Fuel Pump resistance check

[Meotchh]

This past week we had to rescue the crazy Canuck after his pump died in Bellevue WA. Once he dropped the tank we decided to do a few tests on the old pump & the new pump. The pumps were tested using a standard 13.8V DC bench power supply. The old pump worked when we banged it on the ground & it was very noisy. The new pump worked when ever power was supplied. After the Canuck re-installed the tank with the new pump, we tested it & it did not work. We were seeing 12V at the connector to the pump pig tail. We had the Canuck drop the tank again & checked power to the connector that plugs into the top of the tank. As expected we had 12V at that connector. With the harness disconnected from the pump at the top of the tank, we checked resistance across the two terminals for the pump. We found the resistance across the two terminals at the top of the tank way too high. This indicated there was no connection to the pump. After the connectors were reattached to the pump we checked & found the resistance across the two terminals to be approximately 4ohms. This same reading was present on other good pumps we tested.

So for future reference, resistance across the two terminals of a working pump is approximately 4ohms.

[MikeFleming]

Was that for a single,in-tank pump or the in-tank portion of a dual pump system?

The high-pressure single, in-tank pumps pull between 8 and 16 Amps depending, on their pressure (load), so that would mean they'd need to have a coil resistance between 0.5 and 1.0 Ohms.

[Patrick]

That was for a single in-tank system but it had to be installed twice, so multiply by two!!!

[MikeFleming]

^
That math only works with beer bottles.

[Meotchh]

Was that for a single,in-tank pump or the in-tank portion of a dual pump system?

The high-pressure single, in-tank pumps pull between 8 and 16 Amps depending, on their pressure (load), so that would mean they'd need to have a coil resistance between 0.5 and 1.0 Ohms.

The HP in-tank Walbro in the 88 checks out at approximately 0.7 Ohms.

Now back to those beers...

[MikeFleming]

You have an 88 SVO? Wow!