Crappy running 85 GMC.

[Irishman999]

SO you've got some leaking valves huh??? The good news is, you're leaking vavles won't leave you stranded. They will hurt performance and hurt mpg, but won't leave you broke down on the side of the road. You know what you gotta do. Eventually, you need one of those GM $1300 crate motors. I have to say, I'm fairly impressed with my 85 K1500's performance, and so far, I am exstatic with the mpg. I put $20 in the 84 C20 and it last about this long, I put $20 in K1500 and its seems I get over 1 1/4, closer to 1 1/2 the distance. Maybe I'm just not driving as much, but is sure seems I don't stop for gas near as often in the K1500. 2 factors, Small Block vs Big Block, and 3.73 gears vs 3.21 gears. Those 3.73's are much peppier taking off and most of driving is in town. I still think my 84 C20 with the 454 will do much better with 4.10's. And your truck with a manual trans, oughta do even better in mpg.

This has been throwing my head through a loop lately, I have a record of all the times I filled up and divided the average amount of fuel I bought compared to miles and came up with the figure of 16 miles to the gallon highway.

It sounded wrong so I checked the online statement against a map of my trip to be sure and sure as ****... I am getting an average of 16 MPG with a 305 and Carter AFB. The 07 sierra I was driving advertised 17 mpg and it was a 2wd with modern fuel injection.

Explain that one to me.

 

[crazy4offroad]

Was the 07 Sierra a 5.7? You could do a couple ticks bettwe on mpg with the 305, and keep in mind "advertised" mpg on the newer vehicles may not be real-world mpg. I would be happy to get 16 mpg out of mine, it gets around 8.

 

[HotRodPC]

I have a feeling your odo maybe running fast and these 17 miles and not quite miles. Never know though. One way to check it, is using mile marker signs on the side of the interstate. Going from marker to marker, watch your tenths and see if you really get 10 tenths per mile. I have a feeling you're getting 11-12 tenths per mile.

 

[Irishman999]

I have a feeling your odo maybe running fast and these 17 miles and not quite miles. Never know though. One way to check it, is using mile marker signs on the side of the interstate. Going from marker to marker, watch your tenths and see if you really get 10 tenths per mile. I have a feeling you're getting 11-12 tenths per mile.

No odometer involved, I used googlemaps for the mileage info and the bank statement page to see how much I spent.

 

[83K5guy]

like you said if it is accuate why the hell isnt this new more exspensive vehilces with FI knocking down alot better mileage. I just dont understand. Im sure emmisioins is part of it but dam. I am heavily thinking of selling the 05 sierra and buying another square. the wife thinks its stupid because ill be putting money into every week. I told her well look at my payments that would take care of the money i may have to put into it eventually.

 

[bucket]

Well if it's starving for fuel but still runs good enough to get the truck moving just fine, I can see that kind of mileage out of it.

I realize my '84 is 2wd and shorter, but it's a 305 without overdrive. I recently got 18.7 mpg on a 140 mile trip, but that was at speeds of 50-60. I get about 16 mpg on every tank.

 

[Jims86]

like you said if it is accuate why the hell isnt this new more exspensive vehilces with FI knocking down alot better mileage. I just dont understand. Im sure emmisioins is part of it but dam. I am heavily thinking of selling the 05 sierra and buying another square. the wife thinks its stupid because ill be putting money into every week. I told her well look at my payments that would take care of the money i may have to put into it eventually.

Because the new trucks/suv`s are heavier than hell. And, Emissions equipment does not affect vehicles like it did in the late 70`s early 80`s........unless you believe what the old farts are talking about while hanging out in front of the barber shop.

 

[HotRodPC]

No odometer involved, I used googlemaps for the mileage info and the bank statement page to see how much I spent.

Oh hell, if I did it that way, I'd probably end up with 25mpg. Don't think I'd call that very accurate.

 

[HotRodPC]

like you said if it is accuate why the hell isnt this new more exspensive vehilces with FI knocking down alot better mileage. I just dont understand. Im sure emmisioins is part of it but dam. I am heavily thinking of selling the 05 sierra and buying another square. the wife thinks its stupid because ill be putting money into every week. I told her well look at my payments that would take care of the money i may have to put into it eventually.

Also look at power. We're getting alot more power a little better fuel economy back then. Back then you'd have 185hp motor and get about 14-15. Today you get 300-320hp and 17-21mpg. I'm sure if we ran 200hp motors we could get better fuel mileage. Also consider, transmission are now overdrive. That means there are more parts in them, even if just a couple more parts, its still going to be a friction drag to a small degree, and every little bit adds up.

 

[Irishman999]

like you said if it is accuate why the hell isnt this new more exspensive vehilces with FI knocking down alot better mileage. I just dont understand. Im sure emmisioins is part of it but dam. I am heavily thinking of selling the 05 sierra and buying another square. the wife thinks its stupid because ill be putting money into every week. I told her well look at my payments that would take care of the money i may have to put into it eventually.

I drove an 2wd 07 Sierra around a couple years ago and it got terrible mileage. I can almost guarantee that my 85 is doing better.


The drivability issue I have been battling with for over a year is gone. The entire time it was the PCV valve not being hooked up.

 

[HotRodPC]

A whole what? $2.50 and 3 minutes. And it causes how many hours and days of grief? And how much in money chasing and buying possible try parts? Carb kits, Dizzy, etc etc. No big, I am sure those things helped a bit too, and now you don't have to worry about those since they are now out of the way. Again, sometimes, KISS.


And just think, you were ready to trash it, get rid of it, sell it.... Now that its looking decent and running decent.... don't tell your Unlce. He'll want it back.

 

[Irishman999]

The entire time I knew it was going to be something stupid that costs under 5 bucks to fix. Its incredible how much the PCV valve matters to an engine. I am 100% confident that if I had hooked a PCV valve up to my original setup it would have ran like a top.

Now I am selling all the dumb **** i bought trying to fix it, except for the new distributor I got from Mr. Clean.

 

[89Suburban]

like you said if it is accuate why the hell isnt this new more exspensive vehilces with FI knocking down alot better mileage. I just dont understand. Im sure emmisioins is part of it but dam. I am heavily thinking of selling the 05 sierra and buying another square. the wife thinks its stupid because ill be putting money into every week. I told her well look at my payments that would take care of the money i may have to put into it eventually.

No car payments plus at least 50 percent less on insurance.

 

[bucket]

I drove an 2wd 07 Sierra around a couple years ago and it got terrible mileage. I can almost guarantee that my 85 is doing better.


The drivability issue I have been battling with for over a year is gone. The entire time it was the PCV valve not being hooked up.

You don't think the rocker/cover interference had anything to do with it?

 

[Irishman999]

You don't think the rocker/cover interference had anything to do with it?

No. The rockers hit the cover (I think) because I really cranked down on the bolts trying to stop the leak. Since they were on backwards they were just close enough to rub holes in the cover.