First off I'd like to say thanks to all the contributors here on MUD. Your experience and willingness to post how-to threads has been invaluable!
I bought my 92 FJ80 (3fe) in June last year and I've had great fun in it and working on it. I've wanted a FJ since the 90s, and now it finally worked out.
So after a host of fixing, replacing, tuning, and cleaning, I finally improved my power and MPG.
The thing that made the difference was replacing the fuel filter, fuel pressure regulator, and fuel pulsation damper. My current set-up is stock everything except FZJ80 16" wheels and 33 BFG ATs. My highway MPG went from 12 MPG to over 14 MPG. My in town economy went from 9 MPG to 11 MPG.
The fuel system parts replacement did not include replacement of the sock filter near the fuel pump. But replacing those three parts did eliminate another problem too. Up until I replaced the parts, whenever I'd unscrew the gas tank cap, the tank used to release high pressure air from the tank for a few 3-4 seconds. Now, no air pressure is released at all. I attribute that to the past necessity to build up pressure to get past the old, clogged up fuel filter.
Here are a few lessons I learned while replacing the fuel filter, pulsation damper, and pressure regulator.
1 - When replacing the fuel filter, make sure to use a 19mm and 17mm open end wrench when removing the fuel lines from the filter. With just the 17mm wrench, it's difficult to get enough torque on the bolt to loosen it, and you'll end up bending the fuel filter. There's a 19mm slot built onto the filter to provide a counter to the torque you're putting on the 17mm nut. I should've seen it at first, but didn't notice it until after struggling getting the bolts loose for too long. I accessed the bolts from the underside of the frame, and I had a hard time getting any type of socket wrench in there. Once the bolts were loose, using my fingers to do the rest of the job seemed to work best. I think it was a 12mm wrench to take the filter off the frame rail. I did get a bit of fuel on my arm when loosening the rear fuel line, but lifting the end of the line about 6 inches after separating it from the fuel filter stopped the leak. I lost about a cup or two of fuel total during the process, but this could be greatly reduced by being more careful to raise the line sooner. I got all my parts from CDan. He really took care of me and made sure I got not only the right replacement part but also all the right gaskets etc that are required.
2 - The fuel pulsation damper is a mysterious little part. Before replacing it, I originally had found it after finding threads about the "magic screw," and I wanted to see what the condition of my damper was. My initial discovery of the part revealed that the screw had completely backed out and was just sitting on the damper (dampener) just like so many other people have described. Before finding this screw, my idle after warming up had a bit of a stumble, which wasn't too bad, but I was hoping adjusting the screw would help the stumble. I screwed the "magic screw" back in, and low and behold, my senses told me that the stumble went away a little bit. Less than a couple weeks later, the stumble returned, and I had found that the screw backed itself out quite a bit already. I retightened the screw, but it never seemed to help the stumble like it did the first time, and it stayed tightened after the second time I put it all the way back in. I then decided to replace the part. When replacing the part, I did indeed need 22mm crows foot wrench attachment for a 3/8" drive socket. BE CAREFUL when buying the crows foot wrench because if its too thick, it won't fit on the part. The part I got from auto zone was too thick (about 8-10mm). I ended up needing to dremel the thickness of the wrench down to about 4-5mm (which was a major hassle, I just didn't want to buy another tool). Removing the part was very simple and only required the replacement of a couple gasket/washers under the dampener. After the switch, the stumble in the engine appears to have disappeared completely. It's hard to know if it was the filter, dampener, or pressure regulator, but nonetheless, the stumble is gone.
3 - The fuel pressure regulator was also replaced, and I got all the parts and washers etc again from CDan. I didn't know what specific symptoms this old part may have been causing, but the threads here basically recommend changing it out with the other fuel system parts, so I did. The only thing I'd like to mention about this one is that the FSM says to place a towel under the FPR when removing to catch any fuel that my be spilled. This instruction was accurate, but insufficient! My BIG MISTAKE may have been due to my own ignorance, but when removing the FPR from the fuel line underneath it, (not the "union bolt" on the top of it), I needed a wrench to get enough grip on the FPR to get it out. When I pulled out the FPR, the high pressure fuel behind it shot out really powerfully right in to my eyes! That was a terrible experience, to say the least, so make sure to put a towel on the top OVER THE FPR when removing it to make sure you don't have my problem. I did the FPR at a different time then the filter and damper, so the pressure had built back up. I'd recommend doing them all at the same time, too, to likely avoid this problem. Do the filter, damper, then regulator, in that order.
This post is now officially really long, but I'd also like to include the some of the other relevant PM that I've done that didn't seem to noticeably affect my power of MPG. Unless noted, no effect was noticeable.
- Running techron fuel system cleaner through the fuel (did wonders for an old Camry I had, but nothing for the cruiser.
- PCV valve and hose replaced
- Cleaned butterfly valve in throttle body
- Replaced air intake hoses
- Standard engine Oil/Filter
- OEM distributor rotor and cap
- OEM plugs and wires
- Throttle cable and kick down cable
- Timing adjustment to 10-11 degrees
- Adjusting idle screw (in combination with timing adjust, the drive and park/neutral idle speed came started to match at 650, where they used to be about 200 apart (650 in drive, and 850 in park/neutral)
- Valve clearance adjustment (I think I took way too long on this, and the engine got cold, so I feel like I need to do this again. The adjustment sounds right when cold, but when it warms up the clickety clackety of the engine seems to get noticeably louder)
- Replaced all fluids
I'm soon to replace my rear axle oil seals and bearings, replacing all soft/hard vacuum lines and EGR parts if I can find them (you can't get the EGR valve anymore, only the manifold), and will also be replacing the shocks/springs with OEM tokikos (fzj80 shocks, recc'd by CDan and others here on MUD for my use without heavy loads) and OME 861/862 low height replacement springs. I'll post up about that when I get to it. I'm thinking I'll get at least 1.5" from the replacement because my springs are really weak. It only takes about 200 lbs on the tailgate for the rear bump stops to bottom out. Completely empty with only the rear seats in the cruiser, the rear bumpstops are less than one inch away from bottoming out.
Well, that's all folks! Thanks for everyone's help!!!
Please let me know what you think I'm missing or that you'd recommend pursuing at this point.
Thanks,
Ryan
I bought my 92 FJ80 (3fe) in June last year and I've had great fun in it and working on it. I've wanted a FJ since the 90s, and now it finally worked out.
So after a host of fixing, replacing, tuning, and cleaning, I finally improved my power and MPG.
The thing that made the difference was replacing the fuel filter, fuel pressure regulator, and fuel pulsation damper. My current set-up is stock everything except FZJ80 16" wheels and 33 BFG ATs. My highway MPG went from 12 MPG to over 14 MPG. My in town economy went from 9 MPG to 11 MPG.
The fuel system parts replacement did not include replacement of the sock filter near the fuel pump. But replacing those three parts did eliminate another problem too. Up until I replaced the parts, whenever I'd unscrew the gas tank cap, the tank used to release high pressure air from the tank for a few 3-4 seconds. Now, no air pressure is released at all. I attribute that to the past necessity to build up pressure to get past the old, clogged up fuel filter.
Here are a few lessons I learned while replacing the fuel filter, pulsation damper, and pressure regulator.
1 - When replacing the fuel filter, make sure to use a 19mm and 17mm open end wrench when removing the fuel lines from the filter. With just the 17mm wrench, it's difficult to get enough torque on the bolt to loosen it, and you'll end up bending the fuel filter. There's a 19mm slot built onto the filter to provide a counter to the torque you're putting on the 17mm nut. I should've seen it at first, but didn't notice it until after struggling getting the bolts loose for too long. I accessed the bolts from the underside of the frame, and I had a hard time getting any type of socket wrench in there. Once the bolts were loose, using my fingers to do the rest of the job seemed to work best. I think it was a 12mm wrench to take the filter off the frame rail. I did get a bit of fuel on my arm when loosening the rear fuel line, but lifting the end of the line about 6 inches after separating it from the fuel filter stopped the leak. I lost about a cup or two of fuel total during the process, but this could be greatly reduced by being more careful to raise the line sooner. I got all my parts from CDan. He really took care of me and made sure I got not only the right replacement part but also all the right gaskets etc that are required.
2 - The fuel pulsation damper is a mysterious little part. Before replacing it, I originally had found it after finding threads about the "magic screw," and I wanted to see what the condition of my damper was. My initial discovery of the part revealed that the screw had completely backed out and was just sitting on the damper (dampener) just like so many other people have described. Before finding this screw, my idle after warming up had a bit of a stumble, which wasn't too bad, but I was hoping adjusting the screw would help the stumble. I screwed the "magic screw" back in, and low and behold, my senses told me that the stumble went away a little bit. Less than a couple weeks later, the stumble returned, and I had found that the screw backed itself out quite a bit already. I retightened the screw, but it never seemed to help the stumble like it did the first time, and it stayed tightened after the second time I put it all the way back in. I then decided to replace the part. When replacing the part, I did indeed need 22mm crows foot wrench attachment for a 3/8" drive socket. BE CAREFUL when buying the crows foot wrench because if its too thick, it won't fit on the part. The part I got from auto zone was too thick (about 8-10mm). I ended up needing to dremel the thickness of the wrench down to about 4-5mm (which was a major hassle, I just didn't want to buy another tool). Removing the part was very simple and only required the replacement of a couple gasket/washers under the dampener. After the switch, the stumble in the engine appears to have disappeared completely. It's hard to know if it was the filter, dampener, or pressure regulator, but nonetheless, the stumble is gone.
3 - The fuel pressure regulator was also replaced, and I got all the parts and washers etc again from CDan. I didn't know what specific symptoms this old part may have been causing, but the threads here basically recommend changing it out with the other fuel system parts, so I did. The only thing I'd like to mention about this one is that the FSM says to place a towel under the FPR when removing to catch any fuel that my be spilled. This instruction was accurate, but insufficient! My BIG MISTAKE may have been due to my own ignorance, but when removing the FPR from the fuel line underneath it, (not the "union bolt" on the top of it), I needed a wrench to get enough grip on the FPR to get it out. When I pulled out the FPR, the high pressure fuel behind it shot out really powerfully right in to my eyes! That was a terrible experience, to say the least, so make sure to put a towel on the top OVER THE FPR when removing it to make sure you don't have my problem. I did the FPR at a different time then the filter and damper, so the pressure had built back up. I'd recommend doing them all at the same time, too, to likely avoid this problem. Do the filter, damper, then regulator, in that order.
This post is now officially really long, but I'd also like to include the some of the other relevant PM that I've done that didn't seem to noticeably affect my power of MPG. Unless noted, no effect was noticeable.
- Running techron fuel system cleaner through the fuel (did wonders for an old Camry I had, but nothing for the cruiser.
- PCV valve and hose replaced
- Cleaned butterfly valve in throttle body
- Replaced air intake hoses
- Standard engine Oil/Filter
- OEM distributor rotor and cap
- OEM plugs and wires
- Throttle cable and kick down cable
- Timing adjustment to 10-11 degrees
- Adjusting idle screw (in combination with timing adjust, the drive and park/neutral idle speed came started to match at 650, where they used to be about 200 apart (650 in drive, and 850 in park/neutral)
- Valve clearance adjustment (I think I took way too long on this, and the engine got cold, so I feel like I need to do this again. The adjustment sounds right when cold, but when it warms up the clickety clackety of the engine seems to get noticeably louder)
- Replaced all fluids
I'm soon to replace my rear axle oil seals and bearings, replacing all soft/hard vacuum lines and EGR parts if I can find them (you can't get the EGR valve anymore, only the manifold), and will also be replacing the shocks/springs with OEM tokikos (fzj80 shocks, recc'd by CDan and others here on MUD for my use without heavy loads) and OME 861/862 low height replacement springs. I'll post up about that when I get to it. I'm thinking I'll get at least 1.5" from the replacement because my springs are really weak. It only takes about 200 lbs on the tailgate for the rear bump stops to bottom out. Completely empty with only the rear seats in the cruiser, the rear bumpstops are less than one inch away from bottoming out.
Well, that's all folks! Thanks for everyone's help!!!
Please let me know what you think I'm missing or that you'd recommend pursuing at this point.
Thanks,
Ryan
