Volvo KAMD 300 Supercharger Problem

[Hydeaway]

I have twin KAMD300s in my Rivera and I have an issue with the Supercharges. Stb. one will kick in when the motor is started and is idling around 700 rpm and the Port will not kick in until the revs reach around 1400 rpm. I have had 2 pieces of advice ,one said the Supercharges will start when the motor is first started and shut down when it reaches40C temp and will then cutin and out according to the revs ie 1400 and 2800 . The other advice is it is not temp. dependent but will only cut in at 1400 and shut off at 2800 rpm. Does anyone have a definitive answer for me so I can then start to fault fine the problem unit?

 

[ChromeDome]

The workshop manual is quite detailed on the turbo and compressor, function, maintenance etc.

A small clip of it:

 

[Mr Googler]

KAD 42/43 no start up temp dependant and 1700-2800

KAD44/300 start up temp dependant and 1700-2800

 

[BruceK]

the 1700 to 2800 (42 and 43 at least) is only if on kickdown (throttles wide open but still at sub 3krpm) otherwise it should clutch out at around 2400 rpm. this is adjustable on these particular motor's black box. Not sure on ECU models 44 and 300 but having the SC engaged that high on a low load plane wouldnt make sense

 

[kashurst]

the 1700 to 2800 (42 and 43 at least) is only if on kickdown (throttles wide open but still at sub 3krpm) otherwise it should clutch out at around 2400 rpm. this is adjustable on these particular motor's black box. Not sure on ECU models 44 and 300 but having the SC engaged that high on a low load plane wouldnt make sense

MrG is nearly correct on the '44 and 300 series. The S/Cs stay on until 2800 regardless of load, but I think they cut in at 1000rpm regardless. The OP issue could be temperature sensor related - one engine thinks it's less than 40 degs, the other thinks it's over 40 degs. Easy experiment is to swap the temp sensor in the exhaust manifold just in front of the turbo. Need a cork/plug whilst swapping sensors though ;-)
The other thing to check is the flywheel speed sensor at the engine - could be gunked up and misreading engine speed.

 

[volvopaul]

Plug in diagnostic key and read edc temp .
Gauge temp sender reading is from different source .

 

[Hydeaway]

Thank you to all the contributors I have some starting points to fault find.