[RESOLVED] noticed I have started leaning out under boost

[lowexpectations]

I no longer drive the talon much but about a month ago I noticed that I was starting to lean out at wot. I thought it might be that my fuel filters were getting clogged since I have switched to E85. I ordered a new filter sock and I also ordered a replacement filter for my fuel lab fuel filter. Neither filter seemed to be clogged but I figured it would be for good measure. The car remained parked for the last month other than starting it up and letting it warm up but no driving. So today I had some time to take the car out. I noticed on the way to fill up that as soon as I would get boost the car would break up and go lean. I could just drive and it would be fine. I get home from filling up and decided I would start with checking my fuel pressure. I pulled the vac line off and noticed my fuel pressure was lowWTF. It has never been low before. I adjusted to get my fuel pressure to 38psi and was like wtf. The adjustment screw is all the way down. Since I have dual fuel pumps I checked to make sure both were running and they both are. The intank 255 is about 4 years old and the inline one is less than a year old.

I made two logs where in the first one I left my fuel settings the same way they were when things were running correctly. The second log I made, I adjusted my global to see if I could richen things up a bit. In the second log things were really rich untill boost hit. Then it looked the same as my first log.

If anyone has some suggestions let me know.

 

[4g64fiero]

Does your fuel pressure rise with boost?

 

[lowexpectations]

I can't tell at the moment. I need to rig something up to get the fuel pressure guage to be visible.

 

[rstchris]

Try the guage taped to the front window thing. You should also check the connection between the pump and sending unit. Some have a short hose and some have an O ring. If that leaks out pressure it gives issues like this.

 

[lowexpectations]

Well I talked to a few friends with more experience than me and was informed that it was most likely the in tank fuel pump going out. I replaced that and went for a pass. I was pleasently surprised that when it bogged under boost this time was because it was so damn rich. I continued to lean it out quite a bit and things got back to normal except one thing. I think from making a few lean pulls the plugs are done and are causing it to break up at high boost so tomorrow I am going to pick up some new wires and plugs. It was nice to see those afr's rich this time though.

The next task is to find out why running a intank pump and one inline causes the intank pump to take a crap really quickly.