My car has developed a surging problem. It has a hard time idling with the engine constantly revving up and down. With my Auto X-Ray, I pulled a code 44-oxygen sensor lean. The O2 sensor reading runs about 400 to 500mv. How do I go about richening the fuel mixture? Fuel pressure is about 46 psi.
I recently replaced the fuel pump and the car was running fine up until now.

 

Try putting a lower temp thermostat.

Make yourself an adjustable fuel pressure regulator.

Try changing your O2 sensor if it is old.

Hope this helps.

------------------
89Iroc, 305 TPI, WC T5, 3.08 Posi, Headers, Hooker Y-Pipe, 3 inch over the axle, Flowmaster 80, No Cat, Aluminium Driveshaft, Ported Plenum, Air Foil, K&N, AFPR, All free mods,

 

had the same problem and code..
o2 sensor was clogged beyond beleif..
changed it and everything cleared up.

 

The O2 sensor is about 1 1/2 years old (12,000 miles). I had these same symptoms when I rebuilt the engine. The ECM wouldn't go into closed loop status. I added an adjustible fuel pressure regulator, bumped up the pressure to around 49-50 psi and the problem was solved. The AFPR is now maxed out and I'm only getting 46 psi. Could that be my problem?
Are there any other ways to richen my mixture?

 

fuel pump starting to go. fuel pressure dropping and your regulator maxed out. fuel pump slowing down. fixing to lock up.

 

Im thinking the fuel pump you put in doesnt pump enough of the fuel at all,you probally need a fuel pump thats capable of pumping higher amounts of fuel.Either the fuel pump you got it cheap,or else its just not strong enough for the job and you need a better one.

I know im having a problem with a code 44 also right now,and i have a new o2 sensor.And now im wondering if my fuel pump is about shot,cause i also get a code 54 too now(fuel pump relay)...unles its just my relay.By any chance do you get a code 54 too at all.And does your car seem to not want to start sometimes as if its not getting fuel,and then does start but idles pretty cr@ppy and then the idle smooths out after a bit and sometimes changes when it wants almost like you have clogged injectors?I know mine will smooth out and then suddenly break up and almost wanna stall then it smooths out again and purs like a kitten.All i know is its p@ssin me off and i get code 44 and 54.

[This message has been edited by 86TransAmTPI (edited November 14, 2001).]

 

Change the fuel filter lately?

 

The fuel pump I recently installed was an AC Delco unit from the dealer. It was putting out about 52 psi at the time. It's got about 300 miles on it now. The fuel filter was replaced about 10,000 miles ago (same time as engine rebuild, injector service, and O2 sensor replacement) so I should be replacing it too.