New Here - Drive a 1989 YJ Sahara

canon07

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Feb 22, 2024
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St. George, Utah
Recently inherited this 1989 Jeep YJ and I know there's a ton I could do to make her more capable on the trials but at the same time I do want to keep using her as a daily driver so I don't want to do anything crazy...

I took her to Moab last summer and she did pretty good for the most part but every time the engine got too hot, which happened often going up slick rock, she vapor locked. I've switched to running only on ethanol-free gas and that seems to have helped but I know I still need to install fuel injection and ditch the Holly carb.

The clutch also just gave out and she's right now at the shop having that replaced. I probably should have done that myself but, well, that's a long story.

She's also got a whine in the transmission that never stops. It's an AX15 transmission. I've been told there's not much I can do about the whine other than having the transmission rebuilt.

I also just had the transfer case replaced after a rather unfortunate encounter with a deeper-than-expected washed-out portion of the West Rim Trail in Snow Canyon State Park.

She got open diffs so I need lockers, and I probably need to go up a few sizes on the tires, those are 31s on her right now. But I have no idea what steps to take to go up in tire size. The 31s already rub on the leaf spring if I turn the wheel all the way passenger side. It's got the stock Dana 30/35 combo and I think a 2" lift. Do I need to upgrade the axles to go up to 33s or 35s? Do I need more lift? What should I do first?

And on lockers, is it even worth putting lockers in a Dana 35? Should I upgrade the rear axle to a Dana 44 before I do that?

So really my question is, where do I start? What should be the first thing I tackle after the clutch? Replacing the carb? The transmission? Lockers? Lift? Tires?

And most importantly, how do I talk my wife into letting me spend thousands of dollars to get a 35-year-old Jeep ready to go off-road?


IMG_0972.jpeg
 
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First off, WELCOME!

Well, you have the winch. That's always my first recommendation. Make sure it's fully functional and you have all the necessary recovery gear to go with it.

I'd vote good tires first as tires can make or break your vehicles ability on the traction side of things, but you also mention lift and lockers.

If you are serious about a lift, then first I'd recommend a regear to a ratio that will work best with the tire size you want to go to in the end. Add traction aides at this time. I'm partial to truetracs myself as I do plenty of street driving and only enjoy light trail stuff (think washed out forest service roads), but lifting tires on more challenging trails can overcome them.

If the only issue with the fuel system is vapor lock, then get a small electric pump and install it in the tank on the pickup (if possible). I did this on my Grand Wagoneer's 360 before doing the LS swap and it solved the vapor lock issue completely. I used the low pressure in-tank pump from a mid 80s Ford truck with their early efi system. The in-tank pump is basically a lift-pump that supplies fuel to the high pressure unit on the frame, so it is rocking around 4-6psi and 25gph. Perfect for a carb. I shortened my pick up tube on the sending unit assembly and used a small section of rubber hose to attach the pump to the tube, making sure I measured the total length to put the pump's little filter sock within 1/2" of the tank floor. All you need is to supply a 12v when cranking/running and ground to it.

FWIW, the typical heights for tires are as follows:
up to 29"-stock
30" 1" needed (I did new stock springs and a 1" body-mount lift and it looks perfect)
31" 2-2.5" (most I've read really love Old man Emu stuff.)
33" most likely 4" from what I've seen.
You can always combine body and smaller suspension lift to help the wallet.
Note: pretty much any suspension lift is gonna require a SYE and/or new driveshaft to help with vibrations. The rear driveshaft in these things is stoopid short.

My best advice is take your time and eat the elephant one bite at a time.

Side note: Your wipers are 'parked' backwards (unless it's a RHD setup like mine) 😁
 
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First off, WELCOME!

Well, you have the winch. That's always my first recommendation. Make sure it's fully functional and you have all the necessary recovery gear to go with it.

I'd vote good tires first as tires can make or break your vehicles ability on the traction side of things, but you also mention lift and lockers.

If you are serious about a lift, then first I'd recommend a regear to a ratio that will work best with the tire size you want to go to in the end. Add traction aides at this time. I'm partial to truetracs myself as I do plenty of street driving and only enjoy light trail stuff (think washed out forest service roads), but lifting tires on more challenging trails can overcome them.

If the only issue with the fuel system is vapor lock, then get a small electric pump and install it in the tank on the pickup (if possible). I did this on my Grand Wagoneer's 360 before doing the LS swap and it solved the vapor lock issue completely. I used the low pressure in-tank pump from a mid 80s Ford truck with their early efi system. The in-tank pump is basically a lift-pump that supplies fuel to the high pressure unit on the frame, so it is rocking around 4-6psi and 25gph. Perfect for a carb. I shortened my pick up tube on the sending unit assembly and used a small section of rubber hose to attach the pump to the tube, making sure I measured the total length to put the pump's little filter sock within 1/2" of the tank floor. All you need is to supply a 12v when cranking/running and ground to it.

FWIW, the typical heights for tires are as follows:
up to 29"-stock
30" 1" needed (I did new stock springs and a 1" body-mount lift and it looks perfect)
31" 2-2.5" (most I've read really love Old man Emu stuff.)
33" most likely 4" from what I've seen.
You can always combine body and smaller suspension lift to help the wallet.
Note: pretty much any suspension lift is gonna require a SYE and/or new driveshaft to help with vibrations. The rear driveshaft in these things is stoopid short.

My best advice is take your time and eat the elephant one bite at a time.

Side note: Your wipers are 'parked' backwards (unless it's a RHD setup like mine) 😁
I was reading about the regearing last night and am pretty sure I'm still at the stock 3.07 ratio... Fifth gear is almost useless even on the freeway. I have to downshift on even the slightest incline. Although I am running 31x10.5x15 tires on her right now with everything else still stock so maybe that's why fifth gear is so useless...
 
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I was reading about the regearing last night and am pretty sure I'm still at the stock 3.07 ratio... Fifth gear is almost useless even on the freeway. I have to downshift on even the slightest incline. Although I am running 31x10.5x15 tires on her right now with everything else still stock so maybe that's why fifth gear is so useless...
Welcome, I'm new here as well. When my YJ looked like it does in my profile picture, I was running 33's on a 4" Black Diamond lift with the 3.07 gears, drove fine, road a little rough and yes, fifth gear is absolutely useless. I never had an issue with the Peugeot transmission, but once I decided to go all in on a resto-mod, that thing was outta there, replaced with an AX15 with the external slave and 4.88 Yukon gears, lockers & axles. It's not done but I've road in similarly geared Jeeps, so I know what to expect. All the best!
 
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Eh, no. Look up a Carter P74067. (in tank pump for 85 F250 w/302 efi-you'll also want the sock filter that attaches to the bottom.) You'll have to remove your sending unit in the fuel tank to fab it up. You want 100% push with electric pumps. Those cheapie external jobs never last long.

Iqx2H05.jpg


Here is how you'll mod the sender. FWIW, this is from an 84 Grand Wagoneer. You'll simply mimic the design. You need to make sure you have enough room below the sender electrics to mount. If the height is gonna be too short, you may have to bend the pickup tube at an angle, then mount the pump at an angle with it. You want the filter within 1/2" of the tank bottom.

After I did this, the vapor locking issues went away completely.
 
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Eh, no. Look up a Carter P74067. (in tank pump for 85 F250 w/302 efi-you'll also want the sock filter that attaches to the bottom.) You'll have to remove your sending unit in the fuel tank to fab it up. You want 100% push with electric pumps. Those cheapie external jobs never last long.

View attachment 122588

Here is how you'll mod the sender. FWIW, this is from an 84 Grand Wagoneer. You'll simply mimic the design. You need to make sure you have enough room below the sender electrics to mount. If the height is gonna be too short, you may have to bend the pickup tube at an angle, then mount the pump at an angle with it. You want the filter within 1/2" of the tank bottom.

After I did this, the vapor locking issues went away completely.
That part number comes up as an in-line pump... and the others on the list of pumps that fit the 5.0L F250 all have angles to them... will they go all the way down to the bottom of the YJ's tank?

 
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That part number comes up as an in-line pump... and the others on the list of pumps that fit the 5.0L F250 all have angles to them... will they go all the way down to the bottom of the YJ's tank?

Um. Nope. look again at what you linked.
It states:
Position : Front 2 Pump System Requires In-Tank & In-Line Pump

Front tank. As I stated in my 1st comment, this is a 2 pump system. It requires a low pressure in tank pump to feed a high pressure in line pump on the frame.

Now, click on that carter pump link on the page you linked:
'ELECTRIC FUEL PUMP'

Look at the specs...

Inlet Type: Strainer (hard to be an in-line pump without a hose style inlet fitting)
In Tank or External: In Tank (can't be an in-line pump when located in the tank)


Also, you're misunderstanding what you're looking at.

Those 'pumps' with angles are NOT pumps. They ARE complete sending unit assemblies. The pump is serviceable on them, meaning, you change just that pump.

Now follow me here.

You will NOT be using a F250 sending unit assembly.

You WOULD be modifying the YJ's EXISTING sending unit by integrating a F250 PUMP ONLY to the YJ's sending unit.


Again, refer to my last post. The sending unit you see is for a Grand Wagoneer.
From the factory, it did NOT have that pump on it. That pump is from a F250

The Jeep sending unit was MODIFIED to accept a F250 IN TANK fuel pump.
 
Um. Nope. look again at what you linked.
It states:
Position : Front 2 Pump System Requires In-Tank & In-Line Pump

Front tank. As I stated in my 1st comment, this is a 2 pump system. It requires a low pressure in tank pump to feed a high pressure in line pump on the frame.

Now, click on that carter pump link on the page you linked:
'ELECTRIC FUEL PUMP'

Look at the specs...

Inlet Type: Strainer (hard to be an in-line pump without a hose style inlet fitting)
In Tank or External: In Tank (can't be an in-line pump when located in the tank)


Also, you're misunderstanding what you're looking at.

Those 'pumps' with angles are NOT pumps. They ARE complete sending unit assemblies. The pump is serviceable on them, meaning, you change just that pump.

Now follow me here.

You will NOT be using a F250 sending unit assembly.

You WOULD be modifying the YJ's EXISTING sending unit by integrating a F250 PUMP ONLY to the YJ's sending unit.


Again, refer to my last post. The sending unit you see is for a Grand Wagoneer.
From the factory, it did NOT have that pump on it. That pump is from a F250

The Jeep sending unit was MODIFIED to accept a F250 IN TANK fuel pump.
And the light bulb goes on! Now I get what you’re saying. Thanks for the wisdom. That makes total sense.
 
And the light bulb goes on! Now I get what you’re saying. Thanks for the wisdom. That makes total sense.
Hey, I'm a visual person as well. Youtube university helps a lot. :LOL:

Now, what will be important is making sure you can adapt that pump to your sending unit. Well, it WILL work, but you may have to get creative.
The big issue will be tank depth vs overall length of sending unit + fuel pump.

You want the pump screen to be about 1/2" from the bottom of the tank.
This allows maximum fuel usage without sucking up sediment into the screen and clogging it.

Since you don't want to lose the fuel gauge function, you can't just cut the sending unit pickup tube anywhere.
It needs to be cut BELOW the electrics mounted on the pickup tube.

VERY IMPORTANT: Use a tubing cutter to cut the pickup tube. NOT a saw. That will leave fine burrs and metal dust to get sucked into the fuel system.

This may cause the sender and pump to be too long for the tank depth.
If this turns out to be the case, you would need to CAREFULLY bend the pickup tube BELOW the electrics at enough of an angle to allow the pump screen to sit close to the bottom. The pickup tube will kink easily, so a tubing bender for brake lines may come in handy.

The fuel pump I linked typically comes with a short section of rubber hose and some dinky plastic clamps. I use metal screw clamps instead. Using the hose, you connect the pump to the pickup . Again, refer to that picture of the modified sending unit. It shows the setup pretty well.

You will then need to connect a positive and negative wire to the pump and run them to a engine start/run source. This means you'll need to drill a small hole in the sending unit top plate for the wires to pass through. Make sure to use a rubber grommet to protect the wires from chafing. You also want to dab a bit of fuel safe sealer on the grommet to prevent fuel from leaking when you fill the tank all the way up. (Ask me how I figured that out).

The pump I purchased didn't have a positive or negative marking on the terminals. So, I tested the pump and wiring by submerging it in a small bucket of water (for safety, didn't want it to shoot fuel into my face) to make sure the electrics were connected correctly. Then ran it just enough out of the bucket to purge the water. You don't want to run fuel pumps dry for very long at all.
 
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Hey, I'm a visual person as well. Youtube university helps a lot. :LOL:

Now, what will be important is making sure you can adapt that pump to your sending unit. Well, it WILL work, but you may have to get creative.
The big issue will be tank depth vs overall length of sending unit + fuel pump.

You want the pump screen to be about 1/2" from the bottom of the tank.
This allows maximum fuel usage without sucking up sediment into the screen and clogging it.

Since you don't want to lose the fuel gauge function, you can't just cut the sending unit pickup tube anywhere.
It needs to be cut BELOW the electrics mounted on the pickup tube.

VERY IMPORTANT: Use a tubing cutter to cut the pickup tube. NOT a saw. That will leave fine burrs and metal dust to get sucked into the fuel system.

This may cause the sender and pump to be too long for the tank depth.
If this turns out to be the case, you would need to CAREFULLY bend the pickup tube BELOW the electrics at enough of an angle to allow the pump screen to sit close to the bottom. The pickup tube will kink easily, so a tubing bender for brake lines may come in handy.

The fuel pump I linked typically comes with a short section of rubber hose and some dinky plastic clamps. I use metal screw clamps instead. Using the hose, you connect the pump to the pickup . Again, refer to that picture of the modified sending unit. It shows the setup pretty well.

You will then need to connect a positive and negative wire to the pump and run them to a engine start/run source. This means you'll need to drill a small hole in the sending unit top plate for the wires to pass through. Make sure to use a rubber grommet to protect the wires from chafing. You also want to dab a bit of fuel safe sealer on the grommet to prevent fuel from leaking when you fill the tank all the way up. (Ask me how I figured that out).

The pump I purchased didn't have a positive or negative marking on the terminals. So, I tested the pump and wiring by submerging it in a small bucket of water (for safety, didn't want it to shoot fuel into my face) to make sure the electrics were connected correctly. Then ran it just enough out of the bucket to purge the water. You don't want to run fuel pumps dry for very long at all.
I hear you on the fuel leak issues... The filler cap leaks anytime I go up a hill with a full tank of gas. New cap didn't change a thing so I'm thinking I'll replace pretty much everything from the filler cap to the tank while I have the tank out as well. Thanks for all the advice!
 
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I hear you on the fuel leak issues... The filler cap leaks anytime I go up a hill with a full tank of gas. New cap didn't change a thing so I'm thinking I'll replace pretty much everything from the filler cap to the tank while I have the tank out as well. Thanks for all the advice!
Okay so here's what I ordered...


And here's what I got... I did not get the green strainer... and I got installation instructions for an "In-Line Fuel Pump..." So I'm thinking they just goofed up on the instruction manual - which I didn't really need anyway – and I need to contact them about the missing strainer because this pump looks pretty much exactly like your picture except for the missing white strainer you had on the bottom. Also, how did you connect the wires to the pump? Just wrap the wire around and tighten it down? Do you need to do anything to prevent corrosion or sparks inside the fuel tank? And last - at the risk of asking a dumb question, I assume the plastic bag you have around the assembly in your pic came off before it went into the tank?

IMG_4019.jpg
 
Okay, you definitely want the strainer.

I just drilled a small hole in the top of the factory sending unit plate (make sure nothing important is on the other side) and used a rubber wire grommet just big enough for the 2 wires to slip through.

Do not just wrap the wiring. This is automotive, not house. Use crimp style wire connectors.

Go to your local auto parts store and buy a crimp style wire connector assortment. It'll have assorted connectors (butt, female/male spade, and eyelets) in the different gauges. Red=18-22, Blue=14-16, and Yellow is 10-12 gauge.
Here is what you're looking for: https://www.oreillyauto.com/detail/...rminals/cti0/86694?q=Wire+connector+kit&pos=0

Buy a decent wire strip/crimp tool tool (you don't have to go fancy, just a basic one version).
This one will do just fine for what you need
https://www.amazon.com/VISE-GRIP-Stripping-Cutter-8-Inch-2078309/dp/B000JNNWQ2/?tag=yjforum-20

You'll use the eyelet connectors to connect to the pump. Back the tiny nuts off the studs, and slide the eyelet connector on underneath the lock washers and tighten the nuts back down.

Yes, the plastic bag in the picture is a dust cover to keep crap out of the pump while sitting in the shop.
 
welcome, that a lot of money for a daily drive, i can understand what you mean " getting my wife to understand" bumper to tail light your always right with the square lights. safe driving
 
I took my wife with me. “If we had on board air I could air down the tires and the washboard roads would be much smoother”. We put together a CO2 tank system. “If we had sway at disconnects those potholes wouldn’t rock the jeep so much”. We now have sway bar disconnects. “ If we had lockers we would’ve easily made it up/through that instead of struggling”. Lockers are on order. This didn’t happen overnight but it was easier on the budget and she saw the value of it.
 
Okay, you definitely want the strainer.

I just drilled a small hole in the top of the factory sending unit plate (make sure nothing important is on the other side) and used a rubber wire grommet just big enough for the 2 wires to slip through.

Do not just wrap the wiring. This is automotive, not house. Use crimp style wire connectors.

Go to your local auto parts store and buy a crimp style wire connector assortment. It'll have assorted connectors (butt, female/male spade, and eyelets) in the different gauges. Red=18-22, Blue=14-16, and Yellow is 10-12 gauge.
Here is what you're looking for: https://www.oreillyauto.com/detail/...rminals/cti0/86694?q=Wire+connector+kit&pos=0

Buy a decent wire strip/crimp tool tool (you don't have to go fancy, just a basic one version).
This one will do just fine for what you need
https://www.amazon.com/VISE-GRIP-Stripping-Cutter-8-Inch-2078309/dp/B000JNNWQ2/?tag=yjforum-20

You'll use the eyelet connectors to connect to the pump. Back the tiny nuts off the studs, and slide the eyelet connector on underneath the lock washers and tighten the nuts back down.

Yes, the plastic bag in the picture is a dust cover to keep crap out of the pump while sitting in the shop.
@dodgerammit Thanks so much for all the tips on the fuel pump. It's installed and working great! Went Jeeping in Sand Hollow State Park last weekend with temps in the 100s, made it all the way up to the top of the world, and watched the engine temp climb, even had quite a few stalls (my son is still not super proficient with driving stick and I let him do the driving) so plenty of opportunities for heat soak and not once did we get vapor locked!

I actually have two extra pumps now sitting on my workbench in my garage - Carter sent me two extra pumps instead of sending me the strainer when I called to complain they hadn't included the strainer they showed in the picture of the item on Amazon. I wound up just buying a strainer from AutoZone because I got tired of waiting for Carter to ship a $5 part.