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11-28-2012, 11:52 PM | #1 |
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part throttle violent jerking and hesitations
In fifth gear on the highway, driving 75 miles per hour, at more than 30% throttle, my car has violent jerking and hesitations, but no codes. It does it on the stock tune, as well as on cobb stage 1. Plugs, injectors, coil packs, and turbos were replaced 5k miles ago. What should I do to troubleshoot? I've already ordered 6 new coils packs and 6 new plugs, but I'm afraid that that's not going to help. Could it be hpfp(and if so how do I get the dealer to replace it without codes?) The jerking is very pronounced and obvious even to the passengers in the car. I suspect it's misfire, but for some reason there are no codes. It does the same things in other gears, but it's most obvious on the highway in fifth, or sixth. I use the accessport to check for codes, and there are none. Please help. The car has 50600 miles, and is out of warranty.
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11-28-2012, 11:57 PM | #3 |
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I would start with new spark plugs. High load low rpms sounds like a miss fire to me. The plugs should be replaced every 45K miles. And with a tune about every 20K miles. Only use BMW spark plugs.
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11-29-2012, 12:00 AM | #4 |
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Did you replace the spark plugs directly from BMW? It could be a couple things....and since the car isn't throwing codes it's hard to know. Carbon build-up possibly? It could be the HPFP....if your injectors and spark plugs, etc, have been replaced that's the only other thing I can think of that is fuel related. No rattling, or weird noises in engine bay?
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11-29-2012, 12:02 AM | #5 |
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No rattling, or weird noises, and the idle is very smooth. The dealer replaced everything at 45000 miles, car now has 50600 miles. I've ordered new coils and plugs(they should arrive friday).
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11-29-2012, 12:03 AM | #6 |
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Coils and plugs directly through a BMW dealer or another website?
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11-29-2012, 12:06 AM | #7 |
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plugs and coils from authouhasaz - these exact ones:
coils: http://www.autohausaz.com/search/pro...gnition%20Coil plugs: http://www.autohausaz.com/search/pro...2@Spark%20Plug |
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11-29-2012, 12:09 AM | #8 | |
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Quote:
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11-29-2012, 12:57 AM | #9 | |
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Quote:
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11-29-2012, 01:13 AM | #10 |
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Could be your hpfp or you can have bad carbon build up on the valves. Carbon deposits on the valves will cause pre-detonation of the air fuel mixture and lowers fuel economy. Like the other guys mentioned start with the plugs first them work your way up. To me it sounds like the hpfp on its way out if it was no changed earlier. Best of luck to you.
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11-29-2012, 01:23 AM | #11 |
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GOD! Ive been hving this problem for over a year now... Weird thing is that at WOT there's no problem...
Also no codes but a missfire code every now and then when I pushed very hard or spin tires a lot. Other than that, no codes. I replaced filters thinking they were to blame, and the car ran fine but after 2 weeks it came back on. Cleaned the filters a coupe of weeks ago and same history. Ill guess ill order new plugs and coils in the dealers, and if it doesnt work, I hope they have the equipment to do the carbon clean up here in Mexico. |
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11-29-2012, 08:40 AM | #12 |
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I'm on my 3rd set of plugs NOT bought from the dealer. Never any misfire issues or any other problems with the plugs. Never seen any real evidence to support this myth that you have to buy plugs from the dealer. Show some real quantitative analysis as to why the dealer sold plugs are different please.
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11-29-2012, 11:25 AM | #13 |
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My X3 and the 135i with Dinan St2 both do that.
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02-12-2013, 12:34 AM | #17 |
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I finally did the walnut shell blasting service, and I am happy to report that my car is perfectly smooth again! The crazy violent jerking is completely gone, and I can't believe the difference!
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02-12-2013, 01:31 AM | #18 |
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Glad to hear it!
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2008 E88--Fuel-It! Stage 4 LPFP & PI--PS2 turbos--JB4/MHD--FBO--662whp/604wtq
2011 E90--Fuel-It! S2BL LPFP and PI--PS2 Turbo--JB4/MHD--FBO--546whp/589wtq 2013 Mini JCW--Tune--DP--FMIC--a couple Fuel-It! goodies--265whp/320wtq 2013 F10--JB4/BM3 2015 F82--Fuel-It! Stage 3 LPFP & PI--PS2 Turbos-- JB4/BM3-FBO |
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02-12-2013, 09:23 AM | #19 |
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Glad to hear walnut blasting worked.
Kgaler: I spent 3 hours or so troubleshooting same problem, it popped up the day i got Dinan S2 tune on my 1 series. Dinan explained its normal and they're working on a software update to fix juddering/surging during hard acceleration. Root of issue per Dinan: stock turbo BMWs have a barely noticeable surge/juddering during hard acceleration (due to some reason I can't accurately recall...something about either fuel delivery or vanos mapping - not hpfp related), when Dinan tune is applied surging/juddering is amplified to an easily noticeable level due to increased power. They said fix (software update) was coming, I waited a month or so and no fix. Went to battle to get money back and tune uninstalled, got around 85% of initial cost reimbursed. Relatively pleased with how Dinan handled it. |
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02-12-2013, 10:44 AM | #20 |
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Who did the treatment and how much did it cost? Having this same issue...
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02-12-2013, 12:21 PM | #21 | |
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It is 70 miles from me and it was a big pain in the ass to leave the car there and pick it up the next day, but I am glad I did it. The difference is amazing, definitely recommend it. The price I got quoted was 690, but I was able to get it a little lower. Some people here have paid less for this service, but I have absolutely no regrets. Mike is supposed to send me some pictures of the valves from his cell phone, so I'll post them as soon as I get them. |
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