Hi folks,

Without going into a long drawn out explanation of why, I need to determine if any of my COP's are bad. I found a DYI site that explains the process using a multi-meter. But it was kind of generic in the ohm ranges for the primary and secondary windings. Here's the relevant section from the website...

Refer to your service manual for the correct resistance readings applicable to your vehicle and model. Typically, for most automotive coils, a reading of 0.75 to 0.81 Ohms for the primary winding and 10,000 to 11,000 ohms for the secondary winding is correct. To check resistance, attach the multimeter/ohmmeter leads to the two outside poles on the primary winding. For the secondary winding, attach one lead to either of the side poles and the other to the central high tension terminal. If the readings are even slightly outside the resistance indicated in your service manual, get your ignition coil replaced.


Questions:

Are there more specific specs for my engine (2000 5.4L Triton)? I have a service manual but it's the cheap version that does not have electrical info.

What's the proper procedure for getting at the windings to test with the multi-meter? I understand what they are explaining to do, I just can't remember if there was a way to take the coil apart.

Thanks,

Tim

 

Hi.

No - you can't take them apart. They are sealed.

The ohmmeter test is a simple go/no-go (open or shorted) litmus test. If it show a ohm reading ( regardless of what it actually is) the winding is not open, If it shows ZERO - the winding is shorted. If infinite - it's open.

So - pass/fail. Keep the ones showing some range of resistance and see below ...

Past that, they need to be tested under actual load, generating kilovolts, to test them definitively, as most COP's tend to fail in-use ( winding breakdown in the presence of high voltage - something an ohmmeter cannot emulate. A well-equipped shop or dealer can do this.

(Now .... if you had a MEGGER, though ..... )

good luck.
MGD

 

Thanks for the quick reply MGDfan! I'll do the simple test as I really can't afford to just buy a whole new set. But, I was thinking they were like $40/each (per Napa website). I saw on some other COP posts on the forum though that you can pick up a set of 8 for about $90 from a place like GLOBAL or UNEEK. Any thoughts on those as reliable replacements?

BACKGROUND: The issue is that I have three codes I need to clear so I can pass the environ test (so I can renew my plates). They are P0170, P0174 and P0300. I've already done all the (relatively) cheap work to clear these codes (changed the PCV, Idle speed control, vacuum hoses and plugs). The only thing left (I have been advised) is to change out the intake manifold (there appears to be a leak in the gasket but the Dorman is so inexpensive, I decided to pop for the whole thing) and give the throttle body a deep cleaning (for the first two codes). The third code however probably is pointing to a bad coil (or so I have been told). I have all next week off, so I will be starting the job Sunday morning.

 

Hi.

Apparently those vendors' COPs are problematic. Folks here are now advising only Motorcraft or Visteon ( set of 8 ~ $200 or so). DG-508's.

With luck, one of our true experts will chime in and go more in-depth here with you. I am but a simple caretaker that 'answers the door'. lol

good luck!

MGD

 

Fix the lean codes and the misfires may well go away. Did you use Motorcraft plugs and grease the cop boots? Motorcraft PCV?

You sure the PCV elbow hidden behind the intake isn't cracked or mushy?

The $200 Visteon sets are gone. Now you will pay $31.85 each.

http://www.ebay.com/itm/VISTEON-60-1000-Ignition-Coil-Ignition-Coils-/330836213376?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d075ffe80&vxp=mtr

 

Yes on the plugs, the grease and the PCV hose. I want to 'hope' that the lean codes fix the problem, but I already received a 'one time only' extension on the clean air test, and so I'm not really in a position to risk it as I need the truck to make money this summer.

I will at least do the bench test with the multi-meter as a first step sanity check and replace any of them that are obviously bad. Then see if that does the trick.

 

The coils either work or they dont. The only "test" is viewing live missfire counts with a scanner capable of doing that. Pay attention to the advice you have already gotten. Check the PCV elbow!

 

Uh...I already replied that the elbow was replaced.

 

then you have a leak somewhere else! could be your intake manifold gaskets are leaking.