Volvo D4 which test do you trust

[trnsmaster]

Fighting lack of power loss of rpms .
Computer scan shows weak compression/ power output on cyl #1 & 4, and full output on 2&3.
Mechanical compression test shows cyl 1&2 equal and cyl 3&4 equal . However 1&2 are 50 lbs less than 3&4.
Which test do you trust ?
If computer scan is reading wrong would that mean the computer/ecm is bad ?
Thanks

Topic

[Tony Athens]

So far so good, but that looks like an intake valve? —————–Is that #4, the most likely one to have seen water unless this was a v-drive application , then #1..Exhaust valves are the ones that will show what is going on as to water.

[trnsmaster]

Pulled worst looking intake and exhaust valve.
Wetness in all pics was from adding oil to cylinders doing 2nc comp test to check for difference

[Tony Athens]

You are just about there……..Let’s see pics like the attached.. Then maybe we can both say all seems good this way..

Tony

[trnsmaster]

Don’t see any internal problems do you ?

[Tony Athens]

Pictures of Turbos that have never see salt water

Look at what the exhaust side of a MARINE turbo outlet looks like that has never seen salt water splash up thru the exhaust system — Soft velvety carbon that will wipe off with your finger….3 of these turbos have more hours on them than 10+ of the average boats put together that hang out on forums like this………… What do you think your valves look like?

Your call as to what you think has been going on for years.

Tony

[trnsmaster]

New turbo hasn’t seen salt water ???

[Tony Athens]

The answer is in your pics.

Obviously your engine is eating saltwater up the exhaust– Not gross, but nevertheless, it’s doing it and as the pressure builds, the turbo most likely starts to drag on the thrust bearings and won’t come up to speed. .

Since your boost is low, why not put a switch on the supercharger clutch to turn it on manually for testing?

You have a very high strung engine and eating saltwater up the turbo for years has probably also finally done in the valves and overall compression to where internally those are outside the specs they need to make the power YOU NEED..

Turbos & Saltwater have never got along and why builders continue to install engines with an exhaust system that is begging for issues this way blows my mind……

What a Marine Diesel Turbo should look like when Inspected

Tony

..

[trnsmaster]

Turbo pics

Old and new turbo

[Tony Athens]

This is important–Remove the exhaust elbow/mixer ( or ??) and let me SEE inside the exhaust turbo outlet.. Clear & in focus from about 6-12″ away.

[trnsmaster]

Tony Athens wrote:

1) Vessel speed now at 2400 (WOT) vs. when things were good?
Can’t get up on plane 2400 was 18 it now 14k but 1800 was 12kt and still is 12 kt

2) If the vessel is not on plane at 2400, is it possible to remove a lot of weight just for testing purposes? Super low fuel, everything off the boat..

boat is unloaded no gear no ice minimum fuel

3) Dark smoke– This is important–Remove the exhaust elbow/mixer ( or ??) and let me SEE inside the exhaust turbo outlet.. Clear & in focus from about 6-12″ away.
Dark smoke from turbo throwing oil into intake

4) Is the bottom super clean along with the props?
Bottom is clean and same condition all along. Props were changed initially to rule out spun hubs

5) Was this change in performance over 1 day, a week or ??
One day and worsening

6) Is this a in-line drive, out drive, or?.. Post the actual engine rating/RPM (there more than one version of this engine )
Volvo D4 260hp I/o
Tony

[Tony Athens]

1) Vessel speed now at 2400 (WOT) vs. when things were good?

2) If the vessel is not on plane at 2400, is it possible to remove a lot of weight just for testing purposes? Super low fuel, everything off the boat..

3) Dark smoke– This is important–Remove the exhaust elbow/mixer ( or ??) and let me SEE inside the exhaust turbo outlet.. Clear & in focus from about 6-12″ away

4) Is the bottom super clean along with the props?

5) Was this change in performance over 1 day, a week or ??

6) Is this a in-line drive, out drive, or?.. Post the actual engine rating/RPM (there more than one version of this engine )

Tony

[trnsmaster]

So you have no clue either ???

[trnsmaster]

1 )850 hrs when happened hasn’t got fixed 870 hrs now due to testing

2) previously 2800 is 20kt. 3000 is 22kt 3200 is 25kt wo@3600is30

3) can’t get over 2400 rpm now because of issue so can’t compare then to now speeds however then 1800was 12kt and 1800 now is still 12kt

[Tony Athens]

What am I missing……………….I asked 3 questions? Did I get a 1-2-3 answer?

Tony

[trnsmaster]

Vodia scan calls it compression test but is just comparing crank and cam signals for speed of revolution so it was explained to me! Problems started with blowing bearing on outputshaft in adapter from flywheel to transom shield .severe vibrations. engine normally max@ 3600. Couldn’t get past3000. Brought boat home go to do sea trial after changing props to make sure that wasn’t vibration / blown hub. Could barely get on plane as compressor would cut out at about 2200 and turbo didn’t seem to be keeping her going . It would surge back and forth as rpm drop comp kicked in then cuts off . Usually boost reads 28lbs at max 24@cruise of 3000/22knt.now only seeing 18/20.
So pull motor to replace bearing. Install new turbo while out . Check intake air passages , check charge air cooler for free air flow. Change all filters. Get motor back in boat have hard starting . Have to keep pumping prime pump on filter. Temps were freezing at this time . Getting black smoke out exhaust. Get started and runs smooth and runs up fine no load on trailer.
Go for seatrial can’t get on plane starts surging and falling off as compressor kicks in and out . Boost still at 18/20. Can’t get above 2400 rpm.
Changed boost/air temp sensor no change.
Changed crank, cam sensors. Ran off Gerry can gravity fed direct to motor bypassing all fuel filters no change. Still get black smoke. Ran without air filter . No change.
Change injectors, check timing , check cam reluctor for proper index, unplug solenoid on fuel pump making it go max fuel pressure, ran injector test on return lines , passes. So finally get it scanned with vodia . Shows 2 good cyl 2 bad. Swap injectors from good to bad same reading . Made sure injectors seating in cups .
Took old injector and made into adapter for compression testing. Got readings previously posted.
Now have motor back out of boat . They wanted charge air cooler opened up to check even though I already semi checked it . Pulled charge air off now it’s saturated with oil . New turbo is putting oil into charge air cooler.
Dealer tells me turbos leak oil if not making boost ??? My old turbo is bone dry though ??
So I am at a crossroads … do I pull head and have it checked as front two cyl were slightly lower than rear two .
Am wondering if all the vibrations didn’t damage computer/Ecm?
Every problem we ever had with motor was in the evc system. Bad junction modules bad shifters.

[trnsmaster]

Thanks for reply!
260hp D4 I/o 850hrs

[Tony Athens]

Volvo D4 low power issues

I cannot answer your question on the “computer scan” as I was not aware that any make /model of an ECM on a diesel engine could read compression….
.
But maybe I can help another way since it’s “lack of power” and low of RPM’s that you have an issue with..I deal this this issue quite often.

1) How long have you had this issue? Total engine hours now vs. engine hours and the approx date when things were running good and you thought you had more power and made more RPM..

2) Can you go back to where things were right? If so, running at 2800 & 3000 RPM, what was your vessel speed?

3) What is your vessel speed today at the same 2800 & 3000 RPM?

Need a comparison for “back then” and now as to vessel speeds at equal RPM’s..

Curious—————Is this a in-line drive, out drive, or?.. Post the actual engine rating/RPM (more than one version)

Tony

[Author]

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