By the way I've seen setups where they intentionally changed the chain to a belt (who knows why) and run some funky stuff. I've seen it done and now - I too can do it (but why?). Turning the piston will not tell you if you're on compression or exhaust stroke. You must crank the engine fast enough (remote starter with ignition disabled) to see when the valves are both closed and blowing your finger out the spark plug hole (compression - firing stroke). I check exact TDC with a flashlight and end of a wire coat hanger (carefully placed on the piston).

 

Check all your vacuum lines, I don't think it's a timing problem. You have an intake leak or a broken/unplugged hose. If your timming was off you would not run ok a 1500rpm. It would be bad all through the rpm range.

 

If you're not ready to jump on the chain theory - you might check the little stuff first. It sure wouldn't hurt. With high mileage engines I'd say you're more likely to clog your converter then wear out the chain anyways. Look for good exhaust pressure at higher enginespeed - the intake vacuum leakis another vary good idea. If it were the chain it could run OK until it skips teeth. If it's that bad it won't run at all sometimes. A code reader could help save bills, if it's not the converter or something, by narrowing your search. Checking valve timing could be done by a pro. mechanic. Or if you want - check that the valves are closed proper on TDC by removing the valve cover at number 1 piston and crank engine by hand (or remote starter ifyou disabled ignition) until both valves close then check crank is at TDC. Put at TDC and turn to AfterTDC (ATDC). No valve should open until firing mark on crankshaft goes halfway down and faces down away form the timing mark 180 degrees.

 

You can also check the chain there by turningthe engine crankshaft back and forth and looking for looseness in the motion of a valve when opening. If you turn the crank and the valve has some decently noticable play between the crank turning and the chain turning it - the chain is obviously loose.

 

Well I found out what the problem was with my explorer. It wasnt the timing chain, something happened to my exhaust that allowed a hole to be burnt through the side of my intake plenum on top of the intake....when the hot air came outta that it burnt through the back of my DPFE sensor, and my lower intake manifold gasket also burnt out........so i know what parts went bad except for the part that actually caused this to happen, fun times eh? maybe it has something to do with the EGR valve?

 

I have been reading thru this thread and it sounds like your back where you started possible timing issues! i dont know about egr's but i was thinking the possiblity of timing being off and hot exhaust backing up thru the intake or maybe even a bad exhaust valve all together. are you back up and running now and does it seem to run pretty much normal if it does run? your issues have caught my interest i hope you keep us posted whats happening with it and if you get it figured diffently let us know what was going on,, maybe we can all learn somthing new here,,,,good luck

 

No improvements so far. I ordering a new intake plenum. A piece of info i should have included is that where the metal tube that connects the egr to the intake plenum actually enters the intake is right where the burnt hole is...the hole formed(big enough hole to stick three fingers through). the hole is about an inch to the rear of the metal tube. When i took the truck in to get diagnosed, they said that i had a flange that was stuck open in my exhaust manifold......well i dont know what flange theyt were talking about considering that the cast iron exhaust manifold has absolutely no flange that i can see. This all leads me to think that the problem isafter the exhuast manifold. there is a metal tube rail thing that comes outta the end of the Ex manifold that comes back forward with the EGR on the end of it......right after which is where all the problems are. If you need clarification on any of these please let me know on here or email me at rippedrob420@hotmail.com or rippedrob420@yahoo.com i check both of these daily

 

I cant think of what flange in the manifoldthey would be talking about right off hand either, they seem pretty solid to me,,well im glad to hear your at least making some progress with it anyhow good luck on finishing it

 

tap the IAC with a screw driver does the idle change or get better if so replace the IAC andg gasket

 

Problem solved!! The Explorer is once again on the road! This last saturday, i finally had everything i needed to repair it. I already had everything removed off of the engine that i needed to remove then i put the new intake plenum in, got a bad feeling it still wasn't going to run but said oh well and tried to start it.... AND IT RAN! Not only does it run good, it runs a little better than before! Well i appreciate everyones help on this, couldn't have done this with out yall, thank you.