Mileage update...

Torque Junkie · November 2, 2001

Well, since I replaced the vacuum advance canister, my mileage dropped to exactly 10 mpg. ???

33 gallons

332 miles.

Could it be overly advanced or did I retard the baseline too much? (I don't notice any detonation w/ 87 octane fuel)

-Mike

Torque Junkie · November 3, 2001

Figured out why. For some reason my timing self-retarted itself from where I had set it with the new vacuum canister. Must have been in the time from setting it and tightening the bolt, becuase I didn't check it after tightening.

Fixed it now, so we'll see next fillup.

76BBSub · November 4, 2001

Yep...I'm still waiting to use up enough gas for the first fillup since I installed the new distributor...should be sometime this week, I'll let you know what I get.

Jeff

pacodiablo · November 6, 2001

10 mpg?!?! dang!

Torque Junkie · November 6, 2001

Quote from pacodiablo, posted on Nov. 05 2001,7:21

10 mpg?!?! dang!

Yup!

Ahh, the beauty of a classic Inefficient carburetors, bulky weight, and no overdrive!

I'd still take financing 10mpg for a truck I own outright than financing $26,000 for a brand new one that gets 16 mpg, plus, after I'm done all my work (timing set properly, O/D Tranny swap, bigger tires to compensate for the 4.56 gears already in place, etc) to my truck, 14 mpg is not out of the question

76BBSub · November 6, 2001

Well, I had a little time to kill at lunch yesterday so I went ahead and filled up although I had only gone about 300 miles on this tank. My MPG has dropped too, to 9 mpg from 10. Now, part of the problem is likely to be my right foot...the extra power since I put in the new distributor is quite addictive, so I'll try to tone it down for this tank and see what I get. I really want to do some highway driving and see the mileage there, I expect it to improve. But most of my driving is around town, to work, to the auto parts store, etc.

And I agree with Torque Junkie...I had a '99 GMC Sierra X-cab with all the bells and whistles, sold it outright when I got the Sub into shape. No payment, no full coverage, and as little as I drive I'll take a 50-60% increase in gas costs over the payment any day ($24K truck). It makes my road trips more expensive, but alot more interesting...Also, the depreciation is gone on the Suburban, it will most likely begin to increase in value (slightly) over the next few years. The '99 had nowhere to go but down.

Jeff

patrick · November 6, 2001

Quote from pacodiablo, posted on Nov. 05 2001,6:21

10 mpg?!?! dang!

I WISH I got 10 mpg on mine

Torque Junkie · November 6, 2001

Very good point, Jeff. Classics tend to appreciate instead of depreciate (assuming you take care of them, of course) Plus, the uniqueness of a very well kept older truck vs a run-of-the-mill brand-new one is worth the extra gas alone. You see thousands of new trucks, but very few nice old ones.

That sucks about your mileage. That's part of my problem too. I don't get on it very often but when I do, I can almost watch the guage drop with the increase of the tachometer.

Good luck next tank!

Patrick - What kinda mileage are you pulling with that 402?

patrick · November 6, 2001

it actually isnt that bad.. i get between 7 and 9, depending on how I drive

it is 10 miles each way to and from work, and when I drive the truck, i go through a good 8th tank in a day

pacodiablo · November 7, 2001

i get 17mpg!! when i had my V10 i got between 11-14mpg

76BBSub · November 7, 2001

It costs fuel to make power...ain't nothin' free in this world!!

Jeff

patrick · November 7, 2001

Granted, the truck is running a little rich right now, but what kind of mileage did you expect on these, Paco?

pacodiablo · November 7, 2001

14mpg

patrick · November 8, 2001

Quote from pacodiablo, posted on Nov. 07 2001,5:19

14mpg

Not even when it was new....

textruckr · November 16, 2001

I had the same problem. I was getting close to 15 mpg on the 'Burban' and then I started messing around with the timing. It had an intermittent miss at idle that was driving me crazy. It didn't cause any driveability problems, but I like a smooth-as-glass idle. I went through and changed all of the vacuum lines, new plug wires (excellent quality ones too) and went with a new distributor , cap, rotor and topped it off with a Summit Racing hipo coil. I set the idle speed up 50 rpm over the label and then set the timing as sepcified.

Mileage is now down to about 11 (the same as our dooley) but the power is much better.

I advanced the timing a little more and we are up to 12 now.

I had hopes of keeping 15, but I guess those days are gone now. I guess that I couldn't expect more with it having the RV cam and Quadrajet.

I agree with everyone else about being better off without payments. haven't had a vehicle payment in over 5 years now. When we decided we "needed" a Suburban, we couldn't believe how well they held their resale value. We ended up buying the '86 GMC because it was a customized one and the body and interior were in excellent condition. It had 188k on it, and the head was cracked. We got it for $2800. After having a rebuilt engine dropped in (with a few goodies like the RV cam and hipo oil pump), the transmission rebuilt and a new paint job it is just as good as some of the other ones ('92 to '96) we looked at. And better yet - no payments!