RenanMilk

I've seen a few threads on this topic but none of them have the exact same symptoms as I.

My fuel pump fuse (#19 in the PDC) blows as soon as I plug it in, with the keys in the ON position. I tried a 20 amp fuse just to try and get home with no luck. I happen to have copper wire with me, so I tried using that instead of a fuse but my car still won't turn over. I've used copper wire before to get my car home but now it's not helping anymore. I checked the wire and plugs leading out from the pump. No corrosion or visible breaks/damage.

Also, I tried inserting a fuse with the pump disconnected and the fuse still blows immediately on contact.

Just did another test. I unplugged the fuel pump relay in the PDC and plugged in a fuse into #19 and the fuse didn't blow.

Swapped the A/C motor relay with the fuel pump relay since it had the same part number but #19 still blows.

Any help or advice would be greatly appreciated as I'm at my wit's end witg this Jeep.

BlueRidgeMark

I'm going to try to be gentle on this, but putting a bigger fuse or worse, copper wire in to replace a fuse the blows is a about the worst thing you could do. It's a great way to make a small problem into a big problem, up to and including a fire that can destroy a car and kill a driver.

It's one of those things you should NEVER do, unless you fully understand that you are risking a catastrophic fire and are willing to risk that.


Won't turn over? Or won't start? "Turn over" means that the starter makes the engine go around. It's not the same as starting.

So which is it?





Are you saying that you've had this same problem in the past, and it's doing it again? And that you used copper wire on the previous occasions and got home?


If so, you've been making things worse.




Good so far.


Okay, now we know the problem is not in the pump itself. That helps.



Good thinking! So what does that tell us? The problem is not with the relay, and it's not BEFORE the relay, that is, it's not between the relay and the fuse. When you pull the relay, you are separating the fuse from the problem.

This is helpful info. You are thinking, and narrowing down the problem area one test at a time. Good stuff.

You don't know it, but you are doing what's called circuit splitting in the electronics world. Take a circuit, pick a point, and test at that point. Here's a brief write up on it.

So now you need to pick a point between the relay and the pump. Since you have a dead short, you probably want to use a multimeter and test for continuity to ground at that point. Keep the relay out while you do this part.

RenanMilk

I understand the risks. I was doing these things only to get the car home.




I apologize for the mixup. The car cranks but does not start.


This is a HUGE relief.





I'll be checking all this out tomorrow, since it's already dark here in SoFla. My friend had just got off work. He is tons handier than I, so when he was taking a look at my fuel pump line, he traced it leading into my car and under the running plastic leading through the left side of the car. He fiddled with the point where the wire leads in/out of my car above the front of the wheel well under the rear seats, and when he did that, the car started. This leads me to believe the short is in there.

Thank you for the reassuring answers. You've been a huge help. Been stressing about this for 3 hours straight.

RenanMilk

When dealing with these wires, is it okay to solder them together, or is another method better? I'm not experienced with splicing wires, but this is a good time to learn since I gotta get my car running.

BlueRidgeMark

Most folks here will recommend soldering. I used to install two-way radio equipment and cell phones (back when they were installed), and I use butt splices. Done correctly, they are just fine.

Either way can be botched, and either way can be done correctly. If the connection is going to be exposed to the elements, you'll want to use heat-shrink tubing on it, either way you do it.

To do a butt splice correctly requires quality connectors (you can't go wrong with 3M brand) and a quality crimp tool. Also, pay attention to the seam in the metal part of the connector. You want the seam to be at 90 degree angle to the crimp. Look at it like this - if the crimper is horizontal, the seam should be at 12 o'clock or 6 o'clock. Otherwise, the crimping action splits the seam, and you don't get a good connection. When it's at 12 or 6, the seam is crimped tighter.

You can find butt splices that have the heat shrink built in. Crimp, heat, and done. Nice. Nylon (transparent) butt connectors are the best.


The pictures show a garbage crimper (yellow & black handles), a good crimper (red handles), and another style (ratcheting) of good crimpers (all black). And a really bad drawing I made of the seam issue I was talking about.

RenanMilk

Thanks a lot! Looks like I need to get myself a crimping tool. Hopefully, I can find the short with ease and fix it. I'll check back in tomorrow with my progress and pictures, if I made any progress.

freegdr

Were ya located in south florida there a good group of people in this area on the forum....https://www.cherokeeforum.com/f40/so...al-4x4s-57009/