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Using megasquirt to test carbs


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I realise this sounds like a bit of an odd question, but I am working on a rather old vehicle and wish to check the carburettors without going to the expense of a rolling road. I've recently rebuilt the engine using my own camshaft profile and the compression has been modified, as has the cylinder head and the inlet/exhaust manifolds.

Knowing (very little) about megasquirt I wondered if it were possible to rig up a vacuum line, a TPS and a lambda into the vehicle exhaust and take a log on a long run in order to gauge if the carburation is somewhere near right?

Currently I believe it is fine under margainal throttle but not delivering enough at larger throttle openings under high load and consequently running lean.

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At the moment I really am just looking to confirm if my thoughts are correct with regard to the needles being too lean in wider throttle openings/loads. So I guess just introducing a narrow band lambda will show me it dropping off. I have megasquirt already (on another car) and enough bits to lash something together so was pondering...

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It will work, all you'd have to hook up would be +12v to the ECU and the signal from the lambda, unless you wanted an RPM signal, CTS, etc. in the data log as well. For basic testing just using a lambda connected to a £5 multimeter would show similar results.

With a narrow-band you obviously won't see much, and it'll probably spend most of its time nailed to one end or the other of the scale, but if you're only worried about checking if it's going lean then it'll be good enough.

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