Fuel Economy

What gas are you running? Ethanol added crap will give you less mileage than pure gas. The problem is that most of the ethanol free stuff is also high octane and expensive compared to the booze fuel.

Shell 87. Same crap I've been running from the same station for the last 8 postal years. It's the only branded gas station in town. Only time I run stuff from the other places is when there's an oil shortage and I have to buy whatever I can find. I wouldn't mind running ethanol free, but the only place I can get that is well out of the way and is about 60 cents/gallon more so any gain is offset by the price difference anyway.

I've got a game plan for tomorrow. I've got 4 new ACDelco plugs in my tool box plus another box coming tomorrow. So I'll drop those 4 in the back 4 cylinders and inspect my wires while I'm at it. Beat the dust out of my air filter again, maybe even change it. Work on cutting weight. Who knows? Maybe I'll get an extra MPG or 2 out of the deal. At this point I'm just trying to save up to buy a cheap 4 banger out of someone's yard and get it going. I've got my eye on a cavalier that's sitting at a mechanics shop. I know the old lady who used to own it so maybe that's an avenue for me.

Speaking of air filters, does anyone here think I might notice a real gain with my type of driving if I switch to a high flow filter instead of just the regular $10 ones?

After 3 years of owning this truck, and believing that it has been very well maintained by the original and only other owner because everything under the hood is dated with a mechanics marker (including the distributor), through closer inspection, I've come to realize that it still has the original plugs and wires in it. Yes, after market distributor, but original plugs and wires. I pulled the wires of of cylinders 1 and 5 (easiest to inspect when also rotating tires and checking brake pads) and the wires disintegrated. When I took the plugs out, I saw they were the original ACDelco 41-993s that come with this truck. The same ones that I'm replacing them with.

Since I don't have a set of wires handy, I borrowed a pair of wires off of another non-running vortec my dad has sitting at a mechanics shop and popped them in with 2 new plugs. I ordered a set of 10mm wires that'll arrive tomorrow. Once they come I can finish that up and remeasure my mileage. Hopefully I'll get a nice gain out of that.

Funny thing is even with the old plugs and wires in it, it still fires right up and purrs perfectly. Smooth idle, no misses, no backfiring, no hesitation. But with 180k on it, and 21 years, and a gazillion hours, that's got to be a part of the problem. I shoulda known.

Haven't had the time to tinker with it in the last few days but I did get my new plug wires in the mail. Just a suggestion, if it comes up in the future, you might suggest to customers to do something similar to what I'm doing here. Instead of just buying a set of wires purpose made for the 4.3L, I bought a set of performance wires for a small block or big block Chevy, which had the same ends on the wires, just a couple of extra wires, and they're a bit longer and 10mm instead of the regular 7 or 8mm. I don't know those wires will give much boost, but I'll have 2 spares in the toolbox and they won't perform any worse than the OE ones. Plus they were only $31. Paired with brand new ACDelco 41-993 plugs, maybe I'll save a quart/day, which will add up quick.

Here's a link to the wires I bought in case anyone is interested:

https://www.amazon.com/dp/B07LF95HLR/ref=cm_sw_r_cp_apa_glt_fabc_02JTVVC53HWXEZGP6SS2?_encoding=UTF8&psc=1

Well I finished up the plugs and wires. With the new ACDelco plugs and 10mm wires I did get a good carbon burning smell when I first started it and let it idle for a bit. I revved it a few times and it did ok but stumbled a bit in the 2-3k range. So I took it for a drive. First off I'll say I "think" I've got a better throttle response now. I drive it kinda hard. And it performed well. Hit it's gears fine. 0-80 was smooth. So the power is there. But at 1/4 throttle, there is a stumble on the 2-3k range still. It got better as I drove the truck, so maybe it'll work itself out. Or maybe it's time for some seafoam down the intake.

Any other ideas?

No lights. No codes, of course.

The image below is the from infamous cylinder #3 that many people hate fighting with (takes about 10 minutes if you know what you're doing). It definitely has some age on it. And it matches the other 5.

Look at those OSHA safety shoes LOL. That plug is easy if you know the trick, or bought the specific swivel socket for it.

Regarding your air filter it should be changed once a year along with fuel filter if dusty gravel road conditions more often on air filter. The other type you mentioned are good for filtering rocks out. Or racing not much else. You can't put in (air) more than the system was designed for.

No such thing as OSHA in my own garage. But are these better? They're my postal approved shoes.

HMAC that's what I was thinking but I just didn't know if it might make enough difference in the throttle response to actually help with my type of driving

It effects fuel mileage not throttle reponse as well as dirt through the engine

Those are a bit better. Air filter wise, unless you are replacing one that is full of dirt I've never seen any real increases, unless you are running a vehicle that really needs a lot of air like a blower or large turbo otherwise they pass a LOT of dirt and crud, plus the oil tends to mess with the MAF. Speaking of oils, you might try putting synthetics in all the boxes, might give a bit more.

On a hunch, I pulled a wire off of the distributor and compared the contact to one from an old wire. It's considerably more recessed into the boot. Probably by an inch. That would explain why I was thinking I heard arcing going on back there but I couldn't place the sound for sure due to my poor hearing. I'm thinking the random miss (I did finally get a P0300 code yesterday) code is due to a lack of contact between the distributor cap and the wires. So I'm going to shave 1/4 inch off of the boots and see how it goes. I'll shave another 1/4 inch off if needed.

What do you guys think?

Well I cut that 1/4 inch off of the boots. And then a little more off of the ones on the odd side of the engine because they still snugged all the way up to the cap. Now there's only an occasional miss. Much better. So I'll tinker a little more when the engine cools again. I also ran done seafoam through the brake booster line. That ought to get rid of any remaining carbon. I know it's a backyard mechanic trick, but it does work. Sky's the limits here. Maybe 10 mpg before long. And I still haven't got to the weight cutting.

Found you the solution to the problem, Right hand drive, enclosed van, 4X4, diesel available.
Not real cheap but a good solution rarely is... https://www.vanlifenorthwest.com/forsale

I was just there today, these four got to the yard within the last year (since the last time I went)

Revert back to the "Proven" / "Accepted"/ "Reliable" mail method. Inexpensive parts. Computerless. Permanent Code "PO (post office)EZ FIXIN'"

With the money you're spending, one of these could be back up and running with proven MPG modifications!

I feel like one of them will make it back to my house, hopefully a deal (as he's given me in the past) He and my brother and law are best buddies!

They might stop calling you the "mail blazer"/ "mail van" and you earn the "Mail Man" designation as did all of the previous Postal "JEEP" drivers were called!

The Medic

This is a costly idea, but would save you gas in the long run. They have software for remapping the fuel strategy. I watched a video on a shop that does it to hondas alot. It was pretty amazing, the software they were using had pre-sets for more power, better fuel economy, and settings in the middle. Obviously it changes the injector pulse with and shift timing etc. But theres some really cool stuff out there. Id do that instead of throwing a different motor in it. You'd have to buy the software and special scantool the plugs into the obd2 port. Google remapping fuel strategies. See what you can find. Atleast with a remap you wont be losing any power really. It will be running at a different air/fuel ratio, leaning it out but also compensating for it. Just a wild thought.

Just don't get caught remapping and vehicles in the US. The EPA is just waiting to go after folks.

Eh, it's 21 years old. I don't think the EPA would be watching me too closely. Besides, I get stopped at license check points and they never bother actually checking. They just assume it's valid because I'm a mailman. That fuel remaining sounds nice but pricey. But I'll definitely look into it. I know a lot of people around here, maybe someone has the right scan tool for the job.

For right now, I'm looking deeper into cutting weight if I can get some time and maybe gutting the cat.

I will say that with the plugs and wires done the beast is running better than ever. I even did a mean rain assisted burnout the other day

So, my brake booster died the other morning. I haven't had time to put another one in yet (can't get any time off, busy busy at home, you get it). Been riding routes slowly and carefully. To a point where it's taking me an extra hour and a half to run. But, it seems my fuel economy is up. Now I know some will say that's due to granny driving. And maybe a little is. But it needs the question, since I disconnected the brake booster with the massive vacuum leak, could that be giving me any serious bump in mileage? Is there a way to really see? Because I don't plan on driving like my normal self until it's fixed (maybe tonight).

If it is causing that much extra fuel use, is there ab affordable and safe way to convert it from a power brake system to non power brakes?

I know it sounds crazy. Just a thought.

I believe every thing that is vacuum is supposed to be a closed system.

Basically hydraulics, except in "Air" form----No air gets lost or gets added---just on or off actuation

The exception being the PCV, it's sorta like a vacuum cleaner, the air that passes thru it is replenished thru the other end(s) of the valve cover, usually via an air cleaner or a filter.

The "Extra air" the PCV draws in constantly is calculated into the needs of the carburetor (stupid #s example---92% or combustion air goes into the carb's throat----8% comes thru the PCV) ===The 100% used to mix with the fuel to get the mix as perfect as possible.

Stoich or 14 air to 1 fuel ratio

Cutting off (plugging PCV) or adding additional air (a vacuum leak--like the Booster) will mess up the correct burnMPGs will suffer in either scenario. Too much or too little air.
The Medic