power to the ECU to switch/prime the fuel pump. I do not believe there is any other relationship between the ECU and fuel pump other than turning it off/on/prime. The TuneECU folks tell us the ECU must be reset before the 15 minute idle and throttle calibration are meaningful. There is a TuneECU switch for this as well as an automatic reset when loading a new map. Disconnecting the battery may also do a reset. The ECU (from the 690 wiring diagrams) have connections to the following devices:

Lambda sensor
Front wheel speed sensor
Evap valve
SAS valve
Ignition coil
Combo instrument
Throttle position sensor
Intake air temp sensor
rollover sensor
side stand sensor
Accelerator position sensor
Ambient air pressure sensor
Engine coolant temp sensor
fuel level indicator
crank position sensor
clutch switch
Manifold absolute pressure sensor
map select switch

I have not yet disassembled my OEM fuel pump but I'm guessing it will look ok like yours did. It is possible that the ECU is turning the pump off because of some software glitch (I know something about computer science, being a retired CS prof) but, if so, it doesn't seem to happen anymore to the bikes which are running the CA Cycleworks pump. So the mystery continues, but I'm happy my bike runs like gangbusters. I actually trust it again (which is easier for me to do because mine never left me -- just slowed me down)
Remember, you're reading this on the Internet and it was written by a guy who can remember stuff which never happened.
2014 KTM 1190 Adventure R
2008 KTM 300 XC (plated)
2008 KTM 690 Enduro

DirtJack screwed with this post 10-15-2012 at 04:53 PM
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