coil packs cheap or spensive, new or old?

[RichP]

My misfire is getting worse!

On the way home from work, once it got fully warmed up, it was consistently rough as toast, and sounded like a harley. It started under acceleration just at 1600-1900 revs, then crept in at other rev ranges, now its everywhere.

Cant find any intake leaks.
Plugs replaced.
removing leads individually makes no effect on idle, as if its misfiring on all cylinders?! but its not stalling, it runs regular but crappy.

Taking it for diagnosis on monday, but i wanted to ask in advance - if it is a coil pack is it worth getting a second hand one? or getting a cheapo ebay one? I really don't have the funds to throw at it following a heavy mot list last month. Same question if its MAF sensor, pointless buying used? pointeless buying cheap?

thanks in advance!

[Robert T]

You need to get the codes read. Sounds like it could be a camshaft sensor.

Cheers R.

Sent from my Galaxy SII using Tapatalk 2

[RichP]

You need to get the codes read. Sounds like it could be a camshaft sensor.

if so, do i get a cheapy cheapy http://www.ebay.co.uk/itm/BMW-Camshaft- ... 5648def28b, or a decent one for £60+?

will the diagnostic (by an auto electric specialist) provide a fairly definitive answer? or just narrow the range of possibilities? tis costing £50 for the diagnosis (including fault reader, test drive, inspection etc)

http://www.advancedautoelectrics.co.uk/ ... trics.html its fairly local to me.

Thanks for the reply.

Rich..

[siwilson]

If there is a misfire then the diags will tell you which cylinder. You can then move the coil packs around to see if the fault moves before spending on parts. A new coil pack is only around £30 from ECP so it's not worth skimping.

I had a dead coil pack on the way to Gaydon a. Couple of years back. My Peake read the codes, a new coil pack was purchased from ECP and life was good again.

[Del]

A professional using diagnostic gear should be able to pinpoint an electrical problem with a sensor or a coil. It isn’t rocket science on the M44 engine.

Purely as a forum guess, based on the fact that your fault is cutting in and out at a specific rev range, I would guess that it might be the camshaft position sensor (cps) – many members with M44 engines that are now 13+ years old have replaced this sensor, as I have myself. However, I would recommend getting the diagnostics done first.

The “textbook” symptom for vacuum pipe leaks is a poor start from cold and poor idle – you wouldn’t normally expect a specific rev range issue around 1500-2000 rpm. If anything, a weak mixture, caused by a vacuum leak, would be more in evidence at full throttle.

The M44 has an integrated 600m cable between the sensor and ECU socket and so it’s a little more expensive. Most owners opt for the high quality BMW sensors (approx. £95). Companies like GSF & Eurocarparts sell aftermarket M44 cps made by companies like QH and Febi Bilstein (£40 -£60) and I believe the quality of these items is OK. The ones to avoid are the cheap, unbranded ebay ones – likely to be troublesome and possibly faulty from new.

The coil on the M44/M43 is an integrated coil pack unit attached to the RHD suspension strut area. As they are away from engine heat and vibration they tend to be fairly bullet proof. As an integrated (Bosch) pack they are quite expensive to buy new. You can test both this and the HT leads with a simple multi-meter – I won’t go into detail on this post – let me know and I can give you the acceptable readings as I have tested several old and new units.

If I lived in your neck of the woods I would nip round and help you sort it today - but I'm based in Somerset.

[RichP]

If I lived in your neck of the woods I would nip round and help you sort it today - but I'm based in Somerset.

Set off now, you'll be here by 6!

As has been said before get it diagnosed first, if it does come out as the cam sensor buy it from a dealer, and on your model, which is face lift I believe it is easier to fit than the pre face lift as it should be a single bolt and plug and play

Not facelift I'm afraid. 1999. So I get the difficult one

Thanks for the replies.

He squeezed me in for a quick diag this morning. Misfire cylinder 4. And all kinds of sensor issues I'm hoping are related to the misfire. Smoke test on vacuums, they are all fine. Taking it back on Monday and he's going to do a compression test, but that seems unlikely to be the problem. After that its swapping the leads to see if it moves (I don't have a fault reader so he can do that), failing that ill test coil pack. If that's ok ill suggest the cam sensor. He reckons he can get genuine parts pretty cheap, so ill see how much he finds them for and have a hunt for the best price. As the coil is away from the engine this makes no sense with the misfire only occurring when warm?

In good news he was surprised when I said it was 99, he thought it was newer, so I must be doing something right

Cheers!

[RichP]

Reading this back, would it be better if I got a new camshaft sensor rather than spend money testing electrics?

[Del]

MAF approximate test without diagnostics – unplug the MAF – start engine - the engine with then revert to default mode and the ECU with effectively approximate a factory MAF reading If the engine runs much better in this mode than the MAF is likely to be faulty.

Coil test see attached – the text says to expect readings between 0.4 – 0.8 ohms. On my cheap little multi-meter I got readings of 1.2 - 1.4 ohms on both by two used units and a brand new one.

http://bmwrepairhelp.blogspot.co.uk/201 ... coils.html

For original BMW Bremi M44 HT leads the resistance should be in the range 4500 – 5500 ohms – it varies with the length of the lead – I obtained readings:-

1 – 4.9 kohms
2 – 4.98 kohms
3 – 4.95 kohms
4 – 5.49 kohms

I have purchased spare (used) Bosch MAF and coil pack online for between £15 – £20 and both work fine.

Once you get it all running smoothly, sweetly and as new – it’s all worthwhile when the sun comes out and the hood goes down.

[Del]

Problem on hot running engine only, could be MAF or coil - the latter will tend to misfire when under hard acceleration. All guesswork on a forum I'm afraid.

[RichP]

Just been out with maf disconnected. Perhaps marginally better. Seems less predictable, but definitely still present. In 4th at 30mph under heavy acceleration (that would usually be a bit laboured at low revs) it misses over a 1k ish range. Then ok. Happened sporadically in all gears.

The improvement may have been imagination, so no major breakthrough. Don't have time to test the coils today ill try tomorrow.

[Robert T]

No, don't replace random components based on people guessing at the problem on a forum. Yes, there are a number of common components that it could be, but as the symptoms can be quite similar, guessing doesn't really help. The best way is to ask the ECU what it thinks is wrong - if it gives a definitive fault code, then you are sorted - if it doesn't then we can make better guesses based upon what it does tell us.

Whereabouts in the country are you? Your profile says Merseyside, so you may be near to me in Altrincham, if you want to bring the car to me. I have a diagnostic lead and laptop with BMW software.

Cheers R.

[RichP]

thanks zedonist, that could come in very handy when diagnosing.

Robert, thanks for the offer! I'm in Wirral, so not too far, about 40mi according to google maps .

unfortunately i work evenings and weekends, and most people work the opposite when would you have time spare?

does the BMW software give more info than the OBDII?

not sure if i should just offload it at the auto electrics specialist and let him work it out.

Cheers.

[Robert T]

Entirely up to you whether you want me to take a look at it. You're in luck though, as I'm working from home next week, so you can pop it over any time you like during the day. I think the INPA software is a bit more accurate than generic ODBII codes - certainly told us quite a lot on the zeds I've tried it on. I know I can access all the modules on my 01/99 1.9 using the round socket under the bonnet, and yours looks to be the same, so it should be able to read all the codes.

Cheers R.

[RichP]

Looks like i'll have to take you up on that! thanks very much!

i'll pm you about the details.

Mine also has the round socket next to the top of the suspension.

[RichP]

SOooo...

Many many thanks to Robert for helping me for a few hours today!

The codes we read didn't bring up camshaft sensor.

Had misfire cyl 4, and a code about the "final stage intake manifold" however we ruled this out of the misfire diagnosis as it was at the wrong rev range.

tried moving the ht to a different cylinder but it didn't throw up any misfire codes at all, even though it did misfire

Finally, we tried Roberts coil pack in mine, and no misfires on the test drive! So this + it only happens when warm + it happens at specific revs + it happens under specific acceleration load looks like the issue.

I just checked it with my little multimeter according to Del's link:

1: 1.4ohm
2: 1.4ohm
3: 1.6ohm
4: 1.5ohm

when i touch probes directly together i get 0.9ohm, so by my logic the resistance is 0.5-0.7ohms. which is within range.

Is this a definitive test?

i dont want to buy a new pack (£182 at BMW) if our test drive was good (or bad?) luck.

Next step i think i'll get a second hand pack, as i can't be paying £182 for one right now, and see if it works and lasts until a few more paychecks come in!

[Del]

The coil pack test outlined in the attached is not totally conclusive – see note 3 – the secondary resistance cannot be tested with a multi-meter. These Bosch (used) coil packs can be picked up quite cheaply as they were not Z3 specific. The contemporary E36 4 cylinder saloons also had them.

http://bmwrepairhelp.blogspot.co.uk/201 ... coils.html

I have been told (BMW technician) that the diagnostic system is not that sophisticated on the M44 engine and so I guess a coil issue must just show as a general cylinder “misfire”.

I have not encountered the “final stage intake manifold” fault code you mention. The only item in the inlet system I can think of that is wired to the ECU is the DISA valve.

As you swopped coils and the problem went – it looks a good bet that your coil is faulty.

[Del]

Here’s a few on ebay

http://www.ebay.co.uk/itm/BMW-E46-3-Ser ... 4340.l3484

http://www.ebay.co.uk/itm/BMW-E46-IGNIT ... 3a7ed80882

http://www.ebay.co.uk/itm/Bmw-Coil-pack ... 257ba77511

http://www.ebay.co.uk/itm/BMW-318-TI-CO ... 4171396bdd

http://www.ebay.co.uk/itm/BMW-E36-COMPA ... 5d3b9e6306

http://www.ebay.co.uk/itm/Bmw-E46-318i- ... 41672676ee

[RichP]

thanks. good to know what engines i can get parts from.

i'll try my local scrappy tomorrow, failing that i'll pick the best of the above! £21 inc postage seems to be the going rate.

I'll let you now how i get on!

[RichP]

Picked up a pack off a 318 for £20 this morning.

Fitted. fixed. for now at least

Seems so simple/obvious now, but im glad i didnt just start replacing stuff and did my homework first.

now if only i didn't have loads of work to do and i could

Thanks all! esp robert.

[Robert T]

You're very welcome, Rich. Nice to meet a fellow zedder and glad that I managed to be of some assistance.

I promised to post some of the screenshots that I took up, so here they are:

Before clearing the error codes:


After first run (baseline):


After second and third runs (2nd with ignition leads swapped - and 3rd with my coil pack fitted):


And here are the translations:

Code: Select all

175  Endstufe Saugrohr-Umschaltung
     Suction tube amp switching
     final stage intake manifold

62  Aussetzererkennung Summenfehler
    Misfire detection summation error

53  Aussetzererkennung Zylinder 4
    Cylinder 4 misfire detection

75  Aussetzererkennung KAT - schaedigend Summenfehler
    Misfire detection KAT - damaging sum error

66  Aussetzererkennung KAT - schaedigend Zylinder 4
    Misfire detection KAT - damaging cylinder 4

111 Heissfilmluftmassenmesser
    hot-film air mass meter

The ones we made sense of are: Codes 53 and 62 which relate to the misfire. Codes 66 and 75 seem to imply that the misfire is letting unburnt fuel through which will damage the catalytic converter. Code 111 is a fault with the MAF, detected when Rich unplugged it.

Code 175 gets a different translation depending upon whether you include the hyphen, but neither is clear what it means - any input on this one would be useful, as the code is still present after both run 2 (which misfired, but not quite as badly and didn't log any misfire codes) and run 3 (which did not misfire). I have only included one screenshot here, as both logged runs logged the same error, but at slightly different RPM. I cleared the codes in between.

We also managed to have a little play with the service light reset function, as Rich had recently done an oil service himself and had not been able to reset the SI lights. It was rather gratifying to press a key on the keyboard and see the lights on the dash change from an amber and a red to five greens.

Do let us know how the replacement coil pack pans out, Rich. You should be able to tell for sure after a few longer runs.

Cheers R.

[Del]

Robert – thanks for posting up - as I’m a bit of an M44 anorak – very interesting.

The attached site seems to give a practical translation of the codes and under the M44 ECU module type states that error 175 is: - “DISA Control Circuit Electrical”.

http://realitypod.com/2012/06/bmw-compl ... -and-more/

For Rich’s benefit I have put a picture up – this unit changes the intake manifold passageway (longer to shorter) at around 4000? rpm to optimise torque & BHP across the rev range. There is an electrical plug at the bottom facing the engine. At the top there is a valve (set inside the manifold) that presumably rotates under the control of the ECU.

Code 175 suggests a fault. Whether this is connected to the faulty coil I do not know – I have not seen this fault mentioned before.

[RichP]

Interesting.

I've not noticed a lack of power or any effects, but the problem may have existed since i bought the car.

i found this http://www.318ti.org/forum/showthread.php?t=27985
and this http://www.bimmerforums.co.uk/forum/f74 ... ve-t19322/
and this http://www.justanswer.com/car/2jty2-dis ... -318i.html

This suggests i may have a disconnected wire (i'll check that tomorrow) or a failure of that system.

How does making the intake route longer at low revs give more torque?

what effects would we expect from this system not operating? low performance below 4k revs? - its noticeably faster beyond 4k revs, but i assume that is just due to the distribution of power across the range.

Thanks for the pic, that will help tomorrows playing around, sorry, i mean serious manly work

[Robert T]

Thanks for that, Del. I knew I'd seen that page before, but I didn't have time to dig it out on the day and finished up grappling with Google translate and my very poor grasp of German. We were puzzling over what could be measured electronically on the intake manifold, so the control circuitry for the DISA valve would make sense.

Rich, the M44 is known for needing to be revved to get the best out of it. It doesn't really start to pull well until it gets to 3500-4000 RPM. The sixes are a lot lazier and pull from much lower revs. I've not driven a 1.9 8-valve to compare, but I don't believe it is anywhere near as free revving. The M44 is also known for being slightly "agricultural" to quote my BMW mechanic!

Cheers R.

[BladeRunner919]

I'm sure my INPA displays errors in English, rather than German.

[Brian H]

I'm sure my INPA displays errors in English, rather than German.

I had to request a software patch which then allowed my INPA to display in English, I emailed the seller and he sent it FOC.

[BladeRunner919]

I've installed it on two PCs and I remember the second one coming up in German. I copied the dll files from the English installation over to the other one and it switched to English.

[clissold89]

I've had similar problems, loss of power not all the time but at random points in rev range normally just over 2k revs. Running awful. Diagnostics said it had misfire on 3 and 4 and lamda sensor before cat wasn't working. Changed coil pack, and plugs, sounded the same but cured 1 misfire according to diagnostics but dont think it made any difference.
Had injectors tested, compression test and head gasket test, all fine. So took the plunge and went to BMW who couldn't diagnose the problem with their software. Said outside temp sensor could be to blame as it was reading -43 degrees but changed that and did nothing. They also said to change the lamda sensor last as it probably will be something else causing that to be off, so... Took it to another indy and he said the only fault on the car was the lamda sensor, so had that changed and since changing that its been ok, still a little rough at idle but to be expected with that engine. Drives fine though.
Would be intersting to see what fixed yours

[RichP]

luckily the second hand coil pack has fixed the misfire problem for me. for now at least.

i got a few codes (as robert describes above), most of which were a caused by the misfire or by my attempts to diagnose it.

havent got to the bottom of the inlet manifold error code, but it doesn't seem to be presenting any problems, so its pretty low on my to do list.