00jeepXJ96

So here’s the run down, my check engine light came on last week and was flashing meaning it was misfiring along with it running rough so I get it home. My Jeep never liked starting up in the first try since I’ve gotten the old girl, so I figure it’s the fuel pump. I replace the fuel pump and check the valve on the rail for pressure and the pumps clearly doing it’s job. I let the Jeep run for 15 minutes no problem and no check lights on dash and she suddenly dies and continues to die. Is there any steps I missed or anything I should start checking next? Any helps appreciated.

Chick-N-Picker

Could be a number of things but could you please tell us your year, motor, & trans? That will help everybody. Check your fuel pressure at the rail, if yours is pre-97 then it should be 31psi remove vaccum at fuel rail and it should go up to 39psi, or the other way around.....you get it either way. If your 97+ it should be 49psi minues + or - 5psi.

Running fine and getting up to temp then dying. Could be CPS. Maybe an O2 sensor? You should be able to search and figure out how to test it both. This is just me throwing something out for you to test. Can't hurt to test a part...well unless you break it

But posting your year, motor, and trans will help out a lot.

ALSO, what do you mean "died and continues to die"? It will run X amount of minutes before dying every time or it ran 15 minutes one time and now dies suddenly?

By the way, who liked me using that X as a variable......hahaha.

Oswalla

They don't make fuel pumps like they used too, do you still have fuel pressure ? Wouldn't be the first time a new pump lasted a few minutes.

dave1123

Especially if someone put sand in the fuel tank! It's been done before.

jordan96xj

96 is also 49psi. I think the 39 is for 95 and older.

00jeepXJ96

It’s a 2000 sport auto with a 4.0. And when we first fired it up it. Ran for 10 minutes then shut off the moment it was put in reverse. Then it would just shut off at random intervals or when put in gear.

dave1123

It may be delivering pressure, but not flow. Leave the pressure gauge installed are rev it up a little. I should hold pretty close to rated pressure at the increased draw.

alpine.adrenaline

If you can rule out the fuel pump, check the spark plugs. Easy recon.

Chick-N-Picker

^ This. Check and rule out everything you can for free first. Don't just throw parts at it.

You should be able to find out how to test or check anything on this forum. If you can't find how to test something, need guidance, just come back to this thread and ask.

00jeepXJ96

Thank you all for your suggestions and I will have to go through the punch list of free stuff first. I will keep you all informed.

JGravey

Just a heads up, flashing check engine light on OBDII equipped vehicles means the catalytic converters is burning up. Things that burn up cat is usually a large amount of Unburnt fuel (aka during misfires). It’s nice to double check the pump from time to time but with what you said there’s a a huge amount of gas that isn’t getting burned.