How does the ECU cut boost in limp mode?
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Joined: Jul 2002
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How does the ECU cut boost in limp mode?
I'm running an MBC right now (my software isn't complete for my car yet, and it'll be a while), and I've been trying to figure out how to stop the car from cutting boost in limp mode. I do not want to diode the car.
I bypassed the N75 valve, and hooked up my stock DV right to the intake manifold, so the N249 cannot control it. The N249 is located under the intake manifold, right?
The result? It runs real smoothly, but still hits limp mode and cuts boost to 5psi.
What else does the ECU use to cut boost?
I bypassed the N75 valve, and hooked up my stock DV right to the intake manifold, so the N249 cannot control it. The N249 is located under the intake manifold, right?
The result? It runs real smoothly, but still hits limp mode and cuts boost to 5psi.
What else does the ECU use to cut boost?
AudiWorld Super User
Joined: Jun 2003
Posts: 13,834
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I would get software not run a MBC. Have you logged your fuel and timing? ...
That may very well be your reason for limp mode. Running a MBC will not change the fuel and timing maps and the OEM ECU can only adapt so much. There is programming available for your car and I would look into it. cheers! Mike
Junior Member
Joined: Jan 2004
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Thanks to DBW the ECU will close the "flap" in the throttlebody to regulate boost. Limp sux! and so
does Drive by wire for that matter. If you use a MBC then turn it down a notch to keep it from hitting limp, remember as it gets colder in the year you may need to turn it down again. A better solution is getting a software upgrade ie a chip. Even then be careful adjusting boost as you can hit a lean condition very easy. Stock injectors puss out early.
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