90-ROC

Hey guys, new to the forum but have been looking here for info for awhile, Glad to finally find a third gen crowd, Without having to call Bruce at Hawks third gen. LOL So my problem is that I have opened up the exhaust with headers, beefed up the fuel system from tank to intake (including) injectors. and I'm having a tough time overcoming the rough idle. Without the MAP connected it idles fine but, eventually loads up and dies. With the MAP connected I have a very rough idle. Now when I set the FP at 47-50(suggested by TPIS) which vacuum line to disconnect to get my accurate reading? The one that goes to the MAP? Or the main intake vacuum lines. Forgive my ignorance...Ihave owned 7 F4 body cars but never had this problem. Prolly cause this is my first speed density car!

1tpi

The hose that goes to the fuel pressure regulater

90-ROC

Well!!! I guess that makes sense now don't it!! like I said forgive my ignorance this speed density system is new to me! I think there may be another problem as well. I have the Holley AFPR open all the way and I tested the FP this morn. With the eng off and key on acc and I only got 39 max psi. I know I need at least 47-49 (w/no vacuum) to get it dialed in with the vacuum and the MAP hooked up...What gives??

Glenno

You mentioned improving the entire fuel system from tank to injectors. Maybe blockage somewhere in that new install. Debris from the tank, Teflon tape (if used ?), metal bur in connection somewhere, crushed fuel line, faulty fuel pump, faulty regulator? Good Luck

1tpi

You say, you have the AFPR all the way open, I hope you mean you turned the screw down, so clockwise not counterclockwise

90-ROC

1tpi---Yes, It is screwed all the way down (open)
Glenno---As far as blockage goes, I don't believe there to be any. After I installed the new high volume FP and sock w/new hose in the tank, I also replaced the fuel filter and the lines at the frame rail to the (intake) fuel rails. And even pulled the new lines at the rail to check pressure and flow and got a healthy thick flow of gas at the engine bay! I also had the fuel rails high pressure flushed during the process in hopes of eliminating all of these problems.