2014 Ford Expedition misfire and possible compression issue.

Need some suggestions on a compression issue on a 2014 Ford Expedition with the 3 valve 5.4L
This is my fiancé's parent's vehicle and her dad and some other relatives did a timing job on it with all new Motorcraft timing parts and all new Motorcraft rocker arms and roller/followers. They also installed a Mellings High volume oil pump.
After the repair the vehicle has a miss on cylinder 5. They swapped coils and injectors with another cylinder and installed a new Motorcraft spark plug and the misfire stayed in cylinder 5.
I checked injector pulse with a noid light on the cylinder 5 injector and it flashes with the truck running.
I did a power balance test with my scanner and cylinder 5 had no contribution at all.
I did a relative compression test with the scanner and all of the cylinders were 0 or 1-2% except for cylinder 5 which was at 24%.
While turning the engine over in clear flood mode while doing the relative compression, the cadence of the engine was not even further pointing to a compression problem. We also checked spark on cylinder 5 and it's good.
Today they pulled the driver's side valve cover to see if the rocker arms were still attached or if they could see any issues while it was running. They said everything looked normal and intact and all rocker arms were moving up and down the same amount as the engine ran.
They ran a borescope down into cylinder 5 to see if there were any valves that were damaged or if anything looked abnormal, but everything looked good.
We were going to do a manual compression test, but my MAC compression test kit did not have the right connector to install a compression hose into the spark plug hole so I ordered one that will be here on Wednesday because no local parts place had one. We will also do a cylinder leak down test once we get the right connector.
My question is what else should we be looking at? They all swear that they set the timing components were set up correctly and triple checked the marks when setting it up. If they screwed up the timing setup, would it only affect once cylinder? I would think that there would be an entire bank affected.
The truck ran fine with no issues before the repair other than it had some startup rattle that quieted down as the truck ran. The only issue they found on tear down was a bad tensioner. The plastic guides were even still intact. Vehicle has around 170,000 miles on it.
Thanks for any suggestions.

A leak-down test is, exactly, what you should do next. All signs point to a loss of compression on #5. The only question is "where is it going?"
If you have a pulse sensor, it would be worth the time to look at an intake manifold waveform while cranking.
An in-cylinder pressure waveform could be very telling of the valve events. 


 

Thanks for the reply. Hopefully the compression adapter I ordered will arrive tomorrow so we can figure out where the compression is going. The other question is also what caused it since the truck ran fine before the repair. I do have a pulse sensor so I may try using it as well.

We did the leak down test today and we had 100% leak down into the intake so we have an intake valve issue. This engine has two intake valves so now we have to figure out which one is the problem.

Is everyone certain that the misfire didn't exist prior to repairs?

New lifters? Only thing I can think of is a sticking lifter, causing an intake valve to stay open. If you can get the camshaft lobe pointed away, you can try (carefully) popping the intake followers out one at a time. When you pop one out and the leak down stops, you're on the right track.

Yes, we are sure there was no misfire before the repair. The vehicle idled smoothly and the CEL was not on. It does not idle smoothly now, and the CEL is now on.
The owner did use the spring compressor and removed both of the intake lifters because he thought maybe there was air trapped in them but that did not fix the issue.
After talking to him, I don't think that the correct procedure was done when putting the cams back in and possibly they bent the valves. I guess they put all of the rockers and lifters in and then bolted the cams down. From what I have read and the videos that I have watched, that is not the correct way to do it but I have never done timing on these engines so I don't know.

Any time I have done a 3v timing set, there's certain rocker arms that require removal. The camshafts do not need to be removed to do this, really just a big screwdriver is enough to pop them out and back in. I bet they bent valves. As far as which or how many doesn't really matter yet. You'll see when the head comes off.

I'm not sure why they removed the cams. I know they replaced the cam phasers so maybe they thought they had to for that or for replacing the rocker arms and roller/followers.

The owner has decided to pull everything back down to the beginning. I personally would just pull the driver's side head but I guess now he is questioning everything that they did. I told him I didn't think he had any timing issues since the computer has not flagged any and they have driven the vehicle several times after taking out and putting the roller/followers back in.

He is going to tear it back down starting Monday and will also pull the head off because he thinks that he may have a head gasket issue even though there were no signs of that prior to the repair. He doesn't think he has bent valves but I guess time will tell. Thanks for your input.

So here are some more updates on this vehicle. The owner did pull the head off and had the valves checked at a machine shop and they were all straight. They said that the head was slightly warped, so they shaved about 7,000 thousand off. He put the head back on and still had low compression in cylinder 5.
He took it to a shop and they checked the timing and did a mechanical compression check which showed 98 psi in cylinder 5 and about 140 in the rest. Shop said it needed a new head.
I order a new head and three valves for that cylinder. He installs the new head and now he has misfires in four different cylinders. Cylinders 2, 5, 6, & 7 with most of the misfires in 5 & 6. These are not dead misfires like before. I do a relative compression test and now all cylinders are good so the new head fixed the compression issue.
The owner installed all new Motorcraft coils and spark plugs with no change. Vehicle is only misfiring at idle and then smooths out at higher rpms.

Owner installed new IAC today and says that it runs better because the idle was low before. So that is the current situation with this vehicle. I don't know if the CEL had come back on or not but he has not asked me to hook my scanner up to it yet so maybe not.

With misfires on 5,6 and 7 (all the same bank), I would really be concerned with the VVT system. I know you said there was a timing chain and components done prior to the misfire issue. I can only assume there was a running condition that prompted this repair. I see there was also an oil pump replacement, which is not the only factor in maintaining adequate oil pressure. My first step before the initial timing repair would have been a hot idle oil pressure check with a mechanical gauge. The gauge in the truck is just an on/off switch and not representative of actual oil pressure. Unfortunately, it's very common for these engine to have thousands of dollars invested in timing and phasers only to find out far too late that oil pressure is too low to lock the phasers at idle, resulting in misfires and rough running with or without VVT codes.
The published oil pressure spec is not based is reality. If the actual oil pressure with the engine hot at low idle dips below 20psi, I recommend replacing the engine.

There were no running issues prior to the repair. The reason the repair was done because they were getting a rattle on startup and they wanted to fix it before something worse happened. There were no misfires issues prior to the repair. They found a broken tensioner when they tore it down and was the cause of the startup rattle. The oil pump was only done because it was recommended by several people when doing this repair and not because there was an actual oil pressure issue. The VVT solenoids are new Motorcraft ones. They have not said that the CEL has come back on so I'm not sure if the misfires are still present.

Wow, this turned into a mess. I'd be loosing my mind. When the head was brought into the machine shop and they said they looked fine did they actually check to be sure they were sealing?? You already confirmed there was a issue with one or both of the intake valves on that cylinder so there should've been something there without a doubt....... I don't get why they couldn't find it, could've just been carbon build up on one of them or like others said a weak spring or something. Now it sounds like it's worse and all on one bank, someone didn't happen to leave a shop rag in the intake did they?? Honestly when something gets torn down so many times the sky is the limit on what could've happened now, looking at the same thing over and over humans make mistakes and sometimes it's best just to have a fresh set of eyes look at it. New intake gaskets installed and intake tighten down properly?

Yes, it was a mess. The owner checked the head for sealing before he took it to the machine shop. He poured gas in all of the cylinders with the head upside down to see if the gas would leak through the valve seats and it did not. No leakage at all.
We ordered a new head anyway because the shop he took it to after all that said it needed one. The new head fixed the compression issue that was on cylinder 5 so something must have been off with the old head.
All new gaskets were used on the intake and it was torqued down. I don't think they left anything in the engine but anything is possible.
The last thing they have done was install a new IAC valve and that has seemed to fix the low idle that they had been experiencing and they say it runs much better.
I still need to ask him if it's still misfiring, but he has not said it is.