Converting to a carburetor
- Thread starter Engir
- Start date
superj
Well-known member
I haven't done a 4.0 but i have done a few vehicles.
For you, an offenhauser intake for a 4.2 and holley 390cfm four barrel will work great. Thats what i out on my 87 wrangler and the gas mileage and power improved unbelievably. I tried the motorcraft two barrels everyone loves but the 390 holley was bette for gas mileage and performance.
That combination also let me keep all my engine accessories in place and still have an automatic transmission. I also upgraded my distributor using the ford parts, for more reliable spark.
you need to keep your fuel return line in place and use it to help lower the fuel pressure to what a carb uses. You can use a holley adjustable fuel pressure regulator and a t to let the excess pressure return fuel to the tank.
My wrangler would spin 32s all the way across an intersection after those mods.
I tried a weber 34, a weber 32/36, the motorcraft two barrle carbs in two different sizes, and then found that holley forncheap on ebay and dropped that in place. Since the primaries are small, it gets great mileage for normal driving and then when tou floor it and the secondaries open, the power comes in smoothly.
I actually am about to do a carb swap on an old bmw. I am just waiting for the intake to show up in the mail. Alot of people dont like carbs because they are old tech but i enjoy them. I likw fuel injection too but i really loce carbs. The little things about them and working in them are enjoyable to me
For you, an offenhauser intake for a 4.2 and holley 390cfm four barrel will work great. Thats what i out on my 87 wrangler and the gas mileage and power improved unbelievably. I tried the motorcraft two barrels everyone loves but the 390 holley was bette for gas mileage and performance.
That combination also let me keep all my engine accessories in place and still have an automatic transmission. I also upgraded my distributor using the ford parts, for more reliable spark.
you need to keep your fuel return line in place and use it to help lower the fuel pressure to what a carb uses. You can use a holley adjustable fuel pressure regulator and a t to let the excess pressure return fuel to the tank.
My wrangler would spin 32s all the way across an intersection after those mods.
I tried a weber 34, a weber 32/36, the motorcraft two barrle carbs in two different sizes, and then found that holley forncheap on ebay and dropped that in place. Since the primaries are small, it gets great mileage for normal driving and then when tou floor it and the secondaries open, the power comes in smoothly.
I actually am about to do a carb swap on an old bmw. I am just waiting for the intake to show up in the mail. Alot of people dont like carbs because they are old tech but i enjoy them. I likw fuel injection too but i really loce carbs. The little things about them and working in them are enjoyable to me
Engir
Member
What I dislike about FI is the computer and these computers have not changed since 87 as far as I know. I live in Costa Rica and do not need all the smog it is all disconnected some removed. I am wondering about any sensor this motor has is there a throttle sensor or anything else I have to remove?
superj
Well-known member
To get rid of fuel injection, you can remove everything but you might need to get a different distributor. You need to find out if your current distributor has vacuum or weight centrifugal advance or if its electronically controlled by the ecu. If its controlled by the ecu, you have to see if disconnwcting stuff lets it still work.
If yoouput a carb though, you can can get rid of tps and most of the other sensors.
Really, you could easily find a cj5/cj7 page and find what the early engines ran, like the 60s engines because they wouldn't have any computer stuff on them. That would tell you exactly what sensors tou need to get and what distributor works with no computer.
You just need to figure out what turns on the fuel pump, or change to low pressure electric fuel pump and let it get turned on by a relay in the fuse box if the regular fuel pump needs sensors you dont want anymore.
Its very easy to make jeep inline engines run old school. And costa rica means you probably wont even have to worry about having the choke set. You can probably just remove it, or set it so its stays at full open all the time.
You do need to make sure your speedo and stuff still works too, though
If yoouput a carb though, you can can get rid of tps and most of the other sensors.
Really, you could easily find a cj5/cj7 page and find what the early engines ran, like the 60s engines because they wouldn't have any computer stuff on them. That would tell you exactly what sensors tou need to get and what distributor works with no computer.
You just need to figure out what turns on the fuel pump, or change to low pressure electric fuel pump and let it get turned on by a relay in the fuse box if the regular fuel pump needs sensors you dont want anymore.
Its very easy to make jeep inline engines run old school. And costa rica means you probably wont even have to worry about having the choke set. You can probably just remove it, or set it so its stays at full open all the time.
You do need to make sure your speedo and stuff still works too, though
Hey! Converting from fuel injection to a 4 bbl carburetor on your 4.0 is quite a challenge, but definitely doable. The key will be selecting the right carb and intake manifold, as well as adjusting the fuel system. You'll also need to think about ignition tuning.Don't forget that the conversion may affect performance and fuel efficiency. It’s worth looking for guides or videos that show the process step by step. Good luck with your project!
Engir
Member
ThanksHey! Converting from fuel injection to a 4 bbl carburetor on your 4.0 is quite a challenge, but definitely doable. The key will be selecting the right carb and intake manifold, as well as adjusting the fuel system. You'll also need to think about ignition tuning.Don't forget that the conversion may affect performance and fuel efficiency. It’s worth looking for guides or videos that show the process step by step. Good luck with your project!
