Jeep fuel pressure drops

I have a 1995 grand Cherokee it’s got a 5.2 V8
Months back I got dirty water in the tank not knowing and drove it half a mile till it went to sputtering real bad till it died I drained the tank put fresh gas in it changed the fuel pump (came out of a 98 4.0 yes it was used) fuel filter ,fuel injectors , fuel pressure regulator and throttle position sensor and it’s still not running right and I hooked up fuel pressure gauge and as soon as I start it it sits at 40 psi if you leave it running 5/10 min it would bounce between 30/40 psi and if I rev it it would drop down to 0 can anyone give me suggestions on what it may be (When I rev it and it sputters dropping fuel pressure I can spray starting fluid in the throttle body and it will rev up fine but idk why it’s dropping pressure). And it’s only after it runs for about 5/10 min when it does it please help me

Can you try a new 95 5.2 fuel pump?

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The pump you installed is too small to feed your 5.2. Change the pump tom
the correct one for your V8.


Like @Mustangman says, wrong pump

The 5.2 uses a 60 psi, 33 gallons per minute pump
the 4.0 uses a 50 psi, 20 gallons per minute pump


I think the answer here would depend on exactly where you have connected the pressure gauge. I would expect a 20 gpm pump to be satisfactory if you are just revving the engine. There is no significant load on the engine. The fact that the pressure drops to zero seems to indicate a blockage in the fuel line before the point your gauge is connected…or a nearly failed fuel pump. How dirty was that water? Was it sandy?


I suspect the used fuel pump you installed is in the same condition as the used fuel pump you removed. Worn out and the wrong pump to boot.


It was very gritty I washed the back of my jeep (it’s my beater hunting ride) and needed holes in the back floorboards so I drilled some and didn’t know I hit the tank and all the water from the back ran into the tank (I didn’t know it at the time till I started driving and it started sputtering and shut off on me

I got a buddy who derbies and he has small fuel cells I will get a tank and a pump from him when he gets back in town and hook it directly to the fuel rail and see if it fixes it if it does I’ll move to the filter and hook it up there and that will tell me if it’s the line got a blockage if that fixes it I’ll buy a new pump (the right one for the motor this time) Btw thank you all for your input it’s very helpful to me

I am suspecting the new filter has gotten plugged. Your diagnostics methods seem sound (I wanted to say “sound sound”.)