12-08-2018, 02:52 PM | #1 |
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Engine hesitation under load
Friends, my wife drives an '11 35i with 111,000 miles. The car just developed what feels like a subtle hesitation under load. There appears to be no discernible loss of power. And, again, only happens on harder acceleration, not when coasting or low acceleration, and is not constant. Just had the water pump and thermostat replaced. When we did the shop suggested replacing the plugs - but as a maintenance issue, indicating that the replacement should be done at 60k.
Diagnostic thoughts? Much obliged. |
12-08-2018, 03:07 PM | #2 |
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I've read that some of these 'direct fuel injection' motors can be subject to carbon buildup on the intake valves...think this occurs when mileage gets in the range where you're at.
You might run that past your mechanic and get his thoughts. The remedy if this is the issue is to walnut blast the intake valves- believe it requires removing intake manifold, so not exactly a minor kind of procedure. I'm sure others on the forum may have addl ideas as to your car's behavior. Good luck/Bill |
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12-08-2018, 03:39 PM | #3 | |
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Cheers, David |
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12-08-2018, 04:33 PM | #5 |
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+1....diagnostics!
Carbon buildup: my sense would be that if you're seeing a misfire code, slightly rough running AND all other possibilities (faulty coil packs, fuel injector/pump, etc.) are ruled OUT then the intake valves may be at issue. I'm not a mechanic, you need a competent trusty one! Bill |
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12-08-2018, 09:29 PM | #8 |
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12-09-2018, 10:49 AM | #10 |
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I could believe plugs as well, at the mileage it is indeed time for them. In previous cars I've owned over ~ 30 years this sort of behavior stumbling when accelerating was typically the plugs / wires / or distributor cap & rotor, 2 of the 3 which aren't of course on an X3 leaving just the 1 left for where I'd start. The air filter idea is solid as well if you aren't sure the last time it was replaced. That for sure is an easy DIY.
This is the one I put into mine, but it was a 2015 35i and your older one may be different, check to be sure. https://www.amazon.com/Mann-Filter-2...ype=automotive |
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12-11-2018, 12:36 PM | #11 | |
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12-12-2018, 12:47 PM | #12 |
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What RPM is it happening at? I had a similar problem, turned out to be a bad spark plug. Was happening under load just under 2000 RPM.
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