10-23-2015, 07:44 AM | #1 |
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F30 335i JB4 jerking/hesitation?
Hi,
Recently had a JB4 installed with a BMR intake, made a solid 53rwkw which was nice - big difference to the car. However, after having it for around 2 weeks it seems the car started to hesitate accelerating lower speeds. It would jerk back and forth pretty badly when almost coming to a stop and accelerating as usual just before the car stops. Along with that, the car doesn't idle as smoothly when left for 4-5 hours.. it even got to the point where it stalled once.. Shifts don't feel as seamless as they were before either and seem to kick you in the back especially from 1st to 2nd and 2nd to 3rd - it just feels as if something is seriously wrong. Can anybody with a JB4 shed some light on this? I've heard nothing but positive comments about the tune but I'm inclined to think otherwise from this experience. If it doesn't get resolved I will most probably remove the tune and intake and sell them as it seems they're just causing nothing but issues at the moment. Thanks *FYI: The car is a 2012 F30 335i N55 Auto running on Map 2, no E85 only 98. |
10-23-2015, 08:08 AM | #3 |
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10-23-2015, 05:56 PM | #4 |
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I wouldn't be running map 2 if all you have is an intake. The JB4 is great but you need to follow the instructions given by Terry if you want to avoid any issues. To be safe just run map 1 or 5, you wont make the same gains but at least its safe.
Map Info Map 0: JB4 disabled Map 1: Additive target, around 4psi over stock. Map 2: Additive target, around 6psi over stock. Suggested for those with 93 octane and bolt on modifications. Also good for small E85 mixtures. Map 3: Progressive methanol mapping, absolute target of 11-20psi based on meth flow, meth additive setting, and average ignition values. Map 4: Stock performance with JB4 active for logging only. Map 5: Autotuning map, absolute target of 11-17psi based on octane and conditions. Map 6: User definable absolute target map. Suggested for troubleshooting by professionals only. Map 7: Race gas map. Absolute target of 18.5psi. Requires straight unleaded race gas. |
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10-23-2015, 08:16 PM | #5 |
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I thought the same, Map 2 should at least have downpipe so stick to Map 1 or 5 until the next round of mods.
Let us know how you go on Map 1 or 5 but I'm almost certain you'll have no issues on either of those maps |
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10-26-2015, 05:02 AM | #8 |
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So I switched to map 1 and it seems the jerking and vibration has become noticeably more erratic..
Nobody has ever experienced the same sort of symptoms before? Could it be poor install or something related to that? |
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10-27-2015, 05:11 AM | #10 |
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Mmm yeah.. Car has been crazy unlucky with issues this past 6 months. Steering rack knock, PDC sensors faulty, oil filter housing leak, coolant leak, misfires and now this - all in under 50k km's. Sounds like poor build quality and just an unlucky car, may be time to sell it and move on to something less problematic lol.
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03-09-2016, 12:07 AM | #12 | |
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03-09-2016, 04:42 AM | #14 |
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Nah mate, ended up just returning it back to standard and had the rack replaced under goodwill at BMW, along with repairing all the leaks. The knock was still there lol - though, the car did drive much better standard, silky smooth and no jerking or hesitation at all.
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03-09-2016, 05:43 AM | #15 | |
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I wonder if the bmw ppk may be an option for your car. |
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03-10-2016, 01:23 AM | #16 |
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I haven't heard/driven any other F20/F30 having this issue, but I have driven JB4 135i's both N54 and N55.. makes lots of power but really feels "unrefined". However Cobb does not seem to have that issue, they drive very nicely in my experience. PPK tends to be quite underrated, seems to make more difference than people think.. On paper it doesn't add much power at all, but when driving you really feel the difference
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03-10-2016, 10:51 PM | #17 | |
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Before the fanclub get their pitchforks out I'm quite happy to acknowledge it's a popular tune that many are happy with. Horses for courses, so to speak. |
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03-11-2016, 05:44 PM | #18 | |
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