FJ40JOHN
SILVER Star
Now I really have to wait for the 20-25% off sale
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Even after smoothing out the fuel and ignition curve with a true de-smog and a city racer carb, I can still feel the secondaries come on and off. It’s just an observation, but it’s there.
It works and the truck drives as I imagine it should, but it sure would be nice to have it pull completely without a dip in acceleration from 690-3800 rpm.
I think this efi is the only way to achieve that.
Just to be clear I don't have a afi kit. Mine is a pieced together tbi system I put together from used parts and programmed myself. I was getting around 16mpg highway with mountain passes with one of my older programs. For killer fuel mileage Chet Wagner is the guy to get a hold of. But I don't think he's been on here for years. He built his own port injection system and was supposedly was getting low 20s. If he programmed a tbi it too would probably get excellent mileage. I tried to email him a while ago and got no response. I think most of the higher fuel mileage numbers come from having a timing curve that is advanced enough at cruise rpms to burn all of the fuel completely.Man this just makes we want something else.. I really should start an in-depth mpg troubleshooting guide/thread. Currently on my second full tank since swapping @HemiAlex carb in and like he said above, I can actually anticipate and feel when the secondaries kick in with his carb. This tells me there was something seriously wrong with mine as I NEVER had the feeling except maybe when I first purchased her, definitely not after the head and carb rebuild.
My biggest issue is that I commute a max of 15 miles to and from work a day and with that I get an abysmal 8mpg. Throw some highway driving in there and it will go up some but never what other claim of getting a normal 10/14mpg. Best I ever got was this time last year when I went on a club run and we did close to 250 miles of just pure highway driving and she pulled 13.6mpg. I was thinking about spending the $2k this year on getting an EFI setup of some sort (AFI vs FiTech vs. Holley vs. 2FE) and going from there as I feel that the engine itself is still in pretty good shape. But then I wonder if I would be better off just suffering for now as I don't plan on ever getting rid of this truck and thus one day anticipate a diesel or V8 swap. And when guys like @White Stripe talk about their 40 with 35s and an AFI system getting great gas mileage, well that throws me for a loop as well.
Man this just makes we want something else.. I really should start an in-depth mpg troubleshooting guide/thread. Currently on my second full tank since swapping @HemiAlex carb in and like he said above, I can actually anticipate and feel when the secondaries kick in with his carb. This tells me there was something seriously wrong with mine as I NEVER had the feeling except maybe when I first purchased her, definitely not after the head and carb rebuild.
My biggest issue is that I commute a max of 15 miles to and from work a day and with that I get an abysmal 8mpg. Throw some highway driving in there and it will go up some but never what other claim of getting a normal 10/14mpg. Best I ever got was this time last year when I went on a club run and we did close to 250 miles of just pure highway driving and she pulled 13.6mpg. I was thinking about spending the $2k this year on getting an EFI setup of some sort (AFI vs FiTech vs. Holley vs. 2FE) and going from there as I feel that the engine itself is still in pretty good shape. But then I wonder if I would be better off just suffering for now as I don't plan on ever getting rid of this truck and thus one day anticipate a diesel or V8 swap. And when guys like @White Stripe talk about their 40 with 35s and an AFI system getting great gas mileage, well that throws me for a loop as well.
To add to this regarding mileage. My FJ60 weighs ca. 5500 lbs loaded with all the junk in it. I have mileage robbing roof rack, larger mirrors, and lift. The 2F has 200+k miles on it with a fresh JimC carb and recurved dizzy. The exhaust is a 3FE manifold. My typical mpgs were in the 10-13 range. A few weeks ago I swapped in a 88C t-stat because the cabin was cold. Engine temps now run at 195F and mileage has gone up to 15 while interstate cruising at 65-70 mph.
Man, I really feel that the carb was just a lucky change on yours. Something has to be off in a really simple place for your ups and downs of tuning the truck.
Haven't cleaned the ground unit and already have @Fourrunner's kit, that was one of the first things I purchased for BeBe.Have you cleaned the sending unit ground yet at the tank? That changed my truck.
Also, I really suggest one of @Fourrunner ’s battery cable kits to make sure you’re not getting bad grounds.