Wildguzzi.com
General Category => General Discussion => Topic started by: joyinthecenter on April 12, 2025, 05:49:25 PM
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Out for a short ride and it stalled in traffic and wouldn't restart. I found the fuel pump fuze blown (10amp), replaced that and the fuel relay which looked pretty gnarly. Still won't start. Cranks find and turns over, but there are no sounds of the fuel pump doing the usual priming. Can someone point me to how I can diagnose if it is the fuel pump that needs replacing or if it's something else? I'm game to tear things apart, but I could do with some guidance as I'm not versed in this area.
Thanks!
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Could be the fuel line turned to mush and disconnected from the pump. If you have a full tank of gas, open up the cap and try to start it. If you see the gas swirling around, that’s what happened. Or pull the pump and inspect. Fun job…
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Also check the side stand switch, it follows up the LH front down tube on frame and goes to a safety relay. It is for idiot switches to go to. Gives issues like you got.
12V battery hot wire to starter solenoid wire it will go, make sure key is on.
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Don't waste your time cranking if you don't hear the fuel pump sounds.
Problem is still back with the fuse or relay. You used the correct relay?
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The crank sensor probably failed,l had that happen on a California and an EV.
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Is there a way to confirm if it’s the crank sensor? I put in a new relay and that didn’t do the trick.
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Could always throw a meter on fuel pump leads and see if they are receiving power with KEY ON.
If yes then pump issue.
If no then electrical.
I'm assuming the big red switch is working.
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I guess tomorrow’s the day I learn to use my multimeter!
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Is there a way to confirm if it’s the crank sensor? I put in a new relay and that didn’t do the trick.
I think the fuel pump still runs if the crank sensor is bad. There will be no spark and no fuel if the sensor is bad.
Side stand switch and run switch are good things to check. Did the fuse replacement blow again?
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I would try a good crank sensor or buy one,it is good to have a spare even if you don’t need it now.
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If the crank sensor is bad, the EV pump should still prime. So not likely to be that.
If the side stand switch or engine kill switch failed, the EV will not crank. So not likely to be that.
You mentioned the fuel pump fuse popped. I would look for power at the pump for a few seconds with the key first on and priming. Maybe the pump failed.
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Like Wayne said, everything will work, it won’t start if the crank sensor is kaput. Search on this site on replacement. The sensor is shimmed at a specific depth and if you put a drop of quick set JBWELD on the end of the new sensor and let it set you then remove the sensor and cut the drop with a razor you can measure the gap to the phonic wheel. Residual oil acts as a mold release so there is no cleanup inside the engine.
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Like Wayne said, everything will work, it won’t start if the crank sensor is kaput. Search on this site on replacement. The sensor is shimmed at a specific depth and if you put a drop of quick set JBWELD on the end of the new sensor and let it set you then remove the sensor and cut the drop with a razor you can measure the gap to the phonic wheel. Residual oil acts as a mold release so there is no cleanup inside the engine.
But he gets no fuel pump sound when turning on the key. That is not the sensor, right.
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But he gets no fuel pump sound when turning on the key. That is not the sensor, right.
Yep, I thought he said the pump worked. :embarrassed:
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No fuel pump sounds.
I’ll take off the tank this week and see if there’s voltage getting to the pump.
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Here is the schematic
http://www.thisoldtractor.com/guzzi007/schematics/2004_EV_Catalytic.gif
You can try jumping out the ECU power relay (50) relay 30 -87 the pump should run
You can also attach a small lamp to the relay coil pins 85 & 86 to see if the relay gets energized for the initial priming period
This initial pump priming should happen without the engine turning over (no timing sensor input), just as the ECU gets power.
When you crank the bike the timing sensor (56) generates low voltage pulses, the ECU turns on the power relay again to run the pump then it fires the injectors and sparks at the correct time.
There is a 2 pin AMP connector (60) under the tank somewhere, pin 1 should be alive with the key On, pin 2 should be grounded out with the side stand retracted.
The fuse that was blown F6 or F7?, I once had the safety diode go open, I have no idea why.
Reading the post I also thought maybe timing sensor but even if its bad you will still get the initial pump priming when you turn the key from Off to On
Here's a link to the manual for an earlier ECU, it has a lot of useful information e.g. Sensor gap
http://www.dpguzzi.com/efiman.pdf
I use the quick setting epoxy method to check the gap as per John A's post earlier the gap is 0.6 - 1.2mm Page 13 of the Efiman document.
The sensor is a tiny magnet with a coil wound over it, as a tooth of the sonic wheel passes it generates a tiny AC waveform which the ECU uses as a timing pulse.
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Has anyone heard how joyinthecenter is doing with his EV?
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I've been busy the past few days, so I haven't had a chance to try folks suggestions. Friday should be a go for getting back to it.
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You can test the fuel pump after wrestling it out of the tank.
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Someone said that was an outside pump. If so the connector is available under left side cover. Testing can be done by pulling connector without having to dig the pump out.
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I’ve only heard of early ‘03’s having an external pump. Later ‘03’s and ‘04 and on are IN the tank.
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After removing the tank, I discovered a few things. One, the wiring on the whole bike looks very rough. Like new wiring harness territory. Two, the fuel lines are crumbling and need replacement. Three, I need to spend some time learning how to use a multimeter because that was a disaster.
I've managed to get the fuel pump assembly out of the tank as I'm sure it needs a new filter no matter what. The fuel level sensor was dislodged from its proper home, and the wire has a bad kink in it that likely is bad news. This bike has a long journey ahead before I can get it back on the road. I was planning to do a full tear down and turn it into a show project, this just pushes up the timeline for starting that journey.
(https://i.ibb.co/p6VyWmmB/F512-AB7-E-6-F8-D-4230-9-E1-D-FE66-AA887-A68-1-105-c.jpg) (https://ibb.co/p6VyWmmB)
(https://i.ibb.co/PGZFC4BV/0-CA7967-A-FCBA-40-D8-9-D16-16-F052-EC124-E.jpg) (https://ibb.co/PGZFC4BV)
(https://i.ibb.co/7dWJnpHg/5598-D81-E-C44-E-48-D2-9-CB5-BB574-E1-F74-B9.jpg) (https://ibb.co/7dWJnpHg)
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It looks like the fuel line from the pump to the filter was replaced. That was a common thing to pop off in those years.
If the filter was loose, it broke off the level sensor, which it looks like happened. That steel rod can be repaired so don't get too crazy cutting it away.