Today, in an attempt to solve my check engine problems, I tried changing the spark plugs. Went out and got some good NGK plugs and some replacement wires and installed them. My problem my be my own paranoia, but spark plug number 3 (isn't that the second one from the front? Doesn't it go 1, 3, 2, 4?)

The spark plug doesn't seem to want to thread in all the way. Or maybe it is, but it doesn't seem like it. I'm sure I haven't cross threaded it, and I took out the plug and reinserted it many times. I even put in the old plug and it fit the same. It doesn't affect the way the engine runs or sounds, and I just took a trip down the interstate (got it up to 80mph) and drove for about 10 or 15 minutes with no problems and no CEL.

Am I just being paranoid or is this normal for this plug? I've had this truck for about 2 years now and I've worked on it so much and I've replaced the spark plugs about 4 times since I've owned it. I just don't recall this ever being an issue.

 

Thatd be number 2.

What is the check engine code?

 

Front of truck

1
2
3
4

Firewall


And the correct firing order is not 1324

It's 1342

 

Thanks for clearing that up.

The code I have that keeps coming back is a code 71, EGR temperature sensor problem I'm guessing. I've tested the sensor and the EGR valve and they both check out good. But I'm done throwing money at it and now I'm moving on to other maintenance items that may help but need done anyway.

 

When I bought my truck, the #2 spark plug was already cross threaded, and completely came out after about 2 whole rotations. Because of some idiot PO, I had to tap the threads on it, using a lot of grease and only going about a 1/4 turn at a time to keep as many of the shavings out of the cylinder as I could.

So these things do happen. You should be able to get a mechanics mirror and look at the side of the plug. If it's in all the way, you will be able to tell visually.

About the code 71... you said "EGR temperature sensor problem I'm guessing". What does code 71 indicate? I thought that was what the codes were for, so you don't have to guess.

I mean, I realize that codes don't always mean exactly what they indicate, but they can sure point you in the right direction. I tried looking up the code myself, except off-road.com removed or moved the diagnostic code page. I searched and couldn't find it. Or is that why you're guessing?

 

I mean I'm guessing it's just a sensor issue. Nothing actually wrong with the EGR or the flor of EGR gases.

I visually checked out the threads on the #2 plug and I couldn't find any sign of cross threading. It just feels like it's hard to tighten the plug without stripping the threads. It goes in a good number of turns and goes in pretty deep, but it doesn't LOOK like it goes in all the way. I don't know if this is because of the way it's angled or what.

 

Unfortunately, the threads on the spark plug are much stronger than the threads on the aluminum head. If any of them are damaged, it would be in the head. It might not have been cross threaded, but it might have some carbon build up that is making it really tight.

Do you have any prussian blue? Mechanics use this to check and see if parts are making contact or not. You could put a very light coat on only the gasket of the spark plug, then install to the same point that it is right now, and then remove it. If there is some blue on the head, you would know it is seating all the way.

If I was you, and still didn't think it was in all the way, I would tap the threads to clean them up. This can be done half-way safely by using clean grease, and only go 1/4 to 1/2 a turn, then remove the tap, clean the grease and any chunks, re-grease, and then go 1/4 to 1/2 a turn past the last place, and continue this until it's all the way in.

This is almost not advisable, and is certainly not safer than removing the head to do this. But, it saves a lot of time and work for a silly problem. If you do go this route, make sure the piston is far enough down in it's travel that you won't touch it with the tap. Also, make sure the valves are closed, so you don't accidentally contact one of them either.

I see what you mean about the guessing thing now, that was throwing me off before.

 

I bought a spark plug thread chaser last night. Haven't used it yet, but I'll report back with the findings.

 

just be real careful and not get any shavings into the cyl.

 

I'm already paranoid enough, lol. Sheesh. I've got some grease I'm going to use to keep the shavings intact in a glob.

 

I finally got the spark plug in a good amount. I don't know if it's the thread chaser that fixed it or the fact that I finally manned up and decided to quit bitchin' out and tighten the spark plug almost as much as I could get it. I'm always afraid of that final turn to get it tight, where instead of it getting snug it just slips and goes an extra turn. That's what I've always dreaded with the spark plugs.

 

Try removing the EGR temp sensor and cleaning it, sometimes they get carbon build up on them and they don`t work properly when this happens.

 

already tried that multiple times. I also cleaned the carbon out of the egr valve and modulator. i have/had a whole thread on this. so far the new plugs and wires have delayed the CEL. it hasnt come on in the same amount of time it took previously.