How to: 4.0 OHV Refresh

[AngryPossum]

Good Luck trying to find the drivers side Valve cover. They are far and few to locate anywhere,,, including most junkyards. It literally took me 3 months to locate one, I found mine eventually on eBay for $60. My original cover was rusted out by the Valve Cover screws, causing leaks onto the manifold. Here is some before and after pics included **Someone said on a forum that you can use the passenger side valve cover also, if last resort, The only thing is you won't have a PCV valve, and you will have an extra oil filler port.

 

[97Sandbox]

Put it in gear and out of gear and see if the sound changes.... wondering if it could be your torque converter...

It's definitely not the torque converter because I don't have one haha! Maybe a chunk of clutch breaking loose?

Back to your Ex - OK - ANY of your CATS can be bad.

With that said, what I will throw out there is that on the OHV (X-Engine) the Drivers Side Cylinders run hotter because that's the side that the EGR Valve is on.

This is a solid line of thinking, and something I was starting to wonder when I noticed how much louder the sound was in the exhaust. However, I will say that in-person, the noise does not sound like a rattle -- more of a snapping/popping sound. It sounds like more of an active tapping than a passive rattle if that makes sense. It doesn't seem as harsh in the video as it does when you're standing next to the truck.

But hey, it wouldn't be unusual for a cat with 260k on it to fall apart! I won't likely have time until next weekend, but I'll try pulling the cats starting with the drivers side and see what I uncover.

 

[donalds]

Hit the cats and pipes with the palm of your paw
Listen for sounds
I found a few Bad cats using this method

Just wait till it's cool

 

[410Fortune]

Fingers crossed it is the catalyst Broken loose
I also found a 19mm deep socket in a cat converter once that sucker was brown and black like it had been in there for years

 

[AngryPossum]

PS - I used 3 coats of Rust-Oleum high heat primer, and 2 coats of Ford Blue Dupli-Color for the Valve Covers. Along with a lot of grease remover, sanding, and elbow grease. It came out really nice.

 

[97Sandbox]

Hit the cats and pipes with the palm of your paw
Listen for sounds

I tried whacking the cats with a rubber mallet from all different angles. Only rattle I heard was the heat shield on the muffler.

Fingers crossed it is the catalyst Broken loose
I also found a 19mm deep socket in a cat converter once that sucker was brown and black like it had been in there for years

This reminded me I did lose one bolt during this refresh (thankfully all sockets and extensions were accounted for). It was one of the four that held the A/C compressor onto the P/S pump bracket. Since it was a long bolt (~6") and I had covered up all of the openings in the engine, I figured it couldn't have gotten itself into too much trouble. I assumed I dropped it somewhere amongst the front suspension or on top of the trans or maybe one was already missing when I bought the truck and I never noticed. I thought I'd find it during reassembly or clean up, but I never did.

I'm thinking more now about where it could have gone and if it could be contributing to the noise. Due to its length, it couldn't have fallen down into any of the intake valves and the hex head would have stopped it from falling down into a cooling path. The only area inside the engine that I think it could have fallen into is the oil pan (I did shove rags in the pan on either side and in front of the crankshaft gear to stop anything from falling in, but never say never. Suppose it did into the bottom of the pan; I'd expect it would just lay down in there unless it came into contact with a counterweight on the crankshaft -- if that happened I'd imagine it wouldn't be pretty. But a steel bolt slapping a cast aluminum pan full of oil wouldn't sound like what I'm hearing...

 

[410Fortune]

Step son did a ohv engine replacement last year into a ranger.
Dropped a bolt, never found it
Until they started their “new” engine
Destroyed it, the engine that is
Had to find another ohv and swap it out I guarantee you he will find the dropped
Bolt before putting the engine together next time
I stop everything I am doing and find the dropped bolt or tool before moving on
I would drop that y pipe and have a look in there
This is the reason I keep a clean shop , a clean floor is easy to find things on

 

[97Sandbox]

I stop everything I am doing and find the dropped bolt or tool before moving on
I would drop that y pipe and have a look in there
This is the reason I keep a clean shop , a clean floor is easy to find things on

Believe me, I'm also the type to stop everything when I drop a socket/nut/bolt etc. I also make a point to put every bolt back into its hole when I remove a part -- and that's why I think there may have actually been a bolt missing from the start. I did look for quite a while when I noticed a bolt was missing; picked up all the tools, searched around with the flashlight, and climbed under the truck -- it was nowhere to be found while the other three were neatly threaded into the P/S bracket where I left them. Very frustrating, but at a certain point I had to move on.

I'll try to drop the exhaust this weekend and dig around inside.

 

[97Sandbox]

The plot thickens

After spraying some penetrant around all of my exhaust bolts and O2 sensors, I was feeling particularly inquisitive tonight. I decided to fire up the truck once more and poke around. It stumbled badly at first then roared to life (still no CEL). It actually ran decent for a bit, but then the popping came back (as expected).

As I was looking around and listening, something caught my eye:

One of the hoses had come off the DPFE sensor.

I reconnected the hose and watched for a bit. After a few popping sounds, it jumped back off. I put the hose back on again and went to try the next thing on my mind.

Up until now, I've only let the truck idle, but tonight I (maybe foolishly) tried giving it some throttle...boy did the popping pick up! It didn't so much pick up in frequency as it did intensity. These pops under slight load sounded much more violent. After hearing these louder pops, I feel confident in saying the noise is emanating from the driver's side rear area of the engine a.k.a right by the suspect cylinder #6.

At the risk of sounding dumb, I'm going to go ahead and say the sound seemed as if the combustion for cylinder #6 was sometimes happening in the exhaust manifold, not in the combustion chamber. I'm really not an internal combustion expert, but something is telling me maybe the #6 exhaust valve is sticking partially open and the combustion is escaping (that would account for the blast that blew off the DPFE hose). Does this make any sense, oh wise Explorer enthusiasts?

Perhaps more importantly, what could be causing the valve to sometimes be sticking open? Would a few oily carbon chunks be enough to do it?

 

[410Fortune]

I doubt carbon bits could
Hold a valve open

Injector stuck on might drip enough fuel into the manifold to make it ignite, perhaps on the wrong stroke? Speculation

Seems like cyl 5 or 6 are not firing or at least not firing at correct time

I know it’s crazy but I would seriously check the plugs wires and firing order again!
Also check wiring to coil pack and injectors

Sounds like Something is causing fuel in the exhaust
Manifold that is being sparked perhaps by the waste spark of the cylinder next to it or by its own waste spark (ignitions fire twice on these)

What is going on with the spark plug wires in that pic? Assume you were working on cyl 6?

Did you wrap the egr pipe? Looking at the pic trying to find any anomalies

 

[97Sandbox]

Injector stuck on is an interesting idea -- I'm not sure how much trust to put in these reman injectors from ebay. That would account for the extra fuel and the waste spark igniting some excess fuel at the wrong time makes sense. Would an injector stuck on be the fault of the injector or the wiring/cam synchro/PCM?

I've double and triple checked the wiring from the coil pack to the plugs, but I'll definitely do it again.

What do you suggest checking in the wiring to the coil pack and injectors? I thought those are pretty well defined (the 5 & 6 injectors are definitely not switched, no flex in the harness to allow that).

In the picture, you're seeing the old plug wires connected to the plugs and coil pack but the new plug wires are still there dangling next to them -- that's just from me troubleshooting to see if the issue was due to the new plug wires being loose on the plugs (there was no difference switching between new and old plug wires). The #6 wire run was over the manifold because too many wires were running under.

I did wrap the EGR pipe with exhaust wrap because the old woven shield was falling off.

The main thing I'm still confused by, is why the popping is so random. If the issue was something wired wrong, I'd expect the popping to be more cyclical with the engine.

 

[410Fortune]

Usually a backfire through the intake is a lean condition a backfire through the exhaust is a rich condition

Injector can be dripping and not atomizing the fuel from lack of pressure

Check fuel pressure asap

 

[410Fortune]

Brand new/reman parts are always suspect
However if it’s a reputable seller then its
Likely just a pressure issue or an installation issue, like torn o ring, piece or debris on back of injector or piece of debris from fuel rail entered injector

I would test pressure if that checks out consider pulling fuel rail and have a look see
You can bench test these injectors quite easily, it is very handy troubleshooting thing to have setup in your home shop

 

[97Sandbox]

I am both very relieved and very embarrassed to report that upon closer inspection, the left cylinder bank plug wires were 100% mixed up. I must've misread my manual and then assumed I'd read it correctly when I "double and triple checked" wiring. My tail is tucked between my legs to say the least.

The OHV is now running smoothly as ever. I've got a few more details to button up, but it's looking like this refresh is going to be a success. Thank you all, especially @410Fortune and @fast_dave for your help troubleshooting my mistakes!

 

[fast_dave]

I reconnected the hose and watched for a bit. After a few popping sounds, it jumped back off. I put the hose back on again and went to try the next thing on my mind.

Just sayin'

Take off the DPFE so you can see if it's clogged/obstructed.

UPDATE: OK - I see your plug wires were mixed up

 

[97Sandbox]

Just sayin'

Take off the DPFE so you can see if it's clogged/obstructed.

For future reference, can the DPFE be cleaned with MAF senor cleaner? I've done that for the IAC before, but wasn't sure about the DPFE's plastic housing.

 

[fast_dave]

@97Sandbox

Do not spray anything into the DPFE - there's electronics in there!

When it goes bad, don't be afraid to buy a new (aftermarket) one for $13 - $15 on Amazon or Ebay.

Just like the Multi Function Switch (turn signal switch) that eventually goes south on everyone's 2nd Gen, the technology of the DPFE switch is simple enough and old enough that the aftermarket part works as intended - same as the factory original.

It's one of those parts you don't need to spend the $90 premium on a MOTORCRAFT of FORD branded part.

Amazon Link: MOSTPLUS EGR Valve Pressure Feedback Sensor Compatible for 1994-2010 Ford Lincoln Mazda VP8 - Google Search

 

[Fix4Dirt]

@97Sandbox

Do not spray anything into the DPFE - there's electronics in there!

When it goes bad, don't be afraid to buy a new (aftermarket) one for $13 - $15 on Amazon or Ebay.

Just like the Multi Function Switch (turn signal switch) that eventually goes south on everyone's 2nd Gen, the technology of the DPFE switch is simple enough and old enough that the aftermarket part works as intended - same as the factory original.

It's one of those parts you don't need to spend the $90 premium on a MOTORCRAFT of FORD branded part.

Amazon Link: Amazon product ASIN B07HG429D6

howabout electronic cleaner? just curious...

 

[fast_dave]

Try it and let us know -

Just sayin' I'd have a replacement close by because the price of an aftermarket, at a brick and mortar parts store, will probably be at least 4 times the price of the Amazon aftermarket part.

 

[Fix4Dirt]

Try it and let us know -

Just sayin' I'd have a replacement close by because the price of an aftermarket, at a brick and mortar parts store, will probably be at least 4 times the price of the Amazon aftermarket part.

maybe soemday... if it aint broke, dont fix it, especially when its unproven! so if it ever goes bad ill try it!