New Build - Won't start/run - Errors P0100 & U0121

Well, at least it was a (relatively) easy fix.

Definitely could have been worse that’s for sure. I was beginning to think there was something wrong with the bottom end so I’m glad that ended up not being the case.

I even went back and found some of the articles and YouTube videos I watched. In hindsight they don’t say you can use GEN2 F150 exhaust cams, they just say “GEN2 exhaust cams” so really it’s all my fault for not doing more research.

and I am not even sure all of this was worth it. My guess, Ford needed to add another 300 lbs or more and at 8lbs per HP, the extra ratings were needed.

So to recap this. If you have a Gen 1 engine with a burned piston or thrown rod and want to use a Gen II truck engine to replace it, all you need to do is take off all the parts including the cams and hardware from the Gen I engine and reinstall them on the Gen II truck long block. Then your good to go.

Yes, broke a rod and windowed the block. I picked up a 22K mile ‘17 GEN2 F150 engine and swapped everything over but left the GEN2 exhaust cams because they have an additional 1mm of lift. Didn’t see the harm and many have done the same thing...just can’t use F150 exhaust cams. It’s all buttoned up and running fine with all 4 of my GEN1 cams. Just putting the rest of the car back together this afternoon and taking it for a shakedown.

Do you have a cold air intake on it? Just asking because I started mine up with the CAI newly installed but without the revised tune and it ran pretty crappy; very rich. Putting the revised tune in straightened it right out.

I had a car that sat for a few months and when I went to fire it up it would barely start and ran super rich. The only way to keep it running was to turn the fuel pump off and on to keep it lean enough to run. Turned out 2 off the injectors decided to stick open. They had less than 4 hours of use on them. Got them cleaned and the car purred like a kitten.