|
|
|
11-08-2012, 05:07 AM | #1 |
Private First Class
23
Rep 111
Posts |
Car rough idle and stuttering - but only when cold
Hi everyone,
Recently my car has started to idle roughly and stutter for the first 1-5 minutes depending on how cold it is and how cold it is outside. Once it warms up, I can switch off the engine and turn it back on and it's smooth and there are absolutely no issues (at idle, driving or WOT). I have changed all spark plugs and coils several months ago as a preventative measure as I bought this car second-hand about 7K miles ago and had no idea how old these parts were. Any ideas on what this could be theoretically at least? Injectors and HPFP are a possibility, but why would everything work perfectly once warm? I do not experience any long cranks even when cold by the way. Carbon buildup is a possibility I would guess, but again it seems weird that the problem goes away once the car is warm. Codes-wise I get misfiring on cylinder 4 and 6 (and once I had 5), and I also get the misfire on multiple cylinders code. I took a look at my "new" plugs and they do very much look like this guys: http://www.e90post.com/forums/showthread.php?t=532330 Having said that, I took a look at the plug from cylinder 1 (which reports no problems) and it too is blackened. Does anyone have any other ideas or thoughts in general? |
11-08-2012, 05:13 AM | #2 |
European Editor
10523
Rep 22,992
Posts |
Injectors or HPFP ? Have you checked your VIN for any open recalls thru a dealer? IF that doesn't pan out... I would move those two injectors around and see IF the miss fire moves too.
__________________
|
Appreciate
0
|
11-08-2012, 05:26 AM | #3 |
Private First Class
23
Rep 111
Posts |
I'm not leaning towards the HPFP since I don't have long cranks or any problems once the car is warm. I've never seen someone with a failing HPFP report problems like that.
The injectors are my #1 suspect as I found that bulletin somewhere on the forums regarding which series number of injectors qualified for a recall and all 6 of mine qualify (if I was in the US) but unfortunately BMW doesn't do any recalls here. Of course from my understanding one would also have to barcode scan them against the database of suspected faulty batches which I can't do. However, the whole "everything working when warm" thing really throws me and I don't want to spend $700 on 6 new injectors until I am fairly certain they are the cause, so I started this thread to get as many options listed. Looking down the bore into which the injectors plug into, there is a lot of, I believe the technical term is "crap", and the injectors themselves are dirty. I'm not sure how to safely clean this bore, and I think it might be necessary before plugging in new injectors. The TIS manual says you can slide the old injector in and out to try and clean it but it's not working for me, it just always comes out dirty again (the injector). When looking down the bore, is the thing you see the same intake valve that can be accessed if taking off the intake manifold? |
Appreciate
0
|
11-08-2012, 07:25 AM | #5 |
Private First Class
23
Rep 111
Posts |
Nope, just the misfiring codes so far. I thought about the O2 sensors but I read somewhere that the car ignores their output when you start it and it's cold, which is the only point in time that I actually do have a problem. Do you think that makes sense as well and makes them an unlikely candidate?
I'm actually really curious if you, Dackelone or anyone else know if the thing you see when you look down the injector bore is the intake valve... Whatever that thing is, mine was really black and slimy. |
Appreciate
0
|
11-08-2012, 08:41 AM | #6 |
Enlisted Member
3
Rep 48
Posts |
It's more than likley leaking objectors , replace all of them and the spark plugs again they are probably getting fouled , when you replace them they need to be calibrated and saved to the DME
|
Appreciate
0
|
11-08-2012, 12:03 PM | #8 |
Private First Class
23
Rep 111
Posts |
Leaking injectors? First time I've heard of them being referred to as leaking, but that's interesting. It seems the consensus is that it's the injectors, which I'm inclined to believe. I've already even ordered an INPA cable from ebay and received it for the injector coding.
I'm still worried about putting the new clean injector down that dirty bore. So two questions remain: 1) How does one clean the bore? 2) Is that thing you can see down the bore the intake valve or what? As I said mine is seriously dirty and I'm worried about putting a new injector in there and messing it up. |
Appreciate
0
|
11-09-2012, 02:10 PM | #9 |
Second Lieutenant
15
Rep 232
Posts |
Yep leaking injectors. Just had ours replaced on the 335i - symptom was tied to cold days, cold engine. Once it warmed up all was good - for a while. After a month of putting up with it, we'd get CEL or limp mode. Eventually enough rich exhaust went downstream it clogged up one cat and that exploded down-stream trashing the exhaust with honeycomb material.
Only way to check the injectors, I believe, is to bench test them and new ones are not cheap. Good luck! |
Appreciate
0
|
11-09-2012, 02:24 PM | #10 |
Private First Class
23
Rep 111
Posts |
Thanks for the advice =)
I'm pretty set on changing the injectors but I still need to know how I can safely clean the bore and whether my heavy carbon build up that I'm seeing down the injector bore will mess up the new injectors (since the bore is dirty, and the new spark plugs are totally black, I'm guessing crap is being sprayed onto the injectors and upwards in general). |
Appreciate
0
|
11-10-2012, 08:38 PM | #13 |
Major
30
Rep 1,364
Posts |
|
Appreciate
0
|
11-11-2012, 02:33 AM | #14 |
Private First Class
23
Rep 111
Posts |
Getting rid of the carbon buildup is a good idea by itself, so I think I will have to do that. I don't want to shoot myself in the foot with this.
I'm more worried about cleaning the injector bore. I'm not sure if it's all metal, and I have a feeling it's not right around the level where the injector has the rubber ring, cause it sort of pops into place at that point. I'm concerned about which brushes etc I can use but since it doesn't look like anyone has had to do this, it looks like I'll just have to wing it! |
Appreciate
0
|
12-15-2012, 02:31 AM | #15 |
Captain
209
Rep 959
Posts |
Having the same issue, don't want to open a new thread. My car has 113,000 km on it (70k miles) and the past week the weather got colder and I'm starting to have some problems on cold starts.
I'm thinking of replacing all 6 Injector/Coils/Spark plugs. is that a good idea? or is it better to let the dealer check which ones are faulty? the car doesn't show any lights/faults, so not sure if they will find anything. Also I've asked the dealer about intake valve cleaning and they said it is a big job they to remove the head or something, so that's going to cost alot. is it OK to do the replacements, without doing the cleaning?
__________________
|
Appreciate
0
|
12-15-2012, 10:14 PM | #16 | |
New Member
0
Rep 9
Posts |
Quote:
Also, I wouldn't shotgun all new coils, plugs and injectors. That's way to costly for something that isn't that hard to diagnose. Usually coils and plugs tend to misfire when hot. Most likely you have carbon buildup or injector issues (or both). Check the part #'s on your injectors. If the last 3 digits of the part # are 138 then there is a good chance they're failed. The last 3 digits of the current injector part #'s are 261, and while those still fail on occasion, it is far less common. Last edited by threewirefire; 12-15-2012 at 10:19 PM.. Reason: additional info |
|
Appreciate
0
|
12-15-2012, 10:17 PM | #17 | |
Captain
209
Rep 959
Posts |
Quote:
Do you recomend I change everything, coils plugs anf injectors? Or just replace the defective ones?
__________________
|
|
Appreciate
0
|
12-15-2012, 11:06 PM | #18 |
New Member
0
Rep 9
Posts |
If you have 138 injectors, I would replace them all. I wouldn't worry about the coils. If one coil does turn out to be defective at some point in the future it's fine to replace just the defective coil. The plugs are relatively inexpensive-if you want to throw another set of plugs in after replacing the injectors, go for it. Do bear in mind that there are calibration #'s on each injector that need to be changed in the dme when an injector is replaced. Your car absolutely will not run properly if you just slap a set of injectors in it with performing the calibration procedure.
|
Appreciate
0
|
12-16-2012, 12:35 AM | #19 | |
European Editor
10523
Rep 22,992
Posts |
Quote:
Most people are changing the coils at ~80K miles. With high miles it is not a bad idea either. I would only change them once they start to cause an issue though. Cobb and Bav Auto sell red HP coil packs. I don't know IF they are any better them OE ones though. I really think this cold start issue is spark plugs. OP - when you change your plugs - did you use BMW bought plugs? Sometimes the OEM (aftermarket) plugs cause issues like this. Just look at my "changing spark plug DIY" to see why.
__________________
|
|
Appreciate
0
|
12-16-2012, 12:40 AM | #20 | |
Captain
209
Rep 959
Posts |
Quote:
__________________
|
|
Appreciate
0
|
12-16-2012, 12:47 AM | #21 | |
Captain
209
Rep 959
Posts |
Quote:
From what I read online most people say that cold start issues are leaky injectors because the car sits overnight and injectors leak. This issue only happens when the car has been parked for a long time, when car is parked for 2-4 hours no issues in starting.
__________________
|
|
Appreciate
0
|
12-16-2012, 12:51 AM | #22 | |
European Editor
10523
Rep 22,992
Posts |
Quote:
I think first step in fixing a car is to check for any fault codes. Could also be a bad HPFP too I guess. As for reading your injectors... I think you have to pull the plastic cover over the valve cover and physically read the bar codes on EACH injector. I don't know if you can read the injector serial number via BMW's code reader. ?
__________________
|
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|