7.3 fuel pump with Cummins 6.7 issue.

[Project20v]

Setup: 7.3 pump, Dahl 100 on suction side to stock 6.7 filter (new). I have the return plumbed to a Fass regulator set at 18psi.

Issue: The pump runs and sound normal for approx. 3 seconds then makes a fairly loud squeal noise for about 1 second and then repeats. My first thought was cavitation. The Dahl had a 2 micron filter which is a bit small for a the suction side, but always worked great on the 7.3. I replaced the 2 micron element with a 30 micron and tried again. It ran quiet until all the air got out of the system and then started making the noise again. Any ideas?

 

[chvyrkr]

That pump is designed to run at 55psi or so... Runnin at 18psi might be makin it unhappy.

And depending on what demand the CR is puttin on it, it might not be enough pump.

If it was me, I'd be running something more suited to the purpose.

 

[Project20v]

I was thinking too that maybe the pump just does not like the low pressure low load. I'll know if I run it up to 55 and see if the noise is there. Will 55psi damage the CP3? I have not run the engine yet, just now getting it dialed to do so. I was trying to avoid the extra expense of an aftermarket fuel pump, but may have to. Thanks.

 

[Tormentor]

The pump is a high pressure pusher. It is not designed to pull through a 3micron filter.

If you want a filter before that pump, it must be a 10micron or higher primary filter with the 3micron secondary after it.

 

[Project20v]

The pump is a high pressure pusher. It is not designed to pull through a 3micron filter.

If you want a filter before that pump, it must be a 10micron or higher primary filter with the 3micron secondary after it.

I put in a 30 not a 3. I think I have it figured out. I had a 7.3 fuel system mentality when hooking it up. The 7.3 is regulated on the return side. I have the regulator on the return side of the cummins which is allowing unregulated fuel to the Cummins on the supply side. I need to put the regulator on the supply side. That should fix it. I'm probably pushing close to 100psi to the CP3 right now and the pump is stalling, making the noise. I'll redo it tonight. I'm sure that's what it is.