[smccoy916]

My mustang is pinging above 4K at WOT. I have data logged it using my Diablo but I'm not sure what the fuel pressure is supposed to be. Its seems to start around 40psi and then rises to around 64psi at idle when hot. Does this seem normal? The car is very rich at idle. I get a small black puff when I step on it. I'm running the stock tune for break-in and plan to take to get dyno tuned. The car had this problem with the old engine and ended up breaking a piston, so I'm trying to fix it before it happens again.

The engine is new.
Forged internals
patriot heads
262AH comp cams
75mm throttle body & Elbow
K&N cold Air

[Trick Tuners]

IT sounds like you need a retune from your dealer. The FP as read on the rail with an aftermarket gauge should be 40psi + boost, or - vacuum (in psi). So at idle (20inHg~=-10psi) it should be 30. At 10psi of boost it should be 50. These numbers are rounded for simplification, but within about 1 psi of actual. when datalogging the pressure drop across injectors it should be 40psi all the time, except when its real hot the ecu will bump up the FP to keep the fuel from boiling in the rails. It will decrease the injector PW to compensate for the higher pressure. Try pulling some timing out at WOT, and add in some more fuel. If you are still on the stock tune something is very wrong. hopefully you are running the stock injectors and maf or you are asking for trouble.

[smccoy916]

My air intake temp was around 140f so that makes sense. I tryed a new AIT sensor but it still gets up to 140. So much for cold air! Stock injectors and MAF. I am running the stock tune and I installed a steeda timing adjuster to take a little timing out of the stock tune but it didn't help. I do have a PLX 500 system but only have one wideband sensor so if you had to pick a side which one would it be? I'm thinking it may be a fuel pump problem?

[Trick Tuners]

Why are the temps so hot? You need to get that wideband in ASAP and see what the AF really is. Drivers side is normally best, and easier to install. Try running higher octane or octane booster to see if it stops the pinging. I have a bunch of good info on detonation here. Detonation Explained

[smccoy916]

Thanks for the help! I was able to get the intake temp down in the 80's by cleaning the air filter. I never thought it would affect the car that much. I also cleaned the MAF with MAF cleaner and changed the fuel filter. I took some timing out and added fuel at WOT but it is still pinging. I also noticed that it surges a little when cruising at 45 or so. I will get the wideband installed ASAP. Thanks