My 2005 edgehas the cel come on when I idle for a short period of time. Had checked out and ws told it is a cylinder miss fire. changed plugs and wires to no avail. Any suggestions or ideas? I have close to 185000 miles on this truck.

 

if the plugs are gaped right and wires are good i would then look at the coil pack.

 

Do a compression check on the cylinder that has the misfire. Your valves might be going bad.

 

Not sure on the cylinder that has the miss fire yet. Changed coil pack and had a mechanic tell me to change the plug wires again, he had a ranger that went through 3 sets before he got a good set. The shop that I use said it was a short in the system.

 

1LFRD,

You may not like this but I have a 2004 3.0 that I have just sent the heads to get a valve job. 116,000 mi. Mine has been doing the same as yours for the past few months and finally I figured I better fix it before I ruin my engine. I could keep the CEL from coming on at stop lights and such by keeping the RPM about 1500. But you can`t do that forever.

The exhaust valves had worked themselves into the exhaust seats about 1/64th inch or so below the top of the valve seat. That is a LOT of wear. I figure Ford had a very good reason to put softer seats in these heads but hey that`s just me thinking out loud. Since my valves were now closing later there was evidence of back-flow into each combustion chamber coming from the exhaust manifold.

Anyway, If I was you I would run a compression check. I had 190-210 on 4 cylinders and like 180 and 150 on the other two. When I took the heads off all the exhaust valves had worked themselves down into the seats.

I checked my lifters for wear thinking the pickup might have gotten hot at some point but no, the lifters look almost brand new. In fact (I bought the truck used) everything except those valve seats look almost brand new. Something to think about.

If you do it soon you might head off a lot of expensive repairs later. It is going to take some labor though so get your mind right. But it isn`t that bad. Anyway, I can`t wait to get my heads back from the machine shop tomorrow. I miss my pickup.

Anyway, good luck.

 

What about the idle, is it too low ?

 

The idle is fine on my pickup. However at the lower flow of air and exhaust gases through the engine, it would start missing on No. 5. If I kept it revved up at stop lights it would be fine. I have checked the exhaust system and it is not obstructed. The exhaust valves closing a little later eventually rob No. 5 from enough O2 to support combustion and it misses. Usually happens right after I start it up and begin to drive then come to a stop light. But sometimes happens even after the engine has been running a while.

No heads yet. I`m still at the mercy of the machinist. I hope he is doing a good job.

The softer seats? I don`t know why they are made of this material but if I were to hazard a guess I would think because these exhaust valves are so small, it may be the seat material Ford uses is the only thing with proper heat-transfer properties to keep the valves cool enough to keep them from being ruined. After all, the pickup will go a lot further with valves receding into the seats than valves that get too hot and warp. And the penalty for softer seats doesn`t show up until well after any mfgr. warranty period which is exactly how I would do it if I were Ford.

It is curious though that many Rangers are on the road with much more than mine at 116,000 and they need no head work. Oh well, it is what it is.

 

Okay I got my heads back and found out something I didn`t know. The seats for the valves are machined into the head casting. Of course this means rate of heat transfer is equal to the rest of the head. The guy at the machine shop put "hardened steel" insert valve seats in mine for all 6 exhaust valves. They were the only things that were worn out on my heads.

It has been a few years since I did this kind of motor work so maybe my memory is going bad and they all have the original valve seats machined into the head but I thought not.

Oh well, anyway I am glad I got them repaired. Maybe if you can live with the CEL you can go quite a while without having to mess with them. Where I live the enviro-***** have pretty much put a stop to a guy driving with his CEL on from year to year.

Good Luck if you decide to go this route.

 

So how did the tear down and reassembly go? I have to do the same thing because I let mine overheat due to a small leak in the timing cover gasket and now it's leaking a tiny bit of water in the #1 cylinder. Where did you get your parts? Did you find a guide or just fly by the seat of your pants?

Thanks

 

I got a scanner to chck out the code and came up with missfire cylinder 4 at fuel injector. Will be replacing all injectors as soon as possible.

 

I had to replace my motor eventually.