2008 Ford 4.6 Dead miss, very rich, need help

Hey guys.  I dont know why Im having so much trouble on this one.  Seems I must be forgetting the basics?
Customer 08 F150 w/4.6L.  Has a near dead miss on #7.  Customer prior replaced plugs and all coils.  used good motorcraft plugs.  not sure what coils.  He for some reason thought that you needed to remove the whole fuel rail on this, so he did that.  had trouble getting it all back together..lost an injector washer or something - replaced one injector (#5).  truck still has a miss in 7.  brings it to me.  

truck has codes for #7 mis, rich on bank 2, and EGR incorrect flow.  Both side exhaust manifolds are leaking, and the EGR Pipe on bank 2 is broken and leaking.  fuel trims on B1 are normal, B2 are like -40 combined.  But has dead mis on 7, so Im thinking related to that.

I grab a secondary ignition waveform. but first I grab a known good.  the first picture is a capture of a known good.  the second capture is #7.  sorry for the bad pictures.  the only anomaly that I see is the firing line is way higher.  the others spike to a max of like 3kv, and #7 spikes to sometimes over 6kv.   at idle.   I swap spark plugs and coils anyway, no change in miss and high spike stayed in #7

I then grab an injector amperage waveform, and it looks good (sorry no picture), goes to about 1.4ampsish.  I then grab another off the one next to it, and it has a VERY distinct pintle hump compared to the #7 I just looked at, so I am thinking injector.  I grab another known good, and NO distinct hump on that one either.   Well, great.  I do injector flow test through the zeus scan tool with my gauge hooked up, and all perform and drop exactly the same.  maybe 1 lb difference from one another, but nothing at all noticeable on the #7

I perform an RC test, and it is good, all even.  cranking cadence sounds great too

I test drive.  upstream Oxygen sensors are both responding rich/lean.  B2 is MAYBE a little less responsive than B1.  downstreams are both staying pretty middle.  ST trims on B2 are very negative on test drive as well, while sensors are switching.  at wide open throttle, both respond and go rich.  ST trim in B2 goes positive enough to about zero it out.  but on decel fuel cut, the B2S1 sensor lingers rich MUCH longer than the B1S1, before it starts to come down and switch again, all while fuel trims begin to go way negative again to try and pull the fuel out.   the truck will barely get out of its own way.  I suspect maybe plugged Cat

I do an in cylinder test.  1st capture is #7 at idle.  second capture is another known good at idle.  (I am new to in cylinder captures.  I forgot to capture a WOT capture.  but it missing bad and very rich even at idle, so Im thinking my problem has to present at idle as well somewhere.)  but as far as I can tell, everything looks good.   I gave a crack at measuring for timing, but not sure on the autel how to get a 3rd marker out there to measure at 540deg.  But no pressure in the exhaust as I can see.   

Does look like exhaust is opening a little earlier.  does that look like a problem to you guys?  I do have a pico (that I am learning actually, it is also new to me, but I know I could take much better measurements on it) but someone is borrowing it right now lol.  anybody know how to get better measurements on the autel for the timing of this?

Any ideas on next steps I can check on this?  What will make it run extremely rich on 1 bank?  Ignition miss should make it run slightly lean, no?  I also think I have crossed out ignition miss.  I also think I have crossed off injector.  am I missing something that could still indicate a bad injector?   is the rich caused by the miss, or separate issue?  (not asking you guys to answer that, that is just the question that goes through my mind)

thanks for any help or direction!   



 

I actually think I may have screwed up the markers on the one capture. Looks like they are not at the right degree spots. Ughh. Will have to recapture because I also think I forgot to save the waveform. Just screen shot it. I have so much to learn!

truck has codes for #7 mis, rich on bank 2, and EGR incorrect flow.  Both side exhaust manifolds are leaking, and the EGR Pipe on bank 2 is broken and leaking.

Is EGR leaking into the intake?

fuel trims on B1 are normal, B2 are like -40 combined.

Is the B2S1 O2 switching when the fuel trims are -40 total trim?

I grab a secondary ignition waveform. but first I grab a known good.  the first picture is a capture of a known good.  the second capture is #7.

Raise the RPM's, slightly, just enough to switch from multi-strike, to a single ignition strike, and take a screen shot. Then, do a snap-throttle. Post those images, please.

I then grab an injector amperage waveform, and it looks good (sorry no picture), goes to about 1.4ampsish.  I then grab another off the one next to it, and it has a VERY distinct pintle hump compared to the #7

The pintle opening can be seen in the amperage/current waveform. The pintle closing can be seen in the injector voltage waveform. I would like to see both waveforms for cylinder #7.

I test drive.  upstream Oxygen sensors are both responding rich/lean.  B2 is MAYBE a little less responsive than B1.  downstreams are both staying pretty middle.  ST trims on B2 are very negative on test drive as well

What is the Total Trim. (Short term + Long term)

the truck will barely get out of its own way.  I suspect maybe plugged Cat

That was my first thought when I read  " fuel trims on B1 are normal, B2 are like -40 combined".  If the Cat on one bank becomes restricted, that bank will be RICH, and fuel trims on that bank will go negative. However, I do not see excessive exhaust pressure in the in-cylinder waveforms. There is a definite difference in the shape of the exhaust stroke, though.  It might, still, be a good Idea to dig a little deeper into exhaust back pressure on Bank 2.

Does look like exhaust is opening a little earlier.

I stacked both images on top of each other, and added a set of 720° markers. Timebase-wise, both wave forms have the same valve timing, and I don't see anything of concern, timing-wise. However, the vertical voltage scale seems to be slightly different, so it is hard to compare pressures but, the zero voltage lines are aligned. Is the "known good" waveform from Bank 1?
 

Any ideas on next steps I can check on this?  What will make it run extremely rich on 1 bank?

 I would revisit exhaust back pressure












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EGR is not leaking into the intake. the steel pipe is externally broken. I sprayed it with some brake clean to see if the valve was stuck open and sucking in, but it was not.

Yes, they are very negative even WHILE the B2S1 sensor is switching, that was what I was trying to say. about -40ish. LT is pretty stuck at -25, ST bounces around. sensor goes rich during WOT accel, and ST trim goes positive enough to just about even it out at 0. then sensor lingers high around .75-.8v for a while (like 5-10 seconds) on decel fuel cut, and at the same time trims go way negative again. Then, the sensor eventually starts to switch again, and trims STAY negative.

yes, both incylinder waveforms are for B2, the bad bank. I will grab those waveforms and then report back. Thank you for your time!

I got beat up bad by a fuel injector on this same engine.
Did the injector drop test, current ramp, and voltage all passed. I figured I could move on from the injector, but I was wrong.
I don't know if it was spraying stupid or what, but even though it flowed the same amount of fuel as the rest of them during the injector drop test, it was causing a single cylinder miss. I finally decided to move it to another cylinder after in cylinder and leak down tests, and the missfire followed!
I had hours into it and the average parts changer would have fixed it with the three step miss fire diag (a coil, a plug and then an injector).
I'm not saying that is definitely your problem here, but that's what happened to me.

Well that is good information. I am starting to think that must be what is going on with this. Because, as you can see, my secondary ignition waveforms look very rich under WOT compared to others.

Also, I am not suspecting exhaust restriction now based on my in-cylinder at WOT

I took a bunch more captures and labeled them all here by changing the name of the files.  if you hover over the 'i' it should read out what it is.  I think.  lol

Here are a couple more captures

Nice captures.

A couple of them look like there may, possibly, be some valve leakage. I would like to zoom in on the spark line, on these two.

   




This a capture of a cylinder with valve leakage that I had a couple weeks ago. It was a very subtle difference in the RC waveform, and no irregular cranking cadence could be heard.


To prove valve leakage, a "leak-down" test should be performed. Roll the cylinder up to TDC of the compression stroke and pressurize the cylinder. Listen for air flow at the tail-pipe and in the intake manifold, for valve leakage. (You can listen to the Oil dipstick tube to check for leakage past the piston rings.)

I use a pulse sensor to detect the air leakage. This is a capture from the intake manifold, as I blasted air into the cylinder. Each event is a blast of air.
 

When cylinders leak, the air flow can disrupt the ignition spark, causing a turbulence that can be seen in the ignition waveform. This is not the video that I am looking for but, it is worth watching. There is a better video that I will post, if I can find it.