454 EFI making a sqealing sound
 

I have a 1995 454 EFI Magnum that i cannot seam to get to stop squealing. A few weeks ago the water pump belt broke so i went and got all new belts and put them on. With all the belts on and tensioned correctly i cranked it up and it still made the noise. I removed all the belts made sure they were the right belts and then ordered a new impeller kit and idler puller...... after installation it still made the noise. I then took all the belts back off and put just the alternator belt on and the noise was gone..... then i put the water pump belt on and the noise came back. When the original water pump belt broke the water temp got up pretty high so i thought maybe i had scalded a bearng in the pump assembly so i ordered a new pump assembly and installed it (the old pump assembly had no oil in it so i thought this would for sure fix the squeal). The noise was still there. The water circulation pump seems to be fine (spins freely and has only a very very very small amount of play on the pulley). The only other thing that is on that belt is the fuel pump on top of the new pump assembly but i can spin it by hand and the friction that i can feel seems to just be the friction of the impeller spinning. I was told the fuel pump would make more of a ticking sound than a squeal so i am stumped. I can put the boat in the water and it will run fine but still squeals. The only thing left to replace is the water circulation pump and the fuel pump but not sure which one to order. Im chasing my tail replacing all these parts and dont know what to do. Any and all help is greatly appreciated.

Do you have idler pullys? If so replace them as that sounds like an idler pulley sound.

Wannabe

I have replaced the idler pulley, water impeller and housing, and water pump assembly. The only thing not new is the mechanical fuel pump and the water circulation pump.

Take the water pump/fuel pump off and check the oil in that. Common for water to get in there.

Did I miss something? 1st post said this is an EFI motor so I would think this uses a high pressure electric pump and not the old style water/fuel pump combo? Does an EFI motor use the old style pump in some versions?

Low pressure pump feeds high
Could it be an alignment issue, missing spacer possibly?

Thought I had a similar issue with a squealing sound coming from the back of the boat, but it was just the wife squealing for me to slow down. :lolhit:

The motor has the water fuel pump combo and it is brand new and full of oil. I'm going to check the alignment. I don't remember any spacers when I removed it though.

Only thing left is the fuel pump. How can I tell if the pump is failing? It runs fine but I have had some issues just prior to the squeal and went through a couple fuel filters.... I assumed a little bad fuel though. Is this an indicator of a pump going out?

whats the best fuel pump to get? Are they all the same for the EFI, MPI motors ???