Cylinder #1 misfire

[Spurlee]

Hi everyone.

1996 El Dorado ETC with 130,000 miles...

I changed out the plugs with NGK Platinum ones and replaced the wires with a 8.5MM higher performance set.

Now I get a periodic Cylinder #1 Misfire code. It will trip the Check Engine Soon light and it will stay on for maybe 60 to 100 miles, then turn itself off. About 100 miles later, it will trip again.

I reinstalled the wire and all looks OK....I'll beginning swap-testing the plug and wire. Any other ideas?

Thanks

[mmarinov]

Hi everyone.

1996 El Dorado ETC with 130,000 miles...

I changed out the plugs with NGK Platinum ones and replaced the wires with a 8.5MM higher performance set.

Now I get a periodic Cylinder #1 Misfire code. It will trip the Check Engine Soon light and it will stay on for maybe 60 to 100 miles, then turn itself off. About 100 miles later, it will trip again.

I reinstalled the wire and all looks OK....I'll beginning swap-testing the plug and wire. Any other ideas?

Thanks

Hmmm...make sure your contact is clean on the ICM?

Did you get any kind of warranty on the wires? If so, you may go that route. I'm sure others will chime in with better diagnostic info, but I would just want to fix it quickly. My assumption is also that you never rec'd this code prior to swapping plus and wires.

[BodybyFisher]

I hate to beat a dead horse, but if you use OEM you can be sure that its not the plugs or wires, in your instance, using aftermarket parts clouds the issue. That said:

Since its only happening on one cylinder that tells us that the ignition wires overall are ok in terms of resistence and connections and its related to that cylinder (#1). I would just backtrack that cylinder, pull the ignition wire at both ends and look at the connectors for damage or looseness, check to see if the core is burned out of the wire, sometimes the core burns out and the spark jumps a gap, maybe the core burned out due to a defect (just a guess, but I have seen it happen). If you have an ohm meter check its resistence against a few others to see if its 'in the range'.

If this was coil related you would get two cylinders misfiring so its not likely a coil, but check #1's connection at the coil. We recently had a member have a roughness due to his connection at the coil.

Finally, I would check the spark plug carefully for cracks, carbon tracking, etc. Check the gap closely. Did you use dilectic grease? Some wires are already impregnated with the grease and the use of grease is not necessary and has been know to create arching and carbon tracking.

Let us know what you find

[Spurlee]

Thanks for the advice about the coil - that's what I thought. The wires have a warranty, so I'm OK there if that ends up being the problem. I used dialectric grease, it was appropriate for this application.

These wires are significantly larger in overall size as well as core - I'm still lookng for the appropriate spacers to route/loom them correctly. Could it be that I've created some cross-fire, mis-file potential by zip-tying them together at some points? Is that old school thinking given the composition of new wires??

[JimD]

Mutual induction can be a real world problem. As much as possible, try to avoid having the plug wires running parallel. Where they must be parallel, maintain as much spacing as possible. Tied together is not the best situation.

EDIT:

But in the case of odd numbered cylinders, the wires are so short I doubt that you have them tied to anything.

[BodybyFisher]

Oh yea, for sure. Have you seen the length of the spark that these coils produce? Its not like the old days of the old school black can coil, these coils produce a spark 2 to 3 inches long maybe more I am not sure, but its scary powerful and not to be tried as the sparks can fry everything in the area!!! I once left an ignition wire disconnected from a coil and started the car, OMG, 4th of July, that's how I know how long the sparks are! Then, I read in the FSM NEVER to let sparks jump like that, you can FRY stuff! So if you are providing the SPARK a path to a ground sooner in the wire that it travels in will be glad to take the shorter path.. These sparks remind me of the high voltage on the old 1B3 high voltage rectifier tubes in the old days on TVs, it was an intense voltage and it easily arched through insulation.

That is why the NS has wire retainers spaced so widely and why routing is so critical. You are potentially ruining the wires bundling them like this as you could be breaking down the insulation. By not routing them safely, you are providing grounds for leakage when wire runs close to metal, in addition, cross talk and interference can occur between the the wires if they touch each other or if they are routed along side injector, sensor or accessory wires. I even replaced the wireloom when I replaced mine to provide even more distance between the wires and potential leak points.

This is another reason to go OEM (not to beat a dead horse, I might add).

[mmarinov]

That is why the NS has coil retainers spaced so widely and why routing is so critical. You are potentially ruining the wires bundling them like this as you could be breaking down the insulation. By not routing them safely, you are providing grounds for leakage when wire runs close to metal, in addition, cross talk and interference that can occur between the the wires if they touch or if they are routed with the injector or accessory wires. I even replaced the wireloom when I replaced mine to provide even more distance between the wires and potential leak points.

This is another reason to go OEM (not to beat a dead horse, I might add).

I didn't go so far as to replace the wirelooms but I was very careful to maintain the original paths. I could definitely see this as being his issue (and maybe why it's somewhat intermittent).

[stsjoe]

Go ahead Mike, beat the horse )

[Spurlee]

All:

I know the correct thing to do is to replicate the original wire path as much as possible and I suspect my problem is related to the fact that I have the back bank (including #1, of course) sort of squished together as they make the return path (a 180 degree turn) from the distributors to their respective plugs. They made the same turn in the OEM set up but were nicely separated.

I'll find a appropriately sized separators and install them. Interestingly, the OEM arrangement ran the front bank wires parallel and directly adjacent for quite a distance on their way across the rear heads. Go figure...

I used larger-than-OEM wires from Magnaore on my Corvette and it made a big difference in the mid range RPM performance. I mean really noticable. These wires are only 7" long however, each from its' own coil. No chance for positioning trouble there.

Put the same type wires on the El Dorado and the difference in performance is noticable, too. A worthy project.

I'll let you know what happens.

[GreenMachine]

I'd check the resistance of the number 1 wire (for the OEM plugs says not to have any exceeding 15K Ohms or something to that effect), check for carbon tracks on both plug and the coil. If there is a track the wire will have to be replaced along with the plug or coil that was tracked, otherwise the cycle will simply repeat itself.

[PAUL T]

I made the mistake of grabbing the plug wire at the coil end to check for a good connection while the car was running. BIG MISTAKE!!! There IS a LOT of power going through the wires at the coil!! It was one of my blonde moments.