Help with EPA MPG; Corolla identity crisis

[christofoo]

I'm revisiting the Official Fuel Economy Ratings that I entered in the garage for my car.

The reason is I recently made the Top 10 by Percent Over EPA list with my ECOrolla89, but I don't think I belong there (yet), and I certainly think my 22 MPG combined is way off.

My first question is whether I picked the right version of my car. I have a 1.6L 4A-F (carburetor) 5-spd manual. Fueleconomy.gov lists 3 cars that are similar:

1. 1.6L "(FFS)" 5-spd manual - 26city/32highway/28combined MPG
2. 1.6L "4A-GE (FFS)" 5-spd manual - 23/28/25 MPG
3. 1.6L "4A-FE (FFS)" 5-spd manual - 20/26/22 MPG

Is option 1 supposed to be the 4A-F? It doesn't say. I picked the 4A-FE version because "The 4A-FE is basically the same as the 4A-F (introduced in the previous generation of Corollas), the most apparent difference being the electronic fuel injection system as noted by the E." (- Wikipedia)

My second question is what is wrong with EPA on this car? Ecomodder says
- Note: use EPA's "new" (2008) formula.
- Find your EPA rating (link opens new window). [links to fueleconomy.gov]
... but what if I know that the fueleconomy.gov numbers are bogus? I mean, here's a list of my issues with their numbers:

1. The 2 owners reported 31 and 38 MPG for the 4A-GE manual Corolla, vs 25 combined EPA rating. You can add me as a 3rd owner prior to hypermiling in 2007 with a 15,000 mile average of 34 MPG. No way, right?
2. The 4A-FE is the most fuel efficient engine for this car, but it's rated much lower than the others.
3. How can 3 different 1.6L Toyota engines spread the FE for the same car by 27%? (Actually, to play devil's advocate, I wonder if the engine correlates to how tall the tranny is, I think the 5-spd manual in my car feels quite short.)

[Daox]

I would use the 26city/32highway/28combined rating. You said you don't have the 4A-GE, so its not that one. According to fueleconomy.gov the 20/26/22 is for a Corolla with AWD (see the right most in the image below).

Also, I'd be very surprised if your 89 corolla was actually carburated (no offense). Toyota probably still used the 4A-F in 89, but I doubt in this country. If it is a 4A-F, I'd guess the engine had been put in at some point. If it was offered here for that year it would be a selection on the fueleconomy.gov site since the EPA would have to know if it was sold here.

Congrats on the very nice mileage too!

[christofoo]

Originally Posted by Daox

I would use the 26city/32highway/28combined rating. You said you don't have the 4A-GE, so its not that one. According to fueleconomy.gov the 20/26/22 is for a Corolla with AWD (see the right most in the image below).
...

Aha! I didn't notice the AWD. And now my log is fixed; that moved me from 9th to 30th place, where I belong.

Originally Posted by Daox

...

Also, I'd be very surprised if your 89 corolla was actually carburated (no offense). Toyota probably still used the 4A-F in 89, but I doubt in this country. If it is a 4A-F, I'd guess the engine had been put in at some point. If it was offered here for that year it would be a selection on the fueleconomy.gov site since the EPA would have to know if it was sold here.

Congrats on the very nice mileage too!

How surprised? Under-hood VECI label says '4A-F', and there's no doubt that it's wearing a carb. I bought from the original owner, he never mentioned an engine swap, and I'd say the condition of the engine is consistent with 190-222k (acquisition-to-current). Wikipedia says the 4A-F was produced until 1990. As to the origin, I'm trying to remember, for some reason I think it's an import. Maybe it's the 'J' as the first digit on the VIN? Maybe all the Toyotas were imports in that era? Maybe that doesn't answer your quandary? It is still wearing a Medford, Oregon dealer badge on the trunk I'm too lazy to remove. (The origin is not something I discussed with the seller.)

EDIT: I agree it's weird that fueleconomy.gov doesn't list it explicitly.

And thanks!

[MetroMPG]

Just a thought: throttle body injection (TBI) looks a lot like a carb. My '98 Firefly/Metro has TBI - Suzuki design. (I have no idea if Toyota did TBI too though.)

[some_other_dave]

Originally Posted by christofoo

As to the origin, I'm trying to remember, for some reason I think it's an import. Maybe it's the 'J' as the first digit on the VIN?

The "J" denotes that the car's manufacturer is based in Japan.

-soD

[christofoo]

Originally Posted by MetroMPG

Just a thought: throttle body injection (TBI) looks a lot like a carb. My '98 Firefly/Metro has TBI - Suzuki design. (I have no idea if Toyota did TBI too though.)

No no, I insist, it's wearing a carb.

How do I know? Let me count the ways:

1. I plugged the AAP vacuum line, not a component found on EFI engines. http://ecomodder.com/forum/showthrea...tml#post338094
2. Follow the above link then to Toyota Nation forum where others state they have the same car with the same engine with a carb, some of them in the US also.
3. The throttle body has an idle-speed adjustment set-screw which I've tuned, also (I believe) not found on EFI engines.
4. My mechanic calls it a carb, recommended a carb rebuild, but said a clean and tune would also help significantly (what I actually had him do and he charged me for).
5. The Toyota mechanic called it a carb, noted it smelled rich and suggested a leaky float (this was before I plugged the AAP vacuum line, now it smells much better, so he was at least mostly wrong about the float leak).
6. I've wrenched on this so many times with my Haynes manual open for various reasons... the manual calls it a carb, and everything matches 4A-F differentiators. Off the top of my head, some of the differentiators are common with 4A-FE, like the valve cover nuts, but I can definitely rule out 4A-GE. I can't remember whether the distributor timing adjustment, which I've done several times, is unique to the 4A-F or common to the 4A-FE. Certainly Haynes has never been wrong assuming it's 4A-F, just like the VECI label says.

[christofoo]

I want to point out, while fueleconomy.gov doesn't list the specific engine differentiator for the '4A-F', option 1 does actually match this car, at least by process of elimination.

Originally Posted by christofoo

...Fueleconomy.gov lists 3 cars that are similar:

1. 1.6L "(FFS)" 5-spd manual - 26city/32highway/28combined MPG
2. 1.6L "4A-GE (FFS)" 5-spd manual - 23/28/25 MPG
3. 1.6L "4A-FE (FFS)" 5-spd manual - 20/26/22 MPG

Is option 1 supposed to be the 4A-F? It doesn't say....[/LIST]

All option 1 says about the engine is that it's 1.6L 4cyl FFS. All of the engines in 6th gen Corollas, including 4A-F, are 1.6L 4cyl FFS (Feedback Fuel System = O2 sensor). So there is no contradiction with Option 1 = 4A-F, and by process of elimination, that must be it. (Or else the 4A-F cars are a subset of Option 1, for all I know there may be some 2wd 4A-FE Corollas that also belong with Option 1, perhaps that is why they didn't include the specific engine differentiator.)

[Daox]

Do you know if the 4A-FE was offered on non-4wd Corollas?

[christofoo]

I don't know... but (googling) I can find parts that match those descriptors, so it seems plausible. 1991 Used Toyota Corolla Starter Motor Genuine OEM LOW MILEAGE Guaranteed Part.

EDIT: maybe this is better evidence such a thing exist(ed): http://www.theautochannel.com/autopa...8-corolla.html A used 88 Corolla FWD transmission that goes with 4AFE.

So... riddle solved?

[MetroMPG]

Originally Posted by christofoo

No no, I insist, it's wearing a carb.

How do I know? Let me count the ways:

OK - I'm convinced! You've done your homework. I was just putting it out there. (I've seen less homework-y oriented people confuse carb & TBI before!)