Wasnt really sure where to post this. Does anyone know how to wire up and LED or something so that it will be lit when the fuel pumps are on? What im trying to acheive is something that will warn me if one pump is running and the other is not so if a pump fails I dont find out when im at 7000rpm and running 20psi of boost.

 

Does Defi or anyone make a fuel pressure gauge that has a led that will come on at set peramaters?

 

12 volt LED wired into the fuel pump voltage supply?

 

You can get a pressure sensor that is set to close the circuit when it detects pressure has dropped below a predefined low limit. Then just wire it to an LED or other indicator lamp. You would just need a port somewhere in the fuel system to put the sensor.

I imagine the loss of one of the pumps would cause fuel pressure to drop sufficiently that it could trigger the switch.

 

Wouldn’t that just tell me that the power source is good?

Both pumps are the bosch 044 pumps and I am afraid that at idle and normal driving one pump would provide enough fuel pressure to make up for the other one being dead. In that case I may not notice low fuel pressure till its too late.

I think ill have to get a digital gauge and monitor the amperage that the pumps are drawing to see if one is running normally.

 

you can try a marine fuel consumption gauge, as long as you have a base-line with both pumps working you should be able to detect diminished volume.you might even try killing one pump and drive moderately to learn one pumps volume at a set rpm.

 

Yes good point... although I think the pressure sensor option is a good choice. You would need to run one pressure sensor per pump to truely know for sure though...

 

How are the pumps plumbed? If they each have seperate lines that then feed (via a "Y") into a larger single line you could plumb in an inline sensor on each of the feed lines.

Although I'm not sure exactly how accurate that would be given the equalizing effect of the Y on pressure.

 

I don't think this would work because with one pump off the FPR is still going to maintain XXpsi through the whole system. The other problem using pressure is almost all of the people looking for this are using a return fuel system with a boost-referenced FPR. With the FPR driving FP up with boost, there is no constant FP that you could set a switch to trigger a light if it dropped below. The best thing I am able to come up with is just what meatbag said, an amperage gauge to truly detect if both pumps are running.

 

I agree with your post Hal. However I was speaking more of a LOW threashold sensor - say 25-30psi, which would trigger an indicator lamp. Not a sensor that would trigger if pressure fell momentarily just below desired fuel pressure.

I have an oil pressure sensor that will trigger a light in my dash if oil pressure falls below 10psi (so basically if I have NO oil pressure due to a pump failure, etc). The logic behind it being that maybe I can kill the engine fast enough before any (or further) damage occurs. The oil pressure gauge itself would tell me this but it is not as noticible when driving fast as a 1/2" diameter red light.

 

Right now each pump is plumbed separately to feed only one rail and then join at the FPR to a single return. I just ordered the y-pieces so that the lines will be equalized. Looks like i will just order some digital amp gauges and mount them in places of the ash tray.

 

I cant seem to find a digital ampmeter that reads in tenths for automotive use so im thinking i might use these check valves:

http://www.anplumbing.com/shop/index...t=Check!_Valve

and put a fuel pressure gauge sender in between the pump and check valve. That way if one pump goes haywire it will show up on one of the gauges.