blown motor?!? 189k miles

[Mrooney322]

well as the title reads i believe that i have blown my engine but im not entirely sure. about 2 weeks ago i heard a pop in the engine bay while driving followed by a terrible knocking/banging noise and the heavy scent of gas. after getting it off the road i checked the codes and it had said that cylinder 3 had misfired, so i pulled the plug and saw that it had more black deposits near the electrode than the other plugs. i swapped the plugs out and no more misfire code. i got it towed to my house and in the process i pulled a po106 code, which is the "Manifold Absolute Pressure/Barometric Pressure Sensor Range/Performance". despite what hours of searching i did i couldn't find anything really definitive, so i pulled the upper intake off and checked the vacuum lines as well as tested the connector at the Egr module. i cleared the code and it hasn't come back but the truck still makes that horrible knocking/banging sound and it smells like gas is just being poured into the engine. now i dont want to start throwing parts at something that could be a lost cause but is there anywhere else i should maybe look first?

EDIT: my explorer is an 04 4.0l V6 flex fuel

 

[Number4]

I'd do a compression test for each cylinder.

 

[Mrooney322]

Update

well instead of compression testing the cylinders i made the bold decision to remove the passenger side valve cover, which i might add was a major PITA, with that said upon an initial look everything was checking out.

now heres where things go south. taking a closer look at the rear timing chain i noticed that the guide or tensioner piece was pretty marred and flattened on the side in contact with the chain

i turned the engine over manually and had my friend take a video of what happened with the chain and valves. im not sure what to really make of it seeing as the quality of the video is pretty lack luster but maybe someone on here can help me out in identifying the problem. note as i turned the engine over the slack in the chain increased.

in the video it looks like the chain is moving but not operating the valves. if that makes sense

 

[Mrooney322]

found the timing guide after shining a flash light around the chain... looks like ive got to say bye bye to my ex. definitely cant afford to be pulling the engine for this fix

 

[dablack]

How much do you think an engine swap will cost you? I did mine for $1200. $1100 for the 2008 mustang motor and $100 in gaskets. Plus I got a spare coil pack and other stuff. I figure a new car note is about $500 a month. So if it lasts two months then i got my money back! HA!

I posted about the swap here.

http://www.explorerforum.com/forums/showthread.php?t=412348

Austin

 

[2000StreetRod]

broken rear cassette guide

I couldn't tell anything from the video. Does the camshaft move when the engine is manually rotated?

From the photos it is obvious that the rear cassette guide is broken. It probably broke near the pivot bushing.

There are two ways to replace the rear cassette (guide, chains & sprockets). One is to pull the engine and the other is to pull the transmission and work under the engine.

I prefer pulling the engine but for those having access to a hydraulic lift pulling the transmission may be less work.
Apparently your engine still runs but I advise against running it until you determine what's making the noises. It could be parts of the guide getting jammed or it could be the pistons striking the valves if the chain has slipped enough. Checking the compression is the easiest way to determine if there is valve damage. No compression means bent valves. The exhaust valves are the most likely to be damaged.

Low compression usually means the chain has slipped but there is no valve damage.

 

[Mrooney322]

i have been looking into getting a new motor and just having a shop swap the motors but the trouble i am having is really finding a motor, i have read other posts about swapping motors from different years but i just want to make sure im not buying the wrong one. that and trying to find one in reasonable condition in my price range, which ideally is around a grand give or take.

streetrod- i do see the broken chain guide. now its just a matter of replacing the part or replacing the engine. seeing as i dont have the equipment to drop my transmission or pull my engine myself.

ideally i would love to rebuild one myself but thats not entirely cost effective nor do i really have the experience to take on such a feat.

 

[Number4]

If your paying a shop to swap engines, you might as well pay them to fix your timing.
You have no idea when the used one might have the same problem. At least check the pricing.

 

[dablack]

Why have the shop do it? Do you have an engine hoist and a shop jack? If so, then you are set. If not, do you have a buddy? Harbor freight has those tools pretty cheap. The rest of the swap is common hand tools. You might need one or two deep sockets or other misc tools but if there is a Lowes near by then there you go.

It wasn't a hard job for me and I've never messed with anything with Fuel Injection except for changing out a sensor or two. From the work you have already done, it looks like you are capable.

As far as getting the right engine, all SOHC 4.0L engines are the same. I would find the newest 4.0L out of a mustang or explorer as you can find. It is simple to swap over the explorer exhaust manifolds, intake maifold, thermostat housing and other little bits. The explorer parts just bolt on where the other parts used to be.

After doing it once, I wouldn't hesitate to do it again.

Austin

 

[Mrooney322]

yeah i guess ive really just got to get the ball rolling on this, guess ill be scouring the internet and classifieds tonight, hopefully i can find myself a good deal