Ok, I got tired of seeing the lean condition, check engine lite, so I cranked the fuel pressure all the way up, the car seems to be running really quiet and smooth when in park. I cant notice any power gain, and i still get an intermitent lean condition. Whats the deal?? I figured the more pressure, the car would start running rough like it was getting too much fuel, but it doesnt act like that. Is it possible i need even more fuel, do i need to go to bigger injectors?

 

We need more info on your combo. What mods have you done? What engine do you have? It sounds like an O2 sensor problem to me.

 

Try changing your fuel filter or checking the actual pressure while driving. A list of mods would help and did your car stall when put into gear? That's the best and easiest way to tell the car is too lean at idle.

 

Opps my bad, umm i have flowmaster exhast, headman headers, opened up the intake with a chrome airfilter and did the TBI adj mod on my 89 305 formula. THe lean condition started after I got the headers. So ive been bumping up the fuel pressure, and now i dont get the engine light as after, but I still do get it while driving. Ive pulled the codes, 13 and 44 both are lean at o2 sensor. The car idles fine at full pressure. Its never tried to stall on me. Im not sure what it is. The fuel filter is fairly new , on a side note: a few weeks ago i ran at a drag strip and got a 16.8 at 80mph that is the exact same time I ran back in 98 with no mods, so somethings up.

 

sounds like your not getting enough pressure to begin with your fuel pump may be getting worn out. could need to replace that

 

hmm, that is an intersting suggestion. I couldnt really notice a difference when watching the fuel spray out, so maybe the fuel pump is starting to wear out. It doesnt hesatate when starting. Ill have to keep that in mind, any more suggestions before i take the fuel tank off?

 

Yeah, before you do anything hookup a fuel pressure guage to the flex lines under the hood. Run the line up under the hood onto the windshield and watch the pressure as you go WOT.
I have a feeling that you've got some serious fuel delivery problems up top. Could be either a fuel filter or fuel pump. Randy, Tim's friend is having the same problems and he installed 3.73 gears and posi. I really want to get a hold of his car and play with a few things, (cough, eprom, cough). Sorry, had to clear my throat.
Definatly verify that you're loosing pressure WHEN you have engine load. Don't just flip the throttle, it isn't the same.

 

While there may be something going on with the fuel pressure, I think this has something to do with the header install. Did those headers come with a O2 sensor bung? Are you running a heated O2 sensor as you should be with tubular headers?

And get that fuel presure gauge hooked up... the adjustable regulator doesnt do any good w/o being able to see your pressure.

 

Where do you go buy a fuel pressure gauge? Autozone? I'll have to check into that, yeah the headers came with an o2 bung. Im not running a heated O2 sensor though. I bought one a while back, but didnt know where to hook the power lead to. It was an expensive sensor too, about $50, should I go get another one? The fuel pump has 215,000 miles on it. So all this could be the culpret.

 

I think the fuel pressure gauge will give you a good indication if the fuel pump is the problem... I bought mine from a local speed shop. I've seen them in checker. You can mail order them from jegs or summit.

Get that O2 sensor hooked up. Three wires... two are the same, one is different. Wire the diffrent collored one to the wire that went to the old sensor.

Wire one of the pair of same colored ones to ground and the other one to switched power. I pulled mine out of the fuse box. These two wires just go to a heating element so polairty is not important. Thats all there is to it.