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Discussion Starter #1 (Edited)
Ok.... Very frustrating Day at the dealership. My car a 2006 with 65k. I first want to say thank you to Eloy for setting the service guy right at Bill Jacobs in naperville. Here is what happened..



My car had a rough Idle, the slow rpm up and down, it started a week ago and came and went, but was getting worse so i took it to the dealership. My car has RPI scoops and filter and full GT exhaust. When the dealership ran all the tests here is the following faults:

Cylinders 2,4,6,8,10 misfiring (not sure if that is all the exact cylinders it was a bunch)

DME was throwing a bunch of codes

A couple of those codes said a bad cat

They tapped on the cats and said one of them is bad (eloy said they cant really know this because one is a hollow cat and you have to take the exhaust off to determine that)

They tested the 02 sensors and they are fine.

At the end of all the testing it says to replace the DME and they believe a Cat as well from tapping on it and the codes the DME is throwing. Eloy also said he doubts the cat is bad because they are stainless

The dealership called BMW because most people dont know that your DME is covered till 80k. BMW said that this warranty is void on my car because i have aftermarket exhaust (complete BS) because everyone knows that exhaust cant cause my DME to go bad.

My SA is concerned that my platinum extended warranty through Fidelity warranty services is going to do the same thing. At first I thought he was trying to screw me but after talking to him, he said, I want your business I have 3 hours into diagnostic and can only charge you for 1, its beneficial for both of us if we can fix your car.

What do I do, do i have recourse with BMW about the DME since it is covered and the cats because the misfiring might have destroyed them?

#2 if I cant what options do i have? Does anyone have a stock exhaust I could swap out in the Chicagoland area for a couple of days? Thanks for all your advise and help. I have never been more frustrated!!! Thank you Eloy for getting on the phone and letting the SA know that we HAVE PEOPLE :15: In the end he wasnt trying to screw me, but it sure felt like it along the way!
 

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I have an 06 with around 65k miles too.

It does the same thing except not as dramatic as yours.

Now I'm worried if my engine is misfiring too...

As for the cats, I have the GTS exhaust and I had my primary cats replaced by bmw

at no cost with extended warranty, so the dealer should replace your's too. IDK if this

helps but best of luck.
 

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Discussion Starter #3
Thanks my extended warranty is not bmw. Yours? How many miles when yours was replaced and who was your warranty company?
 

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I purchased my warranties through bmw, I have the bmw extended vehicle protection warranty, and a third party

company that my SA recommended, that i purchased at the dealership.

I'm forget the company, but i'll let you know when i find it. And my header was replaced at around 62k
 

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This is a sticky situation but BMW should cover your primary cats and DME due to federal law if your car is under 8 YR/80,000 miles mark. Take it up with BMW to replace them so you can avoid using your extended warranty. Because if you do most likely they will come out to inspect and look for a way to avoid covering your car due to aftermarket items and it'll save you a big headache!

The only thing I can think of is have your service adviser call BMW again to see if they will cover the failed parts. If they continue to decline maybe mention the Magnuson-Moss Act? And have them try to prove that your exhaust would have caused this failure.

Best of luck!
 
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You have stock headers, I'm assuming?

In that case - this is really dumb. The car has no way of telling what kind of exhaust and whether or not there are cats or not after the headers. There are sensors to check for primary cat efficiency, and nothing else. So as long as that is stock, they can't really claim failure due to modification.

Second, if they somehow try to blame it on the scoops, that won't work either unless they'll also void your warranty for driving below sea level.
 

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You have stock headers, I'm assuming?

In that case - this is really dumb. The car has no way of telling what kind of exhaust and whether or not there are cats or not after the headers. There are sensors to check for primary cat efficiency, and nothing else. So as long as that is stock, they can't really claim failure due to modification.

Second, if they somehow try to blame it on the scoops, that won't work either unless they'll also void your warranty for driving below sea level.
Told my irregular SA that exact same thing and she didn't know how to respond haha so they go the shop manger
and replaced my one of my header's, sill need to go to the dealer to possibly replace the other one, i the only
thing they charged me was for the diagnostics, which was originally 380$ 190$ for each time they did it, but i
paid 300$
 

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Hiya mate!
Never have I come across rough idle because of an exhaust system!!
What you need to do is ask the BMW Tech to check the voltage at idle! It could be caused by under voltage at idle!
once the dme sees hat that voltage is to low it will raise the idle untill it see's the correct votlage!
Allso air leaks can cause this problem to.
Have them also reset the fuel trimings and adaptations for the fuel pump!
Check also the eletronic fuel regulator in the front left wheel arch!
BMW techs should have done all these tests!

So ask them to check:
1.alternator out put at idle!
2.Battery IBS unit_-see if they can register the battery.if the have alternator communication failure code come up?
3.check for any air leaks at the intake manifold.
4.check electonic fuel sensor.
5.Diconect both air mass senors and see the difference!
6. RE-CODE the DME and SMG.

let us know how you get on!
I think its an alternator problem! but I need some more feed back from you techs!

Hope this helps

Shak
PS. If you can get me the exact description of the codes I will have a better idea!
 

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Discussion Starter #9
Thanks I will contact the dealership and ask them to run those tests. If anyone has any other advise please post, what is the best way to dal with bmw NA when they have already said no
 

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Discussion Starter #10
Update, they got the engineers from bmw worked on the car with the sa, they are currently re flashing the dme as we speak
 
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The cat is not hollow. :) It is rare that the main cats go bad. The steel core cats are very durable. Those of you who have tried to gut out one of these things will know. You can take a sledge hammer to these things and it would barely make a dent. Since the DME is throwing so many codes, I wanted to visually check to see if the cats were really bad instead of trying to change everything that had a code thrown. Ive had this happen and the change of the o2 sensors had fixed it. The problem with a lot of dealerships is that they are more concerned with billing you for things than actually trying to fix the problem.

I would:

1. take sec 1 off (will take 15 minutes since you have the rpi exhaust. 2 v-band clamps and 4 bolts to the header flange.) inspect the main cats to see if they are indeed damaged.

2. try changing the o2 sensors

3. check to make sure the spark plugs and coils are ok.
 

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Discussion Starter #12
LoOok car is still at dealership going on 2 weeks maybe 3. Reflashed dme no more codes, but still rough idle... I am wondering if the codes w were stored when I had the jaws alpha n tune on for a day....so frustrated!
 

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Discussion Starter #13
Dealer is giving me the car back, they can't figure it out saying I have a bad cat!
 

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Just curious, did they look at the coils as well as check the igniters? They could be clicking but not putting out enough power. I had a 335i with this same issue, I know they arent the same engine, but that is where we went with it.
 

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"Bad cats" is the dealership's way of telling you they have no idea, please give us more money.

If all the codes have been cleared, drive it a bit and have it read again. Will you Fidelity warranty pay for a BMW independent shop to look at it? Typically they charge less and actually have some clue how to fix something without relying on a computer to tell them how.

The misfire statement in your original post is curious though. Do you recall which cyclinders actually reported misfires? 1-5 or 6-10? The way you have those written looks as if there were 5 cylinders misfiring, but you stated not those exact ones. If one bank of cylinders was misfiring, I would start looking at the ionic current sensing unit that is in line to the ignition coils.

I am curious how they tested the O2 sensors. Bad O2 sensors can continue to produce a correct voltage. The problem is that the sensing element of the sensor is inside of a protective shield. As the sensors become fouled for whatever reason (oil contamination is common), the permeable shield becomes clogged and is not so permeable anymore, meaning Oxygen can't get to the sensing element easily anymore. This makes the sensor's voltage output lag behind the change in O2 content. Bottom line is, looks fine, but has slow response, slowing down the DME's ability to correct fuel trim. O2 sensors are far cheaper than cats to purchase and far easier to swap labor wise than cats are.

For the record, it is nearly impossible for bad cats to cause a misfire. Unless they are so completely cogged that exhaust gases physically can't get out, I just can't see it. Bad cats would give the DME a bad cat efficiency signal due to the post-cat O2 sensors. They are referred to as "monitoring lambda sensors" as they do not "control" anything. The "control lambda sensors" are the pre-cat O2 sensors which measure the O2 content of the exhaust and allow the DME to adjust the short term and long term fuel trims which could actually cause a misfire. Long story short, the pre-cat O2 sensors have no idea if the cats are working, not working, stolen, etc.
 

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I am also getting bad cat diagnosis from my ( dependable,factory trained independent mecanic). They pound on the cat and it sounds loose inside
I am also getting fault codes but no performance issues
I am very freaked about the cats cause the calif legal cats are 7k to replace?
 

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"Bad cats" is the dealership's way of telling you they have no idea, please give us more money.

If all the codes have been cleared, drive it a bit and have it read again. Will you Fidelity warranty pay for a BMW independent shop to look at it? Typically they charge less and actually have some clue how to fix something without relying on a computer to tell them how.

The misfire statement in your original post is curious though. Do you recall which cyclinders actually reported misfires? 1-5 or 6-10? The way you have those written looks as if there were 5 cylinders misfiring, but you stated not those exact ones. If one bank of cylinders was misfiring, I would start looking at the ionic current sensing unit that is in line to the ignition coils.

I am curious how they tested the O2 sensors. Bad O2 sensors can continue to produce a correct voltage. The problem is that the sensing element of the sensor is inside of a protective shield. As the sensors become fouled for whatever reason (oil contamination is common), the permeable shield becomes clogged and is not so permeable anymore, meaning Oxygen can't get to the sensing element easily anymore. This makes the sensor's voltage output lag behind the change in O2 content. Bottom line is, looks fine, but has slow response, slowing down the DME's ability to correct fuel trim. O2 sensors are far cheaper than cats to purchase and far easier to swap labor wise than cats are.

For the record, it is nearly impossible for bad cats to cause a misfire. Unless they are so completely cogged that exhaust gases physically can't get out, I just can't see it. Bad cats would give the DME a bad cat efficiency signal due to the post-cat O2 sensors. They are referred to as "monitoring lambda sensors" as they do not "control" anything. The "control lambda sensors" are the pre-cat O2 sensors which measure the O2 content of the exhaust and allow the DME to adjust the short term and long term fuel trims which could actually cause a misfire. Long story short, the pre-cat O2 sensors have no idea if the cats are working, not working, stolen, etc.
Once again, it seems like your feedback may be useful to my current situation :) please check out my latest post and let me know where to paypal you lol http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/247449-next-problem.html
 
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