Misfire & Stalling during cam break in

[mveltre123]

Hello all,

As the title suggests while performing my cam break in on my 01 XJ, my motor seems to some problems. It has a significant misfire, the engine runs relatively smooth but the miss is obviously heard in the exhaust. Additionally, every 2 minutes or so, the engine will sputter and shut off.

No codes are present whatsoever. I have only performed about 10 minutes of break in and I don't want to continue until I get this figured out. That being said i'm in a tough situation since I cannot start the engine and idle it to test any repairs until I complete the cam break in.

Since there are so many possibilities that could cause a misfire, what would you all reccomend checking first? It almost seems like the engine is either running out of fuel or losing spark causing it to rapidly shut off. I am planning on verifying fuel pressure and double checking my positioning of the cam synchronizer first before I do anything else.

I am praying that I have not wiped a cam lobe, this is my 2nd time building this motor this year! The cam is a comp nitrided custom grind from Russ. Running copper champion plugs gapped at 0.035. I can post additional specs if needed.

Thanks in advance

[jason_alex_2009]

Following……

I am sure you have already tested for spark? On all coils or wires I am new here.

[dwg86]

Check fuel sync. Also, what fuel injectors are you using?

[75SV!]

Are you running the Harland Sharp roller rockers? What length or push rods are you using? I think 9.600 is the correct length for the HR roller rocker. Stock is 9.640 to 9.650.