acts funny at a steady throttle

[Superwho05]

first time encountering a problem like this, I have an idea but I would like to hear others if anyone has advice. just did a swap in my dd and after I got everything working right, it still kinda.... "mumbles" when cruising with a steady throttle, and tends to backfire more than my first motor (which was the same thing) I completely redid everything in the engine bay so it looks nice and brand new... could I have wired my O2s backwards? (B16a) running to rich? everythings in perfect time, and idle is normal, it only does it when the engines warmer and Im cruising. appreciate the help

 

[PCT]

Sounds as if the fuel pressure is excessively high.. Check the fuel pressure, disconnect the vacuum line from the fuel pressure regulator and the fuel pressure should read 40-47psi.

It line pressure is correct perhaps an injector is leaking.

Backfires are typically caused my unburnt fuel in the exhaust where it ends up igniting.

 

[awptickes]

Before I go any further, is the ECU tuned for your particular setup? If not, get it tuned, then start from there.


By steady throttle, do you mean steady manifold pressure, or steady TPS percentage?

If you're still below the threshold for open loop, you'll have to worry about the Short Term Trim changing the fuel values. One way to check for this is to hook up a wideband, and a manomoter.

 

[Superwho05]

its a bone stock motor, so I shouldnt have to worry about the ecu. by steady throttle, Im deffining when.... lets say your doing 45 in 4th gear and your half on /half off the gas pedal, it kinda sounds like it purrs. then if I very slowly give it gas, its like the throttle kicks in with a little torque behind it. its hard to explain, and it might be the fuel pressure, just havent had the chance to check it yet (cant find my gauge) thanks for the input guys