Airflite40

I have searched and searched, but just want to get your thoughts.

I get about 190 miles to a tank. it absolutely sucks. I figured it out a long time ago, but thought it was a combo of crappy chips/old O2 sensor/suspect AFM.

I have searched and it seems the usual suspects are not the case.

I have NGK BPR7ES plugs, and WH cleaned stock Injectors 11/07

Scivision MAF/maxHp chips, had previous unknown aftermarket chips, possibly AA copies

Replaced the O2 sensor 2/08

I have run stock wires and both Magnecor wires in the car and no change.

New 3.0bar FPR

venturi delete and all new vaccuum hoses, no known leaks.

I have a known good TPS ready to install, have not had the time to swap yet.

The TPS on the car seems fine though, it clicks like it should.

The car backfires quite often, although it has lessened when I put the MAF/MaxHp chips in.

The engine runs strong, but does have the weird shudder that Keithr726 also has....haven't figured that one out yet, its been a cold cold winter

I don't know how old the fuel filter is.

What else can I be missing?? I have not done a compression check, but I probably should soon....thank god for spring break....

Keithr726

Get that wideband installed. What about your FPR?

Airflite40

What about my FPR??

I'm really kicking myself since someone was selling a UEGO wideband sensor and display on ebay and it sold for $50. I was watching the auction and forgot to bid. damn.

Loquat15

I was getting horrible gas mileage for a while, my FPR was totally screwed... but anyways make sure your fuel rail pressure is correct. I know you said you replaced your FPR, but still... check the pressure out for peace of mind.

If the fuel pressure is too high, it'll of course run too rich, if you're blowing dark/rich smoke and shooting flames/backfiring, you're obviously running rich. Check your vacuum lines too. not sure about how you'd go about testing the afm or tps, but of coures there's only so many different things that could cause it to be running how it is...

good luck!

Van

could you have a leak somewhere?

Airflite40

a leak of what?

MrRob944

how many gallons are you putting in? My gauge goes down fast, but the 944's have 20 gal tanks....

Spidey944

My gauge will be all the way down, but until the light comes on, I'd say about 7 gallons later, I don't fill up.

Rock

I was getting 200/tank with my cabby driving like a grandma

I replaced the O2 sensor. No go, still 200miles/tank

I couldnt figure it out for the life of me. I ended up replacing my fuel pressure dampner, replacing the ignition wires, and REDOING the 02 sensor.

I get 400miles to a tank now.

Im hoping with my new engine to get more. My girlfriends 951 can probably squeeze 500miles out of one tank if she tries.

Van

I was thinking of something like a pin-hole leak in a fuel line under the car...

Airflite40

I don't think I have a fuel leak I would smell it right away, and there are never any fluids left behind on the ground.

I'm starting to think my engine harness is toast, I'm gonna verify that the O2 signal is even getting to the DME when I get a chance.

I have a replacement harness (thanks Rock) just need to fix it up with new connectors and fire sleeve it.

spanky

Change out the fuel filter if it hasnt been recently changed. I was down to 200 mpt and that was all it took to correct my problem. I cut it open and it was full of crap. I now never run my car past 350 miles per tank just to avoid sucking in any solids that migth be in the bottom of the tank.

Airflite40

Ok.....ordering a fuel filter pronto. Thanks spanky!!! <puts hand under chin and does the little rascal thing>

Luis de Prat

That's always something to replace when it's been there a long time and the fuel economy isn't what it should be.

951_for_John

My FPR was bad and i was getting about 250 mi / tank. changed it and went back to about 400+-!