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Poor power and upshifts - MHD Log advice sought.
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06-25-2018, 04:17 AM | #1 |
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Poor power and upshifts - MHD Log advice sought.
Hello,
It has been suggested by another member here that I post a separate thread on some issues I've had with my 35i / N54 (DCT) after a dealer replaced all injectors and the water pump on my car. The car has been owned by myself for nearly 8 years so I know it well. It has driven fine up until an occasional cold start misfire occurred in late summer 2017. Car is stock, no mods. I booked the car in for diagnosis with the local dealer and on the day I drove the car to them, around 1 mile from the dealership the car started to slow on the motorway and an amber 'overheating, drive moderately' error came up on the idrive. I lowered my speed for around a minute and then pulled over as the car continued to slow. I shut off the car, waited 15-20 mins and restarted. Full power returned oil temps remained normal. Around 1/3 of a mile from the dealership, the amber fault returned and I limped the car into the dealership car park. Just as I shut off the engine, the screen went red and stated I should turn off the engine (I'd just done that). I left the car with the dealer, they diagnosed the need for six new injectors to cure the misfire and a new water pump to resolve the overheating. When I got the car back, on the return trip all seemed well. The next day (and subsequent weeks) showed weird upshifts (lumpy/snatchy) and poor power delivery at normal driving speeds. Shifting into too high a gear/bogging and other oddities. At the time I thought perhaps they'd reset adaptations and I gave it a month or two of driving before taking it back to the dealer as I wasn't happy, nothing was improving. Over several months the car has gone back and forth to the dealer, they found an EGR issue and replaced a pipe, they found a leak in the rocker cover and replaced that (£££). Nothing improved the situation until very recently I put in 99RON (rather than 95RON as usual) fuel where the car felt much more responsive, but the shifting issues remained along with inconsistent power delivery. A final attempt with the dealer was to no result (seems fine to us, there's no codes). I've now invested in the MHD logger and attach a number of logs below. I'm told in the other thread that there's some weird timing, lambda and fuelling mode events, but my knowledge of how this all works is limited. I'd be obliged if any of you with knowledge of this engine, coupled with a DCT could review the logs and give me your thoughts. Last edited by ManiacGT; 06-25-2018 at 05:13 AM.. |
06-25-2018, 05:45 AM | #2 |
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Since you had injectors replaced I would also verify that BMW installed the decoupling rings along with the injectors. This can be done visually with the engine cover removed.
That's the most common error made when installing injectors and it seems to coincide with the times that the faults started. |
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06-25-2018, 06:09 AM | #4 |
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I got dct overheated for first time ever the other day after about 2 or 3 wot pulls through 2nd into 4th at the track. Very unusual as the car will usually handle 90 mins of this straight without issue. Dct is freshly serviced, no signs of slipping clutch.
Will follow this. |
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06-25-2018, 06:39 AM | #5 | |
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Short full pedal until after shift: https://datazap.me/u/maniacgt/wot3lo...28&zoom=28-143 Commute shifting: https://datazap.me/u/maniacgt/first-...25&zoom=60-203 40-80mpg WOT (sport+/traction off): https://datazap.me/u/maniacgt/wot-lo...28&zoom=24-138 |
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06-25-2018, 06:40 AM | #6 | |
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Not fitting these will damage the head I'm told? |
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06-25-2018, 07:31 AM | #7 | |
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If you take the engine cover off and take some photos of where each injector meets the head of the engine I'm sure I could spot if the decouplers are present. |
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06-25-2018, 08:10 AM | #8 | |
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This is the best I could get with my rather old iPhone of my actual injectors, you can make out the lower tab and plate with small feet either side that the clamp holds onto but nothing below that. Last edited by ManiacGT; 06-25-2018 at 08:24 AM.. |
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06-25-2018, 09:36 AM | #9 |
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Unfortunately I don't have any photos for comparison. From memory you should be able to make out the silver tabs on the decoupler around the base of the injector.
You might have to look at some injector fitting DIY topics to get an idea what to look for. |
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06-25-2018, 09:51 AM | #10 |
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Yeah I couldn't see any but then it was difficult to see. I'd have to remove that bracket to get a clear top down view to see such tiny little tabs lower in the injector. I'll have another look later and see what I can come up with. Do you know the torque for the injector clamp by any chance?
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06-25-2018, 10:04 AM | #11 | |
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From here: https://www.newtis.info/tisv2/a/en/e...-lines/5lzDB5f |
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06-26-2018, 11:56 AM | #13 | |
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First thing I'd do it throw an aftermarket tune on it via mhd. You can work with a pro tuner to get a custom tune or just use the built in maps in MHD. Then post another log. |
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06-26-2018, 12:03 PM | #14 | |
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It’s a totally stock car, why would it be doing what you’re suggesting? |
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06-26-2018, 03:02 PM | #15 |
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You can ignore everything he just said. Absolutely worthless advice from someone who has obviously not read the thread and has no idea what a stock log looks like.
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06-26-2018, 04:07 PM | #16 |
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Lol I’ve reviewed many stock tune logs. Please tell me exactly where you disagree. Are you saying it’s normal for a stock tune to target 3psi and 14.5 degrees of timing advance? Do you not see those massive throttle closures?
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06-26-2018, 05:07 PM | #17 | |
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He does have too many throttle closures so it would be an idea to check boost solenoids as mentioned in the MHD thread. Sticking a tune on the car is not going fix his issues. |
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06-26-2018, 05:48 PM | #18 |
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sounds like a boost leak to me.
I would replace the boost solenoids and check all the vacuum hoses, pressure test if you can. Ecu is probably targeting boost and cannot achieve that and is closing throttle to save engine. While your at it check the low and high pressure fuel pumps, and confirm flow. My 2 cents. |
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06-26-2018, 07:07 PM | #19 | |
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Those closures are significant though, and uncommon for a stock tune. I had a different car in for a diagnosis where the owner described "inconsistent power delivery and light misfire feeling" that had very similar looking throttle closures and was a result of wastegates stuck shut. Could also be related to boost solenoids not controlling wastegates properly. Did he ever send you the bin? Is it possible they updated his bin while it was in and used the wrong bin Like one for a non-dct car? I doubt the BMW software would even allow that type of mistake but would still be worth checking. Last edited by GODDSPD; 07-14-2018 at 04:45 PM.. |
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06-26-2018, 07:11 PM | #20 | |
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06-27-2018, 02:30 AM | #22 |
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You need a vacuum gauge.
There's a few useful threads around the forums and some good YouTube videos; https://www.google.com/search?q=boos...id+testing+n54 |
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