Jeep died on me this morning...

DrBoost wrote: I think I've replaced 75 CPS on 4.0L engines. I don't think more than 5-10 were instant off scenarios. They've almost all been intermittent or felt like it was starving for fuel. the top bolt is fun to get to BTW. Better see if a doctor can install the second elbow on your right arm....

Can't be worse than doing it on a V8 ZJ... Almost needs that second elbow to get the socket on the bolts. And you need a u-joint and 2 feet of extensions to get the ratchet somewhere that it can move. And then you get to lay on your back feeling for a connector you can barely reach that's somewhere up in the trans tunnel near the exhaust to plug the damn thing in.

XJ engine bays are giant open fields of accessibility in comparison...

How in the flying berkeley are you supposed to get the damn CPS out?!?!?! When I can actually get the socket on the bolts, a feat in and of itself, I can't get them to budge. This sucks ass and is making a car payment on a reliable DD look more appealing by the minute...

Well I'm dying of curiosity. I hope the CPS fixes it for your sake, but I also really want to know what it turns out to be.

Well I've defeated the CPS and taken it for a test drive. Just as I was declaring victory and turning back towards home, it did it again. Great. Guess that's what I get for firing the parts cannon at it.

It's idling in the driveway as I type with my code reader plugged in and streaming data, but I'm just about out of time to berkeley with it today.

Did you changed the fuel filter? I usually hit a no start filter and if it runs, I know the cause.

Sounds like fuel. Bad connection at the pump maybe? Or at the fuse box? Run a wire directly to the pump,or even get fancy and put a fuse and a switch on it for a temporary setup and see if that makes any difference. After, of course, using a multimeter and checking for power; ideally when it won't run.

Also check and clean grounds.

NAXJA link

Screws shorting out the computer? Might be worth a look.

In reply to pjbgravely:

I did not, but I need/plan to. Regardless of whether that's the issue, it needs to be replaced.

In reply to jfryjfry:

I agree, it feels like the cutting out...Kinda chokes and loses power for a second, then dies. I hit the clutch, turn the key off and back on again, and it fires right up while I'm still rolling. No warning in advance and no symptoms otherwise, cant replicate it when I try, which is what's making it a bitch to diagnose.

I had a bit of an "Aha!" moment this afternoon when I remembered a repair I had to do way back when I first got the Jeep. I had the fuel tank out for a few weeks while doing floor repairs and my dog chewed the connector off the fuel pump, so I had to solder a new set of connectors (IIRC a 4 flat trailer harness plug) on to both the body and chassis side. Totally forgot I did this, but it makes perfect sense - could have blasted it with the hose at the car wash and knocked something loose or gotten salty water somewhere, resulting in an intermittent loss of conductivity.

Going to replace the fuel filter and give this Jerry rig a thorough going over tomorrow. Kicking myself for not thinking of this sooner

Well I think I'm on the right track now at least. Took the connector apart and found a bit of mud inside, cleaned it out, slathered it all in dielectric grease, put it back together aaaaaand....Crank no start.

At least I have something I can diagnose now. Zero fuel pressure and voltage going to the connector is weak (4-5 volts with the key turned to on), so I'm going to start at my solder joints.

Saturday morning I woke up on a mission from God-get the damn Jeep running!

I had previously figured out the voltage to the fuel pump was getting lost somewhere between the relay and where the harness exits the dash. So rather than pull the whole damn dash apart and chase wires around to do the "proper" fix, I said berkeley it and ran power to the pump through a toggle switch and relay.

When I first heard the pump hum to life with a flip of the switch I was ecstatic, only to then be let down by a totally flat battery that wouldn't charge at all. After a quick trip to Autozone, I had a brand new battery for $0, as the old one was still under warranty, and the ol girl fired right up.

Ghetto as hell, but it works and I got it done for zero money out of pocket, all just junk I had laying around. Don't know why the hell I didn't just do this weeks ago. Just gotta get in the habit now of turning the fuel pump on and off manually, which I'm doing terrible with so far

Why not just put your new wire to the output of the relay?

Congrats. You are the first person I know who got a replacement from AutoZone right after the battery pooped the sheets, without first hassling through three rounds of "recharging" by the store leading to sequential failures to start two days after each charge session.

FYI, the fuel pump nipple on my 1997 ZJ 4.0 rusted a hole in itself and started spewing gas on the ground in 2014. And I live in Virginia, so it's not like it's salt city around here. Something to think about when you're contemplating fuel pump diagnosis using a bat or a hammer. My advice is do it at the far end of the driveway, not the garage.

That is not a "Ghetto fix". You just installed a new anti-theft system.

In reply to dean1484:

Ha, went to start it yesterday after leaving Tractor Supply and, after forgetting to turn the fuel pump on for like the third consecutive start, thought to myself "Well, at least no one else will ever figure this out." This is especially useful since I can't lock the door if temps are below freezing because it will then refuse to unlock.

In reply to Stampie:

Because now it's more like a race car . But seriously, I decided this was easier than sorting through the mess of wires coming out of the box of fuses and relays. It was the lazy man's approach.

In reply to JBasham:

Yea I only had to hassle through one round of recharging and two trips to the store. Dropped it off, came back an hour later, guy says "Well, it's only charging to 90%, new battery for you!"