Do all Jeeps suck or just mine

I recently purchased a 90 XJ for the wife to drive. It had ABS brakes that did not work so I converted them over to standard vacuum assist using the dual diaphram booster from a Grand Cherokee. And ofcoarse the booster I got from the JY was bad, so I got a rebuilt one thinking I still saved on the core charge anyway.

After putting that one in the brakes were still soft, pedal almost went to the floor. So I adjusted the rears and tried again, same thing. I then decided that since the wife was going to be driving this thing that replacing the brakes was probrably warranted. Went to the store got drums, shoes, hardware kit, pads, calipers, hoses and fluid. Installed all the new parts, went to drive it and brakes still soft. The next day my wife goes out to move it and the pedal did hit the floor no brakes at all. After checking things out I find the new booster is also bad. Get a replacement install it and all is good with a few modifications Jeep stops great.

Now the saga continues
Go to take it for a longer test drive (like around the block). This thing will not shift gears. Seems to be stuck in second.

BTW 90 XJ 4.0L 6cyl AW4 242 TC

So I now have been doing the reasearch to figurte this one out. One month ago I drove this thing home and it drove fine (other than the brakes). Now no shifting

I have checked the fuse to the TCU under the glove box, I cleaned the NSS so it would start like it is supposed to.
I am not a Jeep guy so this thing is a little foreign to me. I have owned Dodges my whole life, they're easy this thing is a PITA
I just don't know enough about them yet. I have ordered a FSM for it but it will be some time before it gets here. So if you have some advise for me lay it out there

Thanks
Chris

Sounds like you got a lemon. Besides, that's a 19 year old truck. What did you expect?

I bought my 97 with almost 250K on the clock and it runs like a top.

I had a no shift in my 90 turned out to be a bad TPS. May want to check that out.

All Jeeps suck air. And sometimes water if you're not careful!

hiimmred said:

I had a no shift in my 90 turned out to be a bad TPS. May want to check that out.

Click to expand...

I will check it out

Thanks

Mine sucks... Kinda wish I wnet Toyota but little late now..

dagr8tim said:

Sounds like you got a lemon. Besides, that's a 19 year old truck. What did you expect?

I bought my 97 with almost 250K on the clock and it runs like a top.

Click to expand...

So does my 89 with 167,000 miles on it..4.0, AW4, np231,



Warlock4x4 you have a pm

well my 89 with 23000 is sound...4.0 aw4 selec trac

Oh come on have faith in your XJ. Did you thoroughly inspect it when you bought it? Have you performed routine maintenance on it? I see these threads all the time. If you buy a vehicle in good shape and maintain it properly you won't have a problem. Now if you don't change you oil but every 10k and haven't flushed the radiator since god knows when thats when you run into trouble. Stop whining and fix it fool................j/k! :twak:

BTW check your TPS and the grounds those seem to be rather common issues!

My 1990 with 111k miles has been a lemon as well. I've replaced nearly everything over the last 3 years of ownership. It has low mileage but my friend with the same model year (and over twice as many miles), thought that maybe the odometer had already rolled over once...somehow, it wouldn't surprise me!

The brake issue sounds like it needs a good bleed. The pedal to the floor is another give away of air in the system.

I'm not sure why you converted to a grand cherokee MC and a YJ Booster. Why not just pull the fuse? Why not put in a OEM booster and MC?

As far as the no shift problem. Measure the voltage at the TCU to make sure there is actually voltage going to it. You were playing around under the dash presumably, and IIRC, the fuse block on a 90 is under there somewhere. Make sure your TCU is plugged into the connector. I don't recall where it is, but it seems to me it's under the dash somewhere.
The TPS is a possibility as the TCM looks to it for position, but the TCM also has other feedback points to look at, like speed. IIRC, there is a speed sensor located under the dash also, inline with the speedo cable.

if its not shifting did you test the tps?
check all grounds?
etc?
also the solenoids in the tranny could be bad, one or more posibbly from threads i just searched for fun on here.
i bet a few of the solenoids from the junkyard would be cheap.

Thanks for the help everyone

I was just reading on how to check to TPS

I don't hate this thing yet, BUT

I would definitely look for power to the TCU and work backwards from there (assuming the TPS is set correctly)

I'm fairly close bye and have fought some of the gremlins out of mine-- lemme know if you get fed up with it, I might be able to scrounge a day off in the near future to put a second set of eyes on it.

PM me if you need a hand:wave1:

While its down being worked on, keep a charge on the battery. check volts with a good meter when starting troubleshooting. Read /search naxja on cooling system and electrics. You will learn about mechanics on Jeeps! There are much worse 'older' cars to keep going.
-On a wife car-be sure to keep a good battery in it.
Good Luck

On the Trans - **Dexronlll ONLY in AW-4** (search). Check fluid is Red and not burnt. For true fluid level must be fully warmed up 20+ minutes and jeep very level.

We all must understand that the XJ was, is, and always has been a BUDGET 4x4. That being said there were compromises in its design to fit a certain price point in the market.

There are literally dozens of things on them that are of lower quality than we would like. Lousy service brakes, useless parking brake, Dana 35 rear axle, crappy electrical system, seats that tear, floorboards that rust, exhaust systems that crack, death wobbles, cracked dashboards, mystery bangs/rattles/shimmys, bad seat belts, little safety features etc. are just a few of these issues.

But most of us love the XJ anyway because everything that is important is actually quite good: 4.0 engine, AW4 tranny, NP231 transfer case.

If we wanted true quality we really ought to be driving a Land Rover or Mercedes Benz G Class. But those vehicles are probably beyond the means of the majority of people who use this forum, and whoever would want to off road a vehicle that expensive is beyond me......

The whole point is "It's a Cheep!" Cheep to buy, cheep to fix. That's how you justify taking them in the woods and bustin em.

you cant just pull the fuse cuse the pump IS THE BOOSTER if you just pull the fuse you get NO BOOST = breaks as hard as rocks

These jeep are almost 20 years old. If something breaks dont be to upset. I dont think when jeep egineers desinged the cherokee they intended them to last that long.