IMT fault 155

[Nick Wootton]

Further to my last post had both turbos reconditioned to cure ‘sticky’ wastegate valve as the main suspect for the temperature fault. (Engines 200 hours so seemed possible – conscious of under use of engines) However went to use yesterday and at low speeds no issue at all – but as soon as add power and turbos engage IMT fault code yet again same side even though not necessarily that old turbo was installed on the same side as both literally came off the bench of a reputable turbo recondition firm…only other obvious difference which I would not know if related was that Gear Temp on the ‘faulty’ side was showing 47 degrees and on the ‘good’ side 78 degrees (that seems a more normal temp to an untrained eye for oil circulating around a gear box?)   So where now – Tony mentioned cleaning the HX but nothing on the diagnostic software led engineer to believe this would stop the fault – coolant temps both sides normal and HX I believe is after the turbos – also no overheating at low speeds. however, post an expensive non resolution, I feel worth rydlyming both sides altho not sure how it would  prevent fault 155 but other than replace temp sensors not sure what else to try – wiring fault? – poor earth connection somewhere? swap ECUS? any help gratefully read and acted upon

Thanks nick  

Topic

[shelby LHP, Florida]

Here is what it sounds like trying to start.

[Nick Wootton]

Sounds like you need the software attached and the fault code cleared – IMT fault one would assume only comes on when the temperature is too high, not when turn engine on – should be able to start her up without that fault so would look at software / code clear and wiring

[shelby LHP, Florida]

Nick,

Yes, the HX and After cooler was cleaned at a radiator shop  It wasn’t dirty as we just did the same cleaning 10 months ago.  

We still can’t get the engine to start, the 155 IMT Fault still appears.  

 

Tony,

is there a way to manually get rid of the 155 IMT Fault, is this why the engine won’t start?  Is there a list of why the 155 IMT comes on?

 

 

 

[Nick Wootton]

Hopefully correct

Very satisfying job to those that havent done it – altho hard work 

Cannot test for 2 weeks now but when I get back will attempt another run to see if IMT fault fixed – certainly hasnt done it any harm having turbos reconditioned and aftercoolers serviced and sensors swapped …going to run it with engineer onboard plugged in to computer

1 user thanked author for this post.

Scotth

[Tony Athens]

Picture of the core as removed from the aftercooler on the bench?? That is what matters.

[Nick Wootton]

Core replacement

Evening 

Can I just check that its ok to put core back in with some of the perfectly cylindrical tubes slightly less than perfect at the opening after removing from ACooler? About 4 on one end have become slightly misshapen – not enough to prevent flow but not as crisp circles as they are when new – all tubes completely free of blockages / limescale and fins all nicely copper in colour

[Nick Wootton]

wiring?

I am led to believe these engines are simple in design – i.e not a lot can go wrong – when you say serviced what do you mean ? – aftercooler been off like I am currently doing – mine was so crudded up as you can see from pics – currently sitting in rydlyme and then in simple green 

i switched sensors and fault remained (so know its not those – cheap fix if it is) – had turbos refurbed as suspect wastegate not opening – again possible corrosion but these are now brand new as will the aftercoolers be –  if i still get fault uk engineer thinks must be a wiring issue as nothing left, however i do think this aftercooler removal will solve it as it was so bad – worse than some of Tony’s examples and only 200 hours – obviously never removed as all paintwork around bolts was intact

[shelby LHP, Florida]

Following, we have the same error, can’t get rid of it

Our Port Engine Won’t start with the IMT Fault 155.

We have Cummins QSB 5.9

Turbo, Aftercooler, Heat Exchange have been serviced

Yes we have fuel pressure

We installed a new IMT Sensor, this didn’t clear the Fault

 

 

 

[Nick Wootton]

Re assemble without plastic strips?

Morning

 

IS this correct procedure to slide backin without plastic strips as per The Drippin Wet?

TIA

[Nick Wootton]

I mean the seawater side yes sorry  – have researched the aftercooler service on here and ‘The Drippin Wet’ who has 2 x very good vids on it – slightly surprised the plastic vanes are removed and not re-inserted as he does (advised by SBMAR) so I will do the same.

Regarding rydlyme and the seawater flush I will connect loop after impeller / pump and where the hose enters the exhaust as per VP engines.

 

[Rob Schepis]

“rydlyme the coolant side”

Do you mean the seawater side?

Have you searched the site for prior posts on cleaning the core tube bundles and other coolers?

[Nick Wootton]

Yes – have the service kit so will so will release the core today and imagine exactly the same – will add photos for future users – and will definitely be doing the s/b side too and then rydlyme the coolant side – not sure if there are any videos out there for the coolant side of the engine maintenance?

[1969Roamer46]

WOW! It wasn’t so much an aftercooler as it was a heat sink!

If your engines are configured anything like my 6CTAs, since all of the raw water passes through the aftercooler before cooling the gear and engine, it’s amazing you didn’t overheat! That really nails home Tony’s insistence about regular off-engine aftercooler maintenance.

I’m very interested to see what the air side of your aftercoolers looks like. I’d bet a nickle the fins are oil caked.

Cheers,<br />Q

[Nick Wootton]

Well this could be the reason….

Disassembled port side today as per Tony and this is her on the bench pre soak etc over 50% of the tubes blocked

[Gene Fuller]

In addition to dirt on the air side, it is also possible that the core was installed incorrectly if someone did take the aftercooler apart in the past. If the rotation is not correct there can be a major bypass of the air, and the air will not get cooled properly by the water tubes and fins.

Open it up on the bench.

[Scotth]

Tony has some excellent references under “Tony’s Tips,” https://www.sbmar.com/articles/cummins-marine-aftercooler-maintenance/

The air side will be visible when you pull the aftercooler core.  The air side can get dirty from oil blowby, salt, and whatever else might be floating air in your engine room.

1 user thanked author for this post.

Nick Wootton

[Nick Wootton]

the aftercooler being dirty on the air side – what does this mean ? – i can see the core which i am assuming is where the raw water flows – thru the tubes – will i be able to clean the air side when i remove the cooler?

[Nick Wootton]

Morning 

Was in salt for 9 years and my guess would be never removed I bet – what was odd was that there was no IMT fault during sea trial before i bought her

I am now definitely removing both sides tho as per the video – I have the service kit from you so will action that this week and send photos for any one else to see the condition

[Tony Athens]

Nick,

 

Two questions

——-How many years have your aftercooler been in salt water since the vessel was new? 

——-How many times have the aftercoolers been removed from the engine, put on the bench and serviced per my protocol?

 

 

[Scotth]

When talking about marine diesels, the heat exchanger refers to the engine cooling system (exchanges heat from engine coolant to raw water), the aftercooler refers to post turbo air cooler (exchanges heat from compressed air to raw water).  Your issue could relate to the aftercooler being dirty on the air side or low raw water flow through the aftercooler.

[Author]

Replies