OmegaNS Gen3 Build Thread - Expedition Newb

omegans

New member
I kept my last car ('05 Mazda3) alive for 419k miles and needed to find something a little bigger now that kids are getting older. I've always wanted an overland vehicle and passively searched for fj80's for years, but never pulled the trigger. I got honest with myself, though, and realized that I would drive it on the streets for 99% of it's life, so why not find something a little more comfortable. Gen3 was the perfect fit all around. I wanted an 01-02 Limited for the leather, 5 speed, lsd, and no throttle by wire/traction control/ASC/electronic doohickory. ASC might be awesome, but I'm so tired of dealing with old faulty electronics disabling my vehicles - and I had to do a lot of maintenance to keep the mazda alive that long so I was leery of having to diagnose faulty traction control issues. Found this one about 2 hours away with 170k on the clock. It was a 2 owner vehicle, but the first owner drove it for 166k if its life. Everything looks great inside and out. As much as I want to start with new wheels and tires and suspension, I have to tackle quite a few maintenance items first. It has a CEL for the following:
P0431 Warm Up Catalyst Efficiency Below Threshold
P0174 System Too Lean Bank 2
P0154 Bank2 Heated Oxygen (front) Sensor No Activity Detected

I fogged the engine, especially driver side (bank2) with carb cleaner while it was running and never registered any change in RPM, so I don't think it's an intake leak. My thoughts are (in order of likelihood I think) 1. Bad bank 2 O2 sensor 2. EGR valve stuck open 3. Cat converter is clogged from burning oil.
It smokes sometimes on startup, leaks quite a bit of oil and I smell burning oil sometimes when I stop. Cam seals need replacing? Valve stem seals need replacing? Probably front main as well. Ohh and I should probably change all the fluids, replace timing belt/water pump, brakes, rotors, struts, bushings ... Cars aren't cheap when you buy them new and when you buy them old. But I like this one I found.
Montero Day1.jpg
 

coffeegoat

Adventurer
Welcome to the forum, there are plenty of people who have done the same laundry list of maintenance so you should have no problem sourcing and performing all those tasks. Check my signature for my 2001 maintenance thread, and a brief search should find 2-3 others with a similar workup. Cheers
 

omegans

New member
I took it for state inspection and it failed for tires and brake pads, so time to open up the wallet. I mounted a set of Yokohama Geolander A/T G015 in 265/75/R16. Would have liked to have bought the BF Goodrich, but I'll do it when I budget some money for different wheels. It sits a skosh higher now - the antenna used to clear a ledge in the garage, now it hits by about 1/2". Also figured I'd change rotors while I was doing pads. I wanted to order the Centric slotted rotors, but I only have 5 days to get re-inspected and getting all the brake components shipped here with enough time for me to install was going to be > $100. So I went with PowerStop Z23 Kit https://www.powerstop.com/product/power-stop-z23-kit/#y=2002&mk=MITSUBISHI&mo=MONTERO&ss=6%20Cyl.%20Eng. Drilled rotors kinda bothers me if they ever got muddy but hey, the streets I drive aren't very muddy :ylsmoke:
New wipers all around and removed the wiper stalk and hit it with some black trim paint before installing. Cheap wiper blades are kind of a bete noire of mine, so I usually spring for the most expensive ones I can find (Bosch). And I changed out some interior lights for LED - and just like that, I can make $1000 disappear.

So a couple questions before I work on my next round:
1. Anyone have trouble with their front overhead interior light? The center wasn't working, so I removed and cleaned the contacts thoroughly. Now only the center light works and it's intermittent.

2. I know I'm going to forget to turn the radio off one day before entering the garage and its going to mangle the antenna. Is there a non-extending [ie. fixed] antenna that I can replace this one with. Looks like I will have to take the fender off.

3. The valve cover gaskets must be leaking more than I thought. Besides a valve cover gasket (with spark plug rings) set, what else should I order? I'm not doing the timing belt/water pump at this time. Should I get upper intake manifold gasket? I'll get plugs, wires, coil packs and EGR valve, but don't know about other gaskets.

4. My center information console used to tell me my fuel tank range - now it's stuck on [I think] 386mi regardless of my fuel level. My fuel level gauge still works though. Any ideas?

5. Is this normal height for 265/75/R16's ? Maybe I have blown shocks and it just feels very wobbly and top heavy (34.5")
Geolander Tires.jpg:


CoffeeGoat, Found your thread with the maintenance work - wow, thanks for that. I downloaded your maintenance spreadsheets as well to help me get my own started.
 

omegans

New member
6. Ohh and my radiator looks ... sketchy. The end tanks are very discolored and they just look brittle and ready to crack. Where could I find an all metal version?
 

EyeInTheSky

Adventurer
I took it for state inspection and it failed for tires and brake pads, so time to open up the wallet. I mounted a set of Yokohama Geolander A/T G015 in 265/75/R16. Would have liked to have bought the BF Goodrich, but I'll do it when I budget some money for different wheels. It sits a skosh higher now - the antenna used to clear a ledge in the garage, now it hits by about 1/2". Also figured I'd change rotors while I was doing pads. I wanted to order the Centric slotted rotors, but I only have 5 days to get re-inspected and getting all the brake components shipped here with enough time for me to install was going to be > $100. So I went with PowerStop Z23 Kit https://www.powerstop.com/product/power-stop-z23-kit/#y=2002&mk=MITSUBISHI&mo=MONTERO&ss=6%20Cyl.%20Eng. Drilled rotors kinda bothers me if they ever got muddy but hey, the streets I drive aren't very muddy :ylsmoke:
New wipers all around and removed the wiper stalk and hit it with some black trim paint before installing. Cheap wiper blades are kind of a bete noire of mine, so I usually spring for the most expensive ones I can find (Bosch). And I changed out some interior lights for LED - and just like that, I can make $1000 disappear.

So a couple questions before I work on my next round:
1. Anyone have trouble with their front overhead interior light? The center wasn't working, so I removed and cleaned the contacts thoroughly. Now only the center light works and it's intermittent.

2. I know I'm going to forget to turn the radio off one day before entering the garage and its going to mangle the antenna. Is there a non-extending [ie. fixed] antenna that I can replace this one with. Looks like I will have to take the fender off.

3. The valve cover gaskets must be leaking more than I thought. Besides a valve cover gasket (with spark plug rings) set, what else should I order? I'm not doing the timing belt/water pump at this time. Should I get upper intake manifold gasket? I'll get plugs, wires, coil packs and EGR valve, but don't know about other gaskets.

4. My center information console used to tell me my fuel tank range - now it's stuck on [I think] 386mi regardless of my fuel level. My fuel level gauge still works though. Any ideas?

5. Is this normal height for 265/75/R16's ? Maybe I have blown shocks and it just feels very wobbly and top heavy (34.5")
View attachment 415619:


CoffeeGoat, Found your thread with the maintenance work - wow, thanks for that. I downloaded your maintenance spreadsheets as well to help me get my own started.
I'll try to go question by question. Please keep in mind I haven't had all my coffee this morning.

1: The mounting screws act as ground in that light fixture, so try cleaning up the threads on both the screws and the ceiling.

2: Antenna replacement is easy. Order a side mounting antenna like in the pic below. None of the generic Autozone antennas worked due to the angle of the fender. Pull the liner partly out from behind your front pasenger tire, remove silver ring around antenna mast, unbolt old with motor, unplug, reinstall new. Also pull the relay from the passenger side footwell to get rid of the annoying click.

1006c66b70f1a9d3189019a225a7b78c.jpg


3: I believe both intake gaskets need replaced if the plenum is pulled, so grab a couple. Don't forget about the EGR pipe gasket while you're there.

4: Same. Will update if I figure it out.

5: Looks about like mine, which has KYB Gas a Just shocks with less than a year on them. This size tire really fills our wheel wells. EDIT: Just looked again. Looks like it's sagging. I'll grab a tape measure and let you know.
 

omegans

New member
P0174 and P0154 were fixed by changing both driver side (left) oxygen sensors. I went through FSM and followed the procedures I had the patience for but much of the work would require a Mitsu specific scan tool. I used a bluetooth OBDII scan tool and Torque app to do what I could. Nothing jumped out as an obvious problem, so I started with what I thought was the most likely culprit - bad O2 sensors. Autozone had them in stock and they have a policy for price matching, so I showed them the price for the part #'s from RockAuto and saved >$100 so keep that in mind. Cheaper than RockAuto since I didn't have to pay shipping too.
Passenger side O2's are very easy to get to - drivers side not so much. Took about 2 hours total. I sprayed penetrating fluid while they were warm to hopefully draw it into the threads. I don't think it did much to help though. Harbor Freight has two different types of O2 sensor sockets. Both are useless if the sensors are really stuck like mine were. The HF sockets open under a lot of torque and slip, rounding the sensor head further. I had to use a long 7/8" wrench. The open end was rounding the head on the sensor, so I cut the pigtail off the back of the sensor and slipped the boxed end over sensor. You'll have about 30 degrees of twist before the wrench hits something. It was a 12 point wrench so this was barely enough to engage the next tooth. Work it back and forth and twist out. I started on the downstream sensor first and it was very slow going. There is the 4wd prop shaft, exhaust and frame in the way. The upstream isn't any better and is located above the cat converter pointing toward engine block. Same thing here - twist one tooth back and forth until you get it free. Mine felt like they were crossthreaded, but it's just rust and threads that have been heat cycled thousands of times.
I cleared the codes and have gone through about 500miles driving with no CEL or pending codes. I don't feel like a mechanic by just replacing parts, but the diagnostic procedure wasn't getting me anywhere.
 

omegans

New member
I started the truck the other day, pulled it into to Reverse to back out of garage and realized the brakes were not working. I could get it to stop but I had to stand on the pedal. After a few seconds the pedal sank to the floor like it had re-gained the brake boost. The brake pedal pressure came back but then whenever I pushed the pedal, I could hear a 'squeak' coming from the footwell. After a little research, I found that this loss of brake assist is a somewhat common problem on higher mileage Gen 3's. Gen 3's apparently use an electric motor to generate brake boost pressure and store the pressure in a small tank/accumulator. Bolted to the firewall where you would expect to find the vacuum booster is a 'cube' that houses the ABS system. On the underside is the electric pump and on the interior side is the accumulator shaped like a cylinder. I ordered the following parts from mitsubishipartsonsale.com:

ABS Pump - MN102843 ($450)
ABS Accumulator - 4630A011ABS ($120)
Resorvoir/Cap - MR527711/MR475850 ($75)

I swallowed my pride and took it to a mechanic to replace the parts and bleed the ABS system although I would have had no problem doing the work myself. Labor was $430. There is a great youtube video here that explains the actual replacement and what's going on with this brake failure.
 

coffeegoat

Adventurer
Bummer - there are some, let's say creative, solutions to fixing the pump and/or the rest of the system, but for peace of mind it's hard to beat a completely new system with OEM parts.
 

omegans

New member
If I had had the time, I would have liked to have done the job myself and seen if I could have had the motor rebuilt or replaced. I suspect the accumulator was leaking and that caused the motor to run constantly and rack up a lot of wear. What fixes are you alluding to, coffeegoat? It may help someone else if this is a common problem. In the video, he mentions that this ABS system may share some component like pump and accumulator with other make/models like Toyota, Lexus, Nissan. That part number I listed is actually a part number for a Dodge ABS pump too, so I wouldn't be surprised if other vehicles used the same components.
 

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