Hello, maybe someone of could give me a tip, my 502 efi doesn’t run. We did put a 502 efi complete used set on a 502 carburetor engine. I did make a new injection pump, new fuel pressure regulator, new injectors inside, ignition works and fuel is coming. But the engine does not start. Only sometimes a misfire. Has anyone an idea what could be the reason?
many thanks in advance for your help

Did you use the EFI ignition distributor and coil ?........MEFI 3 ?

Yes, all from another engine with frost demage engine block

Are you sure that the distributor is clocked correctly on #1 cylinder........firing order all correct ?

You should be able to get a timing confirmation when crank with the timing light setup on #1, no matter what system you have.

checked twice, all correct

just checking the most common issue with clocking the dizzy is being 180* out by not being on the compression stroke,

if its a mefi 3 theres 2 grounds, 1 thats a single wire and one thats 2 wires , they both need a good ground, aside from fuel pressure, correct firing order, spark thats what Id check next, on back of engine, usually go to a bellhousing stud

when you put the ignition on,,does the fuel pump cycle?