An i mean increase by alot!

Everyone on average seems to get about 17 MPG with their 305 TPI I get 11 which is a big difference.

I changed wires, rotor and cap, platinum plugs, fuel filter, air filter, oil filter.

I must be running rich all the time ? but engine runns smooth thoug all the time.... Would it do that even when running rich?

So have you guys ever had a simillar problem changed what i did and finally changed "the problem" ?

If i am running rich would the car perform much better when it runs as it should

I guess the timing could be out, or maybe the temp sensor for the ecu.

Thanks

Sam

 

Timing out of whack.

Vaccum leak.

Bad injectors.

Bad temp sensor(ecm)

Failing injectors

Clogged catalyst.

I could keep going but those arethe usual obvious ones

Failing MAF(if yours is so equipped)

later
Jeremy

 

My vapor cannister was bad once and caused my fuel milage to go to ****

 

Low tire pressure and bad oxygen sensors also....

 

Don't put right foot to the carpet. Atleast not all the time.

 

Believe i drive like a nany and get like 11-12 mpg

The car is at the local mechanic being checked out. I will let you know what it turns out to be, if they figure it out.

Btw. will the car go faster with the right fuel mixture ? I mean noticably

 

It will go slower with the wrong fuel mixture.

 

Got the car back, they had hooked it up to a scanner and it showed that the car is running in open loop all the time. it would go to close loop if you would rev it high and wait a short while.

Then once you let go of the gas it goes to open llop again

They changed the temp sensor for the comp. They said it must be the computer or the prom. Does this sound right?

Reading on the board i hear that going with a heated o2 sensor solves this?

Why is it running open loop all the time, even when engine is nice and warm?


I dont want to spend on a new comp and prom = about 250 when i am not sure that is the problem.

I know the computer has been changed by the previous owner and it is a GM replacement.

Thanks,

Sam

 

one more idea,

since i have headers the o2 sensor is loacted further away then originally could this cause the o2 not to get hot enough causing it to run rich all the time unless reved high?


Please help as i dont want to change a comp and then to find out it was not!

thanks,

Sam

 

You aren't going into closed loop because your o2 sensor isn't getting heated up enough due to the headers.

Easy...replace the o2 sensor with a heated o2 sensor. It should have been done when the headers were installed.

Do a SEARCH on heated o2 sensor...plenty of info for you...

 

Cool, yea i read about it but was not sure

So you think i will acc faster with closed loop?

 

I think that the computer will operate the engine a bit better in closed loop...as GM intended

That way, there is some input to rich/lean as opposed to open loop.

HTH,