Hello,
I am new here. I have small local car shop and we bought this old LS for my work mate.
Car was supposed to get scrapped, but I did not really like that idea. I have UCF21 and my mate was already looking for some jap car.
Story is that previous owner after 340k miles wanted to change engine on driveway using crashed donor car (which was also part of the deal) but it failed I guess in near end.

The engine and transmission is swapped. I had to fix broken connection to fuel pump (both electrical and fuel line...) and connector to gear switch. This got me to make the engine crank and get some decent fuel pressure at the connection near engine.
Both donor and original cars was/are LPGed from different brands so the engine bay is trashed. I removed LPG injectors and things around and sealed holes in intake.
I gave it some cranks to get fuel everywhere where it should be but spark plugs are dry.
I tried to google something, and found here on forum really nice diagram for engine fuses.
Both EFI fuses are ok and i have electricity on both sides of the fuses - which makes me think EFI relay is also ok since there is 12V on no2 fuse. INJ and IGN fuses are also ok. I would like to read some data from OBD port - for example cranking speed - very common and easy way to check crankshaft sensor which can paralyze most of cars in this way, but my cheap Techstream crashes when I want to load live data, it also wont show any DCTs(works with my LS), I also have pretty decent multibrand diagnostic tool it just wont connect with this car.

So my question is - since I dont have that much exp with these cars, what other things could make the ECU not to open injectors? I will try to remove the injectors when time, and use ultrasonic cleaner to make sure they arent clogged - I guess the car is dead for more than year. We filled it with fresh gas too. Also is there some way to check/measure crankshaft sensor to make sure its okay?
I have ECU from both engines but changing them doesnt make a difference. I also checked all possible connectors, earths etc. that could be unplugged or damaged in any way.

Thanks in advance.

 

it is likely an immobilizer issue (anti-theft feature) check the ECU. The ECU codes and Key codes have to match for it to start

 

Hello,
I already sorted it out. The issue was that LPG install disconnected injectors from ECU... I did remove it and fix original cables back together and it started right away...