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car sick after spark plug change

12K views 26 replies 13 participants last post by  soundu 
#1 · (Edited)
Car sick after spark plug change

After changing spark plugs, engine idles very rough, specially if RPM is allowed to go below 1000RPM and shuts down. I was able to drive the car around block. I opened the hood and noticed a tiny hint of burn smell and smoke in the accessory belt area. There is no check engine light. Any ideas what could be wrong? Before the spark plug change, car engine had almost 74000 miles and run perfectly well. I used the motorcraft double platinum spark plugs. I did not remove UIM to change plugs. The front plugs were easy but the rear were very hard.

I can think of these possibilities right now.

1. Bad spark plugs (unlikely).

2. Damaged hoses. Getting to the rear bank plugs was pretty hard, specially the one closest to driver. It's possible that some old hose cracked or was damaged.

3. Damaged spark plug wires. The rear bank boots were ridiculously hard to get to. I never figured out how to remove the driver side cowl. I had the yank the one closest to driver using the door panel removal tool and a combination of other tricks. It wasn't nice. I cut the rubber boot. You can see it on the first uploaded image. Perhaps the wiring was damaged in some other way? This was originally the number 3 plug wire, although I moved it to number 1 plug (I also swapped them at the coil pack). The reason it was swapped with number 1 wire is because the number 1 is easier to get to so that I could replace it more easily if the boot damage is considered serious.


4. The wires were not plugged in the right order. This is unlikely, but I will double check. For most plugs, I wouldn't proceed with the next plug until I finished the previous one, including plugging back its wire.


For the curious I also uploaded the picture of the original spark plugs after 73000 miles. They looked pretty good to me.
 

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#2 · (Edited)
After changing spark plugs, engine idles very rough, specially if RPM is allowed to go below 1000RPM and shuts down. I was able to drive the car around block. I opened the hood and noticed a tiny hint of burn smell and smoke in the accessory belt area. There is no check engine light. Any ideas what could be wrong? Before the spark plug change, car engine had almost 74000 miles and run perfectly well. I used the motorcraft double platinum spark plugs. I did not remove UIM to change plugs. The front plugs were easy but the rear were very hard.

I can think of these possibilities right now.

1. Bad spark plugs (unlikely).

2. Damaged hoses. Getting to the rear bank plugs was pretty hard, specially the one closest to driver. It's possible that some old hose cracked or was damaged.

3. Damaged spark plug wires. The rear bank boots were ridiculously hard to get to. I never figured out how to remove the driver side cowl. I had the yank the one closest to driver using the door panel removal tool and a combination of other tricks. It wasn't nice. I cut the rubber boot. You can see it on the first uploaded image. Perhaps the wiring was damaged in some other way? This was originally the number 3 plug wire, although I moved it to number 1 plug (I also swapped them at the coil pack). The reason it was swapped with number 1 wire is because the number 1 is easier to get to so that I could replace it more easily if the boot damage is considered serious.


4. The wires were not plugged in the right order. This is unlikely, but I will double check. For most plugs, I wouldn't proceed with the next plug until I finished the previous one, including plugging back its wire.


For the curious I also uploaded the picture of the original spark plugs after 73000 miles. They looked pretty good to me.
I did 2 DOHC and removed the upper intake on both. Not a difficult job and lets you see the vacuum hoses. Also took a pic to be sure of the wire routing. Also see in the pic the rear valve cover fresh air elbow I replaced with my own design.

I would suggest you remove the upper intake and check it out. Ohm the plug wires, about 3-4K ohms per foot. Failure would be high ohms or open wires. Check all vacuum lines.

Best of luck.
 
#3 ·
Exactly, issues like these is why I also prefer to remove the UIM manifold when changing spark plugs. It allows you to see and inspect all those vacuum hoses and stuff that are hard to do otherwise, and I just plan on replacing the gasket anyway. Makes so I never have those annoying vacuum leaks.
 
#4 ·
I would have been surprised if the spark plug change in itself could screw up the engine so badly, so I decided to inspect the hoses. Lucky, after 2 minute inspection, I find an unplugged part, facing the firewall. It is not clear whether this is a hose or some kind of electrical connection. The rubber boot has two wires/hoses coming out of it. One of them is red. What surprises me is how easy it's to pull this boot out of engine. You can do it with a finger, which makes me wonder whether there used to be a clamp or something but now missing. Below is the picture of the thing that was unplugged.

By the way, I am still kind of nervous that on of the spark plug wire boots was cut, and now it is not air tight (see the damage on the first set of pictures). Is this very bad?
 

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#9 ·
Fct, that vacuum elbow has 2 hard red lines plugged into the bottom of it. As behlinla mentioned, 1 goes to (supplies) the evr (egr solenoid/vac. regulator) mounted on the pass. side of the uim (upper intake manifold), the other goes to (supplies) the fpr (fuel pressure regulator) mounted on the drivers side front fuel rail. As Jared mentioned, you can either clamp or zip-tie it to the uim nipple. Or get a snugger fitting one at a self service salvage yard.
 
#10 ·
I had the same problem and it was in fact several of the vacuum hoses that came apart on the fittings. The spark plugs were fine but until I got all of the vacuum hoses reconnected the darn thing ran very rough. I would check all the hoses you can find on both left and right sides of the engine. There are a bunch of them.
 
#11 ·
After changing spark plugs, engine idles very rough, specially if RPM is allowed to go below 1000RPM and shuts down. I was able to drive the car around block. I opened the hood and noticed a tiny hint of burn smell and smoke in the accessory belt area. There is no check engine light. Any ideas what could be wrong? Before the spark plug change, car engine had almost 74000 miles and run perfectly well. I used the motorcraft double platinum spark plugs. I did not remove UIM to change plugs. The front plugs were easy but the rear were very hard.

I can think of these possibilities right now.

1. Bad spark plugs (unlikely).

2. Damaged hoses. Getting to the rear bank plugs was pretty hard, specially the one closest to driver. It's possible that some old hose cracked or was damaged.

3. Damaged spark plug wires. The rear bank boots were ridiculously hard to get to. I never figured out how to remove the driver side cowl. I had the yank the one closest to driver using the door panel removal tool and a combination of other tricks. It wasn't nice. I cut the rubber boot. You can see it on the first uploaded image. Perhaps the wiring was damaged in some other way? This was originally the number 3 plug wire, although I moved it to number 1 plug (I also swapped them at the coil pack). The reason it was swapped with number 1 wire is because the number 1 is easier to get to so that I could replace it more easily if the boot damage is considered serious.


4. The wires were not plugged in the right order. This is unlikely, but I will double check. For most plugs, I wouldn't proceed with the next plug until I finished the previous one, including plugging back its wire.


For the curious I also uploaded the picture of the original spark plugs after 73000 miles. They looked pretty good to me.
Your issue is probably a vacuum hose leaking or off like others have said. BUT, do not discount a plug problem. Trust me, its possible you cracked the insulator on one of the plugs (don't ask how i know). When your doing this blind or by feel, the odds go up.
 
#12 · (Edited)
There is no need to go blind if you remove the passenger side cowl. The nastiest part of the job was getting the plug wires disconnected from the shafts. It was very hard to get my hands around to get a good hold of them. The one closest to driver side was basically yanked out using improvised tools and the rubber was cracked in process. Once the wires were off, putting in plugs was pretty easy. I used a 10 inch extension and a universal joint and that was enough. One unpleasant side effect was that the socket would often stay in the shaft once I pulled out the extension. It's one of those sockets that holds onto the spark plug with rubber so it does not get dropped. I got them out using a set of thin pliers. Most likely the engine problem was due to the lose hose plug that I mentioned later..
 
#16 · (Edited)
here is my ghetto picture of the intake....

here you can see the "intake" which attaches to my 1996 duratech sable. i can tell you that this little piece has caused me major headaches. on mine, i have 3 inputs at the bottom... at the junkyard, i could only find the boot to house 2 inputs... so i "tee'd" in the 3rd. Also these are VERY BRITTLE on my 1996. I ended up replacing 4 feet of vacuum lines with rubber line from Autozone. hope this helps.


[/IMG]
 
#18 ·
That just a modern High rise manifold. And its a energy saver and green to
boot!
 
#20 ·
My uncle has a 03 DOHC that had almost the same issue. He called me up saying the car wouldn't start. I went over pulled out a front plug and it was fried\fouled.
Alittle history before hand would help too I guess. He said he had to keep his foot on the gas or it would stall out a month before that h appened. I did the plugs, the L hose, PCV valve, intake gaskets (oval ones) and a air filter. Car now starts,but runs really rough and when you hit the gas, it wants to stall out. Now, the motor was "smoked" to check for any vacuum leaks and there is none. Key on, engine off it throws 11 codes (mostly tranny solenoids and a low fan speed). The alt decided to go right after reading them and it ran worse. I can not check key on engine on codes... computer will not allow it. Now the fuel pressure is jumping from 35psi to 60psi. Pump reads fine, and it does not bleed down pressure while sitting. We disconnected the sensor at the fuel rail and the pressure bounces between 25psi and 40psi. Replaced the exterior regulator and the pressure is less erratic but still bouncing pressure andis running rough and stalling out when you hit the gas.
Any ideas?? Its been sitting in my buddys garage for a month already and we are both out of ideas.
Thanks in advance.
 
#26 ·
it is at a mechanics garage. Engine diagnostics can not be run until the key on engine off codes are cleared. The garage its at is my buddys and he sent it to ford that's how head scratching it is!

If it were my car i would change the computer with one from the JY and start with that. Whenever I see all those codes at once I go right for the mainframe to start. Simple plug and play stuff, first.
I would do that but every junkyard around me does not have a DOHC and the ones they do have are 98 or 99's.. so that puts a damper on things. But I do think that's about the only option left at this point.
 
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