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Discussion Starter · #1 ·
Hi everyone, i've been digging around trying to solve this issue for a while, but can't pin-point anything specific. I've got an 03 325Ci, manual. 143k miles.

The problem is as follows;

I'll start the car, pull away fine. I come to a road exit for example, fully stop, now when I go to pull out of the corner the engine will stall, or I will have to apply a lot of throttle before bringing the clutch in to avoid a stall. This problem goes away when the engine is hot, and this stalling usually only happens once.

The car's recently had a full service, and the CCV is working fine, I also recently rebuilt the DISA. The car has no check engine light on.

I've narrowed it down to a list of what I think it could be;
  • Idle control valve
  • Intake ducting from MAF to Throttle body/ICV have a vacuum leak (I have some new ducting on the way)
  • MAF (unlikely?)
  • VANOS seals
  • Fuel pump (AFAIK it's still original to the car)
  • Intake cam position sensor
I did an interesting test the other day: started the car, sat there for around a minute. I think applied a tiny amount of throttle and the engine started hunting between 500 and 1000RPM, I thought this might be related, and to me, points to a vacuum leak.

Any thoughts would be great! If I find a fix, I'll keep everyone posted.
 

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I'd start by cleaning the ICV. Might as well replace the various rubber bellows in there. I'd also be ordering a fuel pump and filter. You can check the hose clamp on the pump -if crimped on, its original.
 

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Discussion Starter · #3 ·
I'd start by cleaning the ICV. Might as well replace the various rubber bellows in there. I'd also be ordering a fuel pump and filter. You can check the hose clamp on the pump -if crimped on, its original.
Grand. I'll get the ICV out an give that a clean, any recommendations on a cleaning fluid? I've got the two sections of intake piping on order, and I'll check the DISA valve sealing - maybe I messed that up during rebuild.

I'm looking at getting a VDO pump, the full unit. I'm pretty sure fuel filter is an item on a full service so I think that's all good!
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Anyway you can grab and report O2 sensor logs, as well as multiplicative/additive (long/short term) fuel numbers?
 

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You can clean the ICV with brake cleaner. The ICV wil rattle when it’s clean.

You need to check the engine computer (DME in BMWspeak) for codes. The Service Engine Soon light is on only when an emissions related code is present. You can log data as requested with the OBDFusion app. You’ll need a communications adapter that plugs into the obd2 port under the dash. iOS uses WiFi while android uses Bluetooth. VeePeek seems to work best.
 

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To be clear, I'm suggesting the pump more because of your mileage, not as a possible cure.
Since you didn't order the little elephant trunk that connects the ICV to the manifold ("grommet" on realoem drawing) make sure the iCV fits snuggly. It should rattle when you shake it in a circular fashion.
 

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Hi everyone, i've been digging around trying to solve this issue for a while, but can't pin-point anything specific. I've got an 03 325Ci, manual. 143k miles.

The problem is as follows;

I'll start the car, pull away fine. I come to a road exit for example, fully stop, now when I go to pull out of the corner the engine will stall, or I will have to apply a lot of throttle before bringing the clutch in to avoid a stall. This problem goes away when the engine is hot, and this stalling usually only happens once.

The car's recently had a full service, and the CCV is working fine, I also recently rebuilt the DISA. The car has no check engine light on.

I've narrowed it down to a list of what I think it could be;
  • Idle control valve
  • Intake ducting from MAF to Throttle body/ICV have a vacuum leak (I have some new ducting on the way)
  • MAF (unlikely?)
  • VANOS seals
  • Fuel pump (AFAIK it's still original to the car)
  • Intake cam position sensor
I did an interesting test the other day: started the car, sat there for around a minute. I think applied a tiny amount of throttle and the engine started hunting between 500 and 1000RPM, I thought this might be related, and to me, points to a vacuum leak.

Any thoughts would be great! If I find a fix, I'll keep everyone posted.
I don't want to scare you but this happened to me, turns out there were three loose headbolts. When warmed, the car would sometimes run fine. If you have a 3/8 E12 socket, open the valve cover and check that your bolts hold torque, hope its as simple as retorquing or you are looking at a gasket change and inserts. If you do put inserts do not torque to spec 55 NM is enough.
 

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Discussion Starter · #8 ·
To be clear, I'm suggesting the pump more because of your mileage, not as a possible cure.
Since you didn't order the little elephant trunk that connects the ICV to the manifold ("grommet" on realoem drawing) make sure the iCV fits snuggly. It should rattle when you shake it in a circular fashion.
Ahh ok, thanks. I will definitely be replacing it in the near future.
I believe the 'elephant trunk' is integrated as part of the bottom intake ducting - part number 13541435627
 

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Discussion Starter · #9 ·
You can clean the ICV with brake cleaner. The ICV wil rattle when it’s clean.

You need to check the engine computer (DME in BMWspeak) for codes. The Service Engine Soon light is on only when an emissions related code is present. You can log data as requested with the OBDFusion app. You’ll need a communications adapter that plugs into the obd2 port under the dash. iOS uses WiFi while android uses Bluetooth. VeePeek seems to work best.
Cheers. I'll get hold of a VeePeek. I was looking at getting one of the old-fashioned readers but will go for this, does it read fuel trims/live data?
 

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Discussion Starter · #10 ·
I don't want to scare you but this happened to me, turns out there were three loose headbolts. When warmed, the car would sometimes run fine. If you have a 3/8 E12 socket, open the valve cover and check that your bolts hold torque, hope its as simple as retorquing or you are looking at a gasket change and inserts. If you do put inserts do not torque to spec 55 NM is enough.
I really hope it's not this, but thank you for the heads up (excuse the pun...) - I will probably do everything else first, and then resort to trying this. Unfortunately I don't have that socket.
 

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l'm talking about
11611437453
Google that to see what it really looks like.
I'd want to do a bit more research before adjusting the head bolts.
 

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I really hope it's not this, but thank you for the heads up (excuse the pun...) - I will probably do everything else first, and then resort to trying this. Unfortunately I don't have that socket.
I’m hoping you don’t have to use the socket and it’s something else. Any regular 3/8 extension with a torx E12 can work to check the head bolts,if you don’t have a torque wrench try tighten them with a racket or T bar instead. Godspeed
 

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If I'm not mistaken, those are one time stretch bolts, and the torque procedure includes two 90 deg angle settings. With all respect, I would recommend a lot more research into whether you want to start down that road, including how that might be contributing to your problem.
 

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Discussion Starter · #14 ·
If I'm not mistaken, those are one time stretch bolts, and the torque procedure includes two 90 deg angle settings. With all respect, I would recommend a lot more research into whether you want to start down that road, including how that might be contributing to your problem.
Absolutely, I'm very aware of the specifics around this kind of work.
That being said, I think if I did have loose head bolts I would be seeing a lot more problems - loss of power, coolant leaks (depending on closed/open deck..) and all other manner of horrible things.
 

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Absolutely, I'm very aware of the specifics around this kind of work.
That being said, I think if I did have loose head bolts I would be seeing a lot more problems - loss of power, coolant leaks (depending on closed/open deck..) and all other manner of horrible things.
That's kinda what I was thinking.
 

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Absolutely, I'm very aware of the specifics around this kind of work.
That being said, I think if I did have loose head bolts I would be seeing a lot more problems - loss of power, coolant leaks (depending on closed/open deck..) and all other manner of horrible things.
Loose head bolts do not always show the standard symptoms. My issue was stalling and loss of power (intermittent) when cold, when warmed up it ran according to spec. You are right to do the little things first but if it doesn't pan out consider the head bolts. Have you overheated the engine at all?
 

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Discussion Starter · #17 ·
Loose head bolts do not always show the standard symptoms. My issue was stalling and loss of power (intermittent) when cold, when warmed up it ran according to spec. You are right to do the little things first but if it doesn't pan out consider the head bolts. Have you overheated the engine at all?
Not been overheated as far as I know, I've only had the car for about 5 months.
 

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2004 330Ci 115k miles
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Voltron263 said:
If you do put inserts do not torque to spec 55 NM is enough.
Voltron263 said:
if you don’t have a torque wrench try tighten them with a racket or T bar instead.
Let’s not be dispensing incorrect advise. Let the experienced members guide while you observe and learn.
 

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Discussion Starter · #19 ·
Anyway you can grab and report O2 sensor logs, as well as multiplicative/additive (long/short term) fuel numbers?
Did a quick read and my rough numbers were within +/- 5% for long/short term fuel numbers
 

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Discussion Starter · #20 ·
I'd start by cleaning the ICV. Might as well replace the various rubber bellows in there. I'd also be ordering a fuel pump and filter. You can check the hose clamp on the pump -if crimped on, its original.
I did some work on the car yesterday. I wasn't able to get as far as I wanted because I couldn't get the bottom intake rubber out - the jubilee clip was facing in a stupid direction, so I couldn't get anything on it, but the rubber looked fine. I think I'll need to take a few other things out to get to the bottom intake jubilee, just not sure what.

Nonetheless i took off the rubber which attached to the ICV and sprayed a tonne of cleaner in there, not sure if this would do anything but thought I might as well as I couldn't get it out.
 
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