KADP44 EDC supercharger engages and disengages please help!!!!

[GOBBI 375]

I have a GOBBI 375, 37.5’, 12 metric tons displacement, with 2 VOLVO PENTA KADP44 EDC. These motors were commissioned in 2001 and they have 340 hrs each. I have developed a puzzling problem with my port engine and I thought you guys may be able to help.
This is the sequence of events:
1.Everything is smooth until I reach 2850 RPM.
2.I push the throttles little more, (using full trim taps nose down) the engines reach 2950 - 3000, (18 – 19 knots).
3.The port engine’s supercharger disengages, and then it’s engaging again, thus loading the engine, which makes it drop down to 2700 RPM (14 – 15 knots). If I keep the throttles steady the supercharger engages and disengages continuously.
4.When this happens to the port engine, the Star port engine gets overloaded, the rpm drops and the supercharger engages.
5.The whole circle continues until I retract the trim tabs – nose up and then I hear the clutch of the supercharger of the port engine to engage disengage couple of more times.
6.From this point on the rpm goes up and then continue to rise to 3000-3100 and stabilize the speed to 23-24 Knots.
7.Now, I can increase the revs normally with no problem.

Did anybody have a similar problem? Do you know what could be the problem?

My certified VOLVO technician insists that I need a new turbo; he tested the engines and he says that he found out that the port engines’ turbo makes 2 psi less pressure than the specs. But he also said that the turbo spins freely which makes me having doubts as to whether the turbo is the problem.

Also I would like to ask if anyone has the electronics workshop manual for the KADP44 EDC engines.

Thanks in advance,

George

 

[spannerman]

Your VOLVO technician needs certifying I think, as the turbos are only just beginning to work when the compressor cuts out, they should then blow all the way up to 3600rpm.
I would first check the main belt from the crankpulley up to the water pump isn't slipping as this then drives via the 2nd belt the generator and compressor and so has the greatest load.
The other thing to check is the micro switch on the throttle arm on the injection pump as this gives a 'kick down' effect if you accelerate hard, and the relay that controls the clutch on the compressor that could be cycling due to a bad connection.

 

[Peanuts]

"My certified VOLVO technician insists that I need a new turbo;"

He is having a laugh at your expense, as already mentioned check the main belt that normally sorts out the problem.

I almost want to say name and shame, this sort of thing really pi$$es me off.

PM on its way.

 

[Imperial One]

My experience of these engines is that the supercharger comes in from start and then is replaced by the boost of the Turbo.
There are, as I recall, a number of belts driving the turbo and other pumps.
Some of the boats we have seen have rust on the bottom pulley which can make the belts slip and/or snap.
Be sure to check tightness of the belts and cleanliness of pulley.
Good advice above from Spannerman.
Apart from that I would look out for a post from Volvo Paul who will be along soon I am sure!

 

[volvopaul]

My experience of these engines is that the supercharger comes in from start and then is replaced by the boost of the Turbo.
There are, as I recall, a number of belts driving the turbo and other pumps.
Some of the boats we have seen have rust on the bottom pulley which can make the belts slip and/or snap.
Be sure to check tightness of the belts and cleanliness of pulley.
Good advice above from Spannerman.
Apart from that I would look out for a post from Volvo Paul who will be along soon I am sure!

Id quote much the smae as Spannerman, but also add 2 psi isnt a lot at thoses rpm figures as the turbos are only just boosting above the superchargers boost pressure.

Where I would look and this has happened only this week from a similar post regarding tamd73 engines, with smoke etc, is to check all hoses and clips and the o rings at the end of the turbo pipe from the turbo to the intercooler as this pipe carries the boosted air both from the charger and the turbo, any slight leaks as per the 73 scenario in which case the owner was told it was going to be££££££ and injector probs etc will cause a drop in boost pressure.

Moody off this forum has kad300, he recently had full diagnostics to find nothing but has had charger issues at that rpm and surging in and out, as the edcis quite sensitive over the earlier kad 42/43 engine as its rpm sensed not boost sensed the charger will cut in and out to keep an attained rpm figure, 1 new o ring fitted and the bottom washed cured his problem, its also another gobbi but a grand style 425, for sale any takers?.

So that sums it up, maybe down to lower boost/ air escaping/bottom dirty.

Personally if I had these motors, and every time I work on one I tell myself I dont want one!, id drive it on the turbo if conditions allow.

Pm me if you need any more or a visit if its local.

 

[strakeryrius]

I have a similar problem, also with KAD44s - mine seems to be the starboard engine supercharger or turbo. All is fine until you throttle up to about 2700 rpm. If you try to throttle up gently to 2800 - optimal cruising speed - the starboard engine revs keep dropping back to about 2500 and then increasing again to about 2700/2800 for a few seconds and then dropping back again, endlessly cycling like that.

However if I push up quickly to say 3200 rpm I can throttle back to about 2900/3000 gently and all is fine. It just won't settle at 2700 or 2800 revs. I've thrown wads of cash at this problem with Volvo technicians and they've all said different things.

The problem started after a Volvo dealer replaced all the injectors - supposedly doing a sea trial afterwards (and charging me for it) - but when I got back on the boat I couldn't get above 1500 rpm. It was found to be that the supercharger hose was not properly reconnected when they had done some post trial tweaking. Hmm.

They came to do another sea trial with me aboard and their technician said the same thing to me as to the OP - its your turbo producing 12 psi less than the other turbo at the same revs. You need a new turbo - that'll be another wad-load please. Needless to say that I had pretty much lost faith in them by then.

Since then we've eliminated fuel starvation - replaced all the hoses from fuel tank to engines as they were perished; definitely no bug in the fuel - and if there were it would be affecting both engines not just one. Last Volvo technician that looked at the problem said he'd swapped the Supercharger control units over between the engines and the problem had followed it. Paid for a new SCU only to find that the problem still persisted. Grrr!

I'm living with it at the moment as I can cruise comfortably at 2600 rpm or 3000 rpm and don't want to spend any more cash on it at the moment. However suggestions for things to try out will all be gratefully received.

 

[aquatom]

Sorry to disagree with the others on here. Yes check the belts first then check for boost air leaks first.

This problem can be caused by a worn turbo. Remove the exhaust elbow and check the gap between the exhaust turbine blades and the housing. Any more than about 1mm and this will cause supercharger to cut in and out as there is not enough boost preshure from the turbo when the supercharger cuts out.

Having the boat lifted and cleaned helps as a short term fix but the problem will return.

I have seen this problem many times now. Fitting new turbos sorts
it every time but do check everything else first.

Tom

 

[DavidJ]

Any more than about 1mm and this will cause supercharger to cut in and out as there is not enough boost pressure from the turbo when the supercharger cuts out.

How does the turbo make the supercharger switch in and out. I thought the supercharger is only switched via the solenoid which gets it's signal from a speed sensor on the KAD43 and I think a throttle arm microswitch on the KAD44 (could be wrong on the latter!)

I've had similar problems with my KAD43 due to badly fitted solenoid assembly (from new) the circlip was not fully positioned into it's groove which eventually (after guarentee!!) burnt out the solenoid clutch. Most unlikely that you have the same problem but I would have a small bet on something on the electrical line which switches the solenoid. I would expect a loose belt to give a squeeeeel when the supercharger is activated.

 

[aquatom]

No micro switch on a kad44. The supercharger is controled by the edc system. When the supercharger cuts out there should be enough boost preshure from the turbo to allow the revs to continue to climb. When the turbo is worn there is not enough boost preshure so the revs drop until the supercharger is engaged again and the cycle continues.

 

[DavidJ]

Thanks Tom, good explanation.

 

[GOBBI 375]

Kadp44 edc

I have to admit I was not expecting the many responses. From now on i will be visiting this site frequently.
I thank you all for your time and efford and knowhow.
The belts are ok. The diesel is OK.
I tend to beleive its the turbo .... well.. we shall see and i shall let you all know for future reference. The problem is that it will take some time till we know as the dealer in Cyprus, has no turbo on stock , so i have to wait for 14 weeks delivery. Can you beleive this ?

Best regards to all of you,

George

 

[aquatom]

Yes the turbos from Volvo are on back order at the moment I have two on order at the moment. You may be able to find some from another sorce.

Please keep us posted.

 

[volvopaul]

I have just boght 2 brand new units, not exchange from a dealer in the uk, pm me if you want a price for one, 3/4 days delivery.