'94 Ram fuel pump/module ....????

Currently operating on a '94 Ram that really just seems to run only when it feels like it.I have checked the fuel pressure (5.2 port inject)and when it did actually decide to run the PSI was between 45-54.I assume that is within specs while the engine is running.Now from the reading I would assume the fuel pump was O.K.,at least the pumping mechanism,maybe not so much the electrical side of the fuel pump.

The problem is that sometimes there is no fuel pressure at all...turn the key on 30 times and the fuel pump might engage only 2 times.

There are four wires running into the fuel pump module on top,I assume that 2 of these wires are hot wires (1 for sending unit/1 for pump itself)and the other two are grounds right ?
I have the Haynes manual for the truck but the wiring diagrams are too generic to really follow and color codes in the book do not match what I have on the truck.

What I would like to do is bypass all factory wiring and run 12v straight into the pump itself which I am guessing to be the largest red wire that runs into the top.While using a test light I did not have power through this wire,only the one I assume to be the sending unit power supply.The other 2 wires (that I assumed to be grounds or 1 running up to the fuel gauge)also did not have power.

I know this is not a relay issue and have swapped some around to be sure.Has anyone experienced this same issue and is it as obvious as a bad fuel pump like it would seem?

This is not my truck and the owners viewpoint is that a fuel pump cannot be bad one day then work fine the next....Any good ideals before we go through the hassle of dropping the tank ?

you will not constant power to the fuel pump unless the truck is running.turn key on-then the relays turn on then go off within a couple seconds.That is normal.unless the truck is running and recieves feed-back from the pump assy.you will have dead relays.really need 2 people to check this out easily unless you make some extra harness.A good trick is to beat on the gas tank if fuel pump is not working.The jaring/vibration will unlock the pump.Most of the time.

moretoys, you are right !

Just finished putting a '94 5.9l in my '67 fish

The 2 black are ground, the GY/BK is the pump the other is the gauge, if you do not have pressure, may be the filter in the pump is clogged or the line .

Assuming the engine runs fine after.....

Other than that, change pump

Daniel

A very similar thing happened to my 1995 on a trip to Florida two years ago.
The engine would run fine, then suddenly quit, but would restart after a cool down of anywhere from 5 to 30 minutes.

When I changed out the fuel pump assembly I found that the suction filter was heavily clogged at the bottom and this restriction was probably 'cavitating' the pump when the fuel warmed up. This is why letting it cool or hitting the fuel tank with a hammer helps for a short while.

Loosen your cargo box bolts to the frame and jack the bed up to a 45 degree angle from the driver's side, watching the wiring at the rear bumper carefully to avoid snags. This is much easier than dropping the tank.

Be carefully not to break the red plastic clips on the electrical connector to the top of the assembly.

Be gentle removing the 'roll-over valve' because the replacement fuel assemblies expect you to re-use it.

Have a fire extinguisher on hand along with a couple hand fulls of rags, because it is nearly impossible not to spill some gasoline as the assembly is pulled out.

Good luck.

Thanks for the tips !!!

You could also jump the relay and check for power at the pump. I beleive you jump pin 30 to 87 but I would have to look at it to be sure.