I just rebuilt the 4.0 in my 88 wagoneer limited, fired it today and it's running like the timing is off or the sparkplug wires are on wrong but they are on right. I lined up the timing marks on the sprockets and even checked the pin count on the chain like it shows in the book. While it is running it's sucking a lot of air through the intake. Any ideas????

 

When you say "rebuilt" what all did you do? How in depth of a rebuild did you do?

 

Engine: bored thirty over, new pistons, rings, rod and main bearings, timing chain and sprockets, cam and lifters.

Head: surfaced and grind valves

 

sounds like a cam issue

 

Oh ok, so pretty in depth. Ok, so now its running like the timing is off and you're sure you set it correctly? Also, you're sure all the work was done right and put back together right? Are the plugs new?

 

Yes the plugs are new and i lined the timing marks up and checked the chain pin count. i put it together myself. I've put alot of engines together but this is my first jeep engine.

 

What are the lifters torgue to? should be 19ftlbs at tdc,if they are to tight it will cause this problem also.

 

lifters, what, you do not torque lifters (cam and lifters right) no tighten hehe, i think he means rocker arms. Not sure on the older motors pre 1999 4.0 liters but i dont think you need tdc for the adjustment on rocker arms at all . Just check i might be wrong. i dont think there is adjustment or much of one for rocker arms just your 19 to 21ftlbs for torqe down. also recheck all your head bolts rockers etc etc for the retourqe good luck.

 

When you torgue rocker arms you are putting the same pressure on the lifters,torgue rocker arms to 19ftlbs and yes it has to be done on 4.0s at tdc,meaning #1 at tdc,if they are to tight the valve will not seat all the way and on new motors once the lifter pumps up it will get worse,weather you torgue rockers or use lifters to describe it is all the same

 

Thanks guy's for the input i'll recheck the torque in the morning

 

I dunno, I mean if you've done this work before I would think you would have torqued everything according to specs. To me, it sure does sound like that timing is a touch retarded. I would focus my attention to the dist as well as make absolutely 100% sure I set that ignition timing correctly.

Other than that, and also making sure those plugs are in their correct places (and I dont mean to second guess ya, just throwing stuff out there) Im at a loss.

 

Ok so i checked the torque on the rocker arms and they were set to 19 ftlbs. i did a compression check and only had 90lbs. I loosened the rocker arm bolts a 1/4 turn and got 120 lbs of compression, Could they have sent me the wrong lifters with my engine kit?

 

So now i'm thinking it's an electricial issue, where is the ecu located and how do i test it to see if it's bad? Timing is on, plug wires on right, fuel pressure is right, rockers torqued to 19ftlbs. What am I doing wrong?