I had a PPI done before I bought my 98 528i. The service facility said that the ignition coils were bad and needed to be replaced ($700). I ended up buying the 98 528i, but the engine seems to run fine. What kind of testing did they do to find that the coils were bad and is it imperative that these are replaced? Is is possible that they were just trying to get some more cash out of me? Any info would be appreciated. I find it hard to believe that all 6 coils are bad, shouldn't they have identified the bad coils by cylinder?

BTW, the car has 112k miles and I believe that the coils are original.

TIA for any replies

I had a PPI done before I bought my 98 528i. The service facility said that the ignition coils were bad and needed to be replaced ($700). I ended up buying the 98 528i, but the engine seems to run fine. What kind of testing did they do to find that the coils were bad and is it imperative that these are replaced? Is is possible that they were just trying to get some more cash out of me? Any info would be appreciated. I find it hard to believe that all 6 coils are bad, shouldn't they have identified the bad coils by cylinder?

BTW, the car has 112k miles and I believe that the coils are original.

TIA for any replies

I don't know how you'd test the coils to see if they are bad. However I do know that once a coil is bad the whole set has to be replaced. So there is no point in identifying which cylinder has a bad coil. You can do a physical examination of the coils for signs of cracks and tears. If you do want to replace the coils, they should not cost $700. They are about $60 apiece and are very easy to install.

You have to replace all of them? I did not know that.

Thanks for the reply, I have bought one new coil off eBay for only $10, no way in hell I was going to pay $700. And I figured that these wouldn't be that difficult to install.

My question though is the same as beeze above, why will all the coils need to be replaced at the same time? I would like to understand why this is so.

Thanks

I dont see why you'd have to do all the coils at once? In fact, I'm pretty sure you dont. The car would have no clue whether one or all were replaced...plus people recommend buying one new one then switching it around to find the bad one.

I dont see why you'd have to do all the coils at once? In fact, I'm pretty sure you dont. The car would have no clue whether one or all were replaced...plus people recommend buying one new one then switching it around to find the bad one.

I'm probably wrong about replacing the coils in set. However, since all the coils were put in at the same time, if one is bad from wear and tear, it makes sense that the rest are probably going to wear out very soon.

I dont see why you'd have to do all the coils at once? In fact, I'm pretty sure you dont. The car would have no clue whether one or all were replaced...plus people recommend buying one new one then switching it around to find the bad one.

Aaaah. This brings me back to my original question. The car seems to idle and run just fine, no problems whatsoever. But the independent mechanic said the coils were bad. So I don't think I could benefit from the advice to switch it around to find the bad coil, as there will most likely be no change in the way the car is running. This is why I was wondering what kind of testing they do to determine that a coil is "bad." Is this just a ploy to make cash off of repairs that are not easily verifiable by the consumer? I believe he said that they were "arcing" and if not replace could cause further damage...

Any technical info would be appreciated on this subject.

TIA

You can test the voltage coming out of them with a multimeter.


I found details about this by using search and searching for "test coil"

http://forums.bimmerforums.com/forum/showthread.php?t=149324&highlight=test+coil

http://forums.bimmerforums.com/forum/showthread.php?t=51338&highlight=test+coil

Beeze> Thanks for the links, I will check them out.

I ended up calling nine-eleven enterprises in Dallas today to ask how they determined that the coils were bad. They said they removed them to do the compression test and it was at that time that they noticed evidence that they were "arcing" and leaving traces of overheating.

Since I have one brand new coil I decided to remove them today and visually inspect them myself and replace the one that looked to be in the worst condition. To my surprise, I could not empirically determine any differences b/t the new coil and the 6 that are on my car. I removed the sleeves and closely inspected all of the connections.

Since the car is running fine, I am not going to worrry about this problem unless further evidence of a problem in this area surfaces down the line.

The guy at nine-eleven did mention that there was the potential for a bad coil to damage the control unit, but this seems like a pretty unlikely occurance. I would think that there would be time to react to the bad coil before it could transfer excess current to the control unit.

Anyway, correct me if I am wrong on any of these accounts as I don't profess to be a mechanic....

You would know a bad coil if you had one. It would idle like crap and studder under acceleration. Since it doesn't, that pretty much means your coils are good. What they probly did, and since they said they did it, was just visually checked the coils, saw some carbon, and called em bad. You can measure a coil with an ohm meter too, there should be a spec in a book somewhere that tells what the resistance of the coils should be. If they are shorted it will be lower, if broken higher then what it says it should be. Real simple. Not much middle ground...its good or its bad. You do have to remove the coil to check the resistance btw, probly best to unhook the battery too.

~CHUBBIE~

Alright, I would give this a shot if you haven't already. My mechanic was going to charge me about $700 to replace the coils, but I decided to take a look at the problem myself. While changing the spark plugs I pulled out the coil packs and noticed that there was this greenish type goo coming out of the insulator boots on the bottom of the coil that touches the spark plugs. It may just be your "insulator boots" also known as spark plug connectors that have gone out. These run $7 a piece on Pelican Parts and should be easy to replace. You will need 6 of them so you are looking at about $42 plus shipping. Sure beats $700.

Alright, I would give this a shot if you haven't already. My mechanic was going to charge me about $700 to replace the coils, but I decided to take a look at the problem myself. While changing the spark plugs I pulled out the coil packs and noticed that there was this greenish type goo coming out of the insulator boots on the bottom of the coil that touches the spark plugs. It may just be your "insulator boots" also known as spark plug connectors that have gone out. These run $7 a piece on Pelican Parts and should be easy to replace. You will need 6 of them so you are looking at about $42 plus shipping. Sure beats $700.

Yo, thanks for the advice.

I have already removed all of the coils and insulator boots, no goo or any other signs of improper use found. They all looked like new and the connections were clean. I am beginning to think that the place suggesting that they needed replacement was just trying to generate some business. Honestly, the coils and boots looked perfect. The car runs smooth with no hesitation or misfiring.

This place also stated that the power steering rack leaks "badly", but I have driven back from Dallas to Detroit and the fluid level in the reservoir hasn't changed. So it can't be leaking that badly.

When I first spoke to the guy from nine-eleven about the PPI, he stated that some of the local dealerships won't use them for this service anymore because they were finding too many things wrong with the cars brought to them for inspection. Now I think I am beginning to see their point. But I am going to keep an eye on the PS fluid levels just to be safe.

I think I will forget about the coils and invest in a new set of tires. The Kumho Ecsta Supras are shot and the ride is noisy. Even though the tires have decent tread, they haven't worn very well at all, even cupped to a point in the rears. Crappy Kumhos, I won't ever waste my $$ on these. Time for some RE750's....

as far as determining the leaking ps fluid, just take a look with a good light source at the bottom of the car and see if there is oil buildup/dirt under there. If so then there must be a leak, leak does not really mean it will gush out, better safe than sorry.

And for the bad coil, no suggestions, I have thought I may need new coils at 155k but I cannot determine how to test these suckers and see whichi s bad and which is good. So until then I will be driving around with the coils I have.

good luck

Thanks, I'll check out the PS rack when I can find time to get it up on a hoist.

On the coils topic, as long as your car is running smoothly, I don't see any need to change them out...