Help me diagnose this problem, ONLY 17MPG! in a metro!

[Zechariah]

Hello everyone,

I have a '97 Chevy Metro LSI Hatchback 1.3L 4Cyl Auto Trans, and there is a major problem! I am only getting 17MPG! in town. I have changed the air filter and checked the spark plugs. There is no fuel leak and no one has siphoned my gas, I will be getting my new OBD II scan tool in a few days and I check for error codes and test the O2 sensors. I'll also be checking the compression and fuel injector.

The car has 80K original miles and the engine was replaced with a brand new one 13K ago by a shop (This was before I bought it 2 weeks ago).

I have done a brake job including new rotors and now when I step on the brakes there is a quiet hum coming from the rotors until the car stops, is this normal? (I have tested the brakes to make sure they aren't rubbing at all when driving) also the brakes don't seem to stop the car as fast as I think they should.

So if anyone has any suggestions of what to check I would greatly appreciate it.

The gas mileage is the major reason I bought this car, I read that it is supposed to get 30-34 MPG but I have seen where people say they get 40-45.

Thanks,
~Zechariah

P.S. Is it possible replace the drum brakes on the back with disc brakes? and would this greatly inpove the braking power?

[Scrapper]

do you smell gas? if so you got a leak somewhere..and your brakes does it have a hard pedal? if it has a booster on it it's leaking fluid or not enough vaccum to it or air in the lines...good luck....

[Zechariah]

Originally Posted by scrapper1

do you smell gas? if so you got a leak somewhere..and your brakes does it have a hard pedal? if it has a booster on it it's leaking fluid or not enough vaccum to it or air in the lines...good luck....

Thank you for the fast reply.

No I don't smell gas and I have looked around for a gas leak too and found none, the brake pedal is firm and I have not checked the booster, if there is one I'll check that, I also think I'll bleed the brakes just to be positive there is no air in the lines from the brake job.

~Zechariah

[leonbentz]

Check your fuel pressure. Mine was getting 22 when I first got it. I had 60 psi to thank for the problem. It should run 16 - 23 psi on these cars. You can do a simple test on the fuel return line, by seeing how easy it is to blow air through it and you can also use a pressure guage, if you have one. If you have a tough time, then check the line for any kinks or pinches all the way from the TB to the tank.

Good Luck

[Woodie83]

Your engine is two valves per cylinder, not four. My first guess would be fuel pressure regulator or leaky injector.

My front brakes hum quite a bit but I've got the fancy slotted/drilled showoff rotors. I've had two different cars with same brakes as yours that had rear adjusters fail. Made the brakes a little spongy and the e-brake handle came up much higher than normal when applied. Rear disks from the Swift GTI can be installed but I doubt you'd see any difference in performance, the rear brakes on these cars do very little.

With an automatic you can expect 35 mpg when working properly.

[Zechariah]

Thank you both for the replays I'll get back to you after I test all this stuff probably within a couple of days. (my new OBD II scanner was shipped yesterday and I'm kind of waiting on that)

Thanks again,
~Zechariah

[Zechariah]

Alright now I have done a fuel pressure test and it was good, used the scan tool and there was no error codes and the O2 sensors are working right.

Also the injector is not leaking and there is a good spray pattern, What else should I try? I'm still only getting 17 MPG UGG (man I could be driving a full size SUV at that mileage)

And the engine seems kind of laggy going up any kind of slope, (I start going up a hill the trans sort of stays in 3rd and the engine gets up to about 5K RPMs and the car seems to kind of lag behind) is this normal for the 4cly? (if not what might be causing this?)

I am getting very desperate to get this car fixed,
so any other suggestions would be GREATLY appreciated.
~Zechariah

P.S. When I fill the gas tank it wants to backup and out if I fill like you would any other car I have to stand there and fill it as slowly as the pump will allow, this is the vent hose right? probably clogged or something? ~ Thanks again.

Oh hehe one last thing.
The other day I was at walmart and when I came out and tried to start it it cranked over about 10 times then I stopped cranking and waited a sec, then cranked it over and again 10 times without it starting stopped a few seconds, and then tried again and it started on the 3rd crank. It sounded like it just was not getting any fuel at all (no sputtering, no nothing just a sound like if I was completely out of gas) after it started I drove home just fine and it has never done this before and hasn't done it since. So what in the world could have caused that???

[doug2060]

When you installed the new rotors did you clean them with brake or carb cleaner? They have packing oil on them to prevent rusting while on the shelf and can cause that noise if not cleaned properly before installation. It will cause glazing. For the gas issue, check all your vacuum lines and intake manifold for leaks. You may also want to do a cylinder compression test. You can also check that the timing is set properly. You can also try replacing your pcv and other little things before considering a major issue. You may also want to consider a fuel injector leak into the engine causing a flooding effect (unlikely but possible). Good luck...

[Zechariah]

What should my O2 Sensors voltages be?

Thanks,
~Zechariah

[Woodie83]

O2 sensors put out between 0 and one volt, front one fluctuates wildly and constantly, rear one fluctuates slowly and gently.

[doug7x]

check your timing...timing belt may have slipped

[Zechariah]

Alright I have checked the timing and it is at 15, the sticker on the hood says it should be 5, so should I set it to 5?

Sorry but I have no experience with timing, so any help would be greatly appreciated.

Thanks,
~Zechariah

Oh, and I did a compression test (150-150-155-155) that's good right?

[Zechariah]

Well, on Saturday I set the timing to 7 and then drove it around for awhile about 5 miles and my MPGs went up to about 28 in town:

This is what it was like on Friday:



And then after setting the timing to 7 on Saturday and driving 5 miles then it evened out at about 28MPG:



So then today I found step by step instructions on setting the timing with photos and now set the timing to 5 and now I'll be driving it around again today and testing I let you guys know how it turns out.

I don't know how accurate the OBD-II scanner is at MPG so I'll also test it manually.

Thanks you all for the help.
~Zechariah