Farty EGR

[1955moose]

You can test your EGR valve by applying vacuum while the engine is off. Pump it up, then see if vacuum holds. Also feel with a couple of fingers if diaphragm in valve opens up. Then start engine, apply vacuum to EGR port, motor should stumble and want to die, this will tell if ports are clear in EGR. I used to clean carbon out by spraying carburetor cleaner in Port, then run an opened metal hanger, or thick bailing wire in and out of port. Hope that helps. Your #4 misfire can be anything from a coil, up to a clogged injector.

Sent from my N9131 using Tapatalk

 

[GZ123]

Thanks Ulver and Moose. It seems like cleaning out the EGR spacer might have solved the EGR issue. I have an OBDII reader and before I cleaned out the spacer, there would pretty much immediately be a pending EGR code. That doesn't happen anymore. So I've got a small victory!

Yesterday I drove on the freeway for the first time since the misfire on cyl 4 code started popping. It felt really sketchy with super weak acceleration and I even heard a loud pop at one point. Is that normal for this situation? Something that I don't really understand is that when I start up the car and leave it in park it idles fine. When I put it in Neutral it's also fine. I get the rough idle when I'm in D or R. If either of the coil, plug, or injector on cyl 4, why is that cylinder not just acting strange any time the motor is running, whether in gear or not?

Unfortunately my expedition doesn't have the coil on plug (COP) configuration. I've got two coil packs and spark plug wires running all over the place. With this configuration, can I still swap the coil from the top of spark plug 4, to the top of spark plug 3 without switching the other end of each wire at the coil pack sides? I guess my question is, will firing things off out of the normal order mess up the engine, or safe to do for diagnosing?

Thanks again for your help!

 

[1955moose]

I forgot you've got a first year model. Their are tests for the coils, wires. I don't know if you can swap out coils. More than likely you've got a bad spark plug or spark plug wire. You can buy a single spark plug wire at any Auto parts store. I'd start just replacing that one spark plug and wire, and see if it helps. If so, then I'd change the other 7. #4 is passenger side all the way in the back, toughest to get at. Be 100percent sure the EGR port is clear and all the components there are working. For some reason the 03/04 have EGR problems, especially the 4.6.. if you've got a coolant leak above the #4 plug, it could be shorting out that bank. Fix any coolant leaks if you have any.

Sent from my N9131 using Tapatalk

 

[GZ123]

Alright so I finally got new spark plugs, wires, and coil packs in the mail. I just pulled the plug out of cylinder 4 (where I've been getting the misfire code) and it looked like this:

First, wtf is going on here? Second, how do i clean out the spark plug well without pushing whatever all this gunk is into the cylinder?

 

[1955moose]

Looks like an oil leak, leaking into spark plug well. Was the spark plug snug when you removed it? As far as sucking out the oil and gunk, you could try a small adapter on a shop vac, or get ahold of a brake bleeder like the ones for shop use, use just the hose without adapter for brake bleeder. You need to figure out if it's the valve cover leaking, or where. Any fluid, oil or coolant will short out plug and coil.

Sent from my N9131 using Tapatalk

 

[Ulver]

This looks like an oil fouled plug due to either failing piston rings or worn valve stem seals. You could run a compression test to further investigate.

 

[GZ123]

Oh man... Started with an EGR problem and now I'm down the rabbit hole.

So, I finished swapping out coil packs, wires, and spark plugs today. When I got all that finished I got in and turned the key and heard an electrical sounding pop and no start. The inside console started flickering, so I shut it off and double checked that everything was wired up where it should be (it was). I did take off the bracket holding the primary battery fuse to get to cylinders 3 and 4, but I took a bunch of pictures beforehand and matched everything up while putting it back together.

The truck is acting like it has a dead battery, so I hooked it up to my Accord to jump it. When I do this, the starter chugs once but no start. When I disconnected the jumper cables it will try once then behave as if the battery is totally dead.

While working on the plugs, wires and coils today I had both of the battery terminals disconnected, so I'm not sure how the battery could have drained.

I agree with moose and ulver's posts above that there is an oil leak somewhere and I'll have to do a much more serious overhaul with the valve cover off in the near future, but I'm at a loss as to why I went from cyl 4 misfire, but still drivable to now not even starting as a result of new spark plugs, wires and coils. I should note that I got the coil packs a few days ago and put those in with the old wires and spark plugs first and it ran at that point, so the problem is for sure not in the coil packs.

I was wondering if I had maybe blown one of the two 175 amp fuses, so I pulled them out and tested for continuity with a multimeter. Both passed (I'm not sure if this really means that they are still good since they aren't the classic style of fuse, but look more like a chip).

Any thoughts?

 

[GZ123]

Success!

I replaced the two 175 amp fuses and the truck started right up. I must have broken one or both of them when I took that assembly apart to get to cylinders three and four.

I took it on a 40 mile round trip including city and freeway and no codes so far. My OBDII app has made it through all of the readiness check steps (drive cycles) except for catalyst and all pass. This means at least my EGR issue was fixed by cleaning out the EGR spacer.

Power is back to normal while driving, but still a bit of a rumble at idle. Nothing that feels anything near what I was experiencing with the misfire, but not perfectly smooth. I can't tell if I'm just hyperfocusing on that now that it has been a problem. It might just be running fine for an engine from 1998 with 170,000 miles.

Cautiously optimistic for now.