awful fuel economy

[applewew]

Hello, new guy here.

I have a 1985 2wd, 5-speed manual, hatchback.

I've been getting ~20mpg city/highway combined.

It usually hesitates (and sometimes dies) when I start the engine, and hit the gas pedal the first 1-3 times. After that, it runs fine. Also, you can smell gas when sitting on the back seat.

My other car is a 1997 4.2L ford f-150, wich was my first car/truck. I have worked on it (top end gasket and parts replacements), but the Tercel is a whole new world to me.

Tires are usually at 35psi.

Any advice/helps is greatly appreciated!

[dlb]

smelling gas in the back seat might indicate a hole in the gas tank or fuel lines. jack up the back, secure it, get under and look for wet spots.

sounds like some typical carb problems. check to make sure that none of the black vacuum hoses under the air filter housing are disconnected, cracked, or broken. there should be a sticker on the underside of the hood with a diagram that shows where each one should go. check all of the lines and confirm they're going to the right spots. on the diagram, note the thing called the AAP. disconnect the vacuum line from it and note if any gas comes out. if gas comes out, the AAP diaphragm is ruptured and leaking gas into the fuel line. the AAP is easy to replace but can cause big problems if ruptured.

lots of other possibilities but check those first. then check the ignition timing, condition of your air filter, spark plugs, etc.

[applewew]

Hey dlb, thank you for your comments

Forgot to mention:

- New Denso w16exr-u spark plugs are in (pic of previous spark plug below)
- I had a mechanic check the carburetor this weekend, he said it was nasty dirty, but I think it runs the same (if not worse) since then
- The vacuum diagram was gone before I bought the car (got it on december), is it available online? I downloaded the FSM, you can point me the page I can find it.
- Air filter is fine
- I will check the timing, and set it to 10 deg BTDC, since I learned here it helps with the MPG.

[dlb]

the problem with the vacuum diagrams is that there are several different emissions packages and which one you have depends on where the car is from and whether it is an automatic or standard. i'm not even positive that the hatchbacks have the same emissions stuff as the wagons but it's probably very similar.

check out this link. it has a good collection of the vac diagrams. you can also check around page 90 or so in the FSM.

https://tercel4wd.com/forums/viewtopic.php?f=7&t=2810

that plug looks a little oil-fouled but the tip is not worn down. not too bad.

if the carb is filthy, spray some carb cleaner down the barrels while the engine is idling. i don't think it will solve anything but it should help clean it out some.

[Petros]

welcome to the list.

You should be getting about 28-30 mpg mixed driving when you are easy on the pedal. I would simply trace all of the vac lines to verify they are routed correctly and in good condition (check for cracks/leaks) as well as being connected. Even mechanics, many too lazy or careless to bother, will mix them up and make it run crappy. About half the time, even on cars maintained by repair shops, I find the vac lines misrouted.

Also, check for vacuum leaks with carb spray cleaner. And check the Auxilary Acceleration Pump (AAP) line for fuel, if the AAP is leaking it will suck fuel into the intake manifold. Pull the vac line for it and see if there is fuel in it. If there is you can temp cap the line and it will run fine, when cold it will not have as much acceleration when you stomp on the pedal. The APP is to supply more fuel for cold acceleration, it does not affect a warm running engine, and if it is leaking your economy drops and you will ruin the catalytic converter.

Once you sort out the vac leaks/lines, you should get better fuel economy and it will be more drivable. The cold start issue is normal for carbs by the way: from a cold engine, stomp on the pedal 2 or 3 times, start the engine and give it a number of low rev accelerations. Should be drivable after that. All carb engines were a bit baulky on cold starts, we have been spoiled with EFI.

Good luck.

[North of 64]

Petros, check your PM from me please

[applewew]

This one looks like (what's left of ) mine, buut it says FED instead of CANADA

[ARCHINSTL]

So - are you located in Canada or the USA?
If the USA Fed version, there is a Sticky in the Repair Guides section with a colorized schematic; all of the others are in the FSM, accessible at the top of each page here.
Tom M.

[dlb]

the federal and canadian emissions systems share many components but have a few totally different ones. if you're anywhere in the states besides california, it's probably a federal car.

[applewew]

Hello, thank you all for your help.

I removed the air filter / box and looked for issues with the hoses.

Found many hoses disconnected (and some capped). I include pictures of each one I found, they are pretty obvious, but I circled them anyways. I also include a pic of what's left of the vacuum diagram.

[ARCHINSTL]

You have a Federal (USA 49 states) car, per the hood sticker. I would suggest taking a photo of it and print it and then save the two photos at the top of this link and print them and then compare the two.
https://tercel4wd.com/forums/viewtopic.php?f=7&t=2810
Your last photo indicates prob the worst problem; a brokem TVSV. You really need to get one of these, as the car simply will not run right without an operable one - mine was the same way when I got the car and I simply had to get one. I believe the similar year Corollas and possibly other Toys of that vintage used the same TVSV, so perhaps a salvage yard has one.

Frankly, with as much disconnected and plugged as in your photos, it's a wonder the car ran at all.
Tom M.

[dlb]

oh wow, +1 on tom's response. the sticker on the underside of your hood is the same as the third diagram down in the link tom posted. for sake of ease though, here it is in big form:

http://tercel4wd.com/download/file.php? ... &mode=view

amazing the car runs! however, the good news is that those are all super easy and cheap fixes. if you can't find a good TVSV down there, someone on the forum could probably ship one to you. as for the vacuum lines, just take one of the old ones to an auto shop and show it to them so they know what size you need. get a whole bunch (2-3 meters, i would guess) of new hose and replace all of the lines.

[Lil Beast]

I have a couple tvsv kicking around!

[applewew]

I actually need one :p

How much for it?

[Lil Beast]

Dunno what they worth really! How's 10$ plus shipping! Ill go to post office i figure how much to ship, should fit in a flat rate box!