E36 328i - low idle and occasional stalling
Discussion
My E36 developed a rough idle which I finally got round to looking into last week. Replaced the spark plugs and the MAF which fixed some of the hesitation and the idle when warm - it pulls cleanly and has plenty of power. However, when starting from cold, it seems to still be rough and idling too low and feels like it's constantly on the verge of stalling. Up the revs by a few hundred (to around 750-850) and it's fine. When driving, if I pull to a stop and put the clutch in, the engine has stalled on a couple of occasions. Other times it's spot-on.
I'm wondering what else I can check? I'm hoping it's not coil packs as that's a few quid I don't want to spend! Is it possible error codes in the system could be causing issues since the MAF was replaced?
Here's where the car's idling at:
I'm wondering what else I can check? I'm hoping it's not coil packs as that's a few quid I don't want to spend! Is it possible error codes in the system could be causing issues since the MAF was replaced?
Here's where the car's idling at:
Mine sits about there with a slight murmur, I've replaced the crank and cam sensors as those were the error codes, crank sensor made the biggest difference. How long have you had the car? Mine broke down over time, so the drop in power was not that obvious until it got real bad.
Probably not the coil packs if it pulls ok, I tried that and it made no difference.
Hope this helps
Probably not the coil packs if it pulls ok, I tried that and it made no difference.
Hope this helps
I've just driven home (about 8 miles) and the car's idling perfectly. What is interesting is that when the revs fall away, there's a slight pause just above 1,000rpm where they plateau before falling to around 650rpm again. It didn't stall on the way home tonight although it thought about it...
http://youtu.be/XtAntqfm0xw
I think it's time to get my hands on a fault code reader and see what that reveals.
http://youtu.be/XtAntqfm0xw
I think it's time to get my hands on a fault code reader and see what that reveals.
A good idea is to get your codes read, then clear codes, go for a drive and check again but I suspect you may have worn vanos seals which might not show up on a scanner.
It is also cheap and easy to check your intake boots for splits as this is a common fault which can cause weird idling without always throwing a code.
It is also cheap and easy to check your intake boots for splits as this is a common fault which can cause weird idling without always throwing a code.
kev b said:
It is also cheap and easy to check your intake boots for splits as this is a common fault which can cause weird idling without always throwing a code.
Yes, I had this on my E46 - which was throwing the occasional fault code and occasionally stalling at junctions (and generally being unpredictable at low revs). Intake boot was fine with a visual inspection, but had a massive split on the underside - so big I could fit my hand through it.Easy and cheap to fit a replacement, and it's been fine ever since.
I had these exact symptoms on my E36 328i too.
Low and rough idle, stalling when coasting to a stop and it also cranked for longer than usual when starting before firing.
It was the cam position sensor. Replaced with genuine BMW part and the car had noticeably improved low-end and mid-range grunt afterwards so I think it may have been failing for quite some time.
I have the Peake code reader which did actually report it as being the cam position sensor. I never trust fault code diagnosis 100% so I did some searching and found other reports of a failed CPS causing these exact symptoms.
However, I understand genuine BMW is the way to go with these sensors - I've heard reports of people buying cheap clones off eBay to find they didn't work right out of the box!
Low and rough idle, stalling when coasting to a stop and it also cranked for longer than usual when starting before firing.
It was the cam position sensor. Replaced with genuine BMW part and the car had noticeably improved low-end and mid-range grunt afterwards so I think it may have been failing for quite some time.
I have the Peake code reader which did actually report it as being the cam position sensor. I never trust fault code diagnosis 100% so I did some searching and found other reports of a failed CPS causing these exact symptoms.
However, I understand genuine BMW is the way to go with these sensors - I've heard reports of people buying cheap clones off eBay to find they didn't work right out of the box!
Based on the picture you've posted (showing the engine up to temp), that idle is normal.
From cold at this time of the year, the idle will be @ 1000~1100rpm and then it will drop to @ 650rpm when the engine warms up.
In the summertime, from cold it will idle @ 750~900rpm and then drop to @650rpm when the engine warms up.
The pause you describe at @ 1000rpm is also quite normal.
The first thing I'd check out is the intake boot for any splits (they are renowned for splitting and causing intermittent idle problems due to the vacuum leak).
They're only @ £26 from BMW.
For cars without ASC+T: Intake boot Part No. 13541703588
For cars with ASC+T: Intake boot Part No. 13541740073
The camshaft position sensor could be at fault:
Pulse Generator (camshaft) Part no. 12141703221 BMW Price= @ £130.
(As others have said, the best bet is to buy the original BMW part and not a cheap copy - I've read too many stories of them not working correctly and being a waste of money!).
From cold at this time of the year, the idle will be @ 1000~1100rpm and then it will drop to @ 650rpm when the engine warms up.
In the summertime, from cold it will idle @ 750~900rpm and then drop to @650rpm when the engine warms up.
The pause you describe at @ 1000rpm is also quite normal.
The first thing I'd check out is the intake boot for any splits (they are renowned for splitting and causing intermittent idle problems due to the vacuum leak).
They're only @ £26 from BMW.
For cars without ASC+T: Intake boot Part No. 13541703588
For cars with ASC+T: Intake boot Part No. 13541740073
The camshaft position sensor could be at fault:
Pulse Generator (camshaft) Part no. 12141703221 BMW Price= @ £130.
(As others have said, the best bet is to buy the original BMW part and not a cheap copy - I've read too many stories of them not working correctly and being a waste of money!).
Funk said:
Thanks for the info; forgive me a dumb question but what is ASC+T? Active stability control?
Makes sense to continue with the cheapest fixes first...
ASC+T = Automatic Stability Control plus Traction (Traction control basically).Makes sense to continue with the cheapest fixes first...
It depends on the age of your car if you have it or not (it was introduced from mid '96 onwards).
If your car has it, you'll have an ASC+T button just in front of the gear stick.
The intake boot is easy to get off to inspect, and as I've previously posted, it does have a reputation for causing this issue. Be aware though that the split maybe quite hard to see, so you may need to look very closely at it (for the price, if your planning on keeping the car for a while, it might worth replacing it anyway just in case).
Hope you get it sorted!
(And if you do, please post up your solution as it's an issue many an E36 owner has encountered and does a search on!
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