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Diagnosing irradical power delivery
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03-28-2016, 08:33 AM | #1 |
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Diagnosing irradical power delivery
Hi guys i need a bit advice here.
I have been hunting a strange problem with my 2009/10 LCI. If I floor it ten times out ot those ten times 1 or 2 times it pushes me to the seat so that I feel the inflatable bags in the seat. ![]() So other 8 times it like meh... It pulls but not that well I do not feel that crazy torque. I have read all the posts about red hose and vacuum lines. So I began hunting the problem. Installed INPA read the codes and glow plug and relay was changed no codes now. Intake was cleaned and EGR no CBU all in good shape. Silicone applied on swirl flaps to be certain that they are tight. Looked all the vac lines through and my turbo actuator rod operates fine. It lets go after 20-30 sec with pfft sound after shutting the engine off. While I had my intake off i saw that my PRESSURE CONVERTER 11 74 7 796 634 was covered in oil from the stupid swirl flaps oil leakage. Can that make it fail? I have the new designed PRESSURE CONVERTERS for turbos with the cap at the bottom. So what would you do next? Change all converters?S pend 200£ and maybe end with the same problem again? |
03-28-2016, 08:57 AM | #2 |
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pressure converters do seem to go bad. Not sure if that is your problem, but might be worth looking into.
I sometimes notice similar issues that you are experiencing. I have a 2011 335d stage 2 with all deletes, 47k miles and carbon cleaned out by me...so I know it was actually done. New pressure converters, new vacuum lines, upgraded forge red boost hose. Every once in a while I get lack luster power from the skinny pedal. Other times...holy hell!!!! Has anyone ever looked into the LP to HP turbo O-rings??? I have oil/dust all over both ends of that pipe. Plus, how can we test that the (divergent) valve in the compressor side of the turbos is working? I wonder sometimes if this valve sticks, or gets lazy and could contribute to low boost conditions? |
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03-29-2016, 09:40 AM | #3 | |
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04-16-2016, 09:27 AM | #4 |
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I have analysed how the actuator rods behave. When cold if I turn the engine on and off, the rod from the turbo actuator holds and let's go with psshsh sound after around 20 sec as it should. But after a long trip when everything gets hot the rod creeps slowly down(not always). So people should check this after long drive.
Now I am struggling to get the actuators changed. http://postimg.org/image/9tnpjysln/ I understand that I have 5 vacuum hoses to pull off from the actuators and canister. I have removed 4 bolts 3 top 1 at bottom. 4-5 electrical connections. But still the "bracket" stays loosely on there. What did I miss? It feels like one bolt is holding the damn thing somewhere? It's a really fiddly job, so I refuse to give it to the dealer, as I feel that he would cause even more problems, with breaking stuff and cutting vacuum hoses and me ending to pay for it or get a even more broken car back. |
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04-21-2016, 04:05 PM | #7 |
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For the guys in the same situation. After changing the two actuators, with no drastical improvement, I started looking at DPF and injectors. I poured 2x doses of redx in the tank, and ran the ista D injector test-calibration.
Directly in the particle filter I sprayed wurth DPF cleaner and forced a regen in ista. On the way to work the car began gaining power. On the way home it had response and the power back again 100%. I noticed that regeneration lasted alot longer than normal and actually cabin got hotter because of the regeneration, this never happened. Lucky me an A7 3,0 TDi 326 hp wanted to play and I left him in the dust from 50-110++ so I got extra confirmation that all the power is back. If symptoms are: Driving around 50mph press gas pedal 80% before kick down. Car should pull hard from 1500rpm but not being eager to exceed or gaining a lot power at 3000 rpm. Before, the autobox kicked down a lot sooner to 3000rpm and that mehh / medium pull happened. So inspect DPF clean even better remove it if you "know a guy" at inspection/MOT ![]() |
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05-02-2016, 09:31 AM | #8 |
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Nope was not the DPF.
![]() ![]() Measured back pressure etc everything is fine.. Ok I think I have have narrowed it down to Compressor bypass plate. The compressor bypass plate enables a bypass of the small compressor on the air side. The compressor bypass plate is adjusted pneumatically by the diaphragm box. The compressor bypass plate is either opened fully or closed fully. An electric changeover valve applies a partial vacuum to the diaphragm box. Function for high load and speed:The small turbine and small compressor are bypassed when the compressor bypass plate and turbine control flap are fully open. This enables the large turbocharger to deliver high air masses without the small turbocharger obstructing the air. The compression work is done exclusively by the large compressor. ![]() This could be the explanation of the inconsistent and low power sometimes if the plate does not close. Small turbo is still running at high rpm with the large turbo and that will cause this loss of power. I bought a small camera with 3 metres of wire to see it operating down there while pushing it on the road. If this valve fails there is no codes... |
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05-04-2016, 03:34 PM | #10 |
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Camera was very hard to get into the tight space. Was afraid that one of the pulleys would get it. Turbine control flap tested, working can be seen with naked eye ISTA D pulses with it up and down with 2 sec intervals ran about 5 min it kept working perfectly. Compressor bypass plate could be heard and felt while engine was operating differently and again ISTA pulsates with it 2 sec intervals so not that one. Now the hardest one was Wastegate valve to hear or see working but I found out if you run the test and just shut off the engine the test still runs and can be heard. You need a lift and maybe adjust the rods to specifications and measure movement will do that next oil change.
After that I reset my MAF (learned values) and BANG the full power was back. ![]() All tests can be found in ISTA by searching for "air mass". |
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05-06-2016, 09:35 PM | #11 | |
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05-07-2016, 02:37 AM | #12 | |
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http://bmwfans.info/parts-catalog/E9...agr/#7796634_1 P.nr. 11 74 7 796 634 Is the EGR mapped out of the picture or still functioning? I will test EGR function today ista has this test.... I disconnected MAF but it ran the same so I do not think it is MAF anymore. My car is going to BMW specialist tuesday to change thermostats, and I asked them to measure vacuum and test MAF etc. I will report back. Last edited by SoZoX; 05-07-2016 at 02:44 AM.. |
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05-07-2016, 03:39 PM | #14 | |
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05-07-2016, 03:47 PM | #15 | |
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09-21-2016, 10:11 PM | #16 | |
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09-23-2016, 05:52 PM | #17 | |
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funny you should mention that .... i had that when i first got my car (tune, dpf delete ect) had a look and i had the old PV's , changed them out all was good , untill recently its started doing it once in a while again , say every 10th drive , just does it for a moment then all power comes back about 10 seconds later (feels alot longer but its only about that) intrestingly iv put it down to when i go over a hard bump or though a pot hole or something like that , which points me to a electrical fault , maybe sensor , there was a 3rd amal valve i didnt change out , but im thinking about doing all 3 again |
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09-26-2016, 02:21 AM | #18 | |
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07-23-2017, 09:22 AM | #19 | |
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