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Low Vacuum, unresponsive throttle

Grant Baker

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Just converted a customer's car from a modified stock ECU to a Link Fury.

It's a BMW M54 3.0 engine with a Rotrex Supercharger. It drove in on the stock ECU with MAF.

Now it's "running" on the Fury, I've noticed 2 issues...

1) MAP is 97-98kPa at idle at it's lowest, and tends to be closer to 99-100kPa - MAP Sensor is tested and working. Have swapped it out just in case.

2) Throttle is totally unresponsive. The plate is physically moving, but the engine revs do not alter at all when the plate opens and shuts!

I have pressure tested the system and found 1 major air leak, which is fixed, but there is a small "hiss" somewhere that I can't find.

Looking for an opinion or two! Is the small air leak going to be the cause of the above issues?

PCL File attached if anybody is interested.


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  • 3 weeks later...

You've got some very high numbers in the ethrottle target + idle targets.

assuming you want an idle at 1500rpm, you've got a base throttle target of 7%, + (when cold - 20ECT) another 9.8% from base idle table, so at least 16% throttle opening at "idle".  i'd imagine it tries to idle more at 3k or so? Check in a log what the TPS main value is. If its over 6-8% its probably too high and you need to bring this down as a starting point.

Simple test to see if that leak is your problem - either turn off idle control and change the ethrottle target to 0 while its idling, or pull the ethrottle plug and push the throttle closed by hand - if it stays running, you have a big leak. 

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