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2001 Classic 1500 Fuel Pump Relay and Overheating

8K views 13 replies 2 participants last post by  boogeyman 
#1 ·
Hello everyone,
I was wondering if anyone knows if the ECU regulates the fuel to the engine while it's running?
There's a problem with the ignition switch. When I turn on the key, the pump does not hum.
I have to make and break the power to the relay for the pump to respond and turn on. (with a jumper wire to battery) After starting, it runs normally but it's receiving constant 12v as it's connected directly to power.

Is there a wire from the ignition switch to the ecu and then one from ecu to fuel pump relay that turns on pump and then turns the pump off and on during running? Or is it just a constant 12v also when working properly? Could that connection be severed somewhere? I did blow the main fuse awhile back and am concerned that I may have caused some other damage somehow.
Could this be why the bike is overheating? Is the pump sending to much fuel to the engine? It wants to stall and backfires often, otherwise, runs ok. Acceleration is very strong.
There is no smoke or steam from the exhaust. I've flushed the coolant system and added Prestone still overheats. I've also removed the thermostat.. runs a bit cooler, but still gets very hot.
The fan is always turning on. Even while moving.

I'm suspecting a leaky head gasket, but as I stated there is no signs of burning coolant, and the level stays the same apparently.
The idle adjustment came clean off for some reason.. i turned it out too far. Now I can't get it back in! It seems to be stuck when I try to screw it in and won't go in very far.. therefore I cannot adjust the idle.. It just idles a bit lower than it normally does and stalls a bit easier, but otherwise idles ok and runs ok.

Thanks in advance for your help!
 
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#3 ·
I never said I had the problem licked.
I said that if I suspect a part of failing I'm going to replace it.

I suspected the relay was bad so I replaced it with a new one, it turns out that it WAS bad.
So I guess replacing it was a good idea, because now that I've done that, I've determined that the switch to it isn't working for some reason.
If I hadn't replaced that relay, I'd still be at square one.

But thanks for checking in! I appreciate it!
 
#4 ·
1. Ecu controls fuel to engine via fuel injectors.
2. Pump is not turned on and off during running.
3. If upon key on, fuel pump does not run, that is the first problem to address.
4. If you wish to troubleshoot the issue, I might be able to help.
5. What are the wire colors you jumper to force the pump on?
6. Do you have a meter and know how to use it? If not, we can help there too.
 
#5 ·
I really appreciate any advice sfair. You've always been a great resource. Thank you.

Pump does not turn on upon key on. I have to use the old relay which I assume is shorted inside. This allows the pump to be powered up by making/breaking the relay connection a few times.
Or plugging it in immediately after key on, then jigging the starter button a few times. Then the pump powers up.

If I use the new relay, this method does not work. In fact, I cannot get the pump to power up using the new relay at all. I think that's because of a burnt connection somewhere between the relay and the ignition switch.

I'll have to get the wire colours, but I just jump pins 3 and 4 on the relay. This allows current to flow to the pump. I suspect this is what the relay does when working properly and the key is turned on. But pins 2 and 3 are not getting the signal to switch on the other pins 3 and 4.

The burnt relay must have pins 3 and 4 fused together within. This is why I can use it to power the pump without having to use the key. I do however, have to unplug the relay when I park the bike or a dead battery will be the result if I don't.

By the way, the FI light goes on and off as per normal.. so the ECU is not detecting an issue with the DFI system. (as per the Service Manual)

I use a meter regularly.

Again, any advice would be greatly appreciated.

There's also the overheating issue.. not sure if this is connected somehow...
 
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