help new heads now engine runs like crap

[393mach1]

assuming that i just connect #4 on the coil pack (rear drivers side) to the #4 cylinder (front drivers side), #5 on the coil pack (front drivers side) to the #5 Cylinder (middle drivers side)#6 on the coil pack (middle drivers side) to the #6 Cylinder (rear drivers side), then i definitely have it right. that is how i have it looked up.

 

[schmoken]

do the valves need top be adjusted? what is the proper way to do that?

I haven't done this on a 4.0 specifically, but the process should be similar.

Each cylinder is done separately at TDC.

Rotate the pushrod with your fingers while tightening the adjuster until you feel a point where there is slight resistance - you are now at 0 lash. 1/4 to 1/2 turn more is what you want.

 

[393mach1]

I haven't done this on a 4.0 specifically, but the process should be similar.

Each cylinder is done separately at TDC.

Rotate the pushrod with your fingers while tightening the adjuster until you feel a point where there is slight resistance - you are now at 0 lash. 1/4 to 1/2 turn more is what you want.

i'm firmiluar with this process, my 70 mustang has solid lifters and i adjust the valve lash frequently. as far as i can tell, this motor has no adjustment. the rocker arms are on a rail and have no way to move them up or down. don't the hydraulic lifters make this valvetrain self-adjusting?

 

[JDraper]

The 4.0 OHV does not have adjustable rockers. You bolt down the rail and it's done.

One other thing, I ran into a problem once on a Mitsubishi engine where I had 2 lifters pumped up and they were keeping valves from closing..made the motor run like crap. We took the lifters out, bled them down, re-installed them and all was well...just a possibility. We found it by doing a compression test on the motor. With the rocker assembly in place, the compression was almost non existent on the two pistons with the pumped up lifters. With the rockers removed, compression was good.

 

[393mach1]

i really should just go but a compression tester, but i know the valves are closing the whole way because the puchrods did not have tension on them when the valves were supposed to be closed. now i'm really thinking its a coil. it has randomly got much better as time goes by, and now it runs pretty well except when the RPM's are low (under about 2500) and you hit the gas, then it starts missing, but definately not as bad as before. how can i test the coil to see if it is bad?

 

[reserved50]

popping is caused by wrong timing, valves not closing, wrong firing order etc, so its popping and not just running rough like one cylinders down? Im just throwing things out there, dont think a bad coil would cause a pop, but it would cause rough running

 

[393mach1]

popping is caused by wrong timing, valves not closing, wrong firing order etc, so its popping and not just running rough like one cylinders down? Im just throwing things out there, dont think a bad coil would cause a pop, but it would cause rough running

initially, it was popping and acting like the timing was off, but it mysteriously got better slowly and currently only feels like one cylinder is missing. now, it idles smoothly like it should, and when in neutral or park it revs up smoothly like it should, but when driving, it feels like one cylinder is missing.

 

[reserved50]

start unplugging injectors one at a time till you unplug an injector and the idle doesnt drop/change, thats a dead cylinder

 

[exploded99]

To replace heads you must have pulled the camshaft position sensor. That will give you a lot of grief if you don't get it back in correctly. Have you run the engine to TDC and checked that it is in correctly?

 

[393mach1]

start unplugging injectors one at a time till you unplug an injector and the idle doesnt drop/change, thats a dead cylinder

i did what you described but with the spark plug wires instead if the injectors. it seems to be cylinder #6

how can i test to see if the problem is the coil or the injector?

 

[393mach1]

To replace heads you must have pulled the camshaft position sensor. That will give you a lot of grief if you don't get it back in correctly. Have you run the engine to TDC and checked that it is in correctly?

i definitely did not have to pull or even touch the Cam Sensor, it is located behind the intake and does not have to be removed.

 

[reserved50]

remove a spark plug wire and put a spare plug at the end and ground it to a metal part of the vehicle, then crank/start it, if it doesnt spark well it doesnt work.

 

[dynamite196]

To test the injector you have to remove the fuel rail (remove the upper intake manifold first) and they pull out, then you get a couple of wires and connect the injector to a 12 volt battery. If you hear a 'click' noise that means the injector is working, you should also see fuel spray out when it clicks. If either of those doesn't happen you either have a clogged injector or a dead injector. Try cleaning it with injector cleaner first and see if that fixes the problem. I had a similar problem when i did an engine swap in my ex. Bought the engine from a reliable scrap yard, only had 54k on it. Put it in everything looked great but it wouldn't start. I tried everything, finally turned out to be 4 out of the 6 injectors were clogged. Now it runs flawlessely. BTW, the clogged injector/misfire problem on that cylinder probably caused the headgasket problem.