Dyno tuning issues

I've got the car on the dyno now. I've upgraded the entire fuel system. Pressure stays nice and steady then drops off along with duty cycle. Maf pegs at the same time.
Some more info. Pressure spikes right before it drops.

Any ideas?

Edit. Forgot to mention running single turbo.

That happened on my 2010 auto, with the Roush M90 blower. FPDC pegged, but ONLY when trying to get into boost. Fuel rail pressure dropped from normal 40 psi, down to 5-6 psi, again, only when trying to get into boost.

Problem turned out to be the sock filter on the fuel pump, clogged.

What's your fuel system look like? Pump, injectors, etc. What MAF? Got images of Dyno chart results?

Sorry about never replying back to this thread. I didn't think there was ever any response to it. My fuel system is the S&H system from one of the members here. Big pump, big lines, big fittings, pure voltage running directly to pump. The problem turned out to be the maf. I was told by several people that the stock maf would work fine with the inlet tube diameter as long as I didn't go over 9 psi. WRONG. I installed the Big Air 5000 and fixed it. Left me wondering why Triangle Speed didn't figure that one out. He really acted like he was totally disinterested in tuning my car. I've paid them a substantial amount of money. Got not much in return. Manuel (Lito) ended up tuning it. It ran better at first go with Manuels tune than it ever did with Triangles. And much more of a real world tune. Dyno won't give you the same results. It was an expensive lesson learned. ($1100)

MrBhp said:

It ran better at first go with Manuels tune than it ever did with Triangles.

Click to expand...

That happens a lot with Lito’s tunes. Regardless of who tunes it first.

Dyno tuning is for WOT. Pretty much the easiest to dial in.
Idle and part throttle is much harder and takes way more time. Cannot really simulate that on a dyno.