ok so i just finished up on my 89 xj 4.0 i replaced the motor in it that had 274000 miles on it with a 90 xj 4.0 and now it wont run. as i tryed to start it it turned over a couple times and made a huge noise and the motor bound up and stoped turning over pulled the valve cover off to see if my valves still move and they do so i didint snap the cam chain witch i thought had happened, pulled all the plugs and found that my last cylinder was way more wet then the others basicly the last cylinder was filled with so much gas the piston had no where to go and stoped the engine from turing over. its like the last injector is stuck open.

i dont know what to do or what the exact problem is my brother is a mechanic and is puzzeled hes telling me it could be the computer,injectors,or fuel pressor regulator. if this made sence to anyone, please let me know what u think

 

Are you sure your distributor is in right ? Sort of sounds like the problem.

 

sure its gas and not coolant?

 

re did the timeing 3 times its right and yes its gas there was no coolant in the motor

 

It's possible the fuel injector is "leaking down". That is it is stuck open and continually pumping fuel into the engine. OR that plug isn't firing and the fuel is not being burned up. Or a combination of both. I'd suck the fuel out and make sure the engine still freely turns with a breaker bar and socket to make sure it's not froze up and then address those 2 potential problems

 

All good advice ... I would only add that once you get this solved, you'll need to change your oil, since a lot of that gasoline is leaking past the rings into your oil pan.

 

i have spark, and im preaty sure most of the gas is out because when i had the plugs out i turned it over again and about a half a soda can of gas shot out of that last cylinder so yes its not froze up yet but i think was about to hydro lock with gas, but im guna go down to the junk yard soon a get me some different injectors

 

yea thats what i was thinkin gota change it anyhow its still got the oil in it from the last owner

 

ok so i solved the fuel problem and got it started but now it bogs out and back fires out of the intake and will stall if u floor it or dont ease into it im thinking its because my knock sensor is shot or maby my ballist resistor also it takes for ever to start up almost 20 seconds and when i turn it off u can hear the gas drain back into the fuel tank, if anyone knows what can be the problem now let me know

 

Does anyone know if a broken knock sensor would be makeing my jeep run retarded

 

Maybe, my 89 runs just fine with it unplugged, you should unplug it and see.

 

ok so i just went and unpluged it and started it and still it bogs out when u step on the gas could it be that the timeing is off a hair?

 

Did you do all the ordinary stuff like plugs, wires, cap and rotor, and coil?

 

I did all that except the coil

 

Knock sensor will not cause our problem.