383 hammerhead popping/missing

[Tydavis]

Alright guys, I just bought a 2007 23 lsv with the 383 hammerhead. It has an intake popping/miss up to 3000 rpm. It  runs really smooth after 3000 rpm. I already replaced the entire fuel pump in the tank as well as the distributor cap. I replaced the fuel pump because I through a bad regulator was causing the issue. The exhausr still smells rich after the fuel pump was swapped. Any help or insight of how to trouble shoot or what to do next would be appreciated.

[MadMan]

Backfiring through the intake is more of a sign of a lean condition.  Maybe a clogged injector?  Of course it could be ignition related, it's always difficult to isolate which one it is.

[Ndawg12]

Hook up a fuel pressure gauge and run it through the RPM's noting the pressures and report back.  

[Tydavis]

Ok so what I got was 58 psi for key on fuel pressure and as well as 58psi throughout any rpm. This was on the hose so there's no load on the motor. If I rev it up then drop it back down to an idle fast it drops to 40 psi for a split second and the motor sputters. Is this a sign of a sticking injector? I also pulled the plugs, the two front plugs on the starboard side look a little wet but the third plug is lean. Is there any way to test the injectors other than having them bench tested? Thanks for the help guys. 

[BlackBluMalibu]

Sounds like bad fuel pressure regulator.  But before you buy a new one give the old one a good rap with a rubber mallet or something of the sorts that won't damage.  I had mine act up earlier this summer and hit it with a rubber mallet a couple of times and now it runs perfect between 48 at idle and 52 at full throttle.  Check fuel filter and make sure it's not the culprit , but from the sounds of it, the regulator needs a good rap.  Best of luck!

[Tydavis]

I'm back again guys. So I replaced the entire fuel pump assembly including the regulator and the fuel pressure now holds consistent at 58psi. I had the injectors rebuilt as well as new plugs and wires. I am at a complete loss of what else it could be. Does anyone have any other ideas? 

[Rednucleus]

Last time plugs & wires replaced? You mentioned dizzy cap; rotor too?

[nlouthan]

What about the intake plenum gasket?  Bakes sells it..  Maybe it's sucking air through there?

http://www.bakesonline.com/detail.aspx?ID=1653

[Woodski]

@Tydavis:  I suggest a compression and leak down test, could be a head gasket between middle cylinders, but hopefully the test would eliminate that possibility.  Does it pop or crackle at idle also?  High RPM running can mask a head gasket issue.

[Tydavis]

Thanks for the help everyone I finally got it figured out and figure I would post it here if anyone else every had this problem. It turned out to be the cam phasor timing wasn’t advancing off of idle. The timing is supposed to be 705 degrees after 1200rpm. Well it was never moving from the 640 degrees it sit at at idle. So the fix was a new cam position sensor and a retime. It runs like a beast now.