I'm having trouble determining if I have a bad COP. My CEL never comes on when my truck is missing.
A friend suggested using an infrared thermometer (I have a very expensive for work that has a very tight radius and is extremely accurate) on the COPs.
The badone should be significantly hotter than the others.
Anyone agree or disagree with this?

BTW - I have a 1999 F250 Super Duty 4x4 w/ 5.4 Triton

 

I can neither confirm nor deny that method of testing will work.

However, I know of an easier way.

Start with the rear passenger COP and swap it out with a known good you buy from the auto parts store. Play round-robin until your miss is gone. #4 is usually the culprit. Mainly because it is the hardest to get to.

 

I think you'd be better off checking the manifold's temp at the head. The missing cylinder will be colder than the rest. The wires that go the coil are so small that I can't imagine even an completely closed short could heat them up enough to register higher then the rest through the casing.

 

Just because the miss didn't turn on your CEL, you may STILL have codes thrown. Have you put a tester on it? AZ will check it free.

 

I haven't had AZ test it yet....but I did call them and they said that without a CEL their tester would pick anything up??

 

This was posted the other day.

Tester Coil on Plug Quick Probe

Should make find the offending coil easier, I suppose. It's $86, though. Still, not a bad tool to have if you do you own work on your truck.

 

OBD1 systems, such as the one used on the truck in question, will not store a code for misfiring coils unless it totally fails. The "hit and miss" procedure is about the only way to find the bad one until it totally fails.

 

What AZ uses amounts to a cheap pocket tester. They couldn't read mine, I doubt they'll be able to read yours. I was able to find it though using my dad's (quite expensive) code scanner. It told me I had a PO303, which was #3 misfire. I replaced that one with a new COP and my problem went away. I would check and clear codes for about a week. #3 was the only consistent one. I did get #7 once or twice, but I think that #3 being as bad as it was was giving false readings on #7 as I haven't had any issues since. There are $100 scanners that should be able to tell you what's wrong. Look for one that can read the CAN buss.

 

Wasn't it 05 that Ford went to OBDII?? I had no problems getting a code in my 01.

 

Your probably misfired enough to throw a code. Most of the time, they don't misfire "enough" to trigger a CEL.

 

That I don't doubt, it was very obvious that one was bad.

 

Has anyone tried one of those AC inductive testers? The power going to coil can be metered in AC and the output should have enough voltage to trip even a $30 inductive test light.

 

All car manufacturers were mandated by the federal govenment to have
OBD II on their vechicles by 1996. Ford then came out later on their trucks with can bus also. That is why a OBD II scan code reader will not work on ford trucks with out the can bus capability also.

 

I own the above mentioned quick probe, it does work o.k. if you can it to misfire standing still and for a decent amount of time. Anyone with a scanner that can do a power balance test will be able to detect the misfire right away. I do many of these a week, as long as I can get it miss on a road test just a little I can pinpoint the cylinder in seconds.

 

Except those over GVW of 8K. They will have all the outward appearance of OBDII but only have the programming of OBDI.