StarSteele

So i have now checked the coolant, no bubbling. the exhaust, only blowing, there is no suck and blow. cracked head and leaky gasket is ruled out after i have sprayed soapy water around and no bubbles. after running the engine again i do think that it is a valve issue as there is fuel vapour coming back out the intake manifold. i don't understand how though because my timing is lined up. its an interference engine so if it wasn't aligned, if have pistons hitting valves, right? and the valves have been lapped and also don't seem bent. I might take it into a shop and get a compression and leak down test just done so i can get the best readings and find out for sure where my leak is coming from

Thats a good point, ill give that a go, thanks. If that doesn't work, do i Just take it to a mechanic?

Exhaust and intake valves were all lapped. and valve clearances were good

Update, we have taken the Hilux for a drive out on some hills behind our house as, ranging the revs, gears and load. there was no change, engine still misfires, low power etc. Did a compression test today, still no good. front three cylinders are all good, (about 300psi when it cranks) back cylinder still has 000 compression. I have no idea what the issue could be, i have worked on the engine for hours and i simply don't understand.

Thank you guys! ill be taking it for a drive tomorrow, let you know how it goes and ill to a compression test

Hello I have a 1989 Toyota Hilux ln106r. the engine has been swapped to the slightly larger 3ltr 5L engine from the 2.8ltr 3L. The engine is Mechanical fuel injection and non-turbo I recently conducted a partial rebuild as my timing belt needed replacing, the engine was smoking a bit and there were some oil leaks. Here's what I did on the rebuild: Engine fully pulled apart and cleaned Cylinder bore measured and were almost completely stock Cylinders were honed and piston rings replaced with Chromoly rings Full gasket replacement New timing belt, tensioner and Idle pulley New water pump The engine went back together and after starting her up, I had a rough idle and some minor fuel issues. Ordered New injectors, put them in and double checked the timing Again, Started it up and same issue. We realized there was a Misfire and after conducting a compression test, found that cylinder 4 (furthest cylinder from front of engine) had zero compression, and all the other cylinders were low I decided to take apart the engine again. I rechecked the compression ring gap spacings and found that they were almost inline with each other so I respaced them with more care the second time around. I then lapped the valves and replaced the valve oil seals, and the valves seated well. Replaced the head gasket again, and put the engine back together, triple checking timing, torque settings etc. Started her up again today with some hope, but no change. Engine still idles rough, and I can hear it misfire every now and then. I have no idea if there is any other possible issue unless there is something seriously wrong with this engine. I am not giving up on this engine, I have to find out what is wrong with it, even If I cannot repair it. I will conduct another compression test soon but figured I would put up a post on a forum for any input which would be so very much appreciated. Thanks!