Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

[fourd]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Agree ! think westpot is on the trail with the low power indicator light.

The problem should be the nozzle but before you order the nozzle make sure the Turbo is not Jamed as this can give you the same problem and you will get the same code P 1201 . the cost of the nozzle is 380 eur

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

UPDATE

Just got back from the boat, checked the alternator, including all of the tests, and it is fine, as for the battery light sorted, it was the split charge relay causing the light to be on, but as for the engine, Still no change, with the Rinda tool attached and under load the engine revs was fluctuating between 2540 and 2570rpm , as far as Cummins mercruiser is concearned, waste of time, they wont even come to the boat even if I pay them upfront,

I have taken off the ecu/ecm to try and get it tested, but where?
A gentleman in the north of England has offered to test it on one of his twin 300hp engines, but can't for another 2 weeks due to commitments, he is prepaired to come down to see the boat if the ecu/ecm is ok, to strip the timming cover of and get the diesel injector pump tested, (he has known the timming to be wrong even from factory new)
any more ideas??

 

[QC]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

with the Rinda tool attached and under load the engine revs was fluctuating between 2540 and 2570rpm

Can you (did you) see what was "desired" or "commanded" engine RPM? 30 RPM swing under load seems high which might indicate a true low power condition as opposed to a "limp home" type setting. I am also suspicious of such a random RPM setting for limp home . . .

If the desired was say 2550 then I am back to an ECM/TPS/Limp type deal. If the commanded was 3800 (rated) and you could only reach 2570 then I suspect more traditional low power items like air, fuel, timing etc.

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Can you (did you) see what was "desired" or "commanded" engine RPM? 30 RPM swing under load seems high which might indicate a true low power condition as opposed to a "limp home" type setting. I am also suspicious of such a random RPM setting for limp home . . .

If the desired was say 2550 then I am back to an ECM/TPS/Limp type deal. If the commanded was 3800 (rated) and you could only reach 2570 then I suspect more traditional low power items like air, fuel, timing etc.

The Code reader did not state "desired" or "commanded" it only gave flywheel rpm and #1 injector rpm (i think, which makes no senses?) both readings were consistent with each other

Spoke to the Gentleman up North again, he has a spare 250hp ECU/ECM which he is sending down to me for testing, he has had it working fine on his engines, so that should answer that issue one way or the other, should be able to test it before the weekend, if that isn't the problem, the he is prepaired to come down to strip the timing cover and get the injector pump tested as well,
Thank you everyone for your coments and guidence, it is very much appriciated, please keep the ideas coming.

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Has anyone had expierince of a split charge relay/self switching relay causing running problems?

 

[fourd]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Has anyone had expierince of a split charge relay/self switching relay causing running problems?

Do the last cheke with the Rinda you can cheke the nozzle RPM if I am correct it shuld be 2000 rpm if it is higher then it shuld be changed .dont remove the fuel pump before doing this test .

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Do the last cheke with the Rinda you can cheke the nozzle RPM if I am correct it shuld be 2000 rpm if it is higher then it shuld be changed .dont remove the fuel pump before doing this test .

from memory, the injector rpm is similar to the flywheel, please note, it has a new #1 injector recently fitted (1 engine hour ago) Please note, this engine has only 9 hours on it since it was fitted over 2 years ago, so you can all see why I am getting annoyed and all of this time has been spent trouble shooting!!!

 

[BIGALF]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Try checking you flow of fuel. I just found a clogged strainer in my fuel tank that caused my boat for bog down at load full speed. A simple check would be to hoock up a fuel tank to your line to the engine and try that. You might ffind a fuel screen inside the tank the problem.

 

[BIGALF]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Check your fuel strrainer inside your tank. I just found my problem of not getting to full load because my fuel intake tube inside the tank was clogged. Try another fuel tank directly to fuel strainer or fuel pump and see what happen. This could be a fuel flow problem with an easy fix.

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Hi BIGALF,
the boat has a new fuel tank, new fuel lines, new filter, and new lifter pump(as old one had a small filter which was blocked insde), is your engine a D-Tronic? if so, what internal diameter is the fuel line (for flow)??

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Hi all
I have just had a call from the gentlman from up north (England), he has managed to test my ECU on his twin 300hp setup, and guess whatttttt, it wouldn't rev past 2500 rpm !!!! so after over 2 years of trying to get the engine sorted, it turns out to be a dodgy ECU which was brand new from BARRUS.uk (ordered may 2006 but not recieved until Jan 2007), although I have not run the 250hp ecu on my engine yet, I feel confident that it will work, and I will be testing it on Tues, so fingers crossed !!!

 

[QC]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Thanks for the update, and congratulations . . . It always felt electronic to me. I was also very concerned about throwing any more parts at this thing as again, fixed RPM problems like that are not typically as a result of air or fuel issues, especially with no report of excessive white or black smoke. Let us know how she runs with the other ECU.

Just curious, don't you need some sort of factory passwords to be swapping ECUs?

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

No, the D-Tronic is a very simple ECM controlled diesel engine, so no it dosn't need to be matched (unlike modern common rail and sophistocated injection) but I will let you know on tuesday, which after over 2 years is looking very hopfull.
Just one thing, prior to the ecm being tested the gentleman concearned looked inside at the circuit board, and it had been marked in several places with a permanent marker as if it was a test ecm?
will keep you informed

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

looks like I found the problem!!

not only was I supplied a dodgy ECM by EP Barrus UK (UK Mercruiser importer at the time) but also a dodgy MAP/AIT sensor as well.
It all makes sense now, these parts were only delivered the week Barrus Ceased with the diesels as Cummins took over, and it looks like I was sent the faulty parts they had left on the shelf!

It turns out that the ECM was corrupt and although it stored the faults and worked as it should, it did not display them, and as it did not display them you did not know they were there, also this became apparent when the ECM was tried on a diferent engine, giving the same result 2500rpm !, the reason for this is the ECM was still carrying the fault code from my engine but was not visible, and thus could not be removed, as soon as I fitted the 250hp ECM , Bang ! the fault came up, Faulty MAP Code , most people can handle one failed component, but not two, especialy when they were both supplied brand new by the Dealer!!
But I am not out of the woods yet, still need a 300hp ECM and a new MAP sensor,
I will keep you all informed

 

[Alumarine]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

I've been following this thread.

Good luck there.

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

RESULT
Barrus UK have agreed to replace the ECM and the MAP sensor at a total cost of ?2694 what a result

lets hope thats the end of it
(probably not?)

 

[QC]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Their cost? I sure hope so, that's $4K USD

 

[Wandalen]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Good news m8 !
Glad to hear you getting the problem solved. I got a 250HP D-Tronic
And acording to the local Mercruiser dealer here the 250HP and 300HP D-Tronic are exactly the same engine, its only the ECM program that is different. I got a price of 7000NKR (700?) to reprogram mine up to 300HP
Keep us updated mate, let us know how many knots you are getting.
You will probably need a different propeller again, but i will guess 33knots on your boat. Remember this engine is strong as it got 300HP at 3900RPM.

~S~
Wandalen

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

Good news m8 !
Glad to hear you getting the problem solved. I got a 250HP D-Tronic
And acording to the local Mercruiser dealer here the 250HP and 300HP D-Tronic are exactly the same engine, its only the ECM program that is different. I got a price of 7000NKR (700?) to reprogram mine up to 300HP
Keep us updated mate, let us know how many knots you are getting.
You will probably need a different propeller again, but i will guess 33knots on your boat. Remember this engine is strong as it got 300HP at 3900RPM.

~S~
Wandalen

Hi Wandalen
I will be keeping the 250hp ECM until I get the new 300hp ECM, I should get the new MAP sensor first, so I will be able to log the performance, also I will be putting the 22" duo props back on instead of the 20", and keep looking at this thread as I will be updating every step of the way, I have seen your video and your boat moves very well, keep in touch, and yes the engines are the same apart from the ECM

 

[wetspot]

Re: Help, Mercruiser 4.2L D-Tronic wont rev past 2500rpm

WARNING do not be tempted to fit a 300hp ECM to a 250HP mercruiser D Tronic engine, although they apear the same engine, both the turbo and injector pump are diferent and also some internal parts, also the 300hp wont run right with a 250hp ECM, after over 2 years I have finally got my engine to run as it should, MERCRUISER and CUMMINS have got the wrong part number on their Systems, and if you order a new 300hp ECM you will infact get a 250HP ecm, you must demand the Bodensee ECM which is the same as the CMD 300ES,
for those who want to know, my boat (bayliner 1992 2556 command bridge) WOT 3800 24MPH , underpropped with 20" Bravo duo props 2:1 ratio, going to fit 22" props, and even 24" to see whiich is best