Jump to content
Jushed

535d power loss after 3rpm

Recommended Posts

Also, I've taken off the manifold before I went for remap and cleaned out intake, maf sensor boost sensor charge pipes  replaced fuel filter put k and n filter and fresh Castrol. When I took off the manifold that converter there's looked all right and the hoses looked alright and that was about 2 months ago then I put everuthing back in

Share this post


Link to post
Share on other sites
14 minutes ago, Jushed said:

Not all the time but after clearing off the code and shutting down the engine and turning the ignition on and scan it and BOOM!  (like Russian hacker on youtube) the code is there. I spoke a bmw specialist who sorted me out in the past when other mechanics couldn't, I told him the symptoms and told him some figures  he's saying the turbo is over boosting, he said the guy that mapped it he put too much boost on the turbo as a result the sensor detects over boost and cuts down power and hence the fault is intermittent, I've told him after that, the actual boost pressure around 40hpa higher than the set point boost pressure then he said there you go the turbo is over boosting, that's why the oem sensor is detecting too much boost and throwing the code as intermittent, ill be taking it on dyno soon to see how much bhp I lost and how much bhp it goes down to especially the time when it's screaming up the rev with little boost. What he said does kind of make sense he said he'll talk one of his guy that does them things to adjust the boost and things but that means hell put down the overall bhp. When I speak my remapper he tells me change all the vac hoses and pressure converters, he saying the pressure converters or vac hose are bad that's why boost loss 

 

Perhaps the fault isn't deleted. If the engine was still running when you cleared the code perhaps it came back whilst the engine was running. We need to know if the code comes back if cleared without the engine running and comes back before it's started again. If so it cannot be the vacuum system it has to be electrical.

 

The too much boost point raised by your mechanic is valid to a point. If you put too much boost on the map then when you're hammering the car if the boost goes over something like 2 bar the MAP sensor picks this up, throws an overboost error and the car goes into limp mode. But you were fine for a while and the fault has appeared so it can't be the map - that hasn't changed.

 

The mapper guy has a point. If it was OK and now it's not it must be a fault with the car.

 

If the fault only comes on when the engine is running then my money is on a vacuum issue. A hand vacuum pump can be got for about £12 on ebay. You can check the whole system without removing the intake manifold. Although really the intake manifold needs to come off but that only takes 20 mins.

 

Use the vacuum pump to check each feed off the main vacuum pipe holds a vacuum:

 

EGR

Engine Mounts + exhaust flap (on the same feed often)

Swirl flaps (still needs to be plugged)

Wastegate

Compressor bypass

 

Then check when you connect to the splitter these holes aren't blocked by disconnecting two of them and checking you can't pull a vacuum on either of them with another disconnected.

 

image.png.7af975bf576ce888e7549e7f0fa9da2a.png

 

 

Share this post


Link to post
Share on other sites

Thank you so much for this detailed response, i have just ordered a vaccum pump test kit, once I get it ill strip everything down and check all the vacuum hoses make sure they all hold vacuum the thing I'm going to do is replace every vacuum hose and converters if it doesn't solve it ill give up lool and I do remember the code comming on with ignition without engine start but I'm trying to see if it comes again, I'm clearing the code with ignition on and turn it off then give it while then turn the ignition on and rescan it, I've tried it lately I'm not getting the code to come on instantly, sometimes it would take few minutes of driving the car for the code to come, but  it definitely comes back on when I clear the code with the engine on and then check again no code then turn the ignition off and then ignition on and the code is there. So just just confirm, I should check every pipe for holding vacuum right. 

Share this post


Link to post
Share on other sites

You can check the vacuum system without running the engine. Basically every part should hold a vacuum once you've evacuated any reservoirs or actuators on that part of the circuit.

 

Actuators should move and return when you release the vacuum.

Share this post


Link to post
Share on other sites

Hey guys, remember I was saying the car drives fine for the first 10 15 minutes then it loses about 70 or 80 bhp but I was worried it may have lost the overall bhp which was 347.7 bhp on dyno, so I thought it to dyno again, and switched off the engine cleared off the code and re scanned it to make sure it's not there and then after 20 minutes engine off and went for 2 runs, first run 344bhp second run 346 bhp so I'm happy I haven't lost any overall bhp from 347 but I know after 10 or 15 minutes of driving the car, it goes into slight limp mode and power goes back to about 270 stock bhp, meanwhile I have ordered 2 pressure converters and vacuum hoses to replace but if the vacuum leak was the cause, wouldn't I lose the overall bhp weather in the first 10 minutes or after the 10 minutes off driving. Vacuum leak should have resulted in overall power loss but I haven't lost any overall bhp, only after 10 or 15 minutes that's when I lose the extra bhp.

Share this post


Link to post
Share on other sites

The other day I was testing out each vacuum hoses and converters by taking them off and drove it to see what difference they would make, and when I completely disconnected and drove the car, the result of boost loss was instant, when I disconnected them hoses and drove, either I won't have any boost from small turbo, or no boost from the big turbo when I disconnected the other hoses, and when I put them back, it was all good, the point I'm trying to make is, if the vacuum leak was the culprit, the power loss would be instant, and I would have lost some of my total bhp. But the issue I have come to is after driving the car for about 10 minutes it drops the power back to pretty much stock level it becomes sluggish. 

Share this post


Link to post
Share on other sites

I had a similar issue to this last night with my car would not revpast 3k was showing error for maf borrowed one of friends car tried again and issue had gone and power seems back to normal now maybe worth a look on yours?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×