Fuse blowing and high coolant temp after service.

Hey all. So here's the skinny. My frustration is beyond maxed out and I need help. I have a 2016 RC390 with just about 3K miles. It is a track only set up. The water pump gasket went out about two months ago and I got it fixed at the dealer under warranty. I took the bike to the track the next week and it started popping the 15 amp fuse that covers the starter/fuel pump and I get a high coolant temperature warning. I took the bike back to the dealer and they couldn't replicate it and left it at that. I got the bike back on the track, it still does the same thing even after going over every inch of wiring and connectors. The nearest dealers are 5 and 6 hours away.

Here's what always happens:
My warm up sessions always go fine. I can do about 8-10 laps at a very mellow pace and nothing goes wrong. Once I start to turn up the speed a bit, it blows the fuse. It's always the same fuze. I get about 4 hard laps in before I pop the same fuse. I don't get any error codes.

Mods are Power Commander V, flashed AKRA ECU, Akra pipe, Lithium battery, air filter, removed the ABS, Removed charcoal canister, SPAL fan, Samco hoses, dropped all street trim, no headlights, turn signals, etc.

I have seen a few threads that started to talk about this problem, but there have been no solutions. Any help is welcome.
 

simpletty

Member
Country flag
More than likely fuel pump issue. Looks like there are a couple relays powered one for the fuel pump and the other is the power relay. Try pulling the power relay out and see if it gets that high temp warning to show up. I have a feeling that the fuel pump is on the way out, higher demand at a faster pace, probably is drawing more amps than the fuse can hold at one point and once it cools off again, and the fuse is replaced all is well until the next hard run. I dont see the starter on that circuit anywhere btw. You could hook up a meter to the circuit and measure the amperage draw if you really wanted to but its probably a bit difficult at race pace....find a used pump on ebay or buy a new one. Also have a look at your fuel filter and make sure its not plugged up causing the pump to work harder than necessary as well..

FUEL PUMP
90807088000
[FONT=&quot]$330.69[/FONT]
[FONT=&quot]


[/FONT]
[FONT=&quot]FUEL FILTER
$16.99​
[/FONT]

[FONT=&quot][/FONT]
[FONT=&quot]90107018000

O-RING 81X4
J770081020
$8.09

several used for sale on ebay as well....


[/FONT]


[FONT=&quot]O-RING 81X4
J770081020
FUEL FILTER
90107018000
FUEL PUMP
90807088000
FUEL PUMP[/FONT]

[FONT=&quot][/FONT]
[FONT=&quot]90807088000[/FONT]
 
That's worth a shot. To the Ebay!

More than likely fuel pump issue. Looks like there are a couple relays powered one for the fuel pump and the other is the power relay. Try pulling the power relay out and see if it gets that high temp warning to show up. I have a feeling that the fuel pump is on the way out, higher demand at a faster pace, probably is drawing more amps than the fuse can hold at one point and once it cools off again, and the fuse is replaced all is well until the next hard run. I dont see the starter on that circuit anywhere btw. You could hook up a meter to the circuit and measure the amperage draw if you really wanted to but its probably a bit difficult at race pace....find a used pump on ebay or buy a new one. Also have a look at your fuel filter and make sure its not plugged up causing the pump to work harder than necessary as well..

FUEL PUMP
90807088000
[FONT=&amp]$330.69[/FONT]
[FONT=&amp]


[/FONT]
[FONT=&amp]FUEL FILTER
$16.99​
[/FONT]

[FONT=&amp]90107018000

O-RING 81X4
J770081020
$8.09

several used for sale on ebay as well....


[/FONT]


[FONT=&amp]O-RING 81X4
J770081020
FUEL FILTER
90107018000
FUEL PUMP
90807088000
FUEL PUMP[/FONT]

[FONT=&amp]90807088000[/FONT]
 

simpletty

Member
Country flag
You were absolutely correct. Fuel pump replaced, everything is back to normal. I can't thank you enough.

I dont claim to know everything, but being a master ford tech for a few decades has taught me to look past the obvious, plus reading wiring diagrams is something I do daily. The fuel pump was the only obvious load on the circuit so that is where I went, Glad it fixed your problem and happy to help
 
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