Knocking noise

[fourteen8]

Arrived home and notice knocking sound while its idle. Well I have tried to check whether the knocking is ther as well when its not idling.

The knocking last about 5 seconds and gone for about 2-3 seconds and comes back on again.

I dont what that noise is. Anyone experienced this before?

[Blknight.aus]

see if you can get someone to plug a nanocom into it and read what the compensation numbers are doing when its knocking.

[fourteen8]

see if you can get someone to plug a nanocom into it and read what the compensation numbers are doing when its knocking.

Unfortunately I dont know anyone who has nanocom.
What is compensation numbers? What can you tell from that number? Sorry, I am trying to understand what's happening.

[Blknight.aus]

the compensation numbers are a dynamic number thats the computer deciding when to fire which injector.

if its knocking and these numbers are steady it pretty much elminates the brain, the injectors and all the sensors.

if those numbers are changing a little bit its trying to compensate for something and not having a good time geting a stable run this might be because of a couple of dirty sensors or connectors or oil in the harness

if those numbers are jumping around then its possable that its knocking becuase its getting bad info from some sensors.

in both the latter cases you will have some fault codes in the system.

other than that its mechanical and could be anything from a big end to piston slap to something external on the engine to a loose body fitting thats vibrating in harmony with the engine.

without a nanocom to do the easy start your best bet is to let it idle and knock then probe around with a hollow rod on various bits with your ear on the rod to try to isolate the noise.

[fraser130]

Where in Melbourne are you?
I have a nanocom......

[justinc]

If it is a V8 and the engine is at operating temp, then I would be worried about a loose liner...:( If a Td5, then some fuel maps will give a little more diesel knock at idle, cyclically. That is not a problem, as long as that is all it is...

JC

[fraser130]

1 step back, is it a TD5?

Fraser

[gazk]

the compensation numbers are a dynamic number thats the computer deciding when to fire which injector.

if its knocking and these numbers are steady it pretty much elminates the brain, the injectors and all the sensors.

if those numbers are changing a little bit its trying to compensate for something and not having a good time geting a stable run this might be because of a couple of dirty sensors or connectors or oil in the harness

if those numbers are jumping around then its possable that its knocking becuase its getting bad info from some sensors.

.

These (TD5) numbers that you can read with a NANOCOM are described thus:
• Power balancing RPM 1 to 5: In the manufacture of an engine there are unavoidable tolerances which vary. This means that each cylinder's power output relative to the others can be higher or lower than others. This imbalance shows up much more at lower engine speeds such as those encountered at idle. It can make the engine seem lumpy and rough especially under acceleration at low speeds when the power is used. Under normal operating conditions, this factor is compensated for by the cylinder balancing routine built in to the software of the TD5 ECU.

This value shows the adjustments in rpm being applied to individual cylinders by the TD5 ECU to achieve smooth running. With the engine idling, the fluctuations in cylinder speed in rpm from the nominal idle speed can be seen. However, you should note that values outside of the range will be seen if the engine speed is varied suddenly i.e. blipping the throttle.


Source - ECU/Software Module Information System (http://www.blackbox-solutions.com/shop/help/)
Look under Diesel EMS - LUCAS TD5

[fourteen8]

1 step back, is it a TD5?

Fraser

Yes it is a TD5. Thanks for the offer franser but started again this morning and didnt hear the knocking noise. Hopefully its gone totally. But if it comes back, I will go back to your offer :)
I live in Wyndham Vale. South West of melbourne.

[fourteen8]

These (TD5) numbers that you can read with a NANOCOM are described thus:
• Power balancing RPM 1 to 5: In the manufacture of an engine there are unavoidable tolerances which vary. This means that each cylinder's power output relative to the others can be higher or lower than others. This imbalance shows up much more at lower engine speeds such as those encountered at idle. It can make the engine seem lumpy and rough especially under acceleration at low speeds when the power is used. Under normal operating conditions, this factor is compensated for by the cylinder balancing routine built in to the software of the TD5 ECU.

This value shows the adjustments in rpm being applied to individual cylinders by the TD5 ECU to achieve smooth running. With the engine idling, the fluctuations in cylinder speed in rpm from the nominal idle speed can be seen. However, you should note that values outside of the range will be seen if the engine speed is varied suddenly i.e. blipping the throttle.


Source - ECU/Software Module Information System (http://www.blackbox-solutions.com/shop/help/)
Look under Diesel EMS - LUCAS TD5

Should I be worried? From your explantion, it is something that is normal with TD5. But, I just heard this noise only yesterday.

Didnt hear the noise again this morning. Planning to go to city later today and see whether I will hear the noise again.

[gazk]

I've watched the numbers jumping around a bit when idling. Never had any knocking sounds. With mine the numbers seem to remain around 1 to 3. With a nanocom you can record these parameters (and lots of others) while driving along then replay and graph them.

[fourteen8]

I did drive for quite liong distant on the weeked. On the first stop at the carpark after about 30km drive, I can hear the noise and the temp was about 89 degree which is normal (I think thats the operating temp).

After that drive another approx 20-25km and did hear the noise when idling.

Arrived home and didnt hear the noise again but I noticed that the temp was about 85 degree which is lower.

Anyone has a clue?
Is it worth buying a nanocom? What can you with it?

[phuma]

Old thread I know - did you ever get to the bottom of this? Someone said some maps do this - why?