CA18DET Issues,

[Jables2003]

Ok, so I bought this thing about 2 years ago, only recently have I gotten serious with it. Trying to get it to run and what not. I was told it would at least in idle in limp mode with out a MAF hooked up. It'll turn over and start but only run for a few seconds and die. Sounded weird. So I did a compression check. Cylinders 1 and 2 were reading at 90psi, Cylinder 3 read out 60psi and 4 was at 75psi. So yesterday I removed the head and did a leak test, by filling the chambers with brake cleaner and waiting to see if anything would come out of the valves. No leaks at all so are my valves good? What could it be. Also this motor has been rebuilt but I didn't do it. Its got some nifty stuff in here. Any help?