Hey guys. I am hoping someone can help me out. I have a 2001 supercrew 4x4 with the 5.4L engine. While driving home yesterday the truck stated shaking pretty violently and then the CEL came on. I checked the code and got a misfire in cylinder 3. No big deal. Had the same problem a while back on #6. So today I picked up a new cop and a motorcraft spark plug and installed them on cylinder 3. It didn't fix it. And now I got a new code. P0171-system too lean (bank 1). Since I know cylinder 3 is getting spark now could the fuel injector be clogged or just not working properly? Would a clogged fuel injector throw a misfire code? Any help would be greatly appreciated. I hate to buy an injector just to find out that wasn't the problem.

Thanks!

 

Is the missfire 'still' on cylinder three 'by code'?
Next do you have the right cylinder?
#3 is the third one back from the front on the passenger side.
Don't buy parts in hopes of getting lucky.
Find the cause, then the part to fix it.
The only time for a sudden drop of a cylinder would be no spark or no fuel barring a cam lobe or valve failure.
Be sure the new coil is good and your working on the right cylinder and the boot is down on the plug and not jambed up to the side.
Good luck.

 

Yes the trouble code still says the misfire is cylinder 3. When I replaced the cop for #6 I printed off a picture of the cylinders with their numbers on it and kept in the glove box for tracking which ones had been replaced and so I always know which cylinder is which. I did replace the cop and spark plug on the 3rd one back on the passenger side. I also thought I might not have the boot on there correctly so I took it off again and checked. I could tell the spark plug had been in the boot because you could see the dielectric grease had been pushed up into the boot. Is there any way I can check the injector to see if it's getting fuel through it?

 

If the injector is plugged or open you would have to remove the fuel rail for that side.
Maybe you would consider swapping two injector positoins to see if the missfire follows with a code for that cylinder.
Good luck.

 

How did the spark plug look?

 

Did the p0303 come back or just the p0171?

 

Thanks bluegrass. I will try to swap two injectors and see if that changes things.

Neo, The spark plug I took out didn't look that bad I didn't think. It had some carbon on it but didn't seem to me to be burnt up or anything.

Toyz, the p0303 was the original code and was the only code in the beginning. The p0171 didn't show up until after I put a new plug and cop on. But yes the p00303 is back also.

Thanks everyone for your help. I really don't know where to go from here other than to take it somewhere but I don't know anyone around here I can trust to give me an honest estimate. I will try to swap two injectors and see what that does and let you know what happens.

 

You really have to watch the dielectric @ the spring/plug contact point. Meaning "0" grease should be involved with these particular mating surfaces. Simply because there's not enough force pressure to squeeze the grease out adequately for clear and positive contact.

Dielectric = A nonconductor of direct electric current. Trust me, you definitely want complete/maximum pulse contact @ the plug/boot spring connection working with COP ig systems.
They are not same in comparison to plug wire and plug connection. The rules change because of the connector/conductor force. Plug wires have a much stronger force, strong enough to clear grease from contact points once connected, so contaminating the connection isn't really a big deal. You don't have that luxury w/Coil On Plug systems. The only exception would be to run Solid Connectors. AFAIK Granitelli is the only provider of such connectors for these model Fords.

You know what I mean?

There needs to be a certain minimum contact-to-contact force to clear the non-conductive grease. COP systems lack this force @ conductor connections , (-spring plug connect).

So make sure you always clear ALL grease from spring end before mounting a COP system coil onto the spark-plug. Or you may be yanking the rest of your hair out attempting to figure out why the engine is misfiring.

BTW- Easy way to do this is to just grease the snot out of the boot, then shove the coil spring thru. -With a screwdriver or hemostats (works best), pull the spring from boot end approx 1/2". Swab the spring end contact point with Acetone or Lacquer thinner. Let the spring go and it will recoil back into the boot. The coil is now ready to mount.

D-grease is great stuff when used/applied properly. If not, there can be headaches.

 

Hey Jbrew. I did not know that about the grease. So where exactly is it supposed to be applied? The outside of the boot? Or the inside of the boot but not inside the spring itself?

 

Put it inside the boot, but keep it off the tip of the spring that contacts the plug.If unsure, pull it out and clean it as jbrew suggested, and you should be good to go.

 

I finally got around to working on my truck today. I found that #3 cylinder has no compression. Doesn't even move the needle on the gauge. Any ideas? I'm leaning towards broken valve spring. The motor doesn't make any noise and doesn't smoke. At least I'm hoping it's a valve and not a piston with a hole in it.

 

The least you can do is remove the valve cover and look at that cylinders valve train.
If you see it normal, rotate the cylinder to it's compression stroke as evidenced by both valves being closed at the same time.
Try air pressure into the plug hole and listen to the intake and tail pipe for the sounds of air rushing as well as in the crank case.
It would show a valve not sealing or a piston not sealing etc.
Good luck.

 

Thanks Bluegrass, I'll try that when I have time. I'm not looking forward to taking the valve cover off. Looks like a lot of stuff in the way that has to come off first. Is the 2 valve engine an overhead cam engine? If the valve spring is broke I'm guessing the cam will have to come out to fix it?

 

the cam does need to come off.. Still that would be your best case. Get the valve cover off and see whats going on. Good chance your gonna need to pull the motor. Thats a way bigger deal then fixing a broken valve spring.

 

Hey Jet, I'm curious as to why the engine would have to be pulled if the problem was a valve or a valve spring. Looks like there are rebuilt heads available for less than $500. It's not possible to replace the head with the engine still in the truck?