bad Friday ending
#91
Advanced
Thread Starter
The concern is that their threads will seize in the aluminum housing if left unchanged for too long. Dissimilar metals are never 100% compatible, in terms of thermal and electrical properties. Antiseize can help with that, but it can also affect the plug's ability to shed heat, as I understand it.
Probably the #1 reason is the guaranteed employment clause in the dealership license agreement with Porsche. Somebody has to pay for all that free espresso, the 18' gas fireplace, and those awesome service bay doors that open in like 300 milliseconds when you pull up to them.
Probably the #1 reason is the guaranteed employment clause in the dealership license agreement with Porsche. Somebody has to pay for all that free espresso, the 18' gas fireplace, and those awesome service bay doors that open in like 300 milliseconds when you pull up to them.
#92
Advanced
Thread Starter
I had it towed to the shop on Friday. The mechanic hooked it up to his diagnostic and said all he showed was a miss on #5! Note my earlier posts with roughness on #3 and #5 before and after I had switched the plug and coil between #3 and #2 with no change (yes, I cleared codes in between the switch but not after so the mechanic would see what I was seeing. My thinking was if the switch moved the issue to #2, I would put a new plug and coil there and then address #5). He will get into it on Monday and let me know what he finds. Thank you all for your concern and stay tuned (bad pun not intended)...
The following users liked this post:
Watson (02-20-2022)
#93
Advanced
Thread Starter
This is an interesting mystery! Really irritating to the OP, though. We feel for ya, brother!
So, the car ran fine for 35 miles, then spirited driving ... THEN malfunctioned.
- multiple warnings point to something upstream of the coils? (I don't gave a frame of reference on 911s-when one coil is bad, does it feel like running on 5?, and does one bad coil cause all those other warnings?) Seems like more than one cylinder is affected.
- heat caused something to fail (like a position sensor)
- vibration caused an upstream connector to slip apart?
- vibration caused a wire that was moved to rub?
- vacuum hoses? (these are easy to forget or to put on then pull part way off while closing up from the work)
- brake fluid ... hmmm ... does this service get close to wiring in the frunk?
- fuses all good? (something shorted after spirited driving?)
- plugs from same "batch?"
- plugs not correct range? wrong length? (I know, OP - not trying to be offensive, just riffing)
- any water involved that could affect electrical connections?
- fans reconnected?
OK - everyone is thinking of "the answer." Hope it is something simple. Here's a link for a coil pack problem - sounds a bit like yours - coil failure starts ECU light show ... https://rennlist.com/forums/991/1065...s-wrong-2.html
Question from a newbie - why would one change plugs with 10,000 miles if the engine was running ok?
So, the car ran fine for 35 miles, then spirited driving ... THEN malfunctioned.
- multiple warnings point to something upstream of the coils? (I don't gave a frame of reference on 911s-when one coil is bad, does it feel like running on 5?, and does one bad coil cause all those other warnings?) Seems like more than one cylinder is affected.
- heat caused something to fail (like a position sensor)
- vibration caused an upstream connector to slip apart?
- vibration caused a wire that was moved to rub?
- vacuum hoses? (these are easy to forget or to put on then pull part way off while closing up from the work)
- brake fluid ... hmmm ... does this service get close to wiring in the frunk?
- fuses all good? (something shorted after spirited driving?)
- plugs from same "batch?"
- plugs not correct range? wrong length? (I know, OP - not trying to be offensive, just riffing)
- any water involved that could affect electrical connections?
- fans reconnected?
OK - everyone is thinking of "the answer." Hope it is something simple. Here's a link for a coil pack problem - sounds a bit like yours - coil failure starts ECU light show ... https://rennlist.com/forums/991/1065...s-wrong-2.html
Question from a newbie - why would one change plugs with 10,000 miles if the engine was running ok?
The following users liked this post:
GT3FZS (10-31-2022)
#94
Pro
Join Date: Oct 2021
Location: Pensacola, Florida
Posts: 544
Likes: 0
Received 144 Likes
on
101 Posts
Fingers crossed for ya!
Now, looking back on it ... better to just leave things that "Aren't Broke" alone? :-)
So, we're now we're maybe talking odds on:
- wire to the coil (somewhere?)
- bad coil (must have failed after the 35 mile and during the spirited driving)
- plug itself (new plug failure?)
- plug not fully seated (a long shot, but I've done this before on non-ECU based engines and it doesn't run right)
- coil not attached well enough (or something in the boot causing?)
Can one "meter" the coil prior to replacing?
Hmmm .... broad categories?
1. Something randomly failed, or became disconnected, etc during the spirited driving.
2. A new part you installed failed.
3. Something you did during installation caused the failure, but only AFTER 35 miles and then spirited driving.
4. Some else is causing #5 to misfire.
This is FUN - probably wrong word? Probably would NOT be fun if it was my Porsche!
Now, looking back on it ... better to just leave things that "Aren't Broke" alone? :-)
So, we're now we're maybe talking odds on:
- wire to the coil (somewhere?)
- bad coil (must have failed after the 35 mile and during the spirited driving)
- plug itself (new plug failure?)
- plug not fully seated (a long shot, but I've done this before on non-ECU based engines and it doesn't run right)
- coil not attached well enough (or something in the boot causing?)
Can one "meter" the coil prior to replacing?
Hmmm .... broad categories?
1. Something randomly failed, or became disconnected, etc during the spirited driving.
2. A new part you installed failed.
3. Something you did during installation caused the failure, but only AFTER 35 miles and then spirited driving.
4. Some else is causing #5 to misfire.
This is FUN - probably wrong word? Probably would NOT be fun if it was my Porsche!
#95
Advanced
Thread Starter
Fingers crossed for ya!
Now, looking back on it ... better to just leave things that "Aren't Broke" alone? :-)
Yeah, x Porsche says 4 years or 30k miles!?
So, we're now we're maybe talking odds on:
- wire to the coil (somewhere?)......maybe
- bad coil (must have failed after the 35 mile and during the spirited driving)....probably
- plug itself (new plug failure?)....possibly
- plug not fully seated (a long shot, but I've done this before on non-ECU based engines and it doesn't run right)....Nope, torqued 'em sure
- coil not attached well enough (or something in the boot causing?)...double checked that after issue
Can one "meter" the coil prior to replacing?...the coil can be bench tested but one needs to know which 2 blades/terminals to check resistance at
Hmmm .... broad categories?
1. Something randomly failed, or became disconnected, etc during the spirited driving.
2. A new part you installed failed.
3. Something you did during installation caused the failure, but only AFTER 35 miles and then spirited driving.
4. Some else is causing #5 to misfire.
This is FUN - probably wrong word? Probably would NOT be fun if it was my Porsche!
Now, looking back on it ... better to just leave things that "Aren't Broke" alone? :-)
Yeah, x Porsche says 4 years or 30k miles!?
So, we're now we're maybe talking odds on:
- wire to the coil (somewhere?)......maybe
- bad coil (must have failed after the 35 mile and during the spirited driving)....probably
- plug itself (new plug failure?)....possibly
- plug not fully seated (a long shot, but I've done this before on non-ECU based engines and it doesn't run right)....Nope, torqued 'em sure
- coil not attached well enough (or something in the boot causing?)...double checked that after issue
Can one "meter" the coil prior to replacing?...the coil can be bench tested but one needs to know which 2 blades/terminals to check resistance at
Hmmm .... broad categories?
1. Something randomly failed, or became disconnected, etc during the spirited driving.
2. A new part you installed failed.
3. Something you did during installation caused the failure, but only AFTER 35 miles and then spirited driving.
4. Some else is causing #5 to misfire.
This is FUN - probably wrong word? Probably would NOT be fun if it was my Porsche!
Last edited by hcamp19; 02-20-2022 at 07:33 PM.
#96
Pro
Join Date: Oct 2021
Location: Pensacola, Florida
Posts: 544
Likes: 0
Received 144 Likes
on
101 Posts
There as so many threads on bad coils - are they this prone to failure? Apparently way more so than a single coil approach? (I've never had a bad coil, and have changed hundreds of sets of points - and (probably unnecessarily, condensers). Makes one wonder if there is a wire connection issue?
So, cracked insulator around the plug? Broken wire. Bent pin on the connector?
This first video seems to indicate there is significant opportunity to bend the coil pack plug connector enough to potentially damage something ... pretty tight quarters on a 997 - or to not perfectly connect the wiring fitting to the coil ... I could not find a video with same level of detail for 991.
This video is short on detail compared to the 997, above, but does infer tight quarters - easy to imagine alignment of loose clip, bent pin, gunk getting into the connector, etc.
So, cracked insulator around the plug? Broken wire. Bent pin on the connector?
This first video seems to indicate there is significant opportunity to bend the coil pack plug connector enough to potentially damage something ... pretty tight quarters on a 997 - or to not perfectly connect the wiring fitting to the coil ... I could not find a video with same level of detail for 991.
This video is short on detail compared to the 997, above, but does infer tight quarters - easy to imagine alignment of loose clip, bent pin, gunk getting into the connector, etc.
Last edited by RennListUser01; 02-20-2022 at 08:05 PM.
#97
Rennlist Member
I had it towed to the shop on Friday. The mechanic hooked it up to his diagnostic and said all he showed was a miss on #5! Note my earlier posts with roughness on #3 and #5 before and after I had switched the plug and coil between #3 and #2 with no change (yes, I cleared codes in between the switch but not after so the mechanic would see what I was seeing. My thinking was if the switch moved the issue to #2, I would put a new plug and coil there and then address #5). He will get into it on Monday and let me know what he finds. Thank you all for your concern and stay tuned (bad pun not intended)...
#99
Rennlist Member
Yes, it's my impression that it's generally accepted amongst Porsche 911 DIY'ers to replace all coils every other spark plug change.
#100
Pro
Join Date: Oct 2021
Location: Pensacola, Florida
Posts: 544
Likes: 0
Received 144 Likes
on
101 Posts
Not sure I understand - what is the Porsche procedure for a failed coil? I would assume it is replacement?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
Last edited by RennListUser01; 02-21-2022 at 01:55 PM.
#101
Not sure I understand - what is the Porsche procedure for a failed coil? I would assume it is replacement?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
Eventually the coils plastic housing will start to crack around 60-70,000 miles. Ignition coils are consumables IMHO.
As far as plugs go, always use the original spec plugs. IMHO There is no extra power to be had by choosing other brand plugs and the different conductivity/resistivity of the plugs can throw off the normal operation of the engine.
Last edited by 991Targa4S; 02-21-2022 at 02:32 PM.
#102
Pro
Join Date: Oct 2021
Location: Pensacola, Florida
Posts: 544
Likes: 0
Received 144 Likes
on
101 Posts
So, some more learning for me ...
911.2 C has 12 point spark plugs?
Here's a non-911.2 video relating to coil and plug replacement - I must admit it is the very first time I have heard of anyone using Milk of Magnesia on the plug threads ...
911.2 C has 12 point spark plugs?
Here's a non-911.2 video relating to coil and plug replacement - I must admit it is the very first time I have heard of anyone using Milk of Magnesia on the plug threads ...
#103
Advanced
Thread Starter
I agree, doesn't make sense nor is it called for in the maintenance stuff i have read to replace coils as PM. Additionally, this was the first spark plug change for this car.
#104
Advanced
Thread Starter
Not sure I understand - what is the Porsche procedure for a failed coil? I would assume it is replacement?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
Been thinking about past ignition issues - had a V6 engine just instantly develop a "miss." Carbon fiber center spark plug wire started "breaking down" (not transferring high voltage) electrical energy from coil to plug. Carefully examined, but no visible damage - replacement fixed. Did not replace others - worked fine for another 7 years and 120,000 miles. Just a vignette.
Anyone have photos or engineering analysis material on construction of these coil over designs? Is there a specific failure mode - ie is it really the coil part, or internal connection fittings between the coil and the plug end?
And, anyone reviewed coil over failures to see if they are more common on one brand or another?
Finally, I just took a look (newbie) at the various spark plug offerings ... is there really a CHOICE between four ground, two ground, and one ground styles? I can't find mention of the specific plug in my manual but all options (copper, plat, double plat, and iridium all show single ground designs). HCAMP - did you replace with single, two, or four ground design?
#105
Pro
Join Date: Oct 2021
Location: Pensacola, Florida
Posts: 544
Likes: 0
Received 144 Likes
on
101 Posts
hcamp19,
Were your replacement plugs exactly the same? How many sides on the outside casing and how many grounds?
And, another surprise to me is how the coil connector fits to the plug - a new shape, as well?
Were your replacement plugs exactly the same? How many sides on the outside casing and how many grounds?
And, another surprise to me is how the coil connector fits to the plug - a new shape, as well?
Last edited by RennListUser01; 02-21-2022 at 03:01 PM.