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GS won't run after fuel pump change


blaisew

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Replaced the fuel pump on a friends GS. Pump kit from Beemer Boneyard. Install went well, careful on line connection. Bike started and ran for maybe two minutes but quit and will not fire now. Pump primes, and fuel flow out of return (and supply, of course)and electrical connection to wire harness appears good. Used die electric grease on it. Pulled an injector and no spray when hitting the start button. Bike ran from Houston to Tucson before working on the pump. It was making quite a racket on the trip, hence the change. What would be preventing the injectors from? We did do a canisterectomy but didn't fool with any other wiring. Any clues? Bike is a 2001 GS with ABS

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roger 04 rt

Since you get fuel from the return line, you've got enough fuel and enough pressure to run the bike.

 

Sounds like the Motronic isn't getting power from the Motronic relay. You could swap it with the horn relay.

 

Is your RID coming on with key on?

 

Have you tried starting it with the side stand up and the clutch pulled in?

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Replaced the fuel pump on a friends GS. Pump kit from Beemer Boneyard. Install went well, careful on line connection. Bike started and ran for maybe two minutes but quit and will not fire now. Pump primes, and fuel flow out of return (and supply, of course)and electrical connection to wire harness appears good. Used die electric grease on it. Pulled an injector and no spray when hitting the start button. Bike ran from Houston to Tucson before working on the pump. It was making quite a racket on the trip, hence the change. What would be preventing the injectors from? We did do a canisterectomy but didn't fool with any other wiring. Any clues? Bike is a 2001 GS with ABS

 

Evening blaisew

 

If the pump primes then it sounds like the Motronic is energizing the fuel pump relay (so at least that part is/was working)

 

Does it have spark??????

 

If it has spark then MAKE DARN SURE THAT BOTH quick disconnects are FULLY pushed together (only if the bike has had quick disconnects added to the fuel lines)

 

Does the green wire going to the fuel injectors have power while cranking? If so then put a 12v test light across one of the injector plugs & see if it flashes in time with engine cranking speed.

 

Did you plug the fuel lines when removing the tank? If so did you (for sure) remove the plugs (I chased one around a few years ago where one of the fuel line plugs was not removed & worked it's way into the line.

 

If no spark then suspect an HES problem, could still be an HES issue even with spark but far less likely.

 

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Neither pin on the injector plug shows power when cranking, and I can't see any spark either. Dead! I also swapped the motronic relay and the horn relay. Hmmmmm

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Afternoon blaisew

 

Only the green wire at the injectors should have power while cranking, the other terminal gets flashed to low (ground) to make the injector inject.

 

OK, no power at the injectors is usually the KILL SWITCH being turned off, or the side stand being down (or switch broken/disconnected), or broken red or green wire at the ign switch or main harness by the steering head, or fuel pump relay not working.

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Swapped the horn and fuel relay, no change. Sidestand up, but would that make a difference? It runs up or down, right? Just won't run if going into gear. Wiring and switches look good but we didn't take anything apart. It has to be something stupid that I/we did but can't figure what it would be. Looks like we may have to take it to the local dealer, who is good. Frustrating! We also removed the quick disconnects and ran the fuel lines direct just to eliminate that possible issue. Grrrrr

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I wish! Step no. 1 was to check all the fuses. I keep wondering if I did something wrong inside the tank, but if we have fuel flow and all sounds normal that doesn't seem likely. There is a "safety valve" on the fuel fill and the fuel fill was removed, installed backward, and then re-aligned. It doesn't look to be wired to anything though so even if it was screwed with in the turning it wouldn't hurt, would it? I just don't understand why the bike would start, then shut down without something, somewhere, being disturbed. The owner did wrap the wires all around where the old protective plastic had deteriorated, but nothing was cut, etc.

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Evening blaisew

 

Lets go back to square one & start over just to be sure ALL bases are covered with nothing missed.

 

On the fuses--how did you check them?, visually or with a meter? If visually then go back & use a test light or meter as sometimes that look good but are open inside.

 

Does it still start then die or not start at all now??????

 

Are you sure the green wires at the fuel injectors have power --for a couple of seconds at first key on, during engine cranking. If no power at the green injector wires during engine cranking then that is probably the place to look for the problem.

 

You need to see full time 12v B+ at terminal 30 of the fuel pump relay, need to see key-on power to terminal 86 of fuel pump relay, terminal 85 pulled to ground during engine cranking & running, if you jumper 30 to 87 that should run fuel pump full time & keep green injector wires at 12v all the time.

 

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Excellent, now that gives me something to work with. I checked the fuses with my mult-meter so the are OK. Bike won't run at all now. Can't tell which wire is green at the injector as I was afraid to pry off the rubber grommet. It seemed pretty well attached. Cut the wrap to peek? I will see if I can find the various terminals and check voltages. Thanks so much!

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Evening blaisew

 

I'm gone for the rest of the night so if you need more help tonight then someone else will have to step in here.

 

If not I will be back on-line tomorrow morning.

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OK, T86 has full time power. T30 to 87 runs the pump. Measured with relay out. Voltage at the green wire of injector connector is .9 V or so when cranking.

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roger 04 rt

Notice on the schematic that there are 5 possible points to measure the fuel pump relay output:

 

-at the fuel pump connector

-at each injector (2)

-at the lambda sensor heater

-at the canister purge solenoid

 

If you install a jumper in place of the fuel pump relay you should measure +12 at each of those 5 places.

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OK, T86 has full time power. T30 to 87 runs the pump. Measured with relay out. Voltage at the green wire of injector connector is .9 V or so when cranking.

 

Morning blaisew

 

What is the voltage at the green injector wire with T30 jumped to T87 (relay removed)? Are you measuring the voltage from the green injector wire to chassis GROUND (clean connection)? That .9v sort of sounds like you are measuring ACROSS the injector connector.

 

We're still missing something here so we need to get on the same page.

 

I'm still not sure if the fuel pump circuit is your problem but we need to verify the fuel pump/injector circuit is working before we move on to the HES or other circuits.

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Waking up here.... I could probably do better on the injector voltage check. I was measuring to chassis ground but perhaps not completely clean as the voltage was jumping around a bit. Breakfast first and then we'll get back on it, plus check voltage with the jumper in. Terrific help on this site and thanks to all!

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Afternoon blaisew

 

See if it will start & run with the 30/87 jumper in place. If it starts & runs & doesn't stall then we will go back over the relay part.

 

If it still doesn't start & run then check for a (good) spark again (you need to see a snappy bluish spark across a 3/16" spark plug electrode gap. Take an old (known good) spark plug (doesn't have to be for that bike) & open the electrode gap to about 3/16". Then plug that (special plug) into one of the spark plug wires & lay it on the engine or frame.

 

Leave both original plugs in the engine then remove the plug wire on one side (ONLY) for the spark test.

 

If it has a good spark then re-run the fuel return flow test with jumper between 30/87.

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Will not start with jumper. Checked again for spark and no joy. Pulled the plugs, bike in high gear, ignition on, turned the wheel and no pump activation. HES failure?

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Will not start with jumper. Checked again for spark and no joy. Pulled the plugs, bike in high gear, ignition on, turned the wheel and no pump activation. HES failure?

 

Afternoon blaisew

 

 

No spark does point to HES (or even ign coil power issues).

 

For this (turned the wheel/engine and no pump activation) to show HES issues the fuel pump relay must be reinstalled. Did you do the test with the fuel pump relay installed?

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Yes indeed, relay was installed. Is there any trick to installing the HES plate? Alignment, timing, etc.? Any easy way to check the sensors? I read about an led and a 1K ohm resistor somewhere.

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Yes indeed, relay was installed. Is there any trick to installing the HES plate? Alignment, timing, etc.?

 

Afternoon blaisew

 

No real tricks, just bolt it on the check ign timing using a timing box or timing light, or some use the fuel pump ON trigger.

 

About any install timing will allow it to at least start & run.

 

 

Biggest got-ya is the timing cup behind the pulley. That needs to be re-glued to the pulley if it has broken free upon removal.

 

If careful you can re-install without re-gluing but there is the chance that the little tit will not stay in the crankshaft slot & if it slips the timing will be WAY off. (should still get spark just not close enough to run the engine)

 

Other thing I have seen a few times is one of the HES connector pins gets pushed back (loses contact) into the connector when pushing the connectors together.

 

Usual problem with the HES is the wiring insulation breaks down (especially 1100's) so it then fails to provide a proper signal to the Motronic.

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Thanks! I think we may take the easy way out and just get the dealer to do it. 'Just a matter of time. At least we know what the problem is now. If you are ever passing thru Tucson you've got a place to crash!

 

Ken

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Afternoon Ken

 

That is the easy way but you will pay dearly to have it done at the dealer (both parts & labor).

 

Not that bad of a job at home.

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Agreed. Very easy job. When I replaced my HES plate, I made a scratch mark on the plate and on the engine, then transferred (using my calibrated eyeball) the mark from the old plate to the new plate. I never checked the timing afterward, and that was about 90,000 miles ago.

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Follow-up on my post. Easy way complete, and it WAS the HES. While the tech was in there he discovered some tiny gravel in the pulley grooves that was causing the (new) belt to slip and squeak. This stuff was packed into the small gallery behind the lower pulley. All clean now.

 

As a matter of interest, this bike has been sitting for a while, ridden sparingly. On the way here my buddie's bike developed a fuel pump noise (loud), blew one of the front brake lines, and must have gotten here on a wing and a prayer with the HES on the way out. It only ran for about three minutes after arriving before failing. Pump replaced, brake lines replaced. All good now! Gotta keep up with the maintenance.

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