whats wrong with my car

[GVR40]

i have just rebuilt the engine and now it is only firing on cylinders 1 and 2. 3&4 won't work, i have changed the plugs, and i have swapped the injectors from 1-3 2-4, but still wont work, it isn't valve timing because it worked before i pullen the head off and i didn't touch the head at all. plz help

 

[kaotik]

did u check ur leads for spark? check ur coil packs aswell, there is 2 cylinders running from one coil pack, mite explain y 2 cylinders arent firing.

 

[GVR40]

leads all sparking, that was the first thing i checked, the only thing i can think is that the resistor pack for the injectors isn't send the right current through to injectors 3&4 so they are dribbling rather than atomising the fuel, when i pull the plugs on those 2 cylinders they are wet from fuel

 

[rob323]

Try - swap the plugs around to rule out a spark plug problem, then swap leads around on the plugs (if they are long enough) to do the same.
Then swap the leads around on the coil and confirm it is still the same two cylinders not firing.
Then swap the injectors around and see if its still the same two cylinders not firing, if it is, it is not spark or fuel.

If the CAS in the right way around?
Cam timing still all good?

 

[GVR40]

done all of that rob, cam timing is fine, i didn't touch the head when i pulled it off and the other 2 cylinders are working, the CAS is on the right way, could it be a compression problem

 

[rob323]

Thats sort of what I was getting at, maybe the valves aren't closing properly. Either whack a compression tester on it or you should be able to hear/ feel it if you turn the engine by hand with the plugs in. Have the rocker cover off so you can watch to make sure every thing does what it should and when it should.

Could the lifters be pumped up and holding the vales open?

 

[GVR40]

thats possible, i wacked a compression tester on it yesterday number 3 was showing nothing and number 4 was was only peaking at about 70, i will pull the rocker cover off and turn it by hand to see what is going on

 

[rob323]

What did you have the head off for?

 

[GVR40]

to replace the piston that was shattered, (i replaced all 4)

 

[VR-4-PLAY]

are you confident the shattered piston bits didnt damage the valves on the way out?

 

[GVR40]

the piston shattered between the rings, no damage to valves from that

~edit~
the valves on piston 3 intake side are stuck slightly open, could be bent could be valve guides, got to pull it appart and see