83 Celica Poor mpg/power

You didn't mention changing the air filter... did you try that one? Usually a bad air filter will sap a good amount of horse from an otherwise fair engine.

I doubt it's the converter since it did pass inspection, but about two psi differential would be the max to determine if it was restricting. Start with a compression check on all cylinders, and if you have to, do a leak down test on them. Check for any intake manifold air leaks. Did the old plugs all look good? Check or swap out the coil. Check the transmission and drive train for any unusual drag. It could be one or many things on a twenty five year old car. Good luck!

I think an 83 Celica with a 22RE engine would get somewhere around 25 MPG highway unless you are really easy on the throttle.

Follow PH@Boy's suggestions, and look at the air filter. If it is black and sooty, check the exhaust manifold for leaks or cracks. Take a look at the exhaust manifold when the car is warmed up in the dark. If it is glowing red, check for cracks in the exhaust manifold and try disconnecting the exhaust pipe from the manifold and see if the engine runs better. If it does, there may be a restriction in the exhaust. I believe that the heat shield on the exhaust manifold should have louvers - if it is solid, there may be an updated manifold.

Also check for cracks, holes, or gaps in the black plastic tube between the air filter housing and throttle body, and check for vacuum leaks. When you adjusted timing, does it advance properly when you rev the engine? If not, check the timing advance (I don't remember if it has vacuum and mechanical advance or if it has the wide rotor and electronic spark advance).

Thanks for the responses.

Things I already checked.

Same air filter, didn't replace airfilter because it looked brand new. Old plugs looked ok (all same, no oil), probably didn't have to be replace but I already bought new ones. As far as I can tell there is no intake or exhaust manifold leak. Breaks aren't dragging, and trans fluid is clear w/o shards.

Tomorrow I will try to check exhaust and cylinders compression and get back to you guys.

One thing I forgot to say, the car runs better after it worms up, not

100% but better. my brother has an 78 toyota w/ a 20R moter, his car runs on the low end of the temp scale and i run in the mid. Also when running at high rpm for long distances the oil pressure goes up to 3/4, my mechanic says that's normal but idk.

thanks

Any additional help would be helpful.

Check the air filter every couple of weeks for a month or two and make sure it does not get sooty quickly.

Hopefully, you installed the correct Denso or NGK plugs, and ignition parts; some aftermarket brands can cause the symptoms you are describing. Some aftermarket brands are fine, it is a hit-or-miss, depending on the application.

I think the 22RE runs a little hotter than the 20R. Having the temp in the middle of the scale is fine.

Having the oil pressure go up when running at high RPM for long distances is normal and desirable.

If your car has an automatic transmission, the performance is quite a bit less than the manual transmission.

Yeah: take the cat out, take an iron bar, and bust up the internals, and then replace the cat. If the car runs better, you need a new cat.

But, I didn't tell you to do this, and I would buy a new cat ASAP, cause if you get caught it can result in jail time.

Vacuum pressure was good. Cylinder pressure was in the ok range. Exhaust didn't glow but I didn't have time to detach it or bang out the honeycomb lol.

Timing advanced well but I noticed that it misfired and hit the 10 not the 5 some of the time (idle). I think this might be the problem, does anyone know what this might be?

also, does anyone know what type of milage i should be getting on an

22RE, 25 highway sounds low for a car that is only 2500lb.

Walter

Well, I had an '85 GTS, but the engine was pretty ratty. I was getting about 22-25 MPG even burning all the oil it was.

We replaced it with a '91 truck motor with 122,000 miles on it and gas mileage went up to 27 MPG, pretty good for a car that weighs as much as an older Celica.

But I had the timing issues, also. I think it just has to do with the age of the engine. As long (if) it's running well, don't try to make a silk purse out of a sow's ear. Sounds like you've done all the right stuff, there's one more thing I would check, and that's for leaks in the intake tube and the other vaccuum hoses around the car. Before I replaced the engine, mine had a leak, and a tech friend of mine grabbed it with his basketball player sized hands and the engine smoothed right out. I found a couple '84-85s in a junkyard with all the pieces I needed, but they flattened them before I got the parts.

Duct tape is your friend! ;)

You should have 14 to 16 in Hg at idle.

No more than 10% difference between cylinders.

Are you talking about 10 and 5 degrees BTDC? IIRC, you have to short the terminals under the diagnostic connector under the hood when setting base timing. If you are getting misfiring in the same cylinder, check the ignition wire and spark plug for that cylinder. If you are getting a random misfire, check the coil.

As I mentioned before, 25-ish highway MPG is about right for that vintage Celica. I drove about a couple dozen different Celicas with 20R and 22RE engines and got 25 to 27 MPG on the highway.

Vacuum pressure was actually about 18-19, should I be concerned and what this means?

Wire and spark plug are good (checked connectivity/resistance). Got a nice blue spark from the coil, don't know how to check it further.

I don't know what the diagnostic connector or where to look for it. Messed around with the timing a little (w/o shorting out the diagnostic connector) seemed to like it a little advanced. I'll try to check all the vacuum hoses soon, maybe replace cuz there all original.

Thanks for all the help so far, especially from ray.

Any more ideas would be much appreciated.

Actually, "vacuum" is the opposite of "pressure" but I get what you mean. There is no need to be concerned with 18-19 in Hg. Those numbers mean that the engine is drawing properly and that there is very little wear. I had given the 14 to 16 figure because I figured a 25 year old car wouldn't be that good.

Don't bother messing with the vacuum hoses or looking for a leak because the numbers you posted are excellent. If the hoses are cracked, think about replacing them, otherwise, leave them alone because the plastic hose connectors are probably brittle after all this time. When you do eventually replace the vacuum hoses, heat them up with a hair drier so they come off more easily.

The spark plug check you did is probably as good as you can do without a scope or a consistent miss.

If you don't see a diagnostic connector under the hood (usually near the under-hood fuse box), then just check timing at idle. As you increase engine RPM, the timing should advance in a pretty linear fashion. The specs should be on a label under the hood or in a repair manual. For example, if ignition timing is 10 degrees BTDC at 650 RPM, then it should be 15 at a higher RPM.

Hey, Ray, on this car it's one of those green 2-pole connectors, located about 6" behind the passenger's side headlight.

Your memory is better than mine! The OP should make sure not to turn the headlight manual knob.

That's cause I just dealt with one of these 2.5 years ago!!! ;)

It's been more like 24 years for me!

LOL! That's what I was thinking when I typed the above response!

Yeah, I think we can cut you some slack on this one, dude! ;)

Of course, with me being stuck in the 80's (at least automotive-wise) I have a bit more recent first-hand experience.

Hopefully, things will stay that way!

Aw, c'mon, man! Those mid 80's Toyotas were COOL!!!!

Especially anything with a 2.4 or 3.0 L engine and RWD. Of course, a 1.6L TC makes for a pretty cool ride, too! ;)

I even liked that POS '83 AWD Tercel I had. Just something about '80's Toys I really liked.

I also liked 1980's vintage Toyotas, especially the RWD Celica GTS and the All-Trac Camrys, and the price was right!