Fuel pump resistance?

Hi all, first post here, but I’m a long time Toyota truck guy (when they only made one truck).

I’m currently trying to diagnose a crank no start issue. I don’t have any fuel at the rail. It’s difficult for me to tell if the fuel pump is running or not. I have checked all the obvious things first, fuses, relay, etc. I think it’s either the fuel pump control module, or the fuel pump itself.

I have the 12 volts and ground at the control module connector. I have 0.8 ohms resistance at the connector going to the fuel pump. This seems reasonable for an electric motor, but I’m not 100% sure. Does anyone have a value for a good pump?.

The only other thing I can think of is to put 12v on two pins that go to the fuel pump to see if I can hear it run.

I could pierce the fuel pump wires coming out of the control module to see if it’s supplying power to the pump. I think I’ll need to use the oscilloscope to be able to see anything though as the system uses PWM to control pump speed, a DMM may not catch it.

Anyway, I’m really looking for a resistance value for the fuel pump right now.

Thanks in advance.
Glenn

 

According to Ohms law, at 0.8 Ohms resistance that gives 15 amps (180 watts), and the fuse is 15 Amps, so maybe the pump is okay. I’m going to manually feed it 12v with the battery today to see if I can hear it turn on.

 

Well, some good news. I’m able to run the fuel pump from the connector on the pump control module. Pins #1 and 2 to a 12v battery makes the pump turn on. It wasn’t running before. At least the fuel pump works!

I ordered a used OEM pump control module from the salvage yard on evilpay. Hopefully this was the issue.

Stay tuned…

 

Did you check for voltage at the pump at the key was turned on and off?

 

Nope, as I couldn’t find a way to get a connection short of piercing the factory wiring harness.
It’s pretty clear that there is no voltage getting to the pump, so I think it either the pump control module (hopefully),
or it’s the ECU$$$$

 

What about the factory security system? Have you watched the security light on the dash to make sure it comes on for a second or two when key comes on then goes out completely? If it’s not doing this the immobilizer would be tripped, try a second key

 

Thanks, but that was one of the first suggestions I tried. The key light blinks then goes out once I put the key in the ignition. Plus I only have one key

 

If that’s the case your are probably on the right track. Fuel pump control ecu failure is fairly common. Seen it on here several times. They don’t hold up well to the elements being bolted to the rear frame rail

 

I’m waiting on another fuel pump control module since the PO lost my eBay purchase.

I did have another question about replacing this. Does anyone know definitively if the replacement module needs to be programmed to my truck? I’ve read articles that say both no and yes, so it’s not clear. If I do, then I have to get my truck towed to the dealer, not cheap!

 

My assumption is no it does not need to be programmed, should be plug and play.

 

Thanks, I’m hoping that is the case.
I’m just trying to think of my next plan of action if this doesn’t get the fuel pump running.

 

Okay, I received the second fuel pump module tonight. I plugged it in and the truck started right up!!!