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Crank No Start/No Fuel Pressure

JerryG11

NAXJA Forum User
Location
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Bit of an sos.

Necessary details: 92 XJ 4.0 4WD AUTO TRANS

I'm at my wits end with chasing a no start issue. I've been busy lately so this has been my weekend project as of late. About a month ago my XJ wouldn't start out of the blue. I replaced the CPS and it ran until the next day when I went to start it. After throwing a few parts at it thinking it couldn't possibly be the brand new CPS (all new throttle position sensor, idle air, coil pack, fuel pump, and fuel filter). This Jeep was in need of a solid tune up when I got it so throwing new parts on it was mostly for piece of mind.

That being said, I randomly lost fuel rail pressure and can't seem to figure out why. I've begun checking off the list. I put in a fuel regulator, no vacuum leaks, replace CPS and verified that it will run on starting fluid, I've taken out the injectors to clean them and have tested the injector circuit works with a test light. I also have swapped relays for the fuel pump as well as jumped the resistor that quiets the fuel pump.

Here's where I'm at currently: I just warranty swapped my fuel pump for a new one and replaced the filter. When I turn the ignition on I hear the pump engage but I get no pressure at the rail. It will crank and I can get it to start on ether and run but I never get pressure

If there is anything I missed or overlooked I'm all ears and greatly appreciate any input
 
The ballast resistor actually provides a nice place to do some checking. Use the current setting on your meter to make sure the pump is running and drawing current (3-5 amps I think is normal). You can also jump power directly to the bypassed resistor from the battery to eliminate any upstream wiring issues, then check the fuel pressure and/or press the valve to see if you're getting any flow.
 
Thanks for the response!

I checked the current. With the key switched on I get a reading of 1.5 amps. This is the same if I jump to the pump from the battery and also if I try starting. Energizing the circuit also gave me no change in the fuel pressure. In wondering if I got another dud pump, I broke down and ordered a bosch replacement just in case.

Could I be missing something? I know the line isn't closed or anything. I syphoned fuel through the rail connector
 
I went through and upgraded my my ground for the pump as shown. Now when I test my current I don't get any reading. I'm super confused. I can hear the pump wine went ignition is turned on or when jumped from the battery but my multimeter sits at 0a. I also have seen no change to fuel pressure
 
I went through and upgraded my my ground for the pump as shown. Now when I test my current I don't get any reading. I'm super confused. I can hear the pump wine went ignition is turned on or when jumped from the battery but my multimeter sits at 0a. I also have seen no change to fuel pressure

The pump gets power for a few seconds when you initially key-on. Then it turns off again until the engine computer senses rpm/cranking. I'm kinda wondering if part of the pump assembly detached and it's sucking air?
 
Disregard that post. My multimeter busted. The fuse was blown in the current circuit. Must have been from a drop.

I did try one thing and I'm fairly certain I got another dud fuel pump. I unplugged the fuel line and put it in a bucket. When I turn the key I hear that wine but not even a trickle of fuel comes from the pump
 
A long shot but I had one with a jello-like varnish in the fuel lines. I disconnected at the filter and blew compressed air into the line and out the fuel rail at the regulator, an amazing amount of crap came out.
 
Well add another one to the books for shitty fuel pumps. My Bosch pump came into the mail today. It was just installed and it's running strong. Smh 4th time is the charm apparently.
 
Well add another one to the books for shitty fuel pumps. My Bosch pump came into the mail today. It was just installed and it's running strong. Smh 4th time is the charm apparently.

What brand were the duds? For something like a fuel pump or wheel bearing hubs that are a pain to do, I always go for quality parts. I've been burnt too many times on cheap chinese grade parts.
 
Trugrade was the brand of pump that I used. $60 at AutoZone. Luckily I got a killer deal on the Bosch pump because it was "open box" on Amazon. $10 for an unused pump is A-OK in my book
 
I would have voted for a bad hose from the fuel pump to the tank exit, a clogged fuel filter, or clogged fuel lines.

Oh, by the way, it will run better if you put some gas in the tank:flame:
 
I don't know, if it pumped enough fuel without gas in the tank I'd say $10 is an even better deal!
 
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