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post #1 of (permalink) Old 03-18-2004, 07:30 PM Thread Starter
 
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4.3 carb help

hi guys--i'm over from the suzuki forum hoping one of you can help!! i just finished a 4.3/2004r swap into my samurai--got it running great, but getting TERRIBLE fuel economy. it has an edlebrock performer (non egr) manifold & a 500cfm edlebrock 4bbl & i can't get over 8-10 mpg. i rebuilt carb, running a fuel pressure reg set at 4-5 psi. it turns about 2800rpm at 70mph & runs really strong--any ideas???

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frank
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post #2 of (permalink) Old 03-19-2004, 12:51 AM
 
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Re: 4.3 carb help

I had pretty much the same setup but on a chevy 305. I ran 650cfm edelbrock 4bbl. Where do you have the timing set at? Did the engine get rebuilt? Still have stock cam?

2800 rpm at 70mph is pretty high. What's your gearing and what tires are you running? With that high rpm, I would guess your somewhere in the mid 4s for your rear. This gives you great low end torque but your gas mileage will suffer. I have 3.73 gears running 285 75R 16 tires on a 96 K1500 with a 350. It runs around 2000 rpm at 70mph.

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post #3 of (permalink) Old 03-19-2004, 08:13 AM Thread Starter
 
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Re: 4.3 carb help

engine is stock except for intake & carb--timing set to spec,plugs good, etc--no misses or black smoke indicating rich condition. 3.73 gears with 33" swampers--however i'm using the zuk transfer case, which is not 1 to 1 in high gear--it has about 9% reduction if i remember right. my wife's '03 sonoma crew cab with 4.3 turns about [email protected] 70 so i figured i was turning too high--might have to go with different transfer case, though i have everything set up for the divorced zuk case!!
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frank
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post #4 of (permalink) Old 03-24-2004, 10:29 PM
jeepxj66
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Re: 4.3 carb help

How are you figuring mileage? Is your speedo correct? Tires are not stock and niether is the tranny so it would be unlikely the speedo is correct. To get mileage that bad I would think you would be running real rich and since you are not I think the problem is elsewhere.
post #5 of (permalink) Old 03-27-2004, 02:17 PM Thread Starter
 
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Re: 4.3 carb help

i'm figuring the mileage over a known distance since my speedo is about 14% off. i put in the heaviest step up springs at the advice of an edelbrock tech--runs better, but if it helped fuel economy it wasn't much. i am running bosch platinum plus plugs & they are a nice gray/tan color, so it's jetted pretty close. it carburetes pretty much flawlessly so i don't know what to try next!! one thing is that with the 8" lift it's like a big brick going down the road!! any other ideas appreciated!!
frank
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post #6 of (permalink) Old 03-27-2004, 05:55 PM
 
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Re: 4.3 carb help

I think you've hit the brick wall [img]images/graemlins/laugh.gif[/img] [img]images/graemlins/laugh.gif[/img]. As you said, it's like a brick going down the road. With the larger tires, higher gears, taller stance, it's pretty difficult to get much better. If you do find something that helps, please share. I know alot of people looking for ways to increase gas mileage.

1 last question. Is the 4.3 being computer controlled? If so, maybe a reprogram for better fuel economy would help. But with all the mods you've made, I'd assume yours is not.

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