16 MPG? Suggestions?

[BROKINBIMMER]

Okay, so I have read many many threads on here about what to replace for optimal fuel mileage. I am not sure what else to replace/check to fix this issue. So far I have replaced plugs, cap, rotor, fuel pump, fuel filter, air filter, head gasket, coolant temp sensor, cleaned the MAF, and I'm sure I'm forgetting some parts.

What else should I replace/check? Valve adjustment? Plug wires? FPR? Any suggestions and or pointers would be appreciated.


Cliff notes
stock M20
Auto trans
200k miles/rebuilt head
16 mpg mixed driving
Fresh tune up
I drive with a light foot
Tires fully inflated
Stock rear diff

[evandael]

dragging brakes, old hub bearings, gummed up injectors, bad O2 sensor, valves need to be adjusted, timing is off a tooth..

[ELVA164]

I'm assuming it's an M20B25? I would check for vacuum leaks by getting a smoke test done or at the least inspecting the lines for hardness or cracking. If you haven't adjusted the valves in a while that should be done anyway, and I would see if any PO's have messed with the AFM or not. Also, the automatic trans will hurt mileage a little but doesn't account for all of that.

[bmw325csi]

Sorry to thread jack but I'm in the same boat. Would a maf affect mpg's.
I'm subscribing to this thread because I need yo up my mpg's also

[BROKINBIMMER]

Thanks guys. Yea, it's an m20b25

Other new parts:
New o2 sensor
New cat converter


Bought this thing for cheap commuting, and so far it's been anything but...

[BROKINBIMMER]

Should the FPR be suspect? I'm assuming at this point it has to be running rich...

[kingston]

Sorry to thread jack but I'm in the same boat. Would a maf affect mpg's.
I'm subscribing to this thread because I need yo up my mpg's also

Yes it would.

[BROKINBIMMER]

Yes it would.

How would one test a MAF? I can certainly solvent clean it again, or would buying a new one be the way to go?

[bmw325csi]

You have an air flow meter though don't you? Clean it with some carburetor cleaner. Take of you air box, run the car and spray some in whole revving.

I ment I actually changed my afm to a maf sensor. It's works fine but will that upgrade affect mpg's ?

[Rockwool2117]

Try the M10 :up:

[BROKINBIMMER]

You have an air flow meter though don't you? Clean it with some carburetor cleaner. Take of you air box, run the car and spray some in whole revving.

I ment I actually changed my afm to a maf sensor. It's works fine but will that upgrade affect mpg's ?

Mine is bone stock...so I should take apart and clean the air flow meter?

[bastianshaw]

your problem is you think you should be getting better mileage

[BROKINBIMMER]

I'm assuming it's an M20B25? I would check for vacuum leaks by getting a smoke test done or at the least inspecting the lines for hardness or cracking. If you haven't adjusted the valves in a while that should be done anyway, and I would see if any PO's have messed with the AFM or not. Also, the automatic trans will hurt mileage a little but doesn't account for all of that.

This has me. Thinking....Although I am very hesitant to mess with the AFM. Shoul I try adjusting the screw to lean her out a bit?

[ELVA164]

I wouldn't mess with the AFM yourself unless you know what you're doing. Did you pull the spark plugs to check the mixture?

[BROKINBIMMER]

So u guys think its unlikely not the FPR?