My 1987 Mercury Colony Park

[TecNickal]

Good and snug. Its a cast iron head, you aren't going to strip it unless you guerrilla it with a 9 foot prybar screaming this is SPARTA.

Tighten til it stops, then give it a good 1/12th of a turn, firm snug.

[sly]

I've had the plugs in my beater for at least 20K and only changed them because I broke one while checking them. The ones that were in there were good though, just needed a little re-gap.

[gadget73]

Copper with an engine that runs right should be easily good for 30K, but you might get double or more that if its not burning oil or anything like that.

I always run them in finger tight then give it a little extra with the 3/8 ratchet. Don't know what the torque spec is, but my torque wrench likely doesn't go that low and definitely doesn't fit in there.

[Kodachrome Wolf]

Got new plugs from work. No Motorcraft ones were on hand, but we did have Autolite. I'll gap them tonight. I probably won't be able to get to the car until next week as I'm going to be busy with school stuff and work all weekend.

I'll pack those up and take my tube of dielectric grease when I go and I'll report back on the idle status. Something tells me the gaps on the plugs in the motor are probably around .060+, which likely will explain that rough idle. Maybe the fuel economy will improve a touch as well. The whole time I was on the road to PA and back, I was only netting a consistent 20 MPG, but it's done 21 MPG before. I had some expectation of it doing better, but this might explain it.

[DerekTheGreat]

Good and snug. Its a cast iron head, you aren't going to strip it unless you guerrilla it with a 9 foot prybar screaming this is SPARTA..

[Kodachrome Wolf]

Well, I happened to have enough time after class today to swap out the plugs. Definitely different over the 4.6 having the plugs way down low. At least both engines aren't too bad about getting at the plugs.

Plugs:


The oily one only seems to have oil on the threads. The tip was clean. That one did come from the driver's side rear. Gaps varied from acceptable, too wide, and also one that was way too narrow.

New plugs helped with the idle and reduced the studdering feeling upon light throttle applications from a stop, but it still doesn't seem as smooth as it should be. If you rev the engine up, I guess above 2,000 RPM (maybe a bit less; no tach), it smooths out a lot more. I pulled the vacuum line going to the EGR valve with no difference in operation. However, I also did not feel any vacuum pull on that line when I put my thumb over it.

Anyway, at least part of the issue has been taken care of and definitely drives better than it did before. When I have some more time, I'll look into that EGR valve. I suspect there might be a vacuum issue. The vacuum block is hooked up on the passenger side, however I'm not sure what the little units are on the fender liner that the lines run into. Everything is intact and plugged in over there, however.

[sly]

oil on the threads... is the valve cover gasket leaking? May just be picked up from the edge of the head.

[DerekTheGreat]

Some research turned this up:
"
While it may look like dirty oil, it isn't, this is unburnt fuel that all the lighter elements in the fuel have boiled off leaving the heavier hydrocarbon components behind. This is not unusual to find even on race engines. I wouldn't have known this myself if I hadn't run acrossed the explanation from a very respected pro engine builder on another site. This "fuel" is here because the seal(tapered seat or gasket) is above the threads but the threads themselves are shielded from the actual combustion process. Almost sounds crazy but it is true.
"
If that's true maybe the injectors are a bit leaky/dirty? Those plugs do seem a smidge darker than the others.

[Kodachrome Wolf]

oil on the threads... is the valve cover gasket leaking? May just be picked up from the edge of the head.

Valve covers don't have any apparent leaks. Nick re-gasketed most of the engine, and I know the valve covers were done.

Some research turned this up:
"
While it may look like dirty oil, it isn't, this is unburnt fuel that all the lighter elements in the fuel have boiled off leaving the heavier hydrocarbon components behind. This is not unusual to find even on race engines. I wouldn't have known this myself if I hadn't run acrossed the explanation from a very respected pro engine builder on another site. This "fuel" is here because the seal(tapered seat or gasket) is above the threads but the threads themselves are shielded from the actual combustion process. Almost sounds crazy but it is true.
"
If that's true maybe the injectors are a bit leaky/dirty? Those plugs do seem a smidge darker than the others.

I've run fuel system cleaner through it a few times, I so don't know how dirty they would be. As far as leaky, no idea.

[jaywish]

Maybe it was the cleaner but those plugs look almost new.

[TecNickal]

You have a code for EGR. That's part of your idol issue since EGR typically operate during then. It could be like I said above something to do with the EGR valve pentyl not sitting correctly. The position sensor of the EGR may not be sitting correctly. Or the solenoid maybe having an issue.

[Kodachrome Wolf]

You have a code for EGR. That's part of your idol issue since EGR typically operate during then. It could be like I said above something to do with the EGR valve pentyl not sitting correctly. The position sensor of the EGR may not be sitting correctly. Or the solenoid maybe having an issue.

What's a good method for cleaning the EGR? Also, are there any things I should be aware of when removing or re-installing the valve? Also, as I said before, I'm not really feeling much pull on the vacuum line that runs to the EGR. Is there anything I should be checking regarding that?

[sly]

the EVR pulses the vacuum to the EGR. It shouldn't be enough to open the EGR until cruising speed. The way to test that is to pull that vacuum line and plug it. Drive around with the EGR disabled and see if the symptoms go away. If they do, the EGR is fine and the EVR is bad. (EVR is at the other end of that vacuum line on the EGR.) If you do remove the EGR to clean it, you should have a new gasket on hand and ways to clean off the gasket that's on it.

[DerekTheGreat]

What's a good method for cleaning the EGR? Also, are there any things I should be aware of when removing or re-installing the valve? Also, as I said before, I'm not really feeling much pull on the vacuum line that runs to the EGR. Is there anything I should be checking regarding that?

What worked for me was taking the valve off and the sensor attached to the valve and manually cycling the plunger- was very stiff at first but after doing that and cleaning it with carb & choke cleaner I got all the smut off and crusties that were built up where it seats against the bore, which was probably where it was leaking. The EGR spacer looked clean with no build up so I didn't have to clean much in there. Used high temp oil to lube up the one thing that moves the position sensor. You shouldn't feel any vacuum to the sensor at idle, it is meant to open while cruising.

[Kodachrome Wolf]

I was going to yank the EGR valve off on my way home, but forgot my wrench so I could get that upper bolt off since a ratchet won't fit there. I'll try and grab it off tomorrow so I can clean it.

Also, I noticed the coolant lines that run into the throttle body have been bypassed and the nipples on the throttle body capped off. Is this something I need to get hooked back up again?