Bad Gas Mileage? '89 Camry

[axlman]

Hello all,
I bought a used 1989 Camry v6 2.5L back in January '07. I purchased it with 150,000 miles on it.
Since I've had it, it has gotten bad gas mileage. A few weeks ago, I found out that it had a blown/cracked head or something so I decided to have the engine replaced with one imported from Japan.
So, all in all here is a general run down of all the parts replaced.
Engine, Fuel Filter, Spark Plugs and Cables, Cap & Rotar, Radiator (was leaking), TPS, MAF, etc. even with the newer engine that I'm told only has 35-40K miles on it, I still get bad gas mileage. I'm only getting about 200-250 miles per tank of gas, if I'm lucky.
I know that I can't and won't exspect to get "great mileage" out of it compared to what newer cars get today, but I would think that I should be getting at least 300 miles a tank?
From a full tank, I can only drive about 35-45 miles before it tells me that I am down to 3/4's of a tank.
So, any ideas what might be causing this? I'm thinking that maybe it could be the O2 Sensors although I don't have a Check Engine light on but I've heard that they could still be going bad but are not bad enough yet to activate the engine light.
The pipe running from the exhaust to the muffler has a somewhat small hole in the pipe right before it connectes to the muffler.
I really need some help with this! Tired of spending money at the mechanics just to have basic tests ran with no answers yet.

[RIP]

Miles driven divided by gallons purchased. That's how you determine mileage. Going by miles per tank only gives you a ballpark figure.

My 87 with the 4 cyl engine was giving me 30-32 mpg on the highway and 22-24 in city driving back when I was driving it regularly. I would get around 28 mpg in mixed driving. That was about 70% highway and 30% city driving. If I had the 6 cyl I would guess I should get 25/26 mpg in my mixed driving.

What did you have before the Camry and what mileage were you getting? What percentage of stop and go city driving do you do? Use the A/C much? Ride the brakes? Are you a jack rabbit or a tortous? That out of the way, we'll get to mechanical crap.

Are you seeing any symptoms like hesitation, slow acceleration, odors, pulling to one side with or without brake application, unusual tire wear, etc. Have you had the codes pulled regardless of the lack of a light?

There are many possible causes for low mileage. Some of the likely culprits are retarded timing, low compression, weak spark, dragging brakes, poor wheel alignment, clogged exhaust, ... your foot. Troubleshooting all this is just a process of elimination. That process expands when there are no other symptoms. That's why your mechanics perform basic tests. What tests have they done?

I don't recommend throwing parts at it. You can spend plenty of bucks and get nowhere. But, if you insist, yes the O2 sensors would be a good place to start. Pricey but, a start. Your engine has at least two and they run $70-$120 per sensor. Just changed the "upstream" sensor on my daughters 94 Camry and her mileage went up 2 mpg.

Answer my or others questions before you make a move. It may save you some bucks. OBTW - Download your factory maintenance manual from the "Camry Service Manuals" thread at the top of the forum and read through the FAQs thread. There's info there that may help.

[axlman]

Well, I have a '05 Checvy Colorado and get good mileage from that. Can't really compare it to the car though.

As far as the other things go, When the engine was replaced, the mechanic also did the timing with a new timing tensioner and some other timing part. All new pluggs, wires, etc. I do use the A/C now that it's over 100+ degrees here. But the gas mileage is an even without using the A/C.

How can I determine if I got exhaust blockage? I get plenty of exhaust blowing out of the muffler.

The car excelerats just fine. The alignment is fine. No pulling.

[axlman]

Well, here is what I got from the test.

After jumpering the wire, etc.

The check engine light will blink once and stay off for about 2 seconds (2 Locomotives) then blink twice within 1 second. So, going by the code sheet that I found, It's hard to determine if it's normal or if it might be code # 2?

here's the link with the info that I was informed of: http://www.troublecodes.net/Toyota/

So, if it is the air flow meter, would that cause poor gas mileage?

[RIP]

It appears you are reading a code 12 ie, one flash followed by two flashes. This is a fault in the RPM signal from the distributor to the ECM. Specifically, "No NE or G signal to ECU within two seconds after engine has been cranked", according to the Haynes manual.

There are three coils in the distributor used to determine crankshaft reference and RPM signals. They are G1,G2 and NE. These have to be troubleshot. If one is bad the distributor needs to be changed. This can effect engine timing and gas mileage. What symptoms are you seeing?

Can't seem to open your factory manual. I will dig somemore in the AM and find out the troubleshooting procedures.

[axlman]

Originally Posted by RIP

It appears you are reading a code 12 ie, one flash followed by two flashes. This is a fault in the RPM signal from the distributor to the ECM. Specifically, "No NE or G signal to ECU within two seconds after engine has been cranked", according to the Haynes manual.

There are three coils in the distributor used to determine crankshaft reference and RPM signals. They are G1,G2 and NE. These have to be troubleshot. If one is bad the distributor needs to be changed. This can effect engine timing and gas mileage. What symptoms are you seeing?

Can't seem to open your factory manual. I will dig somemore in the AM and find out the troubleshooting procedures.

Excellent info! Thank you very much!

[RIP]

The "coils" I refered to is the signal generator or pickup coil. It has three outputs. Each of the three should read a specific resistance when checked with an ohmeter.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm Scroll down to 2VZ-FE figure 22. Could also be the wiring from the distributor to the ECU.

I could be totally wrong but, I would think if the pickup coil was bad you would be seeing much more than lousy gas mileage. Maybe its just a tad out of spec. Make sure it's not just a fluke by clearing the code. Pull the EFI fuse for one minute with the ignition off. If it comes back after driving a while, then I would press on with looking into the pickup coil. You can also check basic timing to see if it's effected.

[axlman]

Originally Posted by RIP

The "coils" I refered to is the signal generator or pickup coil. It has three outputs. Each of the three should read a specific resistance when checked with an ohmeter.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm Scroll down to 2VZ-FE figure 22. Could also be the wiring from the distributor to the ECU.

I could be totally wrong but, I would think if the pickup coil was bad you would be seeing much more than lousy gas mileage. Maybe its just a tad out of spec. Make sure it's not just a fluke by clearing the code. Pull the EFI fuse for one minute with the ignition off. If it comes back after driving a while, then I would press on with looking into the pickup coil. You can also check basic timing to see if it's effected.

Well, so far I cleared the code (was nice and easy to do) then I just drove the cararound the block to get the car temp up to normal running temp. I rechecked for the code and did not find any codes again.

So, I wondering, how long should I actually drive the car around for after clearing the ECU and retesting?

Oh yeah, Just a big thanks to everyone who has taken the time to help out so far! Forums are a great!

[RIP]

I'd give it a couple days. If the code doesn't return, I would start looking elswhere as stated previously. A clogged exhaust meaning the cat converter usually gives you slow acceleration or stumbling. The only way to check the converter is to remove it and have a look see. Have the brakes inspected. Even a slightly dragging brake can suck your mileage down. Notice any pulling to one side? Could have a stuck caliper piston or alignment problem. Misadjusted parking brakes are common. Any symptom could be a clue.