[Rocklicker]

I hate to post new threads on what has to be a common topic but I haven't found much searching and I'm feeling some time pressure.

2008 328xi manual, at cold startup temperatures, particularily when ambient temp is low, it lugs badly for about 5 seconds on startup, then hunts for about 10-30 seconds, then runs like a top from there on out.

Used with 95k, brand new to me, no service history. I just got a Bentley but don't have a scantool yet. Of course it didn't start doing this until 2 weeks after I bought it. Is there a common culprit for this symptom? Is it a harbinger of a serious problem?

[Bluewater328iT]

Get a Carly and scan it to see what it might be, one like this:

https://www.amazon.com/Foseal-Scanne...=carly+for+bmw


Could be an MAF. Look at the symtoms for that in Bentley. I recall rough running is one of them.
You have to buy the app as well, and the pro version is more desirable. It is still reasonable price for both.

[Rocklicker]

Thank you for the response. I do plan on getting that setup and thank you for the link! I'll have a look in the Bentley but sometimes those troubleshooting matrix guides are too general. I'm guessing then that this is not a super common problem that everyone knows about except this noob?

[Bluewater328iT]

The codes are general just to identify what part of the engine is malfunctioning. Then you can look at Bentley for more clues as to what happens when those symptoms malfunction to identify what happened.

Bentley says a faulty MAF has these symptoms:

Difficult to restart when engine is hot

Engine starts then stalls

Engine starts and runs only with accelerator pedal depressed

Before replacing the MAF, you might consider cleaning the connections with electrical cleaner, very carefully masking the parts around it to avoid overspray. But if they car has 95K miles and still has the original MAF, that might be the issue. Codes would help confirm that area of trouble.

[STR8-6IX]

lots of people around your mileage on this forum complain of a rough idle upon cold starts. these people also follow the BMW oil change intervals which is terrible for your car. try changing your oil ASAP and see if that helps smooth out the idle. if its still dirty, keep changing it until clean. follow 5k mile intervals to ensure a healthy motor.

[Rocklicker]

That's a good point. I honestly laughed when I saw the 15,000 mile oil change interval. Modern synthetics in a non-turbo motor may last that long but no way in hell will an oil filter. The oil is going to get overly contaminated and then the contaminants may degrade the additives. Anyways, I checked the monitoring system and it said I had 9,000 miles left on the oil interval, which I assume means I have 6,000 miles on my current oil. For myself I feel okay pushing the interval out to 7,500 as long as it's full synth and a good filter on a non-turbo engine, so I figured I was okay for a while, but what you say brings up a good point about flushing. I think I may:
1. pull a little oil and send to Blackstone Labs for a UOA
2. Do a full oil change with the cheapest acceptable oil (has to have an LL-01 special BMW cert, IIRC), and dump in some seafoam.
3. Run like that for 500 miles,
4. Change oil again.
It's good to know my problem is common and there may be an easy fix. Electronic Dx tools are on their way though.

But also, last night I found my engine ground strap was broken. I'll try to post a picture because it's honestly funny in a tragic way. While my PPI seemed to show a clean enough car, this ride has clearly been "well seasoned" by Canadian winters. I've been spending the last week underneath remediating the brown, no I guess I need to address the blue!

[mweisdorfer]

Originally Posted by Rocklicker

That's a good point. I honestly laughed when I saw the 15,000 mile oil change interval. Modern synthetics in a non-turbo motor may last that long but no way in hell will an oil filter. The oil is going to get overly contaminated and then the contaminants may degrade the additives. Anyways, I checked the monitoring system and it said I had 9,000 miles left on the oil interval, which I assume means I have 6,000 miles on my current oil. For myself I feel okay pushing the interval out to 7,500 as long as it's full synth and a good filter on a non-turbo engine, so I figured I was okay for a while, but what you say brings up a good point about flushing. I think I may:
1. pull a little oil and send to Blackstone Labs for a UOA
2. Do a full oil change with the cheapest acceptable oil (has to have an LL-01 special BMW cert, IIRC), and dump in some seafoam.
3. Run like that for 500 miles,
4. Change oil again.
It's good to know my problem is common and there may be an easy fix. Electronic Dx tools are on their way though.

But also, last night I found my engine ground strap was broken. I'll try to post a picture because it's honestly funny in a tragic way. While my PPI seemed to show a clean enough car, this ride has clearly been "well seasoned" by Canadian winters. I've been spending the last week underneath remediating the brown, no I guess I need to address the blue!

You can run oil 15k in a 328. Why don't you just change the filter after 8k. ???

[Rocklicker]

Popped open the giant hole in the valve cover that passes as a fill port on these cars, clean as a whistle in there, no sludge buildup at all. Never owned a car where I can easily look at the cams and lifters before!

[Willsbma]

When she's all warmed up, pop her in first, accelerate to around 4K and then let her come back down near 1500 on her own. Then give the throttle the slightest pressure and see if she lugs/bounces.

[dmatre]

Originally Posted by 6IX-F10-N52

lots of people around your mileage on this forum complain of a rough idle upon cold starts. these people also follow the BMW oil change intervals which is terrible for your car. try changing your oil ASAP and see if that helps smooth out the idle. if its still dirty, keep changing it until clean. follow 5k mile intervals to ensure a healthy motor.

Please elaborate on how dirty oil (lubrication system) will affect run ability (fuel mixture and ignition).

These are two separate and unrelated items.

If you DO have oil leakage into the combustion chamber, clean oil burns no better than dirty oil.

[PhaseP]

But also, last night I found my engine ground strap was broken.

That is not the actual engine ground strap. It is only the ground strap for the ignition coils and plugs. BMW calls it "Interference-suppression band"
and is this part for your car:

http://www.realoem.com/bmw/enUS/show...diagId=12_1376

The real engine ground strap is much thicker and bolted on the driver side engine mount bracket and to the side of the chassis there.

If you have the top one broken like that, the big real ground strap is 99.99% broken also, being down below and subject to more moisture/salt and what not.

Ground strap is part #2 in the below link

http://www.realoem.com/bmw/enUS/show...diagId=12_1339

And some info on it at BMW's:

https://www.fcpeuro.com/blog/posts/b...ry-replacement

These maybe indeed your problem. I think, on XI at least, engine somehow finds a ground path through the drive train, since I had seen no ill effect with mine even though I had a broken engine main ground strap for a while. But even if so, that is not healthy. The current can ruin bearing eventually if flows through them.

[Rocklicker]

Originally Posted by Willsbma

When she's all warmed up, pop her in first, accelerate to around 4K and then let her come back down near 1500 on her own. Then give the throttle the slightest pressure and see if she lugs/bounces.

Oooh a mystery test! I'll do it and report back. In the meantime I got the Amazon OBDII WiFi dongle recommended here finally to check codes and.....its a dud

Originally Posted by PhaseP

Ground strap is part #2 in the below link

So over the last week I investigated this and found you were pretty much right, it too was very blue and starting to fray. Actually landed at the same FCpuero.com website too! Problem is this part is hard to get a hold of and is like $37 before shipping. The cable you show in the diagram is just that, a cable rather than a strap. Did they switch to a cable for later model years or is the diagram incorrect. There are very real reasons to go with a more-flexible cable.

So my fix was to get a $14 ACDelco braided lug-to-lug strap to replace it, and something similar for the P-side, both from Napa. I can supply parts numbers if anyone wants, it's a near-perfect fit. My only concern is that the ACDelco strap is a 4-gauge tinned steel, whereas the BMW one has no marking anywhere but "feels" like a 2 gauge and is obviously copper. Obviously new trumps slightly larger and corroded but maybe I should've put 2 of them on?

Immediate difference is that when it cold starts it doesn't lug as low in first 5 seconds, and the start itself has more urgency to it. But the idle still bounces quite a bit for a while.

Also I cleaned the MAF and the MAF electrical contact with appropriate chemicals (WD-40 and white gas )

[Rocklicker]

Borrowed a buddies reader, identical except apparently a different Chinese brand LOL. Anyways this one worked properly with OBDCar Doctor but wouldn't play nice with Carly Lite. Even though Carly has a lot of BMW specific stuff I'm blown away by the raw data OBD Car Doctor will give you.
Anyways, once I realized I forgot to plug in the MAF (I'm amazed it ran at all?!) the only code left was P1017, which is described elsewhere as "valvetronic eccentric shaft sensor".

The code did not immediately return upon restart, so I'm cautiously optimistic. Here is an info page:
http://www.justanswer.com/bmw/4hxxz-...ode-p1017.html

engine isn't perfectly smooth idle but pretty good and it now starts nice too. I need to wait for it to get cold again to see repeatability under true cold start. Would be great if it was just a case of bad electricity (have restored to various degrees a couple older vehicles I can attest to the systemic importance of unimpeded ground flow.)

I'll probably spring for the whole Carly setup but not until after the Holiday Hemorrhaging stops. For now though, any further insite on P1017 would be appreciated!