Fuel Pump Fuse?

[semajzephyr]

To start I have a 91 with a rb25 series 2 swap in it with a walboro 255 fuel pump. I recently changed from stock injector and fuel rail to some 550 and a top feed fuel rail and a sard fpr. Ever since then it keeps blowing the 10 amp fuse. I have read as many post as I can reasonably stand on the topic of fuel pump fuses and haven't found any that fit my scenario. So looking for some other advice. I know not to run a larger fuse on it. I have been driving it for two years without any problems until now. Thanks for any help.

[daemonyk]

Just a guess, but the fuel pump is probably drawing more current now to keep those 550's and the new fuel rail fed. And a 255 pump draws more current than the stocker anywho. So odds are you finally went past what the stock wiring is capable of handling. Apparently the stock wiring is pretty weak, and after 20 odd years often can't even get that much power to the pump. You can try doing a fuel pump rewire - you use the fuel pump feed to activate a relay which feeds the fuel pump direct current from the battery via a heaver gauge wire than stock (usu like a 10 ga?). It's a cheap mod, and helps make sure your fuel pump gets the current it needs. I'm describing it horribly, so look it up, and give it a try

Also, since you changed out the injectors, what are you using for fuel control? TMK you can't just put bigger injectors in and drive off - needs a tune or FC to set the injectors right for the car.

Good that you have an AFPR - whats your fuel pressure set at?

[WDRacing]

When I did the 255lph pump conversion on my 240 I went battery, relay, 30amp fuse, pump. That was in 04. Still running with that setup.

[zerepdivad]

When I did mine 6 years ago or so I didn't have to rewire or anything. Ka-t ran like a champ and the pump never gave me any issues. Actually put it back to stock and kept the pump in there up until a few days ago when I sold the car. Going to be putting another in my cleaner 240 I picked up.

[semajzephyr]

Thanks for the input guys. Think I will go the rewire route. daemonyk I am not driving it anywhere yet it is loaded up waiting to go to a shop for a nistune install and tune. Thanks for the looking out.

[semajzephyr]

Oh daemonyk overlooked your last statement. I was trying to get the fuel pressure adjusted when the fuse was blowing. It was sitting at 40psi.

[daemonyk]

When I did mine 6 years ago or so I didn't have to rewire or anything. Ka-t ran like a champ and the pump never gave me any issues. Actually put it back to stock and kept the pump in there up until a few days ago when I sold the car. Going to be putting another in my cleaner 240 I picked up.

Fuel pump rewire isn't something that's "necessary" on 240's per se, but it helps those of us who have really old janky less than perfect wiring. Sometimes the OEM wiring gets sketchy enough (bad contacts, frayed wiring, etc...) that it can't feed enough voltage or current (or both) to the pump, esp for a high flow pump. Many people like to do it anyways when running a higher flow pump just cos it's cheap peace of mind.