Possible Dead Cylinder

[SCMark]

I just put the engine back in after putting in a crank kit (rod bearing went bad). It seems like is is missing one of the cylinders. It has a bad miss/skip when driving. I haven't driven it much, and don't want to until I figure this out. Any ideas. Another question is how long does it take for the ECU to go through the learning process after the battery being out?

 

[koda2000]

check to see if the spark plug is firing. if it is, do a compression test on that cylinder while the plug is out. if you got spark and compression you probably have an injector issue, although it could still be a valve that isn't opening, but as you didn't do any top-end work, it seems unlikely you have a valve/lifter/push-rod issue. you don't say whether your engine is an OHV or SOHC.

 

[JusTheUsual]

check to see if the spark plug is firing. if it is, do a compression test on that cylinder while the plug is out. if you got spark and compression you probably have an injector issue, although it could still be a valve that isn't opening, but as you didn't do any top-end work, it seems unlikely you have a valve/lifter/push-rod issue. you don't say whether your engine is an OHV or SOHC.

as he said, but to clarify on one thing, check to see what cylinder is messed up if the sparkplug is messed up. Replace that sparkplug, easiest cheapiest way to make sure. If it is sparkplug it is more than likely coolant leaking on to it probably from outside not inside engine. A explorer i'm working on now does that, even though the headgasket was replaced a year ago. Cheap stupid gaskets get felpro

 

[Turdle]

triple check the spark plug wiring-firing order. The driver side is easy to get mixed up. Seriously.

 

[SCMark]

check to see if the spark plug is firing. if it is, do a compression test on that cylinder while the plug is out. if you got spark and compression you probably have an injector issue, although it could still be a valve that isn't opening, but as you didn't do any top-end work, it seems unlikely you have a valve/lifter/push-rod issue. you don't say whether your engine is an OHV or SOHC.

I have the SOHC. I got new plug wires, and will go ahead and replace them. I was going to check the spark on each cylinder with a timing light (came to me at 4am this morning, as well as the injector possibility).

 

[koda2000]

I have the SOHC. I got new plug wires, and will go ahead and replace them. I was going to check the spark on each cylinder with a timing light (came to me at 4am this morning, as well as the injector possibility).

what brand of spark plugs are you using? Ford engines don't like Bosch. if you're going to be pulling plugs anyway, replace them with Motorcraft or Autolite double platinum gaped to .054. also consider removing your coil packs and check the bottoms for rust. if you find any, clean them up and put some dielectric grease on the bottoms.

 

[SCMark]

Drove it around a bit, and it sounds like the timing is off. What can effect that?

 

[Abbondanza]

Drove it around a bit, and it sounds like the timing is off. What can effect that?

The wiring from coil pack to to plugs being off (wrong order), and the cam position sensor/gear being bad, or incorrectly installed, to name my top two reasons.

Although I have only done an upper rebuild...perhaps one of the cylinder rod components is not functioning..maybe a compression test is in order to see if the all cylinders are actually compressing correctly? just a guess there.

 

[SCMark]

Ok, I must come redfaced to announce it was the 5 & 6 plug wires reversed. In checking and rechecking I kept crossing the lead I was tracing as it went behind the intake manifold. I ended up taking them loose, and identifying them by pushing and pulling to see which one moved at the other end to find it. Runs fine now.

 

[Turdle]

I think we've all done that--I knew that was the issue.

 

[SCMark]

I think we've all done that--I knew that was the issue.

Yes in the dead of night finishing up, and in the heat of frustration

 

[JusTheUsual]

...good luck on your truck...

 

[2000StreetRod]

Any DTCs?

I'm glad that you found the problem. The PCM is supposed to compute the power pulse of each cylinder and report misfire codes when one is low compared to the others. But for some reason that often doesn't happen when cylinders 5 and 6 are miswired.