E46 320d won't go!

[russelgillwald]

Hi Guys,

A while back my 2003 E46 320d Auto stopped pulling, especially up hills. Up Kloof Nek in Cape Town it would sit at 20km/h at 1800 RPM and just stick there until it went over the top. Various mechanics said it was the turbo sensor, air flow meter, etc, but none of them seemed sure and wanted to start replacing parts until it came right, the parts being between R2500 and R5500 depending what they are.

Then I had a water leak, and found that the thermostat unit that sits between the radiator and the block had cracked, it was very visible, being right at the top of the motor. I bought a new one and replaced it, solved the water leak but then all of a sudden the car was pulling like a steam train, really going great. I had got used to keeping it floored just to keep going, now mostly I was using maybe 1/2 throttle max.

Sadly that only lasted about 4 days and now its worse than before. When I put in the new thermostat I noticed a bleeder on it and thought maybe there was an airlock. I've tried bleeding it, but that hasn't made any difference.

Any ideas? I really like this car and would like to get it sorted.

 

[moranor@axis]

rough im sure the diesel guys will pop by...

 

[L~C~G]

Have you checked all of the hoses in your engine bay?

I noticed some thin hoses on my car the other day that are very badly perished. and if I move them around a bit the performance of the car changes for a while.

You may have a leak in one of the hoses that controls the boost levels and by fiddling with the thermostat you could have moved one of the hoses enough to get it to seal up for a while and it might have blown through again.

Can you hear if the turbo is spooling up when you put your foot flat?

 

[Hellas]

Definitely a vacuum leak. If you disconnect the turbo vacuum hose, you can still drive, but without the turbo kicking in. But if you have a complete vacuum loss, you will only get to about 40km/h in second gear and that's it.

For a 2003 model, I can say that the vacuum hoses will definitely be perished.

 

[netercol]

sounds like no boost, if you have the diy skills, remove the engine covers and check all the vacuum lines , vacuum tank, and make sure the vacuum pump even delivers vacuum.
if this all operates correctly, it might be the actuator on the turbo, you could try exchanging it with the EGR actuator if it is suspect,
if this all seems fine, it might be the turbo itself, the VNT vanes of the turbo might be stuck/carboned up, this will require an specialist to clean and reassemble.
lastly it might be a boost leak in your boost pipes or intercooler..

 

[ruskus]

Have you checked all of the hoses in your engine bay?

I noticed some thin hoses on my car the other day that are very badly perished. and if I move them around a bit the performance of the car changes for a while.

You may have a leak in one of the hoses that controls the boost levels and by fiddling with the thermostat you could have moved one of the hoses enough to get it to seal up for a while and it might have blown through again.

Can you hear if the turbo is spooling up when you put your foot flat?

Thanks a bunch for your advice bud, I certainly will check all of the hoses for damage. I don't know what to listen for in determining if the turbo is spooling up, but when the car is running well there is the normal turbo lag and now it is as if that lag is permanent, i.e. the turbo isn't being activated.

---

Definitely a vacuum leak. If you disconnect the turbo vacuum hose, you can still drive, but without the turbo kicking in. But if you have a complete vacuum loss, you will only get to about 40km/h in second gear and that's it.

For a 2003 model, I can say that the vacuum hoses will definitely be perished.

Thanks Hellas, checking the hoses seems the best place to start, you're the second person to suggest that's the problem. I'm not even sure which hose is the turbo vacuum one, but I'm sure I'll figure it out! Many thanks!

---

sounds like no boost, if you have the diy skills, remove the engine covers and check all the vacuum lines , vacuum tank, and make sure the vacuum pump even delivers vacuum.
if this all operates correctly, it might be the actuator on the turbo, you could try exchanging it with the EGR actuator if it is suspect,
if this all seems fine, it might be the turbo itself, the VNT vanes of the turbo might be stuck/carboned up, this will require an specialist to clean and reassemble.
lastly it might be a boost leak in your boost pipes or intercooler..

Cheers Netercol, you certainly seem to know your stuff! I'll have to start by identifying the individual bits you mention and then move through your recommendations in sequence. Will keep you guys posted on developments, thank you all for your help.

 

[Hellas]

Have a look on realoem.com and get an idea of where all the vacuum hoses run. They are 4mm ID (about 8mm OD) rubber hoses. You will have to remove the intake manifold to get to all the hoses.

Although it is a wise idea to swop out all the hoses, maybe do a vacuum test first to pinpoint whether one of the actuators is not faulty.

I got my hoses (I used diesel tubing) from Rubber Mouldings & Products in Boompies street, Parow. Paid like R18 per meter compared to the R204 per meter that the dealership quote me. That's right, two hundred and four rand PER METER...

I bought 5m of the diesel hose and ended up using about half that.

 

[ruskus]

Have a look on realoem.com and get an idea of where all the vacuum hoses run. They are 4mm ID (about 8mm OD) rubber hoses. You will have to remove the intake manifold to get to all the hoses.

Although it is a wise idea to swop out all the hoses, maybe do a vacuum test first to pinpoint whether one of the actuators is not faulty.

I got my hoses (I used diesel tubing) from Rubber Mouldings & Products in Boompies street, Parow. Paid like R18 per meter compared to the R204 per meter that the dealership quote me. That's right, two hundred and four rand PER METER...

I bought 5m of the diesel hose and ended up using about half that.

Thanks guys -

Hellas, I went to Rubber Mouldings & Products (Now called Tygerberg Rubber) but the smallest hose they had was 5mm ID 11mm OD. No worries though, I found the right stuff at Cape Town Rubber in Paarden Eiland.

Those diagrams from RealOEM were really useful, thanks a bunch. I replaced the hoses from the pressure converter to the vacuum tank and the turbo, the one that runs from the vacuum tank across the front of the block to the pipe underneath the motor, I couldn't get to the pipe itself so I cut it near the connection and temporarily joined it with duct tape. The schweinehundefingerdinger (it tried to eat my finger) is in the way, so I'll sort it out tomorrow. The reason I concentrated on these particular hoses is that, as you all suggested, they were all pretty knackered.

I then took it for a burn, and WOW! Huge difference, turbo kicks in nicely, even the gear changes are smoother because I suspect the box isn't trying to hold it in gear for more vooma. I'll replace the rest of the hoses anyway as they're all really tired, but right now its going like a box of frogs.

Thanks guys, you are all officers and gentlemen and I am very grateful for your help. I've been unemployed for over a year and doing this myself has saved a whack.

raise:

 

[XMAX]

glad to see that youve found the solution to your problem.

 

[Coisman]

imp:
I remember my 2000 model 320d did the same, and it was indeed a small rubber hose that regulates the preasure to the turbo, or something like that... :thinking:

 

[ruskus]

glad to see that youve found the solution to your problem.


Hi guys, my power loss problem was back again after two days. I noticed that when the car was cold it ran better, but not perfect. I fiddled around with the vacuum hoses, cleaned the intake area at the boost pipe, inside where the EGR valve sits. No positive result, so I disconnected vacuum hoses one by one to see if any actuators were faulty, test driving inbetween.

When I disconnect the hose from the EGR actuator (called a pressure converter on the OEM site) to the EGR valve the car runs perfectly. What I need to know is can I leave it disconnected or is there a risk of something going wrong?

 

[Tjoppies]

thread revival, on the link, under which group would i find the vacuum hoses?

http://www.realoem.com/bmw/enUS/partgrp?id=AL72-EUR-01-2001-E46-BMW-320d