Ok guys, I need your help.
Here's the gig. Working on my 93 YJ 4.0. Yesterday I finished up the installation of my new stock cam, lifters and timing set. After everything was back together I started it up the first time to begin camshaft break-in. Upon initial startup, it seemed to struggle to fire, but that is normal after such a job. I ran the engine for 30 minutes between 1500 and 2000 RPM as directed per the cam instructions.During this time, it felt as if I went over 2000 rpm, it was struggling. I shut it down and changed the oil and filter. Jumped back inside and went to start it and all it did was crank over with a few half hearted fires. I gave it some gas and it would spit and sputter a bit. I continued cranking and varied the throttle and it was firing more and more until it stumbled and took off. When running, the throttle felt soggy and I could tell it wasn't running right. I thought maybe I had the distributor a tooth retarded, as there was NO backfiring or any of the other symptoms I would get with an advanced timing. I put the motor to 0 degrees firing TDC and pulled the cap. The rotor pointed directly at #1. I thought and thought to myself and then convinced myself that I must have botched the timing chain timing and that was the issue. I tore the front of the motor back down to verify. Rolled it around and the timing dots line up perfectly.
The jeep ran and started perfectly before the camshaft job. Only reason I changed it was due to a sticky lifter that liked to tick all day.
Fuel pressure checked and verified within spec with a gauge.
The only thing else I changed was the spark plugs. I installed Autolite Platinum AP985 spark plugs.
When I pull a plug, its dry, no sign of flooding.
Verified all engine electrical connections, double checking nothing was missed during assembly.
What do you think happened?
Here's the gig. Working on my 93 YJ 4.0. Yesterday I finished up the installation of my new stock cam, lifters and timing set. After everything was back together I started it up the first time to begin camshaft break-in. Upon initial startup, it seemed to struggle to fire, but that is normal after such a job. I ran the engine for 30 minutes between 1500 and 2000 RPM as directed per the cam instructions.During this time, it felt as if I went over 2000 rpm, it was struggling. I shut it down and changed the oil and filter. Jumped back inside and went to start it and all it did was crank over with a few half hearted fires. I gave it some gas and it would spit and sputter a bit. I continued cranking and varied the throttle and it was firing more and more until it stumbled and took off. When running, the throttle felt soggy and I could tell it wasn't running right. I thought maybe I had the distributor a tooth retarded, as there was NO backfiring or any of the other symptoms I would get with an advanced timing. I put the motor to 0 degrees firing TDC and pulled the cap. The rotor pointed directly at #1. I thought and thought to myself and then convinced myself that I must have botched the timing chain timing and that was the issue. I tore the front of the motor back down to verify. Rolled it around and the timing dots line up perfectly.
The jeep ran and started perfectly before the camshaft job. Only reason I changed it was due to a sticky lifter that liked to tick all day.
Fuel pressure checked and verified within spec with a gauge.
The only thing else I changed was the spark plugs. I installed Autolite Platinum AP985 spark plugs.
When I pull a plug, its dry, no sign of flooding.
Verified all engine electrical connections, double checking nothing was missed during assembly.
What do you think happened?