I recently put a new fuel pump in my car after the stock one was dying on me. I put in the Walbro 255lph fuel pump and ever since my car seems to be running very rich. It smells really gassy and i've been told if I rev it the backfires will have some small flames coming out of it.
What steps should I take to fix this problem?
Thanks!

 

Check the fuel pressure at idle and WOT. That will tell you if the fuel system is causing the problem.

 

I'd also double check all the connections in the back gas tank area. Especially the charcoal canister.

 

yeah, you need to find out what the fuel press. is at idle and WOT. if its higher then 45 psi or so, then you either need an adjustable fuel press. regulator, or you need to have a custom tune done to account for the higher pressure. Im in the same boat, I also put in the same pump and have the stock regulator, but havent checked the press. yet since I just got it started two nights ago.
chris

 

I was wondering if this might work as well:
I recently aquired a notebook and was planning on putting freescan on it. I believe it tells me what the air/fuel ratio is therefore I'm thinking it would work in letting me know if the fuel is my problem. But, then again, if it is the fuel being my problem i'm going to need a guage for my fuel pressure regulator right?

 

A scanner can tell you if the PCM perceives the engine is running rich or lean, and what it is doing to try and correct the situation, using the long term fuel corrections. You can get a VERY ROUGH idea of the A/F ratio at WOT by looking at the stock O2 sensor mV levels, but they are simply not an accurate measure of A/F ratio at that level. There is no actual "A/F ratio" measurement available out of a scanner. You can get the "target A/F ratio", but that will simply tell you what the PCM is programmed for in closed loop (always 14.7:1) and in power enrichment (PE) mode (aka WOT).... generally around 11.7:1 in a stock program, or whatever your programmer targeted when he did a reprogram.

Even if the scanner told you you were running rich, it wouldn't tell you why. If you suspect the fuel pressure.... you have to measure the fuel pressure. The PCM has no way of measuring the pressure.

 

Yeah all in all your fuel pressure regulator might have gotten stuck in the full open position because your old pump wast providing enough pressure it blocked off the return line maybe. dunno check fuel pressure etc..

 

Err...not the answer I was looking for
If I have to get a fuel pressure guage I might as well get one that mounts in the car so that I can keep an eye on it all the time, including WOT, and it'll probably be useful if I have to get an adjustable fuel pressure regulator right? Is one that mounts in the car much more expensive than a regular guage and what parts do I need and where can I get them?