[omriorion]

I put a G16B from a 2001 Baleno in my 87 Samurai, originally carbureted.

The engine came from a donor car that slightly overheated, so I took the cylinder head apart and sent it to a shop for machining, then reassembled the engine, adjusting valves, timing, water pump etc. The car was in running condition before the engine was taken off of it.

I grafted the Baleno fuel pump so it fits the non-efi Samurai fuel tank.

I run new OEM coils, new plugs.

The first time running the engine in the Samurai went smooth, and it operated for several minutes straight without issues.
Video of first run can be found here: https://streamable.com/bkxdyd

After two weeks of running it for a few minutes each time, issues started. The engine has a hard time starting (turns over a lot and requires multiple starter hits to get going), then starts rough, and then when finally starting it starts "shaking" as if it goes out of sync and roughens up until it dies. Sometimes disconnecting the MAP/TPS sensor (I guess it drives the ECU to limp home mode) raises RPM a bit and the engine has a smoother operation.

Videos of described issue:
https://streamable.com/j2ywx3
https://streamable.com/aly8xt

I bought another donor Baleno car and tried swapping the following, one line at a time

Whole intake manifold (including MAP, TPS, IAC and EGR sensors)
ECU and Immobilizer set
Engine wiring harness
Water temperature sensor
Camshaft position sensor
Crankshaft position sensor

But no luck, symptoms stay the same.

Looking for possible hints or ideas of what I can check to fix this.

[fordem]

I would suggest putting a fuel pressure gauge on the fuel rail and checking the pressure with the engine running.

[sideways]

Got good fuel pressure?

/Beaten by that much

[Gwagensteve]

Is the ecu throwing any trouble codes?

[omriorion]

Great diagnosis with fuel pressure. I brought the whole fuel tank from the extra donor car and connected it sideways to the Samurai to feed fuel, and everything worked. So I thought it must be my fuel pump. Disassembled my tank and pump, connected it on the side - works. Put my pump back in the Sammy tank - engine runs
Turns out the fuel hose coming out from the tank (rubber) was pinched between the body and the tank. I put the fuel lines there when the body was apart from the chassis, and must have pinched it when installed it back. So fuel was reaching but not enough. At least it's over. Thx