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[quote=”bbryan1″ post=82156]In short, with some diagnostic work I didn’t have to replace plugs and wires. I checked the resistance of the wire on the bad cylinder with a known good wire and after swapping them I was able to rule out bad wires. Once plugs are verified as good, and wires are verified as good, then logically the next step is the coil pack. I only use the clear tubing b cuz I want hands free testing of spark. I’ve been bit before and it’s not worth it in my opinion.[/quote]
To be honest Ohming plug wires is a relic of the past. What we found over the years is a ohmmeter is a horrible device to test a plug wire as they can pass a ohm test (very low voltage is sent by a ohm meter) and fail in operation (very high voltage is sent by the coil). What I have done is if I find a wire that is not firing I swap wires with one of similar length and see if the no spark follows the old wire.
The raistian! I did get different readings but close….so I also swapped the suspected bad wire with a know good wire and got the same bad spark results…i also had good spark on the suspected bad wire after the swap. This told me that wires were fine while spark remained bad on that 1 cylinder….ie coil pack. This guy has new wires though…and plugs. ..so after throwing that money at it I’d test spark to isolate the cylinder then confirm by testing the coil. The resistance didn’t really tell me anything, but the swapping sure did….good point.
🙁 In the past I have read that when the check engine light flashes it means that the system is going to fail. If the check engine light is solid, you have a problem, but it is not as serious as a flashing check engine light. You may already be in limp mode for the computer, so you may want to get the ECU checked as soon as possible. I am afraid that The Ford ECU being under the hood is more susceptible to heat from the engine. I may be wrong, but you may want to see if that is the problem. Good Luck.
[quote=”slotcar” post=82169]:( In the past I have read that when the check engine light flashes it means that the system is going to fail. [/quote]
Not really, a flashing check engine light means that the PCM has detected a misfire bad enough to damage the catalyst in the converter (in a short period of time), this is called a misfire Type A. The PCM shuts down or severely limits fuel in the injector for the missing cylinder to attempt to prevent this damage. A solid check engine light related to a misfire indicates a misfire Type B, this is a misfire bad enough to allow the engine to violate Federal regulations at the rate of 1.5 times the legal limit. A type B misfire is not bad enough to cause catalyst damage (in a short period of time, a Type B misfire still does do damage, but over a much longer period of time) The flashing is to let the driver know that the misfire is that bad and needs to be dealt with very soon as engine performance and longevity are diminished in this state.
The reason a Type A is so bad (besides pollution) is raw fuel dumped into the catalyst can ignite in the converter and cause some serious damage and in the older cars that did not shut off the injector cause the car to actually catch fire and burn down.
Ya…it takes a lotto clog a cat now days….and that would be evident under normal city driving…wWhen the engines warmed up at operating temp. What he seems to have is excess fuel not being burned due to lack of spark under heavy load….that’s when it flashes. This screams ignition. Given he has new plugs and wires then we got to be logical (unless you wanna throw a computer at it also with a cat) it’s coil.
Find the coil pack that’s bad, it’s one of two. Replace and verify on the highway….u r cat and computer will be fine.
If u don’t want to diagnose then throw both coil packs at it for 140 bucks and ur fixed. Or diagnose and throw 70 bucks at the bad one and ur fixed. I’d verify. …hope u didn’t throw away ur wires and plugs….cuz they probably weren’t the issue.
Yeah that particular coil pack has a history of failure. What usually happens is the insulating substrate breaks down from years of heat and vibration and the one of the two coils in the pack finds it easier to fire over to the laminated core to get to ground rather down the wire to the plug. Since in waste spark design the path is through the plug wire to plug to block to companion plug and back to the coil though the companion plug wire, often both cylinders in the companion set end up misfiring.
[quote=”slotcar” post=82169]:( In the past I have read that when the check engine light flashes it means that the system is going to fail. If the check engine light is solid, you have a problem, but it is not as serious as a flashing check engine light. You may already be in limp mode for the computer, so you may want to get the ECU checked as soon as possible. I am afraid that The Ford ECU being under the hood is more susceptible to heat from the engine. I may be wrong, but you may want to see if that is the problem. Good Luck.[/quote]
Not true at all. A flashing light means it is serious and ur way above what the govt wants. A standing light means get it checked in ur day off.
He’s referring to the secondary coil pack. There’s one closest to the radiator and one further away. Start with checking spark with a tester (in line or whatever) from the coil pack that’s furthest from the radiator. Raist is right, that’s the one that goes out first…The secondary.
I kept the replaced wires and plugs…il test both coils before I go an buy 2…seems more logical…I appreciate all the tips and advice guys
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