No fuel

Hi. Newbie here. I've got a real problem. I have a 91 Cherokee with the 4.1 six and installed two new fuel pumps in one month. Between the time I discovered the old one was no longer working, (six months ago,) and the time I got around to replacing it, all I did was power wash under the hood. NOTHING else has been touched since it was once running a-ok.

Changed the pump. turned on the key. Heard it run for a couple of seconds, but then found out, (long story short,) the coil was bad. Replaced the coil and now when using starting fluid, it fires right up. But, no fuel pump.

No pressure. It's not working. The plug that goes to the pump has a red, black and tan wires. The tan wire has 6.9 volts with the key on. The red does not show power.

I finally gave up and pulled the fuel pump back out, (the one I replaced one month ago,) only to see the rubber at the ends of the pump was bloated and had grown out of their position. Weird how that rubber did that in such a short time. But, and new pump 3 days ago and nothing.....

I've swapped ALL of the relays into the fuel pump relay position. Nothing.
I've used a paper clip to jump across the relay terminals. Nothing.

Again, don't forget, it starts fine on ether. I have no fuel pump working.

Any help?

thanks
Bruce
So. Cal.
909-844-1081

might check to see you are geting voltage to the relay contacts, also check the coil of the relay to verify that the coil is geting the signal to close the contacts also make sure you have a good ground to the fuel pump.

I am going to ask a couple of simple questions to make sure I understand what you are saying. How do you know you are not getting fuel pressure? Did you check it at the Schraeder valve? You were not explicit.

It is possible that the injectors are not firing, not that there is no fuel.

The pump is not running. So, no pressure at the schrader valve. Also, I cannot tell where the ground wire from the fuel pump ends up, in order to see if it's grounded properly. (help)

Also, I checked voltage at the relay terminals, and there is voltage. Off the top of my head I can't remember how much, but it had voltage. I can go get the exact number if that will help.

thanks for the help

Please help. I need to get this thing off my trailer and moving. Thanks.
:farmer:

Note from DJ
Checking Fuel Pump Procedure No Power

I would first hot wire the fuel pump, there is an electrical connector on the drivers side near the gas tank, should have three wires to it, hopefully there is a smaller gauge wire on it like mine this wire is for the sender, so ignore it. Run a pair of long wires [preferable different colors] from your battery to the connector, one to the + side of the battery and one to the — side of the battery (black preferably) to the black wire of connector, the other color to the probably orange wire of connector to positive side of battery.

The fuel pump should now be running if not you probably have a bad pump.

But you stated that you had no voltage to the pump, this procedure will take care of that problem as a test.

Post back what you discover.

I had said I have 6.9 volts at the pump. Still do. I will try the hot wire method, which I tried already but I had not used a separate ground. I only ran 12 volts to the pump by splicing into the line, so the connecting plug would stay plugged in and therefore (hopefully in my limited electrical mind,) still have a ground.
But that didn't work. This was a couple of weeks ago.

So I'll splice in a ground too, and see if that works.

I was also recommended to jump the relay with a paper clip and THAT should make the pump run. It did not.

if the coil of the relay is engaging the contacts the ignition is calling for the fuel pump to turn on, reduced voltage can be a sign on a weak ground or the pump is bad and drawing down the voltage. the way to check you ground is use your continuity part of your meter and put one end on the ground wire the other to a clean bare piece of metal like the leaf spring or axle might be a good place to start. just a few thoughts hope it helps

I will try that. I also just tried going directly to the new pump. The pump has black, grey, and purple wires. Figured the black was ground, so I grounded it to the frame. I then put 12 volts to the grey wire - THAT was a mistake as it dead shorted, started to melt the wire. Nothing happened when I put 12 volts to the purple wire. Pump never ran.

I suppose I could be lucky enough to have two brand new BAD fuel pumps.....:flame:

I don't know what else to do but to bench test the pump....

I will look at my xj book and see what wire does what one will be from the sending unit the other two to fuel pump i think.

looked at my book no luck on wiring, but i found a thread that might help ya http://cherokeeforum.com/f2/fuel-pump-wont-kick-59569/

Nothing but thanks.

Anyone else have an idea? (thanks)

Any other person have an idea?
:looney:

Note from DJ
If you installed an Aertex pump it has most likely gone bad they have a very high failure rate, this is just on example. There have been many post on hear regarding this problem.
This time spend the extra money and buy a Bosh pump.
Or exercise your lifetime replacement warenty and see how long the next one lasts.

87 XJ cranks no start, fuel delivery issue-Aertex failure
http://www.naxja.org/forum/showthread.php?t=1062589
OP byGoSlowGetStuck:
Post #4by OP GoSlowGetStuck