CDT Injectors, Question

Best_of_British · 30th July 2015, 20:29

Quick question regarding injectors, following replacing one injector yesterday which cured my non-starting issue. After replacing injector with a 2nd hand one that has been sat around for 3 years it fired up straight away but I noticed a serious diesel knock, I can only liken it to an old class 37 diesel electric.

On checking the RPM on tick over it was pretty random, a 100RPM swing. Today I have thrashed the life out of it and gone through several start stop cycles. The result is that it now ticks over sweetly at 779 to 780 RPM, the question is did the injector just need the cob-webs blowing off or is the ECU clever and having been compensating for the the old duff one has it now learnt the new one and balanced it?

bl52krz · 30th July 2015, 20:37

probably a bit of both.

marinabrian · 30th July 2015, 20:38

Quote:

Originally Posted by Best_of_British

Quick question regarding injectors, following replacing one injector yesterday which cured my non-starting issue. After replacing injector with a 2nd hand one that has been sat around for 3 years it fired up straight away but I noticed a serious diesel knock, I can only liken it to an old class 37 diesel electric.

On checking the RPM on tick over it was pretty random, a 100RPM swing. Today I have thrashed the life out of it and gone through several start stop cycles. The result is that it now ticks over sweetly at 779 to 780 RPM, the question is did the injector just need the cob-webs blowing off or is the ECU clever and having been compensating for the the old duff one has it now learnt the new one and balanced it?

Bit of both I'd say

Keep an eye on it though, it may have been a bit of crud or drool of diesel down the bore when you removed the old injector

Brian

DMGRS · 31st July 2015, 10:18

The massive pressure the injectors run at will usually clear out any accumulated bits and pieces around the nozzles - that's probably what's done it (and the ECU can balance any minor issues).

I had a ZS TD with a slightly leaky injector, the knock was rather worrying!

hogweed · 31st July 2015, 10:25

Quote:

Originally Posted by marinabrian

Bit of both I'd say

I'm sure I remember you saying these ECM's don't learn, Brian... or was that just regarding the map or something?

Or have I finally cracked... again...

marinabrian · 31st July 2015, 15:07

Quote:

Originally Posted by hogweed

I'm sure I remember you saying these ECM's don't learn, Brian... or was that just regarding the map or something?

Or have I finally cracked... again...

No, but they do compensate for injector variance though

Brian

Best_of_British · 31st July 2015, 15:21

Seems to have settled and be running fine now, was just rough at 1st. Maybe got a glug of full fat Coke a Cola and didnt like it.

30th July 2015, 20:29	#1
Best_of_British Gets stuck in Rover 75 Tourer & Arden Green Project Join Date: Jul 2012 Location: Ormskirk Posts: 932 Thanks: 159 Thanked 200 Times in 155 Posts	CDT Injectors, Question Quick question regarding injectors, following replacing one injector yesterday which cured my non-starting issue. After replacing injector with a 2nd hand one that has been sat around for 3 years it fired up straight away but I noticed a serious diesel knock, I can only liken it to an old class 37 diesel electric. On checking the RPM on tick over it was pretty random, a 100RPM swing. Today I have thrashed the life out of it and gone through several start stop cycles. The result is that it now ticks over sweetly at 779 to 780 RPM, the question is did the injector just need the cob-webs blowing off or is the ECU clever and having been compensating for the the old duff one has it now learnt the new one and balanced it?

30th July 2015, 20:37	#2
bl52krz This is my second home Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008 Location: Birmingham Posts: 11,397 Thanks: 6,587 Thanked 2,262 Times in 1,729 Posts	probably a bit of both. __________________ Great Barr, Birmingham.

31st July 2015, 10:18	#4
DMGRS Discount MG Rover Spares Rover 75 CDTi, 2x MG ZS180 Join Date: Jun 2011 Location: Hythe, Southampton Posts: 11,320 Thanks: 456 Thanked 3,377 Times in 2,027 Posts	The massive pressure the injectors run at will usually clear out any accumulated bits and pieces around the nozzles - that's probably what's done it (and the ECU can balance any minor issues). I had a ZS TD with a slightly leaky injector, the knock was rather worrying! __________________ Your trusted MG Rover specialist! Tel: 02380 001133 / Email: [email protected] We now have a 'chat' function on our site for even quicker replies. Give it a try! Remember - discount code FORUM5 for 5% off

31st July 2015, 15:21	#7
Best_of_British Gets stuck in Rover 75 Tourer & Arden Green Project Join Date: Jul 2012 Location: Ormskirk Posts: 932 Thanks: 159 Thanked 200 Times in 155 Posts	Seems to have settled and be running fine now, was just rough at 1st. Maybe got a glug of full fat Coke a Cola and didnt like it.