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Discussion Starter #1 (Edited)
Edit: Does anyone have the part number off of the "triumph" branded pump? I saw that a denso 38mm should work but would prefer to find the OE supplier.

I'm diagnosing a crank but no-start no prime issue on my 01'.. If someone could give me voltage across the pump plug leads with key on it'd be much appreciated. I'm seeing 24v.
 

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Discussion Starter #3
I'm should be 12v so not sure how you're getting double that! Have you connected the fuel pump direct to the battery to see if it runs?
Good call, I'll give that a go. A dry rotted pump plate gasket is making me hesitant to just pull it but I'll pull the return line and see what happens.
 

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Discussion Starter #4
My meter was working wrong, it's supplying 12v. Pump is fried. Does anyone know the OE part #/supplier?
 

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The fuel pump is T1240845 but they're very expensive to buy new so I'd go second hand personally. There are alternatives, I identified a list a while ago when I was having starting issues. See here.
 

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Discussion Starter #6
The fuel pump is T1240845 but they're very expensive to buy new so I'd go second hand personally. There are alternatives, I identified a list a while ago when I was having starting issues. See here.
Pump is whirring away happily on battery power. It appears that it isn't being told to turn on which is confusing given voltage at the plug. Is this potentially an ECU issue?

The bike worked when last parked, I've only swapped the bars since last start.
 

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As you can see the fuel pump is powered w/ the same line as the plugs coils. All of them being powered through relay 33 (fuel pump relay) and fuse 8.
The relay command is grounded by the ECU and powered through pin 1 of the alarm blank off connector which also powers the starter slenoid via the start button.
So as your starter is operating normally, this line receives the power.
You may check:
1-whether the relay coil is powered (receiving the 12V). If not check the line and relay connector.
2-whether the relay coil is grounded during the time the pump is supposed to be primed (at the turn key). You may just connect your multimeter on both end of the relay coil. If not there might be a corroded ECU pin or corroded relay socket.
3-check whether the fuel pump relay is operating normally (clicking). If not the relay might be shot.
4-check whether you get 12V at the relay contact on the fuse side. If not you might have a bad fuse or a corroded fuse holder or a bad line or a corroded relay socket.
5-check whether you get 12V at the relay contact on the fuel pump side. If not the relay is shot.
6-check whether the plug coils have the 12V. If not the relay socket might be corroded or you have a bad line between the relay and the coils/pump.
7-check whether the pump is grounded correctly (one multimeter pin on the pump ground and the other on the battery +). If not you got a bad ground. Check the ground line for continuity.
8-check that the pump is powered (we know it's not the case). At this stage you either got a bad line or a bad pump connector.

All the checking performed in this very order. Each time you find a problem, fix it and try to prime the pump. If not priming, continue w/ the next step.
 

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Discussion Starter #11
As you can see the fuel pump is powered w/ the same line as the plugs coils. All of them being powered through relay 33 (fuel pump relay) and fuse 8.
The relay command is grounded by the ECU and powered through pin 1 of the alarm blank off connector which also powers the starter slenoid via the start button.
So as your starter is operating normally, this line receives the power.
You may check:
1-whether the relay coil is powered (receiving the 12V). If not check the line and relay connector.
2-whether the relay coil is grounded during the time the pump is supposed to be primed (at the turn key). You may just connect your multimeter on both end of the relay coil. If not there might be a corroded ECU pin or corroded relay socket.
3-check whether the fuel pump relay is operating normally (clicking). If not the relay might be shot.
4-check whether you get 12V at the relay contact on the fuse side. If not you might have a bad fuse or a corroded fuse holder or a bad line or a corroded relay socket.
5-check whether you get 12V at the relay contact on the fuel pump side. If not the relay is shot.
6-check whether the plug coils have the 12V. If not the relay socket might be corroded or you have a bad line between the relay and the coils/pump.
7-check whether the pump is grounded correctly (one multimeter pin on the pump ground and the other on the battery +). If not you got a bad ground. Check the ground line for continuity.
8-check that the pump is powered (we know it's not the case). At this stage you either got a bad line or a bad pump connector.

All the checking performed in this very order. Each time you find a problem, fix it and try to prime the pump. If not priming, continue w/ the next step.

Which relay here should I be looking at? My wiring doesn't seem to line up with the schematic and it also doesn't match the plug wire colors.

Thanks for all the help! I am very new to diagnosing electrical.

relays.jpg fuel connector.jpg
 

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The wiring is different on the 00/01 955 speeds so those schematics aren't relevant, sorry Fred. There's no fuel pump or fan relays, both are switched directly by the ECU.

That reminds me, because of the lack of relays the transistors doing the switching inside the ECU can fail due to the large current. This locks the pump or fan either on or off, but it should throw an error code if this happened. The fuel pump switching on my ECU recently failed "on" so the fuel pump ran permanently as long as the ignition is on, the bike was unaffected apart from the fault code.

Is your check engine light on?

I'm not an expert on electrics, but if the fuel pump is ground switched by the ECU and the transistor has failed "off" then you would see 12v at the plug but the pump won't run. If this is the case you would need to replace the ECU.

Here's a diagram for which relay is which from where they are mounted on the bike.

Relays.png
 

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Discussion Starter #13
So I'm looking at a fuse, wiring fault, or ECU? I ordered an OBD-USB cord that should be here in a couple days.

Per Decosse in post #5 of this thread: Fuel pump not priming on '01 Sprint ST

I've tested fuel connector positive to bat- which results in ~10.5V (battery at 11.7 currently) for as long as the kill switch is in "on." The negative (ECU controlled) to bat+ gives battery voltage as long as the kill switch is "on."
 

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Here's the correct wiring diagrams from my service manual. I'm not good at electrics so I can't really help much further sorry

EDIT: good find on that post you linked. I'm pretty sure the ground switching D'Ecosse describes applies to your bike. From reading his post it looks like your positive side is working normally, but something is wrong with the negative as it should only give a reading for 3 seconds. Apologies for stupid question but are you 100% sure you had the polarities the right way round (fuel pump plug "+" to battery "-" , fuel pump plug "-" to battery "+")?

I think it's not a fuse, as there isn't a fuel pump specific fuse so loads of other stuff wouldn't be working. I reckon it's your ECU.
 

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@Rampant: Thanks for the diagram. So it's very similar to the 2000 955 sprint gen1. And there is no relay. The pump power line is shared by the speedo and fuel gauge. Is the fuel gauge OK (didn't know there is a fuel gauge on the S3).
I've tested fuel connector positive to bat- which results in ~10.5V (battery at 11.7 currently) for as long as the kill switch is in "on." The negative (ECU controlled) to bat+ gives battery voltage as long as the kill switch is "on."
So while the pump is not running you get 10.5V at the pump while the battery is 11.7V. So there is a problem here. As there is NO current flowing through the pump you should have the exact same voltage at the pump +. It may be that there is a corroded pin inside a "engine connector". Isn't it known to cause problem?
Could you plug a wire directly from the fuse 5 to the pump + and see if it's priming?

As Rampant wrote the pump ground is switched directly by the ECU pin 1/H1 (H1 of the first ECU connector). So putting the - pin of the multimeter on the pump - (while still connected) and the + pin of the multimeter on the battery + should indicate whether the ECU is switching the pump ground or not. If yes you should read the battery voltage just after turning the key on (while supposed to be priming).
If not it can be the power transistor inside the ECU or a corroded pin in the ECU connector. That said there probably is an additional logic that allow or not the pump to be primed. I still have to dig on that point.
 

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No worries Fred :) it's not a fuel gauge on the gen 1 955 Speeds, just a low fuel sensor FYI. None of the fancy fuel gauges like you Sprint lot have lol
 

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Discussion Starter #19
Do either of you know if I could use an 01' sprint ECU in my 01' Speedy if I load a new tune?

I'm still figuring out how to get tuneECU to connect, but with the diagnosis I've done I'm fairly confident it's the ECU and there's a cheap one from a Sprint for sale right now.
 
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