MSefi.com read only forum (Jan.15,2018)

Hi there,

I am using the microsquirt on a Porsche 911 SC with 6 throttle bodies. The engine start just fine but the idle is going crazy up to a steady 4500 rpm, the throttle position are almost close. The megatune is showing WUE on. Is this normal, how the engine can run with such high RPM with closing valve? How can I get that RPM down to the right idle? Is this related to the warm up enrichement.

Thanks

No vacuum leak. Did check everything. Just that my homemade throttle bodies was badly ajusted, slighly open. Wow!, just few degrees make this thing to 4500 rpm. Using 1 throttle body per cylinder is quite something to setup.

Thanks for your response.

What are you using for throttle bodies? You will likely need a Synchrometer to accurately adjust the linkage between throttle bodies to get equal flow on all throttles. What are you using for CLT(cylinder head temp sensor) and where are you placing it? You can get a wide variation of temperature depending on where it is located and whether you are stopped or moving. WUE will have to be adjusted depending what sort of temperatures you are actually measuring.

-Dennis

The bodies are designed and machined by myself. Each one has the ability to have his preset opening at idle, but I realized it will be easier to close then all and control the flow of air by a metering valve installed at the vacuum port. MAP values is obtained to the EC by ganging all 6 vacuum hoses to a manifold. For now, I have no temp sensor on the cylinder at all.

Can anyone who have a 911 with 6 throttle bodies can tell me what is the typical idle speed they run the engine?

thanks

I checked with a friend who uses Weber carbs and he says the idle can be set at 900 or 1000 RPM's.

-Dennis

Great, but for now I cannot do anything since my rpm pickup at the distributor was shorting making the start impossible. That must be the reason why it burns my CDI box.

Thanks for your response.

Alain