M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: HarrisonS on May 15, 2007, 09:45:24 PM
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Hey Guys,
These past few weeks I have been having problems with my engine sputtering at random RPM's. The car will be fine when I first drive it, but after about 5 minutes it acts like it hits the rev limiter and starts sputtering. I will then take it down to a lower RPM and it will be fine.
I do a lot of city driving so not being able to rev the engine as fast as I want when I am shifting is really a pain (ie. shifting at 2k RPM's, before the engine starts sputtering at 2.5k)
Any ideas??
I've replaced the valve cover gaskets and the spark plug gaskets. Because I found oil in the spark plug cylinder, but that didnt help the problem.
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Have you checked your TPS and AFM?
Try cleaning these 2 components out and let us know if there's any improvement. When was the last time you replaced your spark plugs? When this behavior occurs, do you notice your fuel economy gauge swinging erratically?
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Are there any good sites that tell you how to clean the TPS and the AFM. where exactly are they on the engine? Thanks for your help
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And no, the fuel economy gauge doesnt swing erradically when it happens
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fuel pump and or fuel filter?
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I changed my TPS and that symptom went away. But a gauge moving erratically, is that the battery in the SI?
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I was thinking that I may have some sort of vacuum leak somewhere. Once the engine reaches normal operating temperature, those seals get warm and start loosen, causing a air leak. Fuel filter is another option.
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Try another ignition coil pack. They do fail and the syptons are similar to what you describe. It can fry your DME also. I've repaired some caused by the coild pack failing.
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Ok so I have determined that this behavior only happens when the engine reaches normal operating temperature. If that helps any
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Have you checked your TPS and AFM?
Try cleaning these 2 components out and let us know if there's any improvement. When was the last time you replaced your spark plugs? When this behavior occurs, do you notice your fuel economy gauge swinging erratically?
where does the fuel economy guage take its vacume from because i have a bad running problem and my econo guage only works sometimes, and if it does work its at high rpms which makes me think its leaking but i don't know where it gets its signal from.
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where does the fuel economy guage take its vacume from because i have a bad running problem and my econo guage only works sometimes, and if it does work its at high rpms which makes me think its leaking but i don't know where it gets its signal from.
I do know it's based on engine speed and fuel flow rate as a calculated reading but I unfortunately don't know the next tier of hardware components associated with it.
Try download one of the BMW wiring diagrams for a bit more help.
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The fuel econ meter is electronic, not vacuum operated. If memory serves, this combination of symptoms indicated a worn-out air flow meter, an expensive part. Best way to figure this one is to install a known good AFM. There is a way to check the unit with a multimeter set to the ohms scale, but I'd have to look in the ETM to find which terminals to test. BTW, bad SI board batteries can cause various instrument malfunctions, including an erratic econ meter, temp gauge, or tach.
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There are no erratic instrument malfunctions.. all of the gauges (mpg gauge, Tach), seem to be working normally. Is there a way to tell if its a fuel problem or a engine RPM problem? Could not enough fuel be getting to the engine causing it to sputter?
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my car was similar and after changing and checking everything it ended up being a bad coil .car runs awesome now .I don't know if there is a specific test for the coil itself .
good luck