Guys, I hope you can help me with this one.
After doing my introduction, let me get to my persistent problem on the fuel economy of my ride.
I'm getting about an average of just over 8 mpg on this truck (A/C is always on with our weather). A long time ago I took it on a long trip, 340 miles, and I think it got about 20 mpg.
We don't have interstates or that much hi-way around here so this is all pure city driving. It's just an alternate ride so I have the convenience of using it whenever I just want or need to. My office is just about 6 miles from my house and when I put in about 2.6 gl of gas, I have used a significant amount of it when I get back home. I barely run into any heavy traffic with such a short distance.
Everything about the engine for the longest time was stock and with the Mikuni carb. It has more than 81000 miles on the odometer. I never had any issues like stalling, hesitation, stumbling, dieseling, low power, etc. To the best of my knowledge, this is timed and tuned as can be and can do 75 mph on the hi-way effortlessly. The engine will start as soon as you turn the key even if I haven't used it for more than a week. Only last March, I had a problem with loose compressions with piston 2 and 3 because of the gasket. Took the engine apart and while we were at it, had new valves installed. The pistons, although sooty, were in great condition.
So, as the title of the thread suggests, to solve my only problem of this poor fuel economy (after months of research and lurking on this site) I was able to do the Weber 32/36 DFEV conversion last weekend. I had a mechanic with me and I made sure he followed the installation and tuning instructions.
The only thing we were not able to do was install an electric fuel pump, regulator and another filter before the weber carb.
Sunday evening, I took it our for a test drive part hi-way and city. In my assessment, it did just around 10 MPG and there was hardly any traffic. I didn't get any WOW reaction and was totally overwhelmed with disappointment. I had dreams of making it a daily drive and for now I guess I will have to keep on looking for a solution.
My question now is:
1. What did I do wrong with the install?
2. Could there be other reasons for the poor fuel economy? Aside from the carburetor, is there anything else that can make this truck do anything close to 20 MPG?
Any insights, thought or suggestions would be great guys.
If I left out any info that you need to know just ask away.