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Old 06-29-2020, 10:57 AM
juliarbrown64 juliarbrown64 is offline
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Low RPM stall in gear

Hi all,

I have a late model A4. The engine seems to idle well, but when in gear I need to have the engine running at higher RPMs otherwise it will stall (flutter than stall, like it is starved for fuel). My plugs also get sooty very quick, but not wet.

Any suggestions?

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  #2   IP:
Old 06-29-2020, 06:36 PM
Dave Neptune Dave Neptune is offline
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Julia, first welcome to the MMI Afourian Forum.

Stalling at idle can be a few things and the sooty plugs do narrow down the issue.

First a couple of questions, first how long since a tune-up~~IE points, condenser if so equipped. Is it a std (stock) ignition or electronic. Second how old are the plugs?

A quick thing to try is to lean the carb idle down a bit. This is done with the "idle air screw" on the topside of the carb. Try turning it "out" about a 1/2 turn (counter clockwise) to add more air and that will lean the mix a bit. Might help. Also advise if it does or not.

Any other things you have noticed like lack of power, rough running or harder to start?

Dave Neptune
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Old 06-30-2020, 01:50 PM
juliarbrown64 juliarbrown64 is offline
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I have and electronic ignition. I am replacing the plugs tomorrow, but this has still happened with brand new plugs. I will lean out the mixture as suggested and get back to you. I have also ordered the carburetor rebuild kit, as it is probably due for an overhaul.

I replaced the coil last year (engine was shutting down when hot, and starting up again when cool) but did not replace the plugs. I use RJ12C plugs.

No other issues with rough running, the engine starts up like a dream and I replaced the head gasket about 5 years ago. Compression in the cylinders is good to ok, with worse compression in cylinders 3 & 4, 4 being the worse but if I remember correctly should be around 95 or and the others over 100.

I have the 4 bolt late model carb and will also check for a gap tomorrow.
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Old 06-30-2020, 05:16 PM
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roadnsky roadnsky is offline
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Welcome to the forum!
If you haven't already, you may want to read this Tech Tip

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Old 06-30-2020, 05:48 PM
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Is the choke opening all the way? Sooty plugs make me think of rich running.
Try this: After idling for awhile, while still in neutral, rev the engine up a bit then go back to idle and shift into gear and try increasing RPMs. The revving will "unload" the excess fuel from the cylinders if the engine is idling rich.

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