How to tell if fuel pumps are running by current draw?

Is there a PID for that available that an OBD2 reader could monitor? DashCommand is a great app for realtime monitoring hundreds of different sensors that the diagnostic and emmissions controllers use.

Digital panel meter under $10 with shunt on ebay. Need to custom mount.

DC-100V 10A 50A 100A Voltmeter Ammeter LED Dual Digital Volt Amp Meter

Hey! That looks like it might be the ticket!

Is there any idea what the maximum current draw might be for the in-tank and high-pressure fuel pumps?

current in the motor will drop, ONLY if the hot pump has an open circuit

a hot pump 'Stall' with out open circuit, will Increase current drain
and the pump motor will get hotter

Yes, I would assume maximum current would be at zero RPM (stall). So one would need to know the proper operational range of current draw.

Since the RV runs properly most of the time, I should be able to easily determine the normal current draw using the above gauge or a clamp-on gauge.

So now all I need to know is the stall current for the pumps, so I can use an appropriate gauge and/or shunt.

Steve

I got one of these hall effect ammeters on my dash reading current into or out of my battery:
https://www.amazon.com/bayite-Digital-Cu........rds=bayite+ammeter&qid=1570775614&sr=8-7

HEY! Now I am REALLY liking this solution. I did not know such things existed. I knew of clip-on ammeters but not with a handy permanent display like this.

This might be just the thing to install. I could clamp onto the power line to both fuel pumps. Zero current would mean off, of course, I could determine through normal running what the normal current is, and if I catch the problem again and it turns out to be a stalled motor than the current should go through the roof!

Either way, this would let me electrically verify the health state of the pumps!

EDIT: OK, I ordered 2 of the hall effect ammeter gauges. Wish I had ordered them earlier in the week as I am going to be working on the RV this weekend.


Steve

Is there a PID for that available that an OBD2 reader could monitor? DashCommand is a great app for realtime monitoring hundreds of different sensors that the diagnostic and emmissions controllers use.

Sadly, this is a 1990 Ford and still ODB1.

Steve

Since you ordered 2 hall effect ammeters, know that the instructions say each display is calibrated to the sensor it arrived with and not to mix them up.

I added about 6 feet of wire in the center of 3 wire ribbon cable. The ring sensor should not be exposed to the elements. I did not want To put mine in engine compartment and didn't.
Might want to find somewhere to put ring sensor while you wait for their arrival. Or a way to shield it from radiant heat and moisture, and perhaps within the 2 meters distance of the ribbon cable length they provide.

On mine, The voltage display was 0.2v off. Low, if i remember correctly, but i have it set to display only amperage as i have separate voltmeters with sense leads to battery that can be calibrated.

You could wire yours to read fuel pump voltage. You then might see its connector getting sub 10vdc due to undersized wiring and 29 year old high resistance connections that get only worse in the high ambient heat where your problems arise.


Order yourself some caig deoxit d5 or d100 and clean every connection on the fuel pump circuit.

I was more interested in the hall effect ammeter link which also displayed amp hours and watt hours flowing unidirectionally. Just saw that product first time yesterday.

My ~ 15psi system in tank fuel pump on my 89 dodge la318 tbi is about 4.2 amps.

Since you ordered 2 hall effect ammeters, know that the instructions say each display is calibrated to the sensor it arrived with and not to mix them up.

LOL, too late. :)