Idea's please. went from real long crank time to no longer starting. I had a light miss before, so I figured injectors. I replaced all 4 injectors (OEM) same thing. I noticed while cranking I had coolant blowing out so I checked compression through glow plug holes and it was 220, 245, 220 and 220. (1-4) Spec say 345-405. So I pulled the head. blown head gasket between 2 and 3. Replaced head gasket buttoned her up, and exact same thing. Ran compression again. Same thing.. Did wet compression test, went to 320, 405, 320 and 320, give or take a pound or 2.. so I jerked the motor out. Slapped in a new set of rings, cylinders looked good. Still honed them to clean them up.. put engine back in, same thing. crank no start. blow by did go away.. now just puffing white smoke from unburned diesel. I do have fuel spitting out of all 4 injection pumps. This engine does not have your normal fuel rail. Has injection pump per cylinder. They all looked good when removed, all springs intact. I replaced the pushrods while turning the engine over by hand, so none of them bent. Then i checked them visually to make sure they stayed straight once i turned the engine over. I ohmed out all the glow plugs and they are all good as well. Engine has an electric fuel pump added, so it has plenty of constant fuel pressure. I havent rechecked the compression yet. I may do that today. I didnt see any sign of head damage upon visual inspection... Thought anyone. Thanks in advance
Sorry, posted in wrong place.........
not a good practice to "wet" compression test a diesel.. if your fuel and compression are both good. That just leaves air and timing, one of them is not good
Welcome to HEF JRAD ! Ahhh, the hard starting "D" series . No surprise there. The "D" series was a hard starting nightmare of a machine. Those compression numbers (before the re-ringing) are a too low. Definitely check the compression again as well as performing a cylinder leak-down test on each cylinder. Cranking speed above 200-250 rpm? Parasitic load on the engine? Maybe the cam gear slipped slightly throwing the valve timing off?? Do note, special tools are required to check cam timing. Double check that the pushrods were not bent. Those lifters are supposed to be collapsed on reassembly. Also, those engines are a bugger to start when the fuel system has been opened up. So, getting the air out is difficult at best. Another area of issue with those engines are the injection pumps. Seen many of them with leaky plungers allowing fuel in the rail to leak down or allowing air to get into the rail, which most likely was the original hard start cause. Has a clear line been placed into the fuel return to check for air? Has the fuel return check valve been replaced? Has the fuel pressure been checked with a gauge? Any codes, active or stored? If so, post them, then clear them and see if any come back. So many questions, so little time
In our experience the little fuel return fitting in the head is one of the more common hard start problems. If memory serves it should be 29 psi before any fuel comes thru check valve. You can check low pressure sensor reading by going into the service menu.