Does anyone know which fuse operates the fuel pump? I tested the relays and they seem fine but I just replaced my old fuel pump and seem to be having the same issue. The new pump worked great for 5 minutes the shut off, now there's no pressure in the fuel rails and it won't start again. The new pump was operating very loudly when it was working well but now, there's no sound coming from it. This is on the 5.9 V8 Magnum, I did have the computer replaced this summer due to a lightening strike... hoping it's not that again. The fuse panel under the hood of course doesn't specify which fuse operates the pump.


Thank you for your help in advance!! You guys have been awesome.

 

Does anyone know what the voltage to fuel pump is supposed to be? I'm reading around 9.4V. The fuel pump & truck seem to start some times, run great for a couple minutes then stall out with low fuel pressure.


The symptoms began by the truck stalling out while going down the road. It them began to stall when idling. That was the first two days, day three I was hauling heavy loads and it was constantly stalling out while going down the road.


We did have some injectors replaced and an aftermarket fuel gauge installed a few months ago as well. Going to check the wiring job tomorrow.

 

Should be 12v. Sounds like a possible wiring issue. could be a simple bad ground.

 

I did some work on a couple wires today and am going to work on the ground tomorrow. Apparently I'm not the only one who's had those issues with that brand of fuel pump. So, I shipped the old one back and a new unit is on the way. I'm doing the wiring just in case though. LOL Seems like if there's a ground on this thing, it's corroded. It was used for a fire department prior to me, so I assume it was frequently wet. It was also hit by lightening this summer.

 

Ok, I am totally stumped. Checked all the grounds and wiring and it all looks good. It seems like I might not be getting power to the fuel pump relay after the initial prime.


I've seen something about these trucks loosing "Ignition Reference," does anyone know what I need to do to test and/or fix this? Or, could I bypass this?

 

You may need to read power all the way back to the ignition switch. Find where you have correct voltages.

 

Would bad crankshaft and camshaft sensors give these symptoms? Seems like the fuel pump, injectors and plugs aren't getting juice after the initial key-on. I took the distributor cap off last night and everything was completely corroded. The wires coming from the camshaft sensor look kinda beat up too. Thanks for the lead on the Ignition switch, I'd also read that can cause these symptoms.


Glad I started taking this apart though, found out my thermostat housing was leaking pretty badly and was falling apart when I took it out.

 

Ok, so the issue was with the PCM... Changed the PCM out and now I have fuel to the rails. LOL Problem is now I don't seem to have spark and blew the main 140A fuse. Made a new post about the issues I'm having.


After searching for problems, I kept discovering that the electrical components had turned to garbage. If anyone knows about electrical issues, could you please check out the other post? Just found a possible power line that may have been grounding too.