Ran Car Miswired for 20 mins...will soot burn off plugs?

[lobo411]

Problem solved: Miswired AGAIN! 1996 Ford Explorer 4.0 w/ brand new (installed 2 hrs ago) plugs. I had just installed new plugs 2 weeks ago, but as a result of running the engine miswired for 10 mins or so, all the plugs on the 4-5-6 cylinder bank were soot blackened from running way rich (plug body, tip, insulator, the works).

In installed new plugs but didn't properly rewire. Then I ran the car for another 20 mins to try to figure out what was wrong.

Question: I must assume that the new plugs are soot-blackened too. Will the soot burn off on its own just from running the car, or will I have to replace the plugs yet again?

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Preserved old thread:

I decided to update the thread. OP is posted below for posterity.

Long story short, I have a 96 Explorer w/ 4.0 that was misfiring due to my miswiring the spark plugs. I ran it probably 5 mins tops (in the driveway, on and off as I tried to sort out the wiring issue). I've got it wired properly now but it idles pretty rough, and it gets to be very rough in gear.

I had changed the plug wires so I suspected them--swapped them out 1 by 1 until I had done 4. The 5th required me taking off the EGR tube, so I decided to just pull the plug as long as I had done 90% of the work.

The plug (just installed 2 weeks ago) was black with dry soot--tip, insulator, etc...

So now I'm wondering if maybe I ruined the plugs? Or maybe this is just a symptom? Would the soot burn off after some normal running, or should I replace the plugs?

(Edit: I put in brand new plugs, and put the old wires back in. Made no difference. Checked all sensor wires and vacuum hoses--nothing disconnected. Disconnected MAF sensor and it seemed to get a little better, so I'm going to try cleaning that).

Any thoughts definitely appreciated!

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Hi all,
I'm putting my 96 Explorer w/ 4.0 back together right now, and one of the 4 A/C compressor to p/s bracket bolts snapped in half. I'm not sure what the torque spec was supposed to be, but I looked it up in Chilton's and they have two specs listed: compressor bracket to engine (35 ft lbs) and compressor (20 ft lbs). I figured since the compressor is housed in a bracket, I'd tighten to the compressor bracket to engine spec. Maybe that was where I went wrong, or it could be that the bolt was just ready to die. It kept turning really easy without torquing, and it broke right in the area that is exposed to the elements (I live near the ocean + I've had some coolant leaks).

Anyway, the compressor seems pretty solid with 3 out of the 4 bolts. The broken one is in the rear, and I'm thinking of just putting it all back together. I don't know why the bolt wouldn't torque, but the bolt did come out the other side of the bracket by 1/2" or so. I figure it won't be too hard to pull the accessory bracket and then extract the exposed part of the broken bolt with a pair of vice grips or by taking an angle grinder, grinding two flat parts onto the shaft, and using a box wrench to turn it out.

The whole thing seems pretty solid, though...anyone think there are any pitfalls to just letting it run on 3/4 bolts until it's convenient to work on this? I've been doing a lot of work on the car, and I'm ready to let it just run a while!

 

[koda2000]

i'd be more concerned about the uneven torque on the compressor case. this could cause the compressor to fail prematurely. 35ft lbs isn't very much. either the bolt was corroded and failed, or it bottomed out if it broke that easily. all that being said, you'll probably be fine with just 3 bolts, but my OCD would require me to fix it.

 

[lobo411]

WOW. OK. Is this the most worthless diagram in the history of auto repair guides or what?

http://www.explorerforum.com/forums/showpost.php?p=805768&postcount=3

I cranked it for the first time and it shuddered and died. I also heard a loud, irregular banging sound. I shut it off and tried again, same result. Now I'm wondering if anything fell into the intake manifold when I was working on it. I tried again and same result. I also replaced the plug wires so I swapped out the new ones for the old, one by one. Same result. So I took off the accessory belt...the car ran, but it kept making that banging sound. I shut it off, not wanting to kill the battery. Then I tried it again, and it died. So I tried again, and it stayed on long enough for me to see that the banging sound was a backfire coming out of the EGR DPFE sensor tube (it actually blew the small vaccum line off).

So now I figure it's misfiring. I'm also worried that the missing bolt put the compressor at a funny angle and the belt is too tight, killing the engine (ridiculous as it sounded to me at the time). I spend a good 30 mins trying to make heads or tails out of the various idiotic diagrams showing the coil/firing order (really? you're drawing a *picture of the wires* rather than a simple diagram of the coil w/ numbers and the cylinders with numbers??? OK, Rembrandt!). Finally I think I have an idea of it, so I go to rewire. Purely by accident, I see a photograph in the Chilton's manual: the mechanic painted the numbers on the back of the wires at the coil pack. *Purely by accident, they actually helped me figure it out!*

So I rewire according to the accidental assist, and she fires up just fine w/o the accessory drivebelt. I replace the belt. She fires up just fine.

Sheesh! Is it really too much to ask for a simple diagram that's actually useful???

 

[mrboyle]

Coil firing order on the 4.0L is easy once you figure it out. When you are looking at the engine standing directly in front of the truck on your left is bank 1 (cylinders 1,2,3) on your right is bank 2 (cylinders 4,5,6). The coil firing order looks like this:
3 O O 4
2 O O 6
1 O O 5
The first wire on bank 1 goes to the terminal closes to you on the right side of the coil pack. Second wire to second terminal. Third wire to third terminal. Wire closest to you on bank 2 goes to furthest terminal on left side of coil. Second wire goes to terminal closest to you and third wire goes in the middle terminal.

As for the bolt missing, there is no possible way it can cause the belt to be too tight or not allow the engine to run properly. It can however allow the a/c compressor case to twist and cause the seals to fail, resulting in a freon leak and loss of a/c.

 

[lobo411]

As for the bolt missing, there is no possible way it can cause the belt to be too tight or not allow the engine to run properly. It can however allow the a/c compressor case to twist and cause the seals to fail, resulting in a freon leak and loss of a/c.

Thanks for the info!! I got her running again, but the engine was quivering a lot more than normal. So I turned on the A/C, and sure enough, the whole engine started to shake (even the hood was shaking). Turned the A/C off, and the shudder diminished accordingly.

That's the bad news. The good news is that I was able to get the broken bolt out and it was easy as pie! Total case of metal fatigue. I unscrewed the 3 remaining a/c bolts and saw that about 3/8" of the 4th broken bolt shaft was still sticking out from the bracket. So I got a pair of vice grips, snapped them on, and got it to turn. Easy. Way easy. So easy in fact that after just 1/8 turn I removed the vice grips and extracted the broken bolt by hand!

The bolts just must have been ready to die. But now that the bolt is out, I can go to the junkyard tomorrow and get a set of 4 with no trouble. Thank God it wasn't an exhaust manifold bolt or something!

 

[lobo411]

So I'm pretty sure the junkyard will have the bolt, since they usually have ~10 explorers in various configurations plus a bunch more Rangers. According to Ford Parts.com, the bolt is discontinued, though. So if I can't get it at the junkyard for whatever reason, could I use any bolt with approximately the right parameters? According to a parts diagram I found, the bolt is an M8 x 1.25 x 123 mm.

 

[BubbaFL]

Any M8 x 1.25 bolt will work, just go to your local hardware store. If they don't have the exact length, cut it down. Don't forget about washers too!

 

[lobo411]

Any M8 x 1.25 bolt will work, just go to your local hardware store. If they don't have the exact length, cut it down. Don't forget about washers too!

Thanks for the reply! I got lucky--I found a pretty much 100% intact 1996 Explorer w/ 4.0 at the junkyard and was able to get 4 pristine 13 mm bolts. They had about 20 Gen I/II Explorers there, but all of them except this one had 10mm bolts holding the a/c. I guess Ford must have switched to a 13 mm bolt for a short period and then gone back to 10mm.

The car still idles rougher than I remember, but maybe that's because I changed spark plug wires too. Turning on the A/C doesn't make the idle any worse, so I guess that issue is settled.

I torqued the a/c to 20 ft-lbs, going off the listing of "A/C Compressor" in the Chilton's book. I broke the bolt by torquing them to 35 ft-lbs because the same book also listed "A/C Compressor Bracket to Engine 30-40 ft-lbs." I'm pretty sure 20 is the right torque, but can anyone confirm? Thanks!

 

[lobo411]

OK, ya...I just tried to go for a test drive and the car's running like crap. Mild shudder at idle, major shudder in low speed reverse/drive. Water vapor coming from the exhaust smells like paint thinner.

Gad...to think it was running like a top before this "tune up!!!"

 

[lobo411]

Heading to Autozone for a new set of plugs, but I dunno if it's a good idea to install them (what if I haven't fixed the underlying cause, ruining another set of plugs)?

 

[lobo411]

Replaced the plugs with new ones, put the old wires back in, cleaned the MAF, and it's still running like crap. All I did to it was:

1. Change valve cover gaskets
2. Put in new upper intake gaskets
3. Put in new spark plug wires

The engine was running well before, and now it's jerking and bucking its way down the road. I put the scanner on it and I've got no codes, but I did notice that the downstream o2 sensor is reading 0.8-0.9 constantly. Also, it smells like I'm pouring gas straight down the exhaust pipe. No idea what's wrong!

 

[lobo411]

Coil firing order on the 4.0L is easy once you figure it out. When you are looking at the engine standing directly in front of the truck on your left is bank 1 (cylinders 1,2,3) on your right is bank 2 (cylinders 4,5,6). The coil firing order looks like this:
3 O O 4
2 O O 6
1 O O 5
The first wire on bank 1 goes to the terminal closes to you on the right side of the coil pack. Second wire to second terminal. Third wire to third terminal. Wire closest to you on bank 2 goes to furthest terminal on left side of coil. Second wire goes to terminal closest to you and third wire goes in the middle terminal.

As for the bolt missing, there is no possible way it can cause the belt to be too tight or not allow the engine to run properly. It can however allow the a/c compressor case to twist and cause the seals to fail, resulting in a freon leak and loss of a/c.

I'm glad you posted this...I checked again and I had it miswired! I guess when I fixed it last night, I only changed the order so the misfire wasn't as bad as it had been.

And I'm sorry, but there is ABSOLUTELY NOTHING EASY OR LOGICAL ABOUT THE WAY THEY HAVE THIS WIRED!

Thanks for the help!

 

[lobo411]

I ended up checking the plugs since I was putting the new plug wires back on anyway. They looked fine, so I re-installed them. Car runs normally again!