Fancy fuel cell and pump. Now it don't work :(

[sardo_67]

ok put in a fuel cell this past week, added generic high PSi inline fuel pump, cut wires going to OEM unit in the tank, extended the pump wires and attached to new pump. Worked great, cycles the key a few times to prime the system and then started right up, 2 min later it stalled and no power going to the pump. Checked the QD above the rear axle and when I cycle the key it gets 4.2/4.3v, when I crank it over those same wires get 0v.



Any ideas? We got to this point at about 11:30pm sunday nigt so I said enough, cleaned up and went home.

http://m.summitracing.com/parts/vpn-gsl392bx

[konastinky1234]

that's interesting. I did my fuel cell and pump this winter. I may even have the exact same pump. I had no issues getting power to it at any point. Due to the fact it is killing power to it after priming successfully leads me to think that the computer doesn't know the engine is running. That is why it stops pumping after a second or two after you prime and don't start the engine. Maybe this will help you out or spark a thought. You could try to re attach the old pump and see if it will run on that for a minute to isolate the problem.

Let me know how it goes. I don't want this to happen to me in the middle of a race someday.

[Hudson]

There is no "killing power" per se. When he cycles the ignition to the spot where the fuel pump should prime it shoots 4.3v back to the pump. There isn't a full 12v.

He did have a NO BUS issue preceding all of this.

[konastinky1234]

There is no "killing power" per se. When he cycles the ignition to the spot where the fuel pump should prime it shoots 4.3v back to the pump. There isn't a full 12v.

He did have a NO BUS issue preceding all of this.

I shouldn't have said 'killing power.' But the computer would not keep the pump pumping if the engine were stalled or not running with the ignition just on was what I was trying to point out.

So you're saying there should or should not be 12 volts going to the pump? That is something I don't know.

[sardo_67]

I'm not sure what should be going to the pump power wise, but it worked fine and like the OEM tank pump for 5 min or so, then just stopped.


When I get more time this week or weekend I'll be running 12v directly to the pump to make sure it still works.

I prefer to keep the fuel system working like stock so I don't have to ad wires

[konastinky1234]

That's the idea. Shouldn't be any need to change the wiring it should run just like the stock pump did. Curious to see what happens when you put 12 to it if it behaves differently

[sardo_67]

The think made a hell of a lot of PSI and the jeep didn't even crank once before it started up. Makes me think the oem tank pump was all messed up since I've had it as I'd have to crank it a few times before starting and it was always a gutless turd. Even on the 35s.

[customcreationsllc]

For the wiring I would track it back to the relay and fuse and check for power there.
Then check for ground.
Use jumper wires directly to the pump so see if it actually works.
Basically keep checking all the easy spots and find between what to points the break in the wire, or the corroded connector is.
Might be better off just running a new wire.

As for why it has more pressure now than before.
Fuel pumps have a check valve in them that holds the pressure in the line after you are done running the pump, basically to have an instant prime. The check valves go all the time and you end up with extended cranks (waiting for the fuel pressure to come up)
Then the regulator only allows up to certain amount of pressure everything else bleeds off through the regulator.
Some fuel pressure regulators are in the pump assembly (returnless style) easy to tell only 1 fuel line. But they will all have some sort of regulator.
Make sure you didn't remove your regulator.

So without knowing what you have going on it is hard to give you too much advice.

[customcreationsllc]

I'm not sure what should be going to the pump power wise, but it worked fine and like the OEM tank pump for 5 min or so, then just stopped.


When I get more time this week or weekend I'll be running 12v directly to the pump to make sure it still works.

I prefer to keep the fuel system working like stock so I don't have to ad wires

It should work just like OEM power/ground nothing more too it.
The computer will have a timer usually about 6sec after that the pump shuts off unless it see the engine is running. Think how fast a batter would die if it ran with the key on. Never mind the safety aspect.

Only thing is it the new one might draw more power and either popped the fuse, melted a wire, or relay.
In that case you need a larger wire to and from the relay, relay, fuse and ground wire.
The signal wire to turn it on should still be the same.

But I doubt it is overloaded.

[sardo_67]

From the other forum I posted this.

It's had no bus for over a year, I don't think it started when my friend messed with the radio. However I'll be disconnecting it and pulling all the wires out as I do not plan to be using the factory door ones.

It has to be my power block next to the batt, about 3 months ago i had pos/neg wires off the batt with corrosion and wouldn't start, redid that and the gauges worked for a day or so but then went back to No Bus.
Last night I took everything out of the power block, took it apart and cleaned it, blew air, put grease in it and while still no bus the fuel pump circuit started working again along with the AC system not being stuck on. 100yd drive up the hill ended with the AC system stuck on, no fuel pump power, and crank with no start/spark.


We tested the 5v circuit probably 6 times before we finally quit.

I'll be going over all the grounds this week with a wire brush and sand paper.