Oil spraying out of exhaust manifold
 

I changed the head gaskets on my dad's 2001 Sport Trac and when I started it up afterward, oil began spraying out of the exhaust manifold mostly on the passenger side but also a little on the driver's side. I'm showing 150 psi on all cylinders. I removed the intake manifold and found oil mostly in the back two cylinder ports. I also removed the passenger exhaust manifold and it seems that only cylinder 3 was the one spraying oil. I have already checked the PCV hose and also removed the hose to start it and it was still spraying oil. I'm assuming it's bad piston rings, but it was not doing this before (I don't think). Maybe before the oil was being burned up in the catalytic converter and the only reason I noticed was that I started it up before putting the cats back on. The new oil I put in already smells strongly of gasoline. I'm assuming I'll have to remove the engine for the piston rings? I've seen videos of people doing it without removing the engine but not this engine. Also, when cranking the engine, I can hear a strange sound. The best I can describe it is a "glug, glug, glug" sound coming from the oil pan. Almost like the oil is too full and the pistons are hitting it, but the oil level is almost below the low marking on the dipstick. I have also put compressed air in cylinder 3 and I can hear air coming out of the crank case, but nowhere else. I also hooked it up to cylinder one and the sound was nowhere near as loud coming from the oil tube, but it was still there. I know some air will always leak but even cylinder one seemed to be leaking a bit too much, but cylinder three is definitely having issues.

How about we start by asking some questions, What engine, miles on vehicle,
Did you drain the cooling system before removing the heads ?
Did you compare the head gaskets you installed to the old ones you removed , exactly the same?
What was the condition that caused you to replace the head gaskets in the first place?
The 150 lbs compression in each cyl and air blowing by into the crankcase is somewhat confusing
The oil being possibly heavily diluted with gasoline is another thing to look into.
Could you be flooding those cyls with gas and removing the oil film?

From what you describe , There are several things that might be going on from so much oil getting into the combustion chamber , if that is happening, to unusual amounts of gas . With all that oil how are the plugs able to fire and the engine to be able to run on all cyls is more confusing..
It sounds like there is also a timing problem. Don't know if it is involving injectors, spark plugs or something else.
What did you use to clean the block when you had it opened up?
The cats will not clean up excess oil , it just destroys them.
Hopefully some addl questions and suggestions will help out,

174,000 miles.
Yes I drained the coolant.
Gaskets were exactly the same
Changed because oil was in coolant and coolant was in oil. Gas was also in oil, but obviously the gasket wouldn't affect this.
I will re-check compression as soon as I can. I got 150 only after a few tries on cylinder 3. It was 120 before that.
The cylinders were spotless before putting the heads back on and the stuff coming out smelled only like oil.

I used a timing kit to time the engine as you are supposed to.
I used a plastic scraper for the heads and a metal gasket scraper for the block. Both were checked with a .001 straight edge and a .001 feeler gauge and were nearly perfect. I could not fit the feeler under the straight edge in any position.

Thanks for answering,

When some folks get into an engine we have no idea of their background so we ask all sorts of questions. Even had to learn the hard way when I became involved with far out suggestions and assumed things like plugs were routine , when the plugs were replaced the problem was gone. So we learn to take nothing for granted !

Do you think the injector for #3 cyl is overfueling?

Well the injectors seemed to be working fine before replacing the gaskets, but I can check. However, the stuff coming out of the exhaust doesn't smell even a tiny bit like gasoline...just oil. I just started learning about cars in January so I'm fairly new to this, but I've put in over 200 hours of reading and youtube since then. I feel like I have a fairly good grasp on everything.

I don't know if this will help you, but sometimes questions help a lot.
Let's take this a little at a time,
If oil is getting past the oil rings it goes into the combustion chamber and gets burned with the fuel. That, causes blue smoke to come out of the exhaust and fouls the spark plugs eventually causing a misfire and it progresses from there. So if you are not seeing this part, could the oil actually be leaking out of the valve covers and not actually into the exhaust? Do you know if the engine ever overheated, if so , there could be bigger problems than worn rings. Did you give any thought to looking for any cracks in the block or the heads ?
I admire your willingness to study and learn, who knows, you might just choose this as a career.
Oil in the coolant and coolant in the oil can be caused by head gasket problems, but there could be other causes also. What engine do you have in there?

Hey forum members this gent needs some help and so do I !! What do you say ?

I've checked the valve covers and other things already. I can see the oil literally spraying out of the exhaust manifold. I only have the manifolds on and the rest of the exhaust is still off. I have removed the passenger exhaust manifold and looked inside and I can see the trail of oil coming only from cylinder 3. I have also removed the intake manifold and there is oil around the gasket area mostly on cylinder 3 and some on cylinder 6 (both are the rear most cylinders). The engine is the 4.0 SOHC 6 Cylinder. I have checked the PCV hose for oil and it's dry and I've even removed the hose, blocked the holes to maintain a vacuum, and it's still doing the same thing. I have also made sure it's not coming through the vent hose that goes into the air intake tube after the MAF sensor. I have removed the valve cover on that side and watched the valve train and there isn't an excess of oil or anything. Just what I presume is the normal amount is coming out of the oil tube and on to the cam lobes. It is definitely oil and nothing else, since the oil level has dropped by at least half a quart. I have also even made a slow motion video of the intake valve operating through the intake port and there isn't oil dripping down into the cylinder so I know the valve seals are good. Not sure if I mentioned this already, but I also did a valve job and lapped the valves and they now seal perfectly (I know this wouldn't make oil leak unless I damaged the seals by letting lapping compound get in there but I'm positive that it didn't happen since I rinsed the valves, seals, and the entire head after the valve job). There is a small amount of blue smoke happening but not as much as you would think with this much oil in there, but maybe there's so much oil that combustion is being hindered. I have, however, hooked up a scan tool and there are no misfires. Just a DPFE code, which is very normal on these engines. The engine may have overheated at some point because the coolant reservoir was bone dry at one point. I also remember driving it this winter and if I left it running to go into a store, I would smell burning when I came back out. The engine heat seemed normal though. After filling it is when it started mixing with the oil. I don't think the heads were warped or cracked, but I'm not sure about the block, but I am sure that the oil is coming out of the exhaust ports from the cylinders. Also, when cranking the engine, I can hear a 'glug, glug, glug" sound coming from the oil pan which wan't there before doing the head gaskets.

I am trying to learn to start a mobile mechanic business, so thank you for the kind words and for your help.

You couldn't have picked a better project to gain experience.
I'm trying to pull a few hairs to come up with why the problem appeared after the head gasket replacement.

Not sure of this, but some engines have special bolts that go into special holes in the block where oil pressure travels. I'm wondering if that is a possibility here.
The signs and symptoms seem to point to excessive gap in the oil rings of the last 2 cyls.
The glug glug sound has my curiosity. What do the spark plugs look like from the 2 cyls shooting oil? Let's try to approach from that direction.

It would maybe be a good idea to locate an oil lubrication diagram/path for that engine and see just where the oil is supposed to go and it may provide some clue to just why the oil is causing so much problems.

Nick,
What do the spark plugs look like for cyls 3 & 6 ?
Do they show any signs of oil contamination?
If they do, oil is getting into the combustion chamber , if not, oil is getting into the exhaust passages through another path.

The diagram I was hoping to locate is usually in the shop manual and I couldn't find anything for that engine anywhere on the net. Maybe someone has one or knows where to find one. It shows the path of lubricating oil from the sump to the filter then up to the rods and mains and on up to the cams , followers etc. If there are any special bolts to allow oil to pass it will usually show that..

I can't remember where in the AllData manual I saw the oil screw mentioned, but I know it's tight if that's what your concern is. Plugs 3 and 6 definitely have oil on them. The others are completely dry.

I am wondering if some parts of the rear tensioner are interfering with the oil flow..
It may just be time to pull the engine and go the full route.

What do you mean full route? Money is definitely an issue here, but too much money has already been put in to it to give up. To pull the engine, I still need to buy a hoist and a stand, plus the rings and new crankshaft bearings. How would the rear tensioner be interfering with oil flow? Should I be able to smell exhaust coming from the oil fill tube when the engine is running if the rings are bad? Could there be excessive crank case pressure or something forcing the oil through the rings, even if they aren't bad? Sorry if I repeat myself...I have this question posted on another forum.

I believe we tried to examine the possibilities and keep coming up with the same answers.
The miles on the engine
The amount of air that is going into the crankcase at #3 cyl,& 6
The fouling of the plugs with oil for cyls 3 & 6
We tried to look beyond those indications to try to rule out any things that might have been overlooked
I cannot think of any other things to check other than the way the rear timing chain gets its lubrication and the results from where I sit say it is time to get into the engine totally
If there are any other suggestions we're open for them and none are coming forth. Maybe you might obtain some other possible causes from the other forum, I don't know.
I can understand the cost involved and possibly another engine with less miles and in decent running condition may be an alternative.

Can you have someone with engine experience come to look at the problem ? Maybe they will see something that is escaping your observations and I definitely cannot see from where I sit?

Did you ever find why you were hearing the unusual glug glug sound from the oil pan or rear of the engine?
Don't underestimate the family mechanic because he is correct , downstream O2 sensor can affect fuel delivery and in some models is used for fuel control.
Instead of looking for possible answers from those of us who do not know everything you did, It might be a good idea to open up the engine again and look for a possible cause reviewing everything that was done right from following the oil passages through the head gaskets and manifold gaskets. There has to be something you overlooked or missed to make it spray oil out that badly.
By the way, welcome to the world of a mobile mechanic service, there will certainly be more like this . BEEN THERE and right now THERE AGAIN !

It's still making the sound, but it's getting quieter as the oil level drops. I know for a fact the oil is not overfilled. I've checked many times. I think it sounds like the crankshaft appendages (sorry the name is escaping me right now...I'm talking about the part that extends out from the crankshaft that connects to the rods), are slapping against the oil. Could that mean that the oil is barely making it up in to some parts of the engine? I'm not sure how much oil should be in the pan while the engine is running in a wet sump engine, but maybe that's the issue with the glugging. I'd have to think on it, or maybe someone can tell me if a restriction or blockage in the oil ports could cause oil to spray out. Could this increase the crankcase pressure, forcing the oil past the rings on the intake stroke? The combustion forces would not be fighting the oil in this case and the pistons that are firing at the time could further increase the pressure and cause it to worsen. It would make sense that cylinders 3 and 6 are leaking because this engine is tilted way back when properly mounted, so the oil pan is nowhere near level. I watched the valve train go while cranking the engine and oil was just barely dripping out of the tubes probably just enough to coat each lobe. It looked pretty dry in there. I'm also thinking the glugging sound could be the oil pump struggling to fight a restriction or blockage. My guess in this case would be about a 75% restriction. I realize I switched from questions to statements, but I'm not trying to act like I know anything for sure. So I'll remove the heads and see what I can find. I suppose everyone here's gonna tell me not to reuse the head gaskets. I was thinking about using that copper spray stuff. I'm more wary of re-using the bolts though, but if they do not appear stretched I may just have to try.

I did know that very few vehicles, especially the vehicles using the final generation of narrow band O2 sensors (I assume), probably only use the downstream sensors to monitor the cats. I was speaking specifically to him about my 2004 Suburban 1500 at the time and he was insisting that I was still having fuel trim issues because I needed to also replace the downstreams. I remedied the issue without ever changing them. He also says that just barely touching an O2 sensor with your bare hands will completely foul it. I've rescued O2 sensors that were covered in oil (kinda like the ones in the Sport Trac right now) using gasoline and then baking the sensor with a torch. Most substances will vaporize at these temps and leave the surface almost new. Anyway, that's a little off-subject and not necessary, but I already typed it so I'm leaving it lol.

Thank you for the welcome and for everybody's help!

Ok heads will be coming off tomorrow and I'll keep everyone updated, but I'll more than likely ask more questions first and include pics. I'm planning on buying new head gaskets, but the reason I was even considering reusing is because the truck has only idled and not long enough to get over probably 140 degrees. Also, at 210 horsepower and a low compression ratio (not sure exaclty what the ratio is)...maybe 8.5:1 or so sounds right. I'd be much more concerned if I was reusing them on my 295 hp Suburban or a more powerful vehicle. These factors would affect the outcome and increase chances of getting lucky and having no problems? But at only $40 for a pair, it's probably worth just getting new ones. Just curious, say I reused them and blew the gasket...wouldn't that only damage the gasket? Shouldn't affect the timing unless the bolts also break and lift the head off. I probably just answered my own question with that seemingly possible outcome, especially if bolts were reused. Should I attempt to remove that oil restrictor screw? It's corroded in and I stripped it already trying to remove it. Should I just drill it out and use a left hand extractor screw and order a new one? I failed to check the oil passages at all simply because I was already cramming way too much info into my head and I didn't think I had it in me to learn about how oil flows and whatnot. Oh and this is my dad's vehicle, not a customer's. I'm not comfortable working on other people's stuff yet, mostly because I'm too slow because there's too much to learn in during the job and every vehicle model is a new learning experience. I also don't have much for tools yet, a big van to travel in, or a business license. It's in the plans though...that's for sure. In this economy you have to do things on your own or you'll just be stuck at the bottom of the totem pole your whole career. I know many would disagree, but millenials (I call it the DIY Generation) are severely mistreated and underappreciated compared to older people...and now for the angry responses from generation X and Baby Boomers haha. Also, I've had issues in the past drilling out steel bolts from aluminum, where the bit goes off-center into the soft aluminum. Is the restrictor screw made of steel? I will be extremely hesitant to use a drill bit in that case. I'll probably use my new MAP/OXY torch and weld something to the screw and remove it. It has a tiny pinpoint flame, so the heads couldn't possible crack or warp if done quickly. Plus steel and aluminum don't weld together nicely so I don't think it'll get fused to the block. Not sure of the diameter of the screw head though, I'm just assuming it's as wide as an oil passage.

Ok so quick update...I am an idiot for not realizing what I now believe to be the problem. I have everything but the valve covers and heads removed. After eating dinner, I went to move the intake plenum and a very runny substance ran out. Too runny to be oil and it smelled strongly enough of gasoline to be sure that's what it is. Something all of us overlooked was the fact that my O2 sensors are just hanging out in the outside air, causing the computer to dump most likely extreme amounts of fuel. I believe the gas was dissolving carbon deposits and evaporating enough that the smell of the deposits overpowered the gasoline, but there was still enough gas to make the substance oil-like. I'm sure some of the carbon deposits are oil deposits as well. Another stupid thing I overlooked was the fact that my driveway is tar/blacktop. I was sampling the substance with my had off the driveway, which gasoline readily dissolves. And what is tar made of? Oil. Another thing that confirms this is that I pulled the number 3 spark plug and it was bone dry and clean as a whistle. The intake and exhaust ports are also very clean and dry. The intake plenum is full of carbon so all the surfaces around it were still wet and covered in "oil". I'm going to try to get it back together tonight, but it took me 3 hours to get to where I just did plus I'll have to install the cat section of exhaust and clean and test the O2 sensors using a multimeter and a torch. They will function well enough that I will be able to confirm my suspicions. They are currently covered in "oil". I may be wrong, but I don't think it's wise to remove the heads before confirming or denying this. The truck did run very well before this project so there really can't be a crack in the heads. I thoroughly cleaned every area of them and I'm sure I would have seen a crack large enough to dump this much oil. Also the reason this "oil" was only mostly in cylinders 3 and 6 is that the EGR tube was sucking up the excess from that bank and depositing it into the intake, where it (mostly) flew over the first 4 cylinders and into the back two. I didn't see gas in the pcv or egr tube before because the gas must have evaporated before I could remove them. Oil would most definitely still be visible in there. Let me know what you guys think, but I'm gonna go spend at least an hour getting some stuff back together. The one thing that doesn't make sense is that there was no black smoke as if running rich, but could it be that waaay too rich would hinder combustion enough to not create the smoke? I believe some of this substance to be water as well (from combustion)...more fuel=more water. There were no misfires though, but I'm not sure if maybe I need a crank sensor relearn. The truck seemed to actually be running pretty well for what is going on. Last thing I did to confirm was recheck my oil again. The oil level reading changes dramatically depending on which direction the dipstick is inserted. When inserted with the level markings facing down, I got the same reading as I did after filling the oil. Sorry if this post seems fragmented, but I've been in and out between the truck and computer adding to this post. This should be it though lol

Do you know what a head slap is?
Don't feel badly, the important thing is you found the source of the problem and hopefully the reason for the glug glug sound.
Unfortunately, we could not see that part of the problem from where we are. Your logic makes sense and thanks for the update !

Different manufacturers try to make a line of parts where they try to have a few cover most requirements. Not to knock aftermarket replacement parts which sometimes we have no other option, but I have found OEM parts especially the original parts most of the time solved the problem when some aftermarket parts did not.

One vehicle manufacturer will specify certain parts and design their systems to work only with those parts and you may find as did I , that that is common practice.
Some aftermarket suppliers will make an improved version of an original part and that is appreciated. Unfortunately , the other side of the equation is there too.
I appreciate your updates and wish you all the best for your hard work and diligence.Thanks for keeping us informed and will try to assist as you grow in this profession,,,,,,,and you never know you may just be assisting me with a problem, thanks.

Got a little busy with some other stuff, but I'm about to go out and put the battery in and bolt on the exhaust and see what kind of readings I'm getting from my BlueDriver. The Denso O2 sensor will go after the cat and I'll move the one that's currently in that spot forward to fill in for the broken one. Could be a few hours because I had to hack the siezed and broken bolts out of the exhaust pieces so I need to find a way to be sure they're secure.

Decided to try to fire it up before installing the exhaust just to be sure it'll fire and it did for a couple seconds, then it backfired (very muffled sounding backfire, almost like a potato gun or something like that). Tried to crank it again and it wouldn't start. At this moment I look up and I'm like "that doesn't look like where the smoke was coming from before". I thought for sure I blew a head gasket, so I sat there, defeated for about 10 seconds and decided to go check on the ever increasing amounts of smoke. Well, I was met with a small engine fire. It was very easy to extinguish with a garden hose, however so there is no lasting damage. I think it was just gas burning on the surfaces that were sprayed. This I believe defeats my O2 sensor theory on why it is overfueling, since the ECM was reset before this and the engine would have been in open loop since it was cold. The fire does very much confirm that it is fuel and not oil. After a couple more cranks, I reached into the manifold, and sure enough, the substance was almost straight gasoline instead of the oily substance from before so I'm guessing whatever deposits were in there before were mostly dissolved. The only thing I've done since then is check the fuel pressure and it's an even 60 psi. I assume this is probably correct, but I should probably check on that spec before drawing conclusions. My next course of action would be checking for a stuck open injector. I was not able to test the pressure at the rail because I don't seem to have the proper adapter, but being a returnless system, I was able to test directly after the fuel filter with a T-fitting. My biggest fear, and probably most likely answer is that the timing slipped on bank 1 for sure and maybe bank 2 as well, but most likely to a lesser extent, if at all. The fire was on bank 1 by the way. I do have the required timing kit, so it was set correctly at one point and the problem DOES seem to be getting progressively worse. It would make sense, since bank one's camshaft sprocket bolt is much harder to properly torque with the engine in the vehicle. Improper timing would explain the raw fuel in both the exhaust and intake, and most likely explains the backfire/fire. So, unless anyone has any other suggestions, I'll be tearing down everything to the camshafts for the fourth time lol. I'll stop and check the injectors before going any further though.

Just noticed that the camshaft bolts are TTY. I guess this is what happens when TTY bolts are reused though. They were torqued correctly and let the sprocket slip within a minute of running. That is if the timing is the problem...

Hi Nick,
Yea we're on a first name basis by this time lol.
If you found the timing did slip you might consider looking into the chain tensioners that are spring loaded and should have been replaced with the chains etc.
Something else to consider, since it sounds like a lot of raw fuel has gone down into the pan , that oil is diluted and can allow other problems to begin. Might be a good move to get it out of there and add fresh oil.
If you suspect too much gas is getting into the cyls , pull the plugs and it should tell you which if one cyl or all are getting too much fuel. Based on what you find there should help determine your next move.
If you need to crank the engine over to do anything , it might be a good idea to pull the fuse that provides power to the injectors so they don;t keep adding fuel to the cyls., just don't forget to reinstall it when done. You can also disable the fuel pump by pulling that fuse or you can rap the inertia switch and open the circuit that way.
These are a few of the tidbits that might help. Thanks for the updates.

Sorry for disappearing like that on everyone. Had a touch of the flu. Anyway, today I decided to take the passenger front tire off to get a better look at the OIL leak. Yes, oil, not gas, oil. I thought the oil was coming out of the exhaust because it was leaking above where the exhaust blows out, so I'm sure you can see my rookie mistake. It's very funny that hanky mentioned the timing chain tensioner, because as soon as I had the tire off I had a perfect view of the leak and it turned out easier than I thought and it was free to to fix. I feel stupid even admitting to it, but I left the crush washer off the rear tensioner, leading to a massive oil leak. Washer has been replaced, tensioner primed and torqued to spec... and not a single drop leaking anymore. I will have the a chance to look at fuel trims later as I'm sure there will be issues from the oil soaked O2 sensors, but for now, I have to get the exhaust bolted together tightly so that it seals and doesn't piss off the neighbors more than I have already. However, the engine seems to be purring like a kitten but obviously much louder. It did quiet down as soon as I took care of the leak at least to the point where it just sounds like it has straight pipes or maybe a glass pack. The exhaust pieces are very messed up because I had to cut seized bolts right out of the cast iron, leaving a U shape for the bolts rather than holes, but I think with some effort and some exhaust putty, I'll get it figured out. So I think we can finally put an end to this thread. Thanks for everyone's help. I really appreciate it. And remember...USE YOUR WASHERS!!!!

Ok so some new problems have surfaced. I have the exhaust back on and it is sealed (no excessive noise), and I also replaced both upstream O2 sensors. I started the engine to check fuel trims and noticed that there seems to be a constant misfire, but I'm not getting a misfire code. Short term trims on Bank 2 were perfect, but Bank 1 started at 26% and climbed up to 42% before I shut off the engine. The only code I have is a DPFE code which was there before I started the entire project. Using my stethoscope, I narrowed the issue down to a hanging injector on cylinder 1. It was barely clicking and all I could hear was a "whoosh" sound like it was not closing nearly fast enough. Like it opens nearly normally, then slowly slides closed or something. The resistance checks out at 13ohms, so it must just be dirty. I assume that it's so rich that it wasn't igniting, causing the lean code. That is not the only issue. I also noticed something new or something I didn't notice before, but most likely would have if it was there the whole time. There is now a moderate amount of white smoke coming from the exhaust. I know this screams coolant leak, but I've also read that raw fuel can cause this (mostly diesel but I've read about gasoline causing this as well), especially in the case of a stuck open or hanging injector. Unfortunately, the smoke smells what I imagine coolant would smell like. After killing the engine, the remainder of the white smoke slowly flows out of the tailpipe and falls toward the ground. Kind of like dry ice fog. If anyone's ever seen what vapor from a vape pen looks like, it's nearly identical. Since the vape pens contain propylene glycol and antifreeze contains ethylene glycol, I imaging it has to be coolant. I did however look into the coolant reservoir and there were no bubbles while the engine was running and last time I did the compressed air leak test, there were no bubbles. Today I retested compression on all 6 cylinders (only dry). From 1-6, the results were 165, 165, 155, 210,210,220. The specs that I found say no lower than 100psi and no greater than 70 psi difference between the highest and lowest, so I'm sitting on the edge of normal. It seems very strange to me that one bank is so low and the other is very high. For this compression ration, 220 seems almost too high. So I was thinking that the only thing that could cause such a difference between the two banks would be a slipped timing sprocket like I was worried about before and never checked. This would not explain a coolant leak though. Tomorrow I'm going to improve my set up so that I can control the compressed air going in to the cylinders better than I could before and see where the compression is going. Last time I did this, I am certain I found DTC on cylinder 1, but air was rushing out of the intake, so I had to turn it until I could hear that both valves were closed. I can't remember how much I had to turn it, but it was at least an 1/8 to 1/4 turn. First I guess I'll have to take care of cleaning the injectors with an ultrasonic bath which I still need to order, but I'll also check the timing while I have the intake off. I'm really starting to hate this engine for how much work it takes just to get to the injectors. It takes me about 15 mins on my Suburban to get to the injectors, while it takes about an hour and a half on this one. I know that I could just loosen the intake plenum and try to push everything out of the way, but I'd rather not have to struggle. I could probably get the heads off my Suburban also in the time it takes me just to get the injectors off the Sport Trac. Anyway, probably shouldn't be bashing Fords and praising Chevy here, but what is with the complexity of this engine? It definitely has nothing to do with reliability, that's for sure.

Hi Nick,
The on time of the injectors is what you are reading and the higher # is because not enough fuel is getting into the cyl/bank.
Because there is extra oxygen at the O2 sensor as you know means not complete burning. Does the misfire go away when you raise the RPM ?
If so , you are looking at a vacuum leak on that bank. You could be right about the injector and if you can, check the other injectors on that bank as well.
I don't know the condition of the O2 sensor on bank one, so I would consider switching it with bank 2 to see how much if any difference we get.
Think about this,
If the injector is barely clicking , it most likely is not because it is dirty but may have an electrical supply problem. I know it is a PIA to switch it with another cyl,but that way you can narrow down some of the possibilities.If you can , confirm that full power(voltage) is available at that injector and the same for the ground that the PCM supplies.
That smoke you see could be the result of the high injector on time that the cyls can't burn all that fuel.
Tell us you did not put any old O2 sensor on that bank, did you?

Well O2 sensors only sense oxygen and there is a 14:1 ratio of air to fuel. So if the fuel does not ignite in that cylinder, neither will the oxygen, so both pass through and the oxygen only gets read. Now if it were igniting, it would probably make the O2 sensor read rich. There is a spark though so it must be way too rich to ignite or something. I could be wrong, but I've read this in a couple different places. Both upstream sensors are brand new NTKs. I was using one that I spliced on from my Suburban but the readings did not change with the new O2 sensors anyway. The NTKs are all they had in stock but they seem to be a good brand. Bank 2 is reading normally, so the sensors are most likely compatible. I didn't check to see if the misfire goes away with higher RPM and I already have the injectors off. I tested the power to the injector with a test light and it pulses as it should and it reads 12v. If I blow through the bad injector, you can very easily tell it is stuck open slightly. The others do not let any air through. As I said, the resistance on all of them is between 12 and 14 ohms. I removed the filter baskets and all but one were completely deteriorated, so I assume either there's gunk or pieces of the filter basket stuck in there. I'm going to try spraying compressed carb cleaner in them while pulsing them with a 12v power supply, otherwise I'm going to order an ultrasonic cleaner and a new set of filter baskets. New injectors are out of the question for now. Maybe a single replacement, but the whole set is probably not worth the money at this point.

I've never understood how there can be a vacuum leak on only one bank, since the entire vacuum system is connected. Also, the intake ports are separate from each other, so how could air possibly be leaking into only 3 cylinders? I'm going to check the timing on bank 1 since half the top end is already removed anyway. As far as vacuum leaks go, I noticed the PCV valve was not in its hole, but that's on bank 2. Also, it's a one way valve and there's usually positive pressure in the crank case, so this shouldn't have caused the problem. How would you explain the lack of compression on bank 1 vs bank 2? I've been searching and searching for answers but couldn't find anything. The only thing I can come up with is a timing issue on that bank since it was very hard for me to properly torque that cam sprocket bolt since the engine was in the vehicle and my torque wrench was most likely not calibrated correctly.

Go ahead and blame it on the torque wrench !! lol
It would be a good idea for you to save these posts and look back over them as you become a little more experienced,
Wonder if your thinking might have changed some .
As far as the 4.0 being a dog to work on, that will not change , pretty sure of that.

If you have a means of pulsing the injectors in milliseconds , OK, but if you put 12 volts to any of them, plan on replacing it .

You don't have to take my word for it.
If you have a spare injector around , try it !

I got the sticky injector to work consistently after using an ultrasonic bath and pulsing 12v through them. Also, I was right to suspect that the timing on bank 1 had slipped (pic below). I reset the timing and will report back later to say whether or not I'm still having problems.https://cimg1.ibsrv.net/gimg/www.for...d8599ecda6.jpg