89 Wagoneer... 6 mpg

[WSC]

To the FSJ faithful:

My daughter and I have been working toward getting her 89 Grand Wagoneer on the road for a year or so... she's going to be 16 in a little over a month. We're getting 6.7 mpg at present and she is understandably discouraged that she will ever really be able to drive it. I promised to take it to a shop I searched out which I think can get it up to its original 11 mpg but... here's the question.

The GW has a 360 which was evidently rebuilt close to the time we bought it. We live in Minden, NV and I think the restrictions on our cars for smog control modifications are minimal. We are harboring the suspicion at the moment that the carb is sorely in need of a rebuild.

* What is the best milage we could get out of this engine for a reasonable cost?
* What would be the best mileage we could get out of this engine?
* What engine swap would be a better mpg choice?

BTW: While not wanting to limit discussion, otherwise we are Ford centric.

I would like the car to continue improving in it's off road ability.

Bill

[Ristow]

that thing should be able to get in the 12 mpg overall average range easily.

is the power valve in good working order?

what's your base timing set to?

is the vacuum advance in good working order?

have you set the idle mixture with a vacuum guage?

[AMX factor]

I agree with Ristow should be in the 12mpg range.

Sounds like that carb need rebuilt badly. Also the usual suspects, plugs, wires, timing, check for vac leaks, pvc, etc.

Putting a different motor is not gonna do any better for you. The hours of work & cost to install any other motor to gain 3-4mpg is not worth it. Also remember that any vehicle shaped like a brick and weighing over 4,000 lbs is not gonna get super mileage.

If you want to do motor work look at a bigger camshaft and 4 barrel carb. My 87GW had a stock 215,000 360. I installed a 260H Comp Cams camshaft, Edelbrock Perfomer intake and Edelbrock 625 carb. Mileage went up to 14 on average. The orig 360's were under cammed.

[YellowJeep]

The hours of work & cost to install any other motor to gain 3-4mpg is not worth it.

You sure about that? If you drive 15000 miles a year at $3.50 a gallon, the difference between 12MPG and 16MPG is about $1100! I'm not a ford fan in the least bit, but a nice late model mustang motor swap would be cool (4.7??) GM motors are the popular swap...others have had good luck with their diesel swaps. I'm swapping a late model GM 5.3 motor in my rig.

As for the existing motor...12-13 seems to be pretty average. I would agree to take a good look at the carb. Or, better yet, replace it with a junkyard GM TBI setup for a few $$s. That should bet a little better than 12-13 (don't expect miracles) add some reliability as well.

Good luck with your project!Q

[Wagabond]

With a well tuned carb you should be able to get 14 max. It's not the engines after that as much as the trannies. lack of OD is the difference between old rigs and new, more than the engines. That and they dyno them at 6000rpm to get recackulous HP numbers.

[79-88fsj]

yea the past week I got about 14.5 mpg mostly highway(well back roads with no stops for miles) past 2 month 13mpg. I have a 88 wag with no mods exept the cat and muffler is removed fresh plugs and wires and rebiult the carb also has the jeep steel wheels insted of the aluminium ones. I drive the crap out of my truck about 10mph over the speed limit its got 188000 miles and runs good I expect the bottom to fall out soon it cant run perfect forever

So basically tune it up and rebiuld the carb and that should put you somewhere near 10-13mpg

[shimniok]

The GW has a 360 which was evidently rebuilt close to the time we bought it. We live in Minden, NV and I think the restrictions on our cars for smog control modifications are minimal. We are harboring the suspicion at the moment that the carb is sorely in need of a rebuild.

I suppose this has already been covered but this is almost certainly due to a blown power valve. Mine was getting 7mpg in that condition and it jumped to 10-11 after repair and that is with tall tires. A lot of opinions surface about gas mileage. I have tracked mileage on all my cars 99% of the time since I've owned them. That's 10 years of history for the 86 and 3 or 4 for the 85 before I sold it. Figure on 11-12 city, 13 hwy. Others have done better, some worse. It'll cost you about $20-60 for a rebuild kit depending on where you get it and a few hours of your time if you're so inclined to DIY.

No engine swap is going to pay for itself in gas mileage. I'd leave well enough alone. If you want to eke out another 1-2 mpg, consider ordering a QuadraJet carb from JET performance and having them tune it to your specs.

Michael

[WSC]

Great responses all!

Thanks guys... you've not only given me a lot of good ideas but you've given me hope! I'd be interested in any links to articles on that GM TBI swap I heard a couple of mentions on. My oldest boy and I might be able to figure out how to do it with a little help. We chanced apon the Edlebrock Intake manifold and EFI last night and drooled at everything but the price. That GM swap sounds tantalizing.

Bill

[Ristow]

i've not seen any evidence of a TBI giving any better mileage over a properly set-up carb,and the m/c carb you currently have is among the best for economy,also,they have an excellent choke system,in sub-zero weather mine would immedietly start,and stay running,with one tap on the accelerator prior to cranking.

[YellowJeep]

http://www.ifsja.org/forums/vb/showthread.php?t=69362

All the info you could need...especially in the binder forums.