I have an 02 mustang gt with basic bolt ons, svt focus fuel pump and 100 shot nx single nozle wet kit. The problem when I got the car dyno tuned for nitrous is that it went lean in the begining, even more lean in the middle of the run (mid 13s) and then in the end it went to good air fuel ratio. I checked my nx hookup and found that it had a small fuel leak where the fuel pressure safety switch and fuel line hooks up to the fuel solenoid. Even if it is a really small leak (dont even think its dripping just kind of seaping on and around the fittings a little) could this be the reason for it to run lean because maybe im loosing a little fuel pressure to cause this. Im guessing this could be the problem because in the beginning im not getting enough fuel pressure in time because of the leak and then once it keeps building pressure after awhile it started to have good air fuel but too late because of the leak it couldnt build up pressure quick enough. What do you guys think? Any help would be appreciated.

 

https://mustangboards.com/power-adde...ning-lean.html


someone already answered your question about this problem. wet systems have a nasty lean spike nothing you can really do to help get rid of it.

your other problem needs to be fixed asap. i wouldnt want to be driving a car that has a fuel leak. you are a fire hazard waiting to go up in flames.

 

This is an abnormal lean. It lasts over a 1000 rpms. The leak spike usually everybody talks about is the initial hit in the begining that only last a couple or few hundred rpms. I have a big lean that lasts over a 1000 rpms witch is a different kind of lean problem, so I was just wondering if that fuel leak can have something to do with it. I want to find out as many solutions before throwing it back on the dyno again so I can save some money.

 

the initial lean spike thats common with many systems is nothing at all to worry about. Try making sure there is no fuel leaks and make sure that your fuel AND nitrous lines are as short as possible. If your still going lean then you have a problem thats occurring all the time and not just when you spray.