420 Sel Starting Problems After Repiars
 

Hello, Need some advice and help in troubleshooting an 86 420 Sel that I have completed some repairs on. I have changed the head gaskets, replaced the intake and exhaust valves, timing chain and guides. After reassembly of the engine the engine will only attempt to start after sitting for several hours, at which point I get either a loud pops with some smoke coming out from under the intake manifold or the engine will start and run for 2 - 3 secinds then will die out. If I attempt to restart the engine again the engine will just crank but not turn over.

I have double checked the timing and have it set correctly, all vacuum lines are set as per the vacuum diagram on the frame rail support. Double checked all the electrical connections to make sure they are covered and correctly connected.

I am at a loss as to what else it could be, it seems to be flooding out. Any help would be greatly appreciated. The vehicle was starting and running just fine prior to the part being replaced.


Thanks in advance
CDB

Do you have the electronic portion of the fuel system working correctly? Also might want to check mixture after head work... Mine needed adjustment after a valve job.