voltage at pumps

[kevinvan6000]

I recently installed a DW X2 fuel hat that has 2 walbro 274 pumps. Have it setup to run both pumps all the time so no hobbs switch. At idle, I noticed that one pump is drawing 14.5v and the other is only drawing 12.5v when testing it with a multi meter. Shouldn't they be drawing the same? Car has been tuned for the new setup.

Sponsored

 

[Proshop]

Same exact direct power source or is there a relay in between?

 

[kevinvan6000]

I have a 2 relay setup, each pump has its own. I tried switching the + leads on the hat to see if the difference followed the wiring, but the voltage remained same as before.

 

[WildHorse]

inconsistencies with walbro pumps. Or maybe the one pump has more of a restriction.

 

[JCN]

an electric motor doesn't draw voltage it draws current (amps). I don't have any knowledge of these pumps in particular but feels like one pump is using more current drawing down the voltage than the other. A good start would be to unhook both and ohm through them, I'm guessing they won't match. Then ask Walbro which reading is closest to correct. Could be pump it self or wiring may have a high resistance in circuit for one of them
If the pump readings are close then examine your wiring for a poor connection, ohm relays, fuses if separate ect. This could be a pita to find and hard to help long distance!

 

[Grimreaper]

Google voltage drop test. Easy way to isolate the wiring from the pump as the cause.

Anything over 200mv needs attention.

 

[Jackson1320]

99% chance it is the pumps. Test the resistance. If they are the same (I doubt it) you can share power to them

 

[kevinvan6000]

So found the cause if the difference. I notice in my recent logs I was loosing fuel pressure at high rpms. I pulled the fuel hat and found one of the wires for one of the pumps had pulled out of its crimped connector. It was on the post that was reading 14.5v. I fixed that put it back together and on start up at idle, both terminals displayed 12.5v. This fixed the fuel issue as well as the car now holds 65-70psi of fuel pressure to 7400rpms.

 

[mindo389]

If you have the time, go back through your crimped connections, solder the wires and use some heat shrink covering on them. I've encounter many issues with loose wires in my field of work. That can be a PITA to troubleshoot.

Sponsored