[greenberet123]

2008 E93:

Dec 2019: All coils replaced @ 75k miles w/ Delphi
Dec 2020: Coil #5 failed and replaced @ 84k miles
Jan 2021: All spark plugs replaced @ 87k miles
This week (2026): Coil 2 failed first, and while diagnosing it, now coil 5 has failed too @ 110k miles

So, it's been 5 years since the last coil replacement - but only 30k miles.

1. Is this normal?
2. Is it still covered by Delphi warranty? Should I bother with it?
3. Should I just replace ALL again with Delphis?

Thanks!

[marvinstockman]

First, only replace the coil that is bad, as the others are good. BTW, if you saved the old coils from your previous work, use one of them.

Second, a coil will only go bad if it has a hard time firing the plug, and needs to generate a higer voltage, which cause heat in the coil. Be aware, excessive heat is a bad, bad thing.

[Mike K]

I tried to measure coil resistance and good and bad coils measured about the same. A coil by nature measures low resistance. So my test was inconclusive.

I sometimes think if a coil isn’t fully seated all the way down, they’ll then fail. Maybe arcing at the plug top connection?

[tlow98]

I generally find the more you pull and mess with coils the more often they fail. Also, if eldor coils fit you should buy those as they’re the best. Generally they’re very dependable for 2 plug cycles, which in these cars is a very long time!

[e91Owner]

Delphi coils are warrantied for 3 yr/36000miles if you bought them from anyone other than Amazon in which case there is no warranty.

If you bought them from FCP, they are covered for life.

[mainbearing]

Make sure the coil harness plug is fully seated. Delphi has 3 different part numbers for the N52/51.

The way BMW buried the coils in the cylinder head makes them more prone to failure. That is why some N54/55 owners did B58 Coil Swap. The B58 coils are like the Audi style, with the coil all the way on the top end, the way it should have been.



If Eldor is available then sure. Eldor is OEM for Audis. Rockauto shows 2 NGK parts, one says w/ Delphi coils and the other w/ Eldor coils. Not sure if these are interchangeable though.

When I picked the Delphi coils I used the factory Bosch part number to cross reference. The old Bosch junk where swollen slightly and pulled the heat shields out with them. The new Delphi coils went in the NGK Ruthenium spark plugs.

[The Nightman]

Worn spark plugs with large gaps increase the wear on ignition coils:

https://www.denso-am.eu/news/causes-...n-coil-failure

[greenberet123]

I did buy from FCP in 2020. So then I should return them and use the warranty? Is it easy and worth doing?

Originally Posted by e91Owner

Delphi coils are warrantied for 3 yr/36000miles if you bought them from anyone other than Amazon in which case there is no warranty.

If you bought them from FCP, they are covered for life.

[StradaRedlands]

Originally Posted by greenberet123

I did buy from FCP in 2020. So then I should return them and use the warranty? Is it easy and worth doing?

Other than paying shipping, yes, totally worth it.

[lookalikehuuh]

Originally Posted by greenberet123

I did buy from FCP in 2020. So then I should return them and use the warranty? Is it easy and worth doing?

Yes, although there is a gotcha nowadays. FCP changed their warranty process a bit. You have to buy the new set of coils, then once you swap them, start a claim to return your old ones. They will then issue you a store credit in the cost of the original coils. They used to just refund your money, but I believe since credit card fees on returns changed for all the major providers post COVID. So now you will just have that store credit until you need more parts, which you will owning an E90.

I replace my coil packs around every 50K miles on my tuned 335i and every 75K miles on my 330i. They all work perfectly still, I do it more as preventative maintenance to avoid having a misfire in the future.

That being said I use the Bosch units on my N52 and Eldors on my N54 car so I don't have any real life experience with the Delphi units, although many have said Delphi are better than the Bosch coils.

Is your car heavily tuned? also what kind of spark plugs are you using?

[whyzee125]

Yes, I wouldn't sweat it one bit if purchased through FCP. Replace them all with new Delphis for free and change the plugs while you're at it.

I've had premature failure from Delphis too. The shop I go to doesn't like them because of the uncoated metal sleeve, saying they've seen more than a few times where that arcs against the block and causes them to short out.

Then again, plenty of Bosch failures too. Thank goodness for FCP!

[greenberet123]

They are also asking me to upload documentation from a certified technician. Is there some way I can get that?

- no tuning in my car, just plain ol'
- BMW ILZFR6D11 Spark Plug (Iridium) also from FCP, but I have not checked their condition. I just swapped coils and the code moved, so concluded its the coils.

Originally Posted by lookalikehuuh

Yes, although there is a gotcha nowadays. FCP changed their warranty process a bit. You have to buy the new set of coils, then once you swap them, start a claim to return your old ones. They will then issue you a store credit in the cost of the original coils. They used to just refund your money, but I believe since credit card fees on returns changed for all the major providers post COVID. So now you will just have that store credit until you need more parts, which you will owning an E90.

I replace my coil packs around every 50K miles on my tuned 335i and every 75K miles on my 330i. They all work perfectly still, I do it more as preventative maintenance to avoid having a misfire in the future.

That being said I use the Bosch units on my N52 and Eldors on my N54 car so I don't have any real life experience with the Delphi units, although many have said Delphi are better than the Bosch coils.

Is your car heavily tuned? also what kind of spark plugs are you using?

[greenberet123]

The plugs are also from FCP, but I don't have any evidence that they are faulty. Can I still send it back / is it ok to send them back?

FCP is asking me to upload documentation from a certified technician. Is there some way I can get that?

Originally Posted by whyzee125

Yes, I wouldn't sweat it one bit if purchased through FCP. Replace them all with new Delphis for free and change the plugs while you're at it.

I've had premature failure from Delphis too. The shop I go to doesn't like them because of the uncoated metal sleeve, saying they've seen more than a few times where that arcs against the block and causes them to short out.

Then again, plenty of Bosch failures too. Thank goodness for FCP!

[lookalikehuuh]

Originally Posted by greenberet123

They are also asking me to upload documentation from a certified technician. Is there some way I can get that?

- no tuning in my car, just plain ol'
- BMW ILZFR6D11 Spark Plug (Iridium) also from FCP, but I have not checked their condition. I just swapped coils and the code moved, so concluded its the coils.

FCP Euro is asking you for documentation from a certified mechanic? I just did a warranty with them last week and they didn't ask for any of that.

If you were taking the car to a certified mechanic, you wouldn't be buying the parts from them... their entire platform is based on DIY'ing so that makes no sense. All their DIY videos they put out on youtube is also not being watched by real mechanics...

[greenberet123]

Yes, like this:

View post on imgur.com

I guess I could ignore it and send it without that?

Originally Posted by lookalikehuuh

FCP Euro is asking you for documentation from a certified mechanic? I just did a warranty with them last week and they didn't ask for any of that.

If you were taking the car to a certified mechanic, you wouldn't be buying the parts from them... their entire platform is based on DIY'ing so that makes no sense. All their DIY videos they put out on youtube is also not being watched by real mechanics...

[lookalikehuuh]

Originally Posted by greenberet123

Yes, like this:

View post on imgur.com

I guess I could ignore it and send it without that?

Yeah your doing it wrong:

Go here:
https://www.fcpeuro.com/returns/selection

Select the 3rd option, under "Submit Lifetime Guarantee Replacement"

Then select your part, and for reason select "WARRANTY - Lifetime Replacement" and then enter your most recent order #, and the correct quantitiy of course.

That should work for you.

Also for their lifetime warranty, you have to replace them with Delphi coils, they will not allow you to change to the Bosch or Eldor coils.

[oVeRdOsE.]

I assumed that the engine beauty cover and the acoustic liner in the cover was keeping the coils way too hot.
especially in traffic.

I dont know if it's a coincidence, since I removed the cover, I did not experienced any failure in 60kmiles

[lookalikehuuh]

Originally Posted by oVeRdOsE.

I assumed that the engine beauty cover and the acoustic liner in the cover was keeping the coils way too hot.
especially in traffic.

I dont know if it's a coincidence, since I removed the cover, I did not experienced any failure in 60kmiles

The only coils I ever had an issue on were the Bosch ones, to be fair those had like 130k+ miles and one would misfire under full load on my N52. Both of my cars still have the engine beauty covers on, both get run hard and will sit in traffic for up to 1.5 hours on days that I have to drive into the office.

I was actually thinking more along the lines that the parts are just not as good as they once were. I definitely experienced that recently with the Rein hoses, F A G wheel bearings, Valeo Alternator, and from the sounds of the posts on here, the Bosch refurb alternators. Seems liike mfgs are cheapening out on the parts more and more as time goes on. I'm affraid to buy parts now, even OE/OEM ones.

[gbalthrop]

My experience differs. I have the Original Bosch coils on my 3/2007 build 328xi, N52K, now at 144K miles. Two weeks after I got it in March, 2017, I had misfire at 5,000+ RPM on two different occasions. On both instances, the injector on the misfiring cylinder was shut down for ~ one minute, causing Rough operation on 5 cylinders. Proper operation returned without engine shutdown, after ~ one minute of moderate RPM (< 3,000 RPM).

Inspection showed plug gap on Bosch plugs to have enlarged to .055"-.060", causing misfire at high RPM. Plugs were replaced with same Bosch FR7NPP332, gapped to .040". I replaced ONE Bosch coil with same Bosch 0221504470, simply because there was a nick in the plug boot.

4 years later, that replacement coil, "Made in Slovenia", went bad, causing misfire at low RPM, misfire following coil when swapped. I re-installed coil taken out in 2017 (when I replaced the plugs), plug boot wrapped with electrical tape, & NO misfire since.

While this is totally "anecdotal", my theory is that Old parts are Good parts. Quality Control may have taken a "hit" since 2008 recession, with manufacturers & parts retailers looking for cheaper sources/suppliers. I have not replaced ANY other engine parts in nearly 9 years since the plug change. I keep an Auto Database, so the above is documented & reliable. YMMV.
George

[e91Owner]

Originally Posted by greenberet123

Yes, like this: https://imgur.com/a/Dt2ElJv

I guess I could ignore it and send it without that?

You need to be using the lifetime replacement guarantee, not the defective returns.

To add to what someone else commented on… I prefer the Delphi over the older Bosch. Never had a Delphi go bad on a BMW yet, but have had several Bosch go bad. I also change them about every 5 years along with the plugs simply due to FCP’s generous return policy. The mileage is more important, but I don’t drive it very much.

[greenberet123]

Which service do folks typically use for returns? USPS?

Originally Posted by whyzee125

Yes, I wouldn't sweat it one bit if purchased through FCP. Replace them all with new Delphis for free and change the plugs while you're at it.

I've had premature failure from Delphis too. The shop I go to doesn't like them because of the uncoated metal sleeve, saying they've seen more than a few times where that arcs against the block and causes them to short out.

Then again, plenty of Bosch failures too. Thank goodness for FCP!

[e91Owner]

Originally Posted by greenberet123

Which service do folks typically use for returns? USPS?

You can use anything. I use UPS simply because that is the cheapest option from where I live.