Cylinder 4 misfire plus EVAP System Monitor and Catalyst Monitor won't complete cycle

[BrentDJ]

I have two 1999s 5.4s. One I've had for over 20 years and the second one for about 5 years. They both have the exact same problem: 304 code (cylinder 4 misfire). The other clue is that the trip cycles won't complete for the catalyst monitor and the evap system monitor.

Expy #1 is the one that I've had the longest. For no other reason than that I've been working only that one. #1 also has a very small amount of valve clatter like you might hear in an 8-cylinder with 250,000 miles. Wife can't hear it, but I can. Expy #2 doesn't have any valve noise at all.

Road situation: In town there is no difference at all in driving quality. It's normal. But out on open road, going uphill there is a chopiness and slight shaking. If I turn off the overdrive the shaking stops at the point that the engine is running an additional 500 rpms faster.

-spark plugs- -coils- -injectors- all checked, rotated and triple-checked. all functioning normally.
-coolant leaks- verified by driving several hundred miles with a white cotton towel covering cylinder 4 area and the underside of coolant quick connectors. No leaks.
-egr system- verified underhood. No vacuum leaks.
-evap system- verified underhood. followed to the evap connector hose located underneath the frame near the front driver's side tire. No vacuum leaks.

Early last Spring I decided to change the intake manifold. I installed a Ford replacement intake manifold. I bought several intake manifolds on closeout for 100 bucks about 10+ years ago. It was dry underneath the manifold (except for small amount of coolant released during teardown) I did see some evidence of an earlier coolant leak or spill underneath the intake manifold. This was before I owned it. I vacuumed out a lot of dry crumbly rust. Since I was in the general vicinity, I checked the block sensor and the coolant tube. You may assume that the manifold replacement was done correctly and that all the cylinders were protected and that the correct torque sequence and torque stages were followed.

So then... The engine light didn't come for about 600 miles. During that hopeful time period the 2 trip cycles for evap and catalyst still wouldn't clear.
My gut tells me that this is a leak somewhere along the evap route and also that this is a typical problem that happens after 25 years of plastic drying out. There were a few times, I thought I smelled a bit more fuel than normal when I've had the hood open. But I haven't noticed any particular pattern at all.

Last week, my wife made me take #1 to the Ford dealer. They insisted that it was a broken valve spring. I know what a broken valve spring sounds like and mine does not sound like a typical broken valve spring. They might have gotten me too if I didn't have my wife drive up in #2 (an almost identical 1999 5.4) with exactly the same symptoms but without any noticeable valve noise. The service manager then changed his tune and said that the tech's diagnosis was a "worn but not yet broken" valve spring. If my internal bs-ometer were an actual functioning siren, I swear to G that everyone within a 1/2 mile radius would have been completely deaf at that point. The other clue was that the service tech wasn't at all interested to listen to #2 Expy with same code/clues but with no valve noise. So we got out of there $160 lighter and still without a clear diagnosis as to what's the actual problem. I suppose that I now a free pass for the next month or two that I won't have to act on any other wife requests.

Would a compression test on #s 1-4 tell me anything at all useful that I don't know already from my own eyes and ears?

Is it possible to shorten the evap route so that I could verify that the evap route to the gas tank isn't sealed? I'm thinking that the evap lines need to register a certain amount of flow/pressure for the catalyst monitor to work correctly. Is there any way at all to isolate that portion of the evap hose/tube route to the gas tank for diagnostic purposes?

Anyone else have any ideas how to solve this?

 

[Yupster Dog]

-spark plugs- -coils- -injectors- all checked, rotated and triple-checked.

Was one of those checks changing out the coil pack with another cylinder and see if the misfire moves? Then the same thing with the spark plug?

 

[BrentDJ]

Yes. that was done very early on. friend, you forgot to mention the injector. also swapped and no change.

FWIW, the mileage on both trucks is almost the same. 240K on #1 and 250K on #2. It seemed like #1 had the problem first and then a few months later I was informed that #2 had the check engine light. I saw immediately that it was exactly the same as in #1. My theory is that #2 was at first a Canadian truck (A web search of the VIN # shows that it was first registered in SK in 99) So it was probably garaged in the Winter. This might have slowed down the drying-out process of whatever it is that dried out.

I've already decided to start going through the back half of the evap system. The canister doesn't seem like it's hard to get to. But some of the videos online mention a canister vent valve/solenoid located above the spare tire. I'll have to let that down so I can have a good look in a reasonably uncomfortable position.

Our small town Ford dealer mechanic doesn't even have a smoke machine. I suggested to the service mgr what tests I'd seen from online videos. My questions about whether they used a smoke machine for diagnosis just seemed to confuse and irritate him.

If I can't find anything obvious from a visual inspection then I'll next check to find out if my code reader (Zurich ZR8) has any engine-running analytics that might be able to give some additional clues. One thing I've noticed already is that the check engine light comes on sooner after I've cleared the code during the summer than it did during the Spring when I first noted the problem.

Since I have two vehicles with exactly the same problem, it's got to be something that has deteriorated naturally and not something mechanical that's failed.

I will solve this. Hopefully my inner dialogue and thought process may be of use to someone else.

 

[JVinOlathe]

Your symptoms seem to indicate a vaccum leak but typically you would get P0171 and P0174 codes with it. Some vacuum leaks are very difficult to detect using the simplistic starting fluid/water spray method since the leak can be well hifdden under the maze of hoses on top of the engine; you might have better luck using the propane test. Sometimes, leaks only show up after the engine is warm and hose expand and expose leaks. A smoke test is by far the best way to test for leaks. I had a similar issue with my 1999 5.4 and a smoke test found a leaf on the throttle body and the issue was easily resolved.
Other things you can check are the right angle hose on the PCV valve and you can also clean the MAF sensor, only using MAF sensor cleaner as any other cleaner will damage it. You can google for ways to test the MAF senso using a voltmeter. Last you can clean the throttle body; amazing how much crud acumulates there and how much better it runs after you clean it. Just my 2 cents...

 

[EngineerMike]

Its strange that there is no code for the catalyst trip cycles not completing, I get that on my Nissan (code P0420) for an upper ox sensor that isn't reporting (assume it would be same for lower ox sensor that is also involved in the analytic to assess cat efficiency). The ox sensors report to ecu to modify fuel trim "curve" and appropriately load the cat w/hydrocarbon for a complete afterburn. I wonder if that could load #4 badly in a disproportionate way to cause the misfire. I would definitely conclude there is a misfire issue based on your over the road experience, not sure its isolated to #4; can you read pending codes that don't fully set w/your code reader? I have a OBDLink MX bluetooth adapter that reads to my phone & an app which can read real time ox sensor data and pending codes in addition to clearing MIL etc., I've found it excellent for diagnostics.
No idea why/how the above would be involved in the evap system if at all.

 

[BrentDJ]

Here are updates after my initial repairs-changing out the old evap hoses. I can only upload 5 photos per message so I will have to do this in two messages.

 

[BrentDJ]

And here are the rest of the pictures.
I combined the code reader pics.
the first picture top left does show a bunch of drive cycle monitors incomplete.
However, this was midway through a complete drive cycle verification.
The picture I took of only the two incomplete monitors at the outset was blurry. So it goes.
The only two system that wouldn't complete were the evap and catalyst system monitors.
Today, the gas tank level is still above 3/4.
I've read that some vehicles are very particular that the tank needs to be below 3/4 before the evap monitor will clear.

This is Expedition #2. It was #1 that I took to the dealer. I did replace a few of the evap hoses in the engine compartment of #1. I haven't yet touched the rear evap hoses on #1.
Expedition #2, is now driving noticeably better. But there is still a slight shudder when going up any hill that the AT automatic transmission needs to downshift.

I can't even find a part number on the Ford site for the vapor canister connector shown in my first two pictures.
I've never had any success changing out an o-ring of unknown specifications and then praying that it won't leak.


Other thoughts: A lot of times with older vehicles there is more than a single concurrent problem. That could be what I'm facing here. I remember that 7-10 years ago I had to improvise a wrench that would fit in the limited space to remove the EGR riser tube from the exhaust manifolds years ago. I did this to be sure that the tubes were free flowing and clear. I would have used the same improvised wrench on both Expeditions. This is another kind of thing that makes any reasonable person lose his mind--second-guessing if possibly, conceivably, some mistake was made during an earlier repair.

So I'll be back at it again this weekend.

Thanks for all your helpful suggestions.

 

[BrentDJ]

Last you can clean the throttle body; amazing how much crud accumulates there and how much better it runs after you clean it.

Yep. Agreed. About 10 years ago, I took an extra throttle body home from the bone yard. It was very quick swapping a clean throttle body without having to go back and forth cleaning it. Please ignore the obviously dirty spare throttle body in this picture. Up until my 50s I would have stored it clean and ready for installation even if I didn't need it yet. I'm just not that energetic anymore.

Another thing about having a spare throttle body hanging around is that you can take it in hand to harbor freight or walmart and easily find the exact sized brushes to snake the orifices without even having to remove the entire throttle body. Of course if you had a spare throttle body (for example if you were some crazy old coot who owned 2 expeditions) you'd just swap it out entirely anyway.

 

[BrentDJ]

I have an update as to Expedition #1. I was going on a short trip of about 60 miles to see an old friend. At about 3/4 of the way up a 1000 feet climb, Expy #1 stalled out. It threw code P0320 as it died. Got it back home and got out the parts box. Looking inside the parts box (thinking inside the box) showed that I never did change out the crankshaft position sensor when I changed out the timing chains, guides and tensioners about 2 years ago. So I removed tension on the belt, removed the 3 10mm AC compressor bolts and then could get to the 8mm bolt holding in the sensor. The connector looks like it's been on the road for almost 25 years. Even though it doesn't appear to be shorting, I'll change the connector on general principle alone. All of the following part numbers for pigtail connectors show as compatible for 1999 5.4 PS812, 816, 817 and 820. That seems a bit weird to me. I'm guessing that these different wire gauges since the connector is the same for all of them. 820 seems to be the thickest at what visually appears to be 18 gauge? Is that right? Also, the same motorcraft part number shows that WPT 579 is compatible for both the ignition coil connectors and also for the CKP sensor. Is that correct?

It looks to me like the sensor took some heat damage.

I usually don't like to work on 2 things at once. Because if after doing two things the problem is then fixed, the question is then: Which fix worked? But my hand has been forced since #1 just isn't going to start without a functioning CKP sensor. I'll swap out the sensors and then see if I have time to finish up changing the old evap hoses.

UPDATE: CKP Sensor was indeed the culprit. Started right up. But I'm beat after all this excitement. So drive cycle monitor testing will need to wait for tomorrow.

I took a picture of the damaged sensor next to the new one that I installed.
Picture also of the odometer for my first Expedition. #1 has only 232k miles while #2 has 258k. So you see now why I can't possibly let #1 go with such low miles!

I wouldn't think that a faulty CKP sensor could cause a #4 misfire.
At least I have never read of such a thing in these types of forums.
I guess I'd better have a look at the CKP sensor in #2.
I'll report back when I am able.

I'd sure appreciate a heads up on the pigtail wiring gauges on those numbers if anybody knows.
Otherwise, I'll just hit a few of my local parts stores and start comparing whatever they have stock to see my theory on the wire gauges vs. part numbers is correct.

 

[BrentDJ]

Its strange that there is no code for the catalyst trip cycles not completing

I've actually spent some time thinking about what you said. You are right. It's definitely strange behavior for the trip cycle.
and for both of them. So it's probably time to spend some time investigating "the nut behind the wheel" as some people say.

One thing that I've noticed is that when I replace things on one Expy, that I generally do it for the other one as well. My thinking is that once I've bloodied my knuckles on a set of rear trailing arms, stabilizer links and the track bar, that I've become an expert at that one thing. Other than the money (I'm not in HS or college) there's no excuse not to do the same replacement to the other Expy as well. So this has been my work pattern. So it's not unusual that they might both have the same issue.

I'm going to go through my receipts of everything I've bought over the past 4 years and see which jobs might possibly have some connection. I'm going back 4 years because if I've done something incorrectly this amount of time seems to be the average amount of time that a well-made but incorrectly installed part would survive. FWIW, this is also about the same amount of time that a poorly made part that was installed correctly will last. ***CORRECTION to my Earlier Comment*** The CKP sensor that I replaced last week was actually a ten dollar POS part. I ordered two motorcraft crankshaft position sensors last week. They were supposed to be here already. I'll look into that.

There was a definite improvement in the idling and higher gear shifting with the new evap hoses. I haven't had time to follow up on the charcoal canister O-ring issue. I suppose that I could coat it with some silicone caulking. When I do eventually locate an actual connector and a new O-ring, it should then be easy to peel away the dried silicone.

Do charcoal canisters ever go bad? Certainly someone somewhere must have submerged a charcoal canister while trying to launch a boat and succeeding in fouling it with water getting inside. I wonder what were the DTCs (if any), the mode 6 codes and engine behavior? I've not done anything like that. I prefer to stay on dry land. But often seeing how a component acts after it's been abused can be highly informative.

Well, I'll let you know what I find out. In addition to going through my receipts I'll inspect the exhaust manifolds, cats and muffler to tailpipe. (Mufflers and end pipe were changed a few years back)