KAD 44 loosing boost slowly

[CraigC]

Hi, any suggestions would be welcome

2 x KAD 44 on DPE, 1000hrs

In the last year port boost slowly dropping. Two new turbos replaced 2 yrs ago and now at cruising 3200 rpm about 5 psi difference, also 10% less fuel.

My understanding is the fuel computer EDC will allow more fuel if enough boost being created.

So far the following has been completed.

Normal yearly full service, filters etc. checked for air charge leaks in pipes and aftercooler box, no leaks of water or air.

Mixer on port engine removed to allow visual inspection of exhaust side of turbo and all good.

1000hr top end service on both engines, injectors, valves and compression tests, all good (injectors nozzles replaced etc)

Swapped fuel computer with each engine and fault did not move, so not the computer.

Air pressure sensor on manifold my last option that I can think of which I will test this weekend, sensors looked ok when swapping over.

Has anyone had an issue like this and have suggestions of what to consider ?

Regards.

 

[Mr Googler]

Dirty charge air cooler?

 

[petem]

Hi, any suggestions would be welcome

2 x KAD 44 on DPE, 1000hrs

In the last year port boost slowly dropping. Two new turbos replaced 2 yrs ago and now at cruising 3200 rpm about 5 psi difference, also 10% less fuel.

My understanding is the fuel computer EDC will allow more fuel if enough boost being created.

So far the following has been completed.

Normal yearly full service, filters etc. checked for air charge leaks in pipes and aftercooler box, no leaks of water or air.

Mixer on port engine removed to allow visual inspection of exhaust side of turbo and all good.

1000hr top end service on both engines, injectors, valves and compression tests, all good (injectors nozzles replaced etc)

Swapped fuel computer with each engine and fault did not move, so not the computer.

Air pressure sensor on manifold my last option that I can think of which I will test this weekend, sensors looked ok when swapping over.

Has anyone had an issue like this and have suggestions of what to consider ?

Regards.

Is there an air pressure sensor on the manifold? The boost pressure sensor is inside the EDC unit.

It could be the Charge air temperature sensor that has a default value if an open or short circuit is detected.

There's also a Fuel temperature sensor that does a similar thing and can be tested too with a multimeter.

Plugging in Vodia would tell you what's going on.

Do you have the EDC workshop manual? It's very useful. Message me your email address if you want a copy.

Hopefully @volvopaul or one of the proper Kad whisperers will be along soon.

 

[Mr Googler]

or one of the proper Kad whisperers will be along soon.

bit rude ???

Yes.....wait for BruceK......he’ll have it in bits toot sweet ?

 

[petem]

bit rude ???

Yes.....wait for BruceK......he’ll have it in bits toot sweet ?

I was comparing them to an armchair mechanic like myself!

 

[CraigC]

Is there an air pressure sensor on the manifold? The boost pressure sensor is inside the EDC unit.

It could be the Charge air temperature sensor that has a default value if an open or short circuit is detected.

There's also a Fuel temperature sensor that does a similar thing and can be tested too with a multimeter.

Plugging in Vodia would tell you what's going on.

Do you have the EDC workshop manual? It's very useful. Message me your email address if you want a copy.

Hopefully @volvopaul or one of the proper Kad whisperers will be along soon.

Have a manual, thanks for offer. Yes moved the manifold sensor but due to weather couldn’t test it today. It’s the temp one I believe ( had a filament type wire over a structure).

 

[CraigC]

The swapped sensor didn’t unfortunately change the lower boost, any suggestions welcome for other possible solutions. I feel it must be one of the many sensors feeding the EDC

 

[Mr Googler]

The swapped sensor didn’t unfortunately change the lower boost, any suggestions welcome for other possible solutions. I feel it must be one of the many sensors feeding the EDC

Why? Have you removed the charge air cooler stack and cleaned?

if it needed new turbos.....probably threw a bit of oil down them over the years.

 

[CraigC]

Thanks for your suggestion, yes both removed and cleaned when turbos done about 200Hrs ago. no water leak and only air coming out of Small drain hole at base of air charger box. Air filters new from service so shouldn’t be any restrictions to air supply

 

[petem]

Thanks for your suggestion, yes both removed and cleaned when turbos done about 200Hrs ago. no water leak and only air coming out of Small drain hole at base of air charger box. Air filters new from service so shouldn’t be any restrictions to air supply

The instructions for testing the resistance for each sensor are in the manual.

Plugging in Vodia might save a lot time.

 

[volvopaul]

Is there an air pressure sensor on the manifold? The boost pressure sensor is inside the EDC unit.

It could be the Charge air temperature sensor that has a default value if an open or short circuit is detected.

There's also a Fuel temperature sensor that does a similar thing and can be tested too with a multimeter.

Plugging in Vodia would tell you what's going on.

Do you have the EDC workshop manual? It's very useful. Message me your email address if you want a copy.

Hopefully @volvopaul or one of the proper Kad whisperers will be along soon.

Actually plugging In vodia doesn’t tell you what’s going on so don’t be lead into thinking a plug in is the answer it’s not.
I attended a KAD 300 boat this week , poor guy has had 3 different VP dealers one of which an old time company who fitted thousands in parts , turbos , elbows etc etc and no improvement whatsoever, another dealer on it spending hours same results.

I plug in original key to read Engine history of faults , compare parameters of both engines , carry out trial on river with limited space to find internal injection pump problems , no doubt owner will report after my next visit .

Vodia is not always the answer , ask any car garage about diagnostics plug ins they don’t always show the fault or the path to repair.

 

[petem]

Actually plugging In vodia doesn’t tell you what’s going on so don’t be lead into thinking a plug in is the answer it’s not.
I attended a KAD 300 boat this week , poor guy has had 3 different VP dealers one of which an old time company who fitted thousands in parts , turbos , elbows etc etc and no improvement whatsoever, another dealer on it spending hours same results.

I plug in original key to read Engine history of faults , compare parameters of both engines , carry out trial on river with limited space to find internal injection pump problems , no doubt owner will report after my next visit .

Vodia is not always the answer , ask any car garage about diagnostics plug ins they don’t always show the fault or the path to repair.

But Vodia would tell you if a sensor had failed causing it to use a default value.

And to be fair Paul, I did suggest some good old fashioned mulimeter testing of the sensors (no Vodia required) too!

When you say "plug in original key", what do you mean?

 

[volvopaul]

But Vodia would tell you if a sensor had failed causing it to use a default value.

And to be fair Paul, I did suggest some good old fashioned mulimeter testing of the sensors (no Vodia required) too!

When you say "plug in original key", what do you mean?

EDC key before vodia was invented the first generation diagnostic tool
Its not all about the sensor values sometimes it’s how they send the info to the ecu .

 

[CraigC]

Still chasing this root cause.
After checking more items potentially it is looking towards the injector pump. KAD 44 have the electronic actuator which turns an eccentric cam that allows more or less fuel to the injectors etc..
Has anyone any experience with this and can it be adjusted. Seems it is working but engine running lower on boost and using less fuel and is not the turbo or injectors.

 

[kashurst]

have you checked for fault codes recently? If the fuel temp sensor is playing up the engine, by design, deliberately holds back a bit. Check the resistance between pins on the fuel injection pump connector. The pump itself is a modified VE design. The actuator inside the pump that moves the spill collar, is directly controlled by the ecu and it's position is sensed by the ecu. There isn't very much to go wrong in the pump itself, and there are no mechanical adjustments as it is a closed loop feedback system. If the actuator fails the engine won't run at all, if the actuator sensor fails the engine may run at a rough 1500rpm and will not respond to the throttles.
It sounds like your engine is basically OK but for some reason its not working quite as hard as the other. It's either lack of air or lack of fuel - have you checked your fuel pipes for kink and tight bends? And again plug in a code reader its a lot quicker.
edit 5 psi boost pressure difference is nothing to worry about.
Have you checked the other engine and outdrive is actually OK - there may be a reason why it is working harder and using more fuel.

 

[petem]

Have you checked the other engine and outdrive is actually OK - there may be a reason why it is working harder and using more fuel.

I was thinking the same. Check the props. I've read loads of posts over the years where this has been the cause. Often is the prop on the 'other' engine that is causing an engine to under or over work.

 

[CraigC]

have you checked for fault codes recently? If the fuel temp sensor is playing up the engine, by design, deliberately holds back a bit. Check the resistance between pins on the fuel injection pump connector. The pump itself is a modified VE design. The actuator inside the pump that moves the spill collar, is directly controlled by the ecu and it's position is sensed by the ecu. There isn't very much to go wrong in the pump itself, and there are no mechanical adjustments as it is a closed loop feedback system. If the actuator fails the engine won't run at all, if the actuator sensor fails the engine may run at a rough 1500rpm and will not respond to the throttles.
It sounds like your engine is basically OK but for some reason its not working quite as hard as the other. It's either lack of air or lack of fuel - have you checked your fuel pipes for kink and tight bends? And again plug in a code reader its a lot quicker.
edit 5 psi boost pressure difference is nothing to worry about.
Have you checked the other engine and outdrive is actually OK - there may be a reason why it is working harder and using more fuel.

Thanks for your response
I will check the fuel temp sensor.
The starboard engine (Other engine) at its recent full service, the leg was taken off and All ok and no prop issues etc. the boost is correct as per manual 21psi at around 3200rpm.
The port engine gets to WOT just boost down. Gauges checked on weekend. Fuel lines ok as all checked when injectors serviced at the 1000hr.
Both sides of the turbo inspected and the y non return valve in the air line to the turbo so air is ok.
thanks for help

 

[kashurst]

Boost pressure is proportional to load, not engine speed so if one engine is not working as hard the boost will be a bit lower anyway.
How have you calculated your fuel consumption?
Something else to try is measure the temperature of the link pipe that goes from the turbo to the charge air cooler - use an IR thermometer or buy a cheap BBQ wireless thermometer and tape the sensors to the link pipe. The temps should be about the same, when measured at the equivalent point on each engine. At 3200 rpm on my KAMD300s with a clean hull the link pipe is about 125 degs C. close to the air cooler.
If an air filter is starting to bung up, that engine will do less work, burn less fuel and there is a distinct temp difference. My Port engine air filter starts bunging up faster than the starboard as it gets exposed to more belt dust and does what you seem to be describing. KAD air filters bung up pretty quickly (20 hours or even less) because of the belts, so as an experiment try the test with the air filters removed as well (obviously make sure nothing is going to get sucked in) for a few miles and see what difference in temperature you measure.
On the picture below I measure where the black insulation tape is.