I Need More Power!

[irowiki]

Less moving parts, less stuff to adjust!

[Mark]

The points type has 4 small "points" that wear as the distributor shaft rotates and they open and close. The gap has to be re-adjusted every few months or the timing changes. It's also a 6-volt system (the unused 6 volts is eaten up by a resistor). The more modern electronic distributor is a 12 volt system and requires no adjustments.

[Petros]

points systems suck, the first six cars I owned had points. lots of maintenance to keep them working properly, they suffer from points bounce at higher RPMs, corrosion, poor concoct, irregular timing, as they wear the timing changes, etc.

The more modern solid state distributors are superior in every way, and than even fewer parts in the system on the modern distributor less system, more accurate timing, better control over ignition. The only thing I do not like about the distributor-less systems is the 4 small coils tend to break down more often, they randomly fail when their housings breach. I do not know if that is common, but the system on my daughter's 2001 Suzuki seemed to need a mini-coil replaced about one every other year. Other than that, ignition was zero maintenance besides spark plugs.

[Mark]

I don't really get why the in town (highway fuel economy is pretty much the same) fuel economy is worse in the '81 either. It has much lower kms (100,000 vs 260,000) and I checked for vacuum leaks in the various components (I found one in the AAP and disabled it). Both cars idle nice and smooth. Maybe the gearing ratio is different (I'm sure it is, but I haven't looked up what it is). I assumed the points-type distributor might have been an issue, but I replaced it with an electronic one with no difference. I'm hoping the switch to timing advance at idle might make a difference.

So after a few $20 "fill-ups" using manifold vacuum advance instead of ported on my distributor, the fuel economy has increased slightly, but not enough to be conclusive yet. Before with ported vacuum I was getting around 23 mpg with short, in-town trips. Now with manifold vacuum, I'm getting around 26 mpg. I'm going to continue with manifold vacuum for another couple of months and see if the improvement is consistent.

[Petros]

26 is about as good as you can get in heavy city traffic, if that included hwy or mixed driving, that something is still very wrong in your engine. should be closer to 28-29 mixed city/hwy, and over 30 mph on hwy (presuming you do not push it too hard, driving at 80 mph or above the economy drops off rapidly, best seems to be about 70 mph).

[Mark]

26 mpg is the US EPA rating for it in the city so I guess I can't complain. My in-town driving isn't being stuck in traffic jams or anything. They're just short trips and there are lots of traffic lights. The wagon is supposed to get 21 in the city and 23 on the highway so mine is much better than that (27 or so in the city and 30+ on the highway).

[lucafusi]

Sidenote, just idly browsing random Tercel searches and found this claim on a CL ad.

Is 40MPG ANYWHERE near reasonable for these models?

[irowiki]

Mine gets 30+ in the summer. When they were new they were supposed to get around 40-45 MPG?

With a tune up, low elevation, proper tires, and not driving like a nut, I could see 40 MPG.

[Mattel]

41 mpg! it's on an ad so it must be true!

[Notmikeb]

I love that the fine print basically says "you probably won't get 41mpg, but we'll say you might anyway"

[lucafusi]

Mine gets 30+ in the summer. When they were new they were supposed to get around 40-45 MPG?

With a tune up, low elevation, proper tires, and not driving like a nut, I could see 40 MPG.

Last half-tank clocked at ~21MPG--seems like I've got some work to do <_>

[irowiki]

Yeah but was it city? Highway? Hotdogging it? How much stuff in the car? Have you done a full tuneup? Is your AAP leaking? Is your fuel cut solenoid working?

[lucafusi]

Yeah but was it city? Highway? Hotdogging it? How much stuff in the car? Have you done a full tuneup? Is your AAP leaking? Is your fuel cut solenoid working?

• Mixed city / highway, probably more city.
• Even on highways I feel I've got to go pretty aggressively (up to 4kRPM in 2nd / 3rd both to get up to speed, then get into 4th / 5th when I can. At highway speeds 5th stays around 3kRPM. Can't really push the car past 60-65 without going downhill a bit)
• Not sure how you'd define hotdogging it--not trying to drive reckless, but I'm always a little concerned about being too slow for the modern cars around me, so maybe I accelerate a little faster than I could..
• Nothing in the car but me!
• No full tuneup since acquisition, convinced I should do it myself / don't have tools yet / was storming this weekend / excuses
• Can't confirm AAP or fuel cut solenoid, will do it when I get the air filter off and hunt around for vac leaks (seem to be usually issue #1)

Are vac hoses a pretty standard thing I could just pick up from AutoZone? Multiple sizes / diameters, I mean?

Not to turn this into a crazy repair thread or anything, I've got one of those going on

[irowiki]

I rarely go above 2-2.5k rpm when accelerating in my 83 SR5, and get 30 MPG

3k RPM in 5th at 65-70+ is normal.

High accelerating in the city will just kill MPG.

A tuneup is next on your list then!

[lucafusi]

Sounds like I need to just chill 'er out a bit during my city driving--good to know! Maybe the tuneup, adjusting timings and an eventual carb swap will bump the power enough to let me kick it at those RPMs while doing errands without forcing anyone to honk.

Thanks for the fast responses.. this board is the best.