Crappy MPG s14

[R_G]

Well my car had a damage o2 sensor and i replaced that also it had a bad maff and bad harness connector to maff.

My car is a stock 1995 s14. I replaced o2 sensor and maff and harness connector. Now it feels like it runs smooth but when im on the throttle it sucks gas so fast. I filled up and i got on the car for about 10 minutes and the gas gauge dropped 1/4.

I have been doing major research and found a thread on nico READ POST # 6 (1992 240sx coupe, unstable idle, hesitation, loss of power, and bad gas mileage: Nissan Online Mechanic: Nissan Forums / Infiniti Forums - NICOclub). The op said that her o2 sensor wire had burnt and the car was running a learn mode that retarded the timing. Even with the problem gone that she still needed to tell the ecu to go back to stock timing. Is there a way to reset the ecu with out buying nissan datascan?

tHANKS

[HyperTek]

dont stop at looking at the o2 and maf etc.. check out the fuel filter, and the fuel sock on the pump, check for fuel leaks, leaky injector etc.

[R_G]

How do i check for leaky injectors?

Never mind i remembered how to.

[Iron_Zenki]

Carefully :]

[R_G]

Originally Posted by Iron_Zenki

Carefully :]

[R_G]

any more tips?

[R_G]

So i checked out the fuel pump screen and it was black. Cleaned that and also i checked the fuel filter it looked new but i removed it and black fuel came out.

I should of study cars instead of motorcycles. So many parts on a car .

Any one have any tips?

[dfitzg]

i need to take notes mine get bad mpg too

[chituntang]

Originally Posted by R_G

So i checked out the fuel pump screen and it was black. Cleaned that and also i checked the fuel filter it looked new but i removed it and black fuel came out.

I should of study cars instead of motorcycles. So many parts on a car .

Any one have any tips?

Some how there is some bad fuel in your fuel tank. Better getting the tank clean before you go any further.

When the fuel pump was taken out during my engine swap @220k miles, the thing was yellow-ish, not black.

[R_G]

Originally Posted by chituntang

Some how there is some bad fuel in your fuel tank. Better getting the tank clean before you go any further.

When the fuel pump was taken out during my engine swap @220k miles, the thing was yellow-ish, not black.

thanks

[enkei2k]

are you sure your needle's working properly? just a thought...

[EDT007]

1) Disconnect your battery for 20 mins and reconnect. This is usually enough time for the ECU to reset.

2) Check the FSM to see if there's a way to check the fuel pump assembly specifically for the fuel guage.

3) As previously stated make sure you don't have any apparent fuel leaks. Also check for vacuum leaks. You can try spraying carb cleaner around the intake manifold while the car is running to see if the idle changes. If the mileage is unknown on the fuel filter change it to be sure.

4) Last but not least. Could be bad gas like someone said or combination of things. Try running it down and fill-up somewhere else.

Goodluck!! Let us know how it works out.

[R_G]

Originally Posted by enkei2k

are you sure your needle's working properly? just a thought...

You know that never crossed my mind. I did not know s14's had buggy electrical. I have noticed the needle goes down with any little movement . How much is a sending unit? my s14 was sitting for 2 years untill i purchased it.

Originally Posted by EDT007

1) Disconnect your battery for 20 mins and reconnect. This is usually enough time for the ECU to reset.

Thanks will do this.

2) Check the FSM to see if there's a way to check the fuel pump assembly specifically for the fuel gauge.

will do this also.

3) As previously stated make sure you don't have any apparent fuel leaks. Also check for vacuum leaks. You can try spraying carb cleaner around the intake manifold while the car is running to see if the idle changes. If the mileage is unknown on the fuel filter change it to be sure.

4) Last but not least. Could be bad gas like someone said or combination of things. Try running it down and fill-up somewhere else.

Goodluck!! Let us know how it works out.

thanks i will let u guys now.

[stinky_180]

Originally Posted by R_G

my s14 was sitting for 2 years untill i purchased it.

this says a lot. full complete tune-up. if there was some gas in the tank for 2 years, i would highly recommend removing the tank and getting it cleaned. or, run the car until theres almost no gas. before refilling, change the fuel filter (might as well get z32 while your at it). use a bottle of fuel injector cleaner, and pump a FULL tank of chevron w/techron. try cleaning the MAF and throttle body with carb cleaner.

[R_G]

Originally Posted by stinky_180

this says a lot. full complete tune-up. if there was some gas in the tank for 2 years, i would highly recommend removing the tank and getting it cleaned. or, run the car until theres almost no gas. before refilling, change the fuel filter (might as well get z32 while your at it). use a bottle of fuel injector cleaner, and pump a FULL tank of chevron w/techron. try cleaning the MAF and throttle body with carb cleaner.

I clean the maf with carb cleaner now it does not start.... ahh . I should of used maff cleaner. Shitty. I replaced the fuel filter. Before i clean the TB and Maff i checked the gauge and it does move easily up and down when i drive. Looking for a maff now.

[R_G]

Ok also another problem. The car would take a while to start in the morning like 6 cranks. Then after that it usually you turn the key car cranks about 3 to 4 times then starts. I HATE THIS i want it to be one or to cranks then start. Could this be the maff also?

[EDT007]

Originally Posted by R_G

Ok also another problem. The car would take a while to start in the morning like 6 cranks. Then after that it usually you turn the key car cranks about 3 to 4 times then starts. I HATE THIS i want it to be one or to cranks then start. Could this be the maff also?

This can be known to happen when a battery or starter is on it's way out. Try doing a battery/charging test to see what the results are. MAF issues are usually along the lines of erratic idle, etc. Hopefully you get these gremlins figured out soon. Goodluck.

[R_G]

i will go check the charging system right now. Thanks