335i Loss of Power - No Codes

[Cliver]

Hi all. My first post as long time "lurker" on this forum.
I would appreciate any suggestions:

I have a 2008 335i N54 with 83000 km. I live on the East Rand.
The car has suddenly lost about 30% power. I have the icarsoft i910 scanner/code reader and there are no fault codes. I took the car to a official BMW garage and they also say no errors could be detected (they basically suggest to carry on driving until something "really breaks" that is detectable).

I can best describe the performance is as if it feels like I am driving a perfectly functional normally aspirated 2 litre average car. It idles perfectly smooth, accelerates perfectly smooth. Just very little power. It feels as if the turbos are hardly working. It is as though some sensor somewhere has developed a problem which makes the ECU think all is perfectly normal and the turbos are giving enough boost. But they are clearly not.

I do have the GIAC stage 1 software installed (for several years)which allows me to select between "stock" and slightly higher "pump gas" programs. Whereas before the loss of power, there was about a 100nm and 60hp difference between the two programs, now I cannot feel any difference in power when switching between the two.

Any ideas would be appreciated. Or any suggestion of someone I could take it to on the East Rand.

 

[corp]

I had lost a similar about of power with no codes. Couple places didn’t spot the issue but at the end of the day, I had small leak on the boost pipe seal and the intercooler had a crack. Once that was fixed the car was fine again.


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[akash]

You may have a boost or vacuum leak, without anymore data its going to be hard to diagnose.

Have you ever changed your vacuum lines?

 

[sash]

I do have the GIAC stage 1 software installed (for several years)which allows me to select between "stock" and slightly higher "pump gas" programs. Whereas before the loss of power, there was about a 100nm and 60hp difference between the two programs, now I cannot feel any difference in power when switching between the two.

My feeling is that if the above is a plug and play unit it may not be functioning as it should. In other words, you have gone back to stock.

 

[Cliver]

I had lost a similar about of power with no codes. Couple places didn’t spot the issue but at the end of the day, I had small leak on the boost pipe seal and the intercooler had a crack. Once that was fixed the car was fine again.


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I don't have much DIY capabilities (changing the ignition coils which all started breaking through is about my limit!). Is the place who eventually sorted it out by any chance in my area (East Rand)?

---

You may have a boost or vacuum leak, without anymore data its going to be hard to diagnose.

Have you ever changed your vacuum lines?

No, I have not. BMW claim to have "checked" for bad/perished connections, but I have my doubts. The icarsoft gadget I have is capable of monitoring quite a few parameters while driving (all via OBD port). Is there any thing specific I can monitor which may indicate the problem?

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I do have the GIAC stage 1 software installed (for several years)which allows me to select between "stock" and slightly higher "pump gas" programs. Whereas before the loss of power, there was about a 100nm and 60hp difference between the two programs, now I cannot feel any difference in power when switching between the two.

My feeling is that if the above is a plug and play unit it may not be functioning as it should. In other words, you have gone back to stock.

The power now is quite a bit less than stock. e.g. if I drive quite hard through the gears, my 0-100 time is in the region of 8/9 seconds...

 

[akash]

Hard to say. Wish you had a JB4, you could have provided a log.

Monitor your boost level in 4th gear to 6500rpm and see the boost reading across the rpm if you can.

if your car has the stock vucuum lines its hard to pick up a crack because the silicone line has a weaver over it, so an underlying crack is very hard to spot.

Do you get any support from your software provider?

 

[maleven-GP]

Had similar issue.. turned out it was some boost pipes..
Paolo @Supertek sorted me out, he's based in Germiston..

 

[LOW BOOST]

Had the exact same issue a few years back..
It turned out to be a tear in my boost pipe on the clamp of the intercooler.
Maybe jack the car up and try to physically check for any leaks on your boost pipes.

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[bimmer330]

Boostleak!!!!!!!!!
Da Boost Shes Leaking!!!!

 

[corp]

Tune Tech sorted out my intercooler. The dealer’s independent guy who works on his BMWs found the boost pipe leak.


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[Cliver]

Thanks for all the responses.
I guess now it is a case of "find da leak"!!!

 

[corp]

By the majority of replies, definitely start at the boost pipe and work from there.


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[corp]

Have you found anything to be the issue?


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[Cliver]

Have you found anything to be the issue?


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I am taking it in to a guy I know who runs a Bosch dealership this week. I will post here if they find something.

 

[corp]

I hope it is something minor.


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[Cliver]

So a week has passed and I still have no solution. The Bosch workshop claim they searched meticulously for a boost leak but could not find any issues. They ran the car on a dyno and only get maximum of 80kW and 210Nm at wheels? They say there is absolutely no boost. They think the GIAC software is masking some fault codes and suggest that I ask BMW to reload stock software back into the car and they are sure it will start to give fault codes. The problem for me is that GIAC do not appear to exist anymore in RSA, so I have no means of reloading the software (R6k down the drain).
I did a test with my icarsoft code reader and monitored the Intake Manifold Pressure as reported on the OBD. Before the throttle valve it varies from about 0-50kpa (0.5bar) when I drive. After the throttle valve it stays at a pretty much constant value of 1.8bar (26psi) even at idle. In my understanding this would mean there is serious boost. But there is obviously none. So this implies a faulty intake manifold pressure sensor. However Bosch say that there might be some other issue in the engine which causes it to report a false pressure value so as to not damage the engine. I do not have enough knowledge to agree/disagree.

 

[SubLoaded]

80kw :skit:

 

[Jeremy.d]

So a week has passed and I still have no solution. The Bosch workshop claim they searched meticulously for a boost leak but could not find any issues. They ran the car on a dyno and only get maximum of 80kW and 210Nm at wheels? They say there is absolutely no boost. They think the GIAC software is masking some fault codes and suggest that I ask BMW to reload stock software back into the car and they are sure it will start to give fault codes. The problem for me is that GIAC do not appear to exist anymore in RSA, so I have no means of reloading the software (R6k down the drain).
I did a test with my icarsoft code reader and monitored the Intake Manifold Pressure as reported on the OBD. Before the throttle valve it varies from about 0-50kpa (0.5bar) when I drive. After the throttle valve it stays at a pretty much constant value of 1.8bar (26psi) even at idle. In my understanding this would mean there is serious boost. But there is obviously none. So this implies a faulty intake manifold pressure sensor. However Bosch say that there might be some other issue in the engine which causes it to report a false pressure value so as to not damage the engine. I do not have enough knowledge to agree/disagree.

Wanna race? I'm feeling confident.:cartel:

 

[akash]

So a week has passed and I still have no solution. The Bosch workshop claim they searched meticulously for a boost leak but could not find any issues. They ran the car on a dyno and only get maximum of 80kW and 210Nm at wheels? They say there is absolutely no boost. They think the GIAC software is masking some fault codes and suggest that I ask BMW to reload stock software back into the car and they are sure it will start to give fault codes. The problem for me is that GIAC do not appear to exist anymore in RSA, so I have no means of reloading the software (R6k down the drain).
I did a test with my icarsoft code reader and monitored the Intake Manifold Pressure as reported on the OBD. Before the throttle valve it varies from about 0-50kpa (0.5bar) when I drive. After the throttle valve it stays at a pretty much constant value of 1.8bar (26psi) even at idle. In my understanding this would mean there is serious boost. But there is obviously none. So this implies a faulty intake manifold pressure sensor. However Bosch say that there might be some other issue in the engine which causes it to report a false pressure value so as to not damage the engine. I do not have enough knowledge to agree/disagree.

I would firstly try to perhaps load an MHD flash since you no longer have your stock file available and considering that a hardware issue cannot be found.

 

[RDD666GP]

Take it to 357 on Rivonia. Sanjay will sort your problem out. Great workmanship from those guys :thumbs: