Kad44 issue

[Dannyrscott]

Compressor on my Kad44 Edc stopped working. I can get it to work by connecting to battery just fine and get voltage on the wire that comes from fuse. It seems to me that the other wire goes to the Edc unit. Any ideas on how to fix other than swapping edc unit? Not sure how the edc unit grounds the wire for the compressor? Thanks

 

[simonfraser]

sounds like the electric clutch of the comressor is not engaging
you need to be v careful with the EDC as that is a component which is not available new & v v rarely second hand

 

[Dannyrscott]

The clutch works fine if I apply battery voltage to it (disconnected from edc unit).

 

[Portofino]

Compressor on my Kad44 Edc stopped working. I can get it to work by connecting to battery just fine and get voltage on the wire that comes from fuse. It seems to me that the other wire goes to the Edc unit. Any ideas on how to fix other than swapping edc unit? Not sure how the edc unit grounds the wire for the compressor? Thanks

It’s belt driven ?
Do you mean you can energise it’s clutch by direct 12 v connection ?

There might be a relay whereby the ECU signal switches the 12 v on ……and off later .
The ECU needs a rpm sensor to know both points obviously.

So logically
1 - hunt down the relay and ck it
2- the rpm sensor ?
3 hope not the ECU …as that’s game over this season for you .

Ck all the wiring .

Be careful throwing 12 v about .Wrong wire wrong way = fried ECU .

 

[kashurst]

The supercharger is controlled by a transistor inside the ECU. There is no relay. Sounds like it has died. So bad news I suspect. Second hand ones do turn up.

 

[Portofino]

The supercharger is controlled by a transistor inside the ECU. There is no relay. Sounds like it has died. So bad news I suspect. Second hand ones do turn up.

Same principle ( different name ) hunt down the switching mechanism - test .
Then hunt down what sensors ( presume rpm?? ) that feeds that .

Its not rocket science this stuff you know . .

 

[kashurst]

Does the engine start and run.?

 

[petem]

To confirm what Porto says...

The S/C is belt driven with an electro magnetic clutch.

If it's a twin engine boat then it's worth swapping the ECU's to see if the problem goes to the other engine.

Also worth swopping the clutches over to eliminate that.

RPM sensors do go and can cause similar issues. People are reporting these sensors failing now do that could be the cause . New BOSCH OEM ones are £35 from eBay.

Pete

 

[simonfraser]

To confirm what Porto says...

The S/C is belt driven with an electro magnetic clutch.

If it's a twin engine boat then it's worth swapping the ECU's to see if the problem goes to the other engine.

Also worth swopping the clutches over to eliminate that.

RPM sensors do go and can cause similar issues. People are reporting these sensors failing now do that could be the cause . New BOSCH OEM ones are £35 from eBay.

Pete

RPM sensors are getting contaminated too, limiting the revs

 

[Dannyrscott]

Engine is running fine without it. It is a single motor so no swapping the ecu. If the rpm sensor was gone would the tach stop working as well? Could the clutch be bad and direct voltage just magnatizes it and ecu doesn’t have the amps to pull it tight? I forgot to mention that it was intermittent for an hour or so cutting in and out before it stopped working completely. Thanks for all the help here, it’s very helpful in solving these types of issues.

 

[kashurst]

The tacho gets its rpm sense from the alternator. The ecu has its own sensor immediately above the flywheel. You can test the ecu rpm sensor easily off the engine with a volt meter and wave a spanner or screwdriver just in front of it. With the voltmeter set to @ 2V or similar it should show a reading briefly as the metal moves across the face of the sensor. I have sent you a PM - not sure if you can see them yet. The clutch is very simple electrically - it's just a coil of wire. It either works or it doesn't. From the test you describe it sounds like the ecu is not switching it on. If you can, put a voltmeter across the clutch wires and see what happens when you rev the engine up. It should show @ zero, then @ 12V when the supercharger is/should be on. Is the engine showing any fault codes? Have you disconnected and cleaned with contact cleaner the main connector to the ecu (slide red lock tab down with a large screwdriver, then pull/rotate backwards away from the ecu) Make sure you isolate the battery first!!!!

 

[captaindan]

Compressor on my Kad44 Edc stopped working. I can get it to work by connecting to battery just fine and get voltage on the wire that comes from fuse. It seems to me that the other wire goes to the Edc unit. Any ideas on how to fix other than swapping edc unit? Not sure how the edc unit grounds the wire for the compressor? Thanks

I’ve had a problem similar. But from the clutch on compressor it made loads of sparks when trying to engage

 

[Dannyrscott]

Rpm sensor seems good. I get no voltage across the clutch wires, however, if I unplug the clutch I do get voltage across the wires on the motor side.

 

[kashurst]

Rpm sensor seems good. I get no voltage across the clutch wires, however, if I unplug the clutch I do get voltage across the wires on the motor side.

thats not good`. If there is no voltage across the clutch wires there is no current going through it so it will not operate. Measuring the voltage across the other side of the connector going back to the ecu, may - as you have found show a voltage. Unfortunately that will depend upon how the ecu/transistor has failed. Sorry, but I think the transistor that controls the clutch in your ecu has failed.

If you know any electronics people maybe they could make a piece of electronics to turn the s/c on/off at the correct engine speeds if the rest of the ecu is working OK.

 

[BruceK]

If you know any electronics people maybe they could make a piece of electronics to turn the s/c on/off at the correct engine speeds if the rest of the ecu is working OK.

I wonder if he couldnt just add a separate system in the black box system from the 43 / 43 series and the hall switch for WOT kick down engagement. After all all they do is operate the SC. IIRC the black box is around 250 and so is the kickdown switch. A relatively cheap solution to an otherwise currently unobtainable ECU?

 

[volvopaul]

Compressor on my Kad44 Edc stopped working. I can get it to work by connecting to battery just fine and get voltage on the wire that comes from fuse. It seems to me that the other wire goes to the Edc unit. Any ideas on how to fix other than swapping edc unit? Not sure how the edc unit grounds the wire for the compressor? Thanks

The clutch has a permanent live From the fuse , it’s the earth that’s switched from the ECU , so no earth no clutch .
Clutch should engage in neutral below engine temp of 40 deg c , it’s possible the edc temp sensor has failed telling the ECU it’s above 40 deg c .

 

[kashurst]

I wonder if he couldnt just add a separate system in the black box system from the 43 / 43 series and the hall switch for WOT kick down engagement. After all all they do is operate the SC. IIRC the black box is around 250 and so is the kickdown switch. A relatively cheap solution to an otherwise currently unobtainable ECU?

I was looking at the spec of the kad 42/43 speed sensitive relay the other day. That component is the right sort of thing but its switching range is too narrow. Kad 44/300 wants a supercharger from 1000 rpm to 2800 rpm. The 42/43 gets s/c from 1700rpm to 2400rpm (I think). The cut out speed is a bit adjustable but I don't know how much. As a piece of electronics it is pretty simple. I wonder if VolvoPaul or others can comment on how often a kad 44/300 ecu fails and it is only the supercharger driver that has gone pop. If such a device was fitted an otherwise good ecu I think would still work and control the fuel pump etc. Wouldnt be hard to add the temperature bit for when the engine is cold, but I don't think it is really adding much to a 20+ year old engine looking to heat up a bit quicker when starting from cold.

 

[BruceK]

the 42/43 control box is set to start at 1700 rpm and off at 2400rpm but the switch off can be adjusted to 2800rpm. I tried that once to see the effect and if you have slightly worn turbo's it does help but it also has a downside in parasitic drag and can actually retard the the acceleration of revs to the 3k transition to turbo only. when set to 2400 rpm cut off once I reach 2600 but still have them in because of kickdown WOT, I come off the throttles slightly to disengage them and transition fully onto the plane at 3krpm

 

[petem]

I wouldn't write the ECU off yet until replacing the two sensors suggested above.

I know this is a wild shot but might be worth getting someone with Vodia to see if that tells you anything (like whether the temperate is being read).