I have a 1999 XJ. I am trying to see if I can key one of these Mopar locking fuel caps to my ignition. I need to figure out my ignition key code. I am assuming you can do that with a pair of calipers, but I am not sure how.

I have found most of the parts here: https://www.factorychryslerparts.com...roduct=4431914

The only parts I am unsure about are the tumblers because I need to figure out my key code to know which tumblers it will require. I'm assuming each number in the code stands for a tumbler? I'm unsure, but that seems likely. The parts at that link are what is required to do it for a JK. It might be the same parts, but it might require different tumblers. Just the very fact that it can be keyed to a JK ignition though is enough for it to be possible for an older XJ.

Anyone ever do this?

 

Normal key stuff usually has a number for each pin or wafer, and the size of the number matches the depth of cut for the key. That would mean a kwikset house key with code 00000 would be an uncut blank key and 99999 would be all deepest cuts. I expect a car key would be the same. Once you have your ignition key code you should be able to tell if they start counting from the tip of the key or from the head. A rekeying set should come with a bunch of each cut depth pins/wafers so you can match up your code.

I've done this for house type locks but never for a car. I don't know how to disassemble a car lock, but it can't be rocket science.

 

just my unsolicited (and possibly unwanted & unreciprocated) personal opinion lol,

disable or replace the locking fuel cap, dang nuisance things

 

My locking cap was broken (wouldn't always lock in, and wouldn't always unlock) and I put on a plain one. OTOH I've been in places/times/situations where a locking cap was absolutely required. So I get wanting one and wanting to make it as easy to use as possible. I hope he does rekey and report back.

 

Most locking caps are only a mild deterrent for most people if you understand how they work. A pair of channel locks in the right place and 2 seconds it's off.
I have one just to ward off the clowns that might think it's funny to put something in a tank that shouldn't be there...
As far as re-keying... that's just personal preference,... I have 3 keys and it doesn't bother me... 1 for the doors/rear gate, 1 for the ignition that I had to replace about a year ago (OEM wore out). and 1 for the cap.
It was like 70 bucks at the time to rekey to the door and I was like "big fat hairy deal"...I don't care... but that's just me. Makes me feel old school in a good way... all these new cars with their proximity keys with keyless start...
An actual physical key?.... add that to the list of millennial anti-theft devices just like a manual trans..lol.

 

I been in some bad *** places, but never worried about someone syphoning fuel out....do people still do that ?

So bad that you would be more worried about your car getting vandalised..or robbed yourself

On another forum, one of the guys with many Vintage cars doesnt even lock his vehicles, as he opines this is MORE likely to lead to damage during a possible break in

 

Back the I was more worried about something going in the tank. Brainless high school rival.

I don't typically lock the 88 Jeep or the 76 Volare unless I'm leaving some portable item in there that I want to keep. No one is going to steal either vehicle.

My newer stuff is always locked, even inside a locked garage. This habit also goes back to that high school kid.

My personal stake in this thread is that my Jeep ignition lock doesn't match the doors so if someone gets deep into rekeying, I might follow along.

 

lol..I actually have 2 locking Jeep caps and one non-locking...I am inclined to think the cap keyhole is going to be too small to accommodate an ignition sized key ?

I leave my locking cap partially undone

btw...if you are going to cut someones grass, park the car around the corner

reminds me off a funny story from my earlier years...a guy I know had a love rival, so he went and mixed up a batch of explosives (using the internet) very alike to military stuff, I think they call it TATP, blew up his rivals car, got himself a jail sentence too

 

We weren't that crazy. All I got was slashed tires, smashed lights, keyed paint, and the girl.

 

Yeah, I was passing by the Jeep dealership and I pulled in. I talked to the Service / Parts guys and they gave me my key code. Pretty cool that they can look that kind of thing up all the way back to '99. No idea how far back they go, but I got my first hurdle out of the way.

I think on wafer locks the "pins" are called "tumblers"? I have very little experience with automotive locks and wafer locks in general.

Haha, yeah, I am not going to use one unless it can be keyed to my ignition key. I don't want to worry about another key.

I got the key code. Now I need to get the tumblers. I need to figure out though how many tumblers the locking cap actually has. The ignition has 8, but I think the caps are like 4. Not 100% on that yet though.

Yeah, it's definitely not strongly locked. I will not have a fuel door when I am finished this other project, so I mostly want it for "piece of mind" and so some kid can't throw Jolly Ranchers in there to get a laugh from his friends. Not that I really expect that to happen, but sometimes kids do mildly destructive things for no reason just to see what happens. If I really needed to siphon gas or destroy a fuel system there is no locking gas cap in the world that would stop me. It's also just to see if it can be done. It's become something like a challenge.

 

Looks like my key is 4 or 5, but I don't know if it was a OE cap or some parts store unit. If needed I can share a pic of mine since the cap is already in the landfill.

 

I think I have everything figured out. I just placed an order for the parts. If I am successful, do you folks think that this is something that I should write up a `How-To` for and post it in the appropriate section? I could see others looking to do this, but I know most don't care. I've never written one before, but I wanted to start.

@doublechaz @awg @RocketMouse

 

I'd like to know more, but I might be the only one.

 

x2

 

My first Cherokee got stolen. I think it was just the easiest one in the area. No one is going to steal my new one though because it has what appears to be a normal relay, but that "relay" has a sim card and I can text the Jeep to shut down and give me it's coordinates, haha. Something cool I stumbled across that was pretty cheap. As far as the write-up, I might just send you the resources I used to do it. It's not very hard. Keying the lock is tedious, but that's all. I am still waiting for the parts to show up.