AQAD30a noise

Slobbit

Slobbit

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Hi,
I have two AQAD30a engines powering a FJord 30', one of them runs fine but the other is down on power under load (2000 rpm max).
If you push the throttle full open it just stays at 2000 rpm but doesn't sound like its straining, with no load the engine will rev freely.
There is also an intermittent noise which I can only described as a marble pinging around and clacking.
I have checked the injector pump timing with the correct gauge and found it to be about 1.5 degree out and is now corrected; looking back on the documentation the pump was reconditioned about 2 years ago for the same reason (lack of power).
I have removed cleaned and refitted the injectors with new seal washers.

My question is would a faulty injector cause this sort of noise from the engine, I am thinking the next step would be to get the injectors checked for wear.
All fuel lines, lift pump and filters have been checked for blockages and air leaks.

Regards
Slobbit
 
Check the turbo boost pressure! Also check the smoke limiter hose!
Air leakage? Clogged charge air cooler?

Do you see any smoke? Color? The sound are they wery strong ? Or just normal diesel combustion?

If you have a bad nozzle losen up one hi pressure pipe at time and se if the sound is dissapearing!
 
Hi Ulyden,
Thanks for the pointers, where would I find the Smoke limiter hose?
Not sure what you mean by the charge air cooler but if you mean the air filter it has been replaced for a new one.
There was white smoke (not Steam) before I did the injector timing but it now seems to have cleared.
The noise is a bit strange, it's louder than a loose tappit and you can hear it above the normal engine noise a bit like a small end going but there is no rhythm to it.
The noise doesn,t get louder as you increase the revs but it happens more often.
I will try cracking open each injector pipe next time I'm down there, I did do this a couple of days ago to bleed the injectors and to see if they had equal affect on the revs which they did.
 
The smoke limiter hose you find between the air inlet manifoild and the top of the fuel pump. On the fuel pump there is a membran with a spring bellow!
If you dont have boost press it dont give maximum fuel! To prevent black smoke. If the hose is bad or the line is clogged it dont sense the boost pressure and you dont get any power! If the engine have 110hp it has a intercooler! This can be clogged! Measure the boost pressure after this!
 
Had a look at the drawngs but no sign of smoke limiter, there isn't anywhere on the injecton pump for a hose to fit onto only the 1 fuel in and 4 out.
It is 110hp but with after cooler.
Not sure how the boost is controlled unless its governed by the fuel demand or engine rpm.
 
The last tamd 40 I heard that noise from had dropped the valve seat out of the head, which the net result was, new head, new piston, new turbo!!!,

I would test each cylinder in turn with the engine running, slacked off each injector pipe in turn and listen to which cyliner drops power, the engine may even stall.

If one cylinder makes no difference when the pipe is loose and spitting fuel out its that cylinder thats the problem, it could also be an injector nozzle thats failed, the noise could be pre ignition, is this a fault after the timing was done? maybe its too far advanced now and causing the noise (pre ignition too far advanced ), did you use the correct tools to dial the timing on the pump and set to correct injection angle?
 
Hi Volvopaul,
I checked the timing because of the noise and loss of power with the correct tool, but yes the noise was there before timing it.
I have already cracked open the feed pipes they all make a difference of around 100 rpm at tick over. I suppose if a valve seat had dropped it could be still held by the valve and jumping up and down with it. The only problem I have with this idea is that the engine runs quite smoothly apart from the noise and the lack of power under load.
Thanks for your input.
Slobbit
 
If the sound is the same before and after adjusting the timing its propably not combustion noise! Else the other engine could have had to low timing and nicer sound! This engine is a prechamber engine and the nozzles is different from a direct injection engine!

If you are tough guy you pull out the nozzle and mount the hi pressure pipe so you can run the engine with the nozzle outside the engine. Then you can se the spray pattern.Dont spray it on a hot surface and dont smoke! Shuld be a 15 deg V shape.No big droplets or uneaven spray! The fuel shuld be nearly vaporised! I have tried this on my car!

When the nozzle is out you can cheeck if the sylinder is leaking or not!
If the valve seat is out it will be leaking!
 
Ulyden,
I was going to try the inectors out of the engine but I would have to make up a hp pipe to allow me to do this as there is no movement on the hp pipes to the injectors.
It would be a good idea to pressure test the cylinders but I don't have a gauge to that would fit, I'll have to try and get hold of one.

Thanks
 
If you dont have anything! Keep the nozzles in! Mark the weel on the crankshaft front end and crank the engine 2 revs. You will then feel 4 kompressing cycles! They should feel quite equal! If you take off the valve cover you can check wich sylinder you are testing. If there is a mark on this weel that is syl1. If the valves on syl 1 has clearens in this posisjon you are in the combustion stroke! Next cylinder is then 3 then 4 then 2 starting from flyweel cranking clocwice seen from the front!

Have seen use of an current clamp ampermeter on the starter + cable and an osiloscope. Dont know if its good! The current peeks shuld then be even!
Havent tried this myselve!
 
I can't turn the engine over by hand there is too much compression to do that.
I can understand the theory of the scope, current drawn should be equal on each compression stroke, but I think it may easier to get hold of a compression tester.

I have been thinking other area's that I could look at would be push rod's, worn lifters and broken valve springs.
 
ulyden said:
If the sound is the same before and after adjusting the timing its propably not combustion noise! Else the other engine could have had to low timing and nicer sound! This engine is a prechamber engine and the nozzles is different from a direct injection engine!

If you are tough guy you pull out the nozzle and mount the hi pressure pipe so you can run the engine with the nozzle outside the engine. Then you can se the spray pattern.Dont spray it on a hot surface and dont smoke! Shuld be a 15 deg V shape.No big droplets or uneaven spray! The fuel shuld be nearly vaporised! I have tried this on my car!

When the nozzle is out you can cheeck if the sylinder is leaking or not!
If the valve seat is out it will be leaking!
Click to expand...


Never and absolutely never run an engine with the injector out of its sleeve to check the spray pattern.

If one of my engineers got caught doing this, I would sack him on the spot.

If you suspect a bad injector, get em checked and overhauled.

Very Very dangerous and not knowing the different engine types of anyone reading this, could pop an injector sleeve, resulting in an engine full of water.

A VERY BIG no no.
 
tinkicker0 said:
Never and absolutely never run an engine with the injector out of its sleeve to check the spray pattern.

If one of my engineers got caught doing this, I would sack him on the spot.

If you suspect a bad injector, get em checked and overhauled.

Very Very dangerous and not knowing the different engine types of anyone reading this, could pop an injector sleeve, resulting in an engine full of water.

A VERY BIG no no.
Click to expand...

I do agree dont do this on any engine! On a 31 or 41 it can be dangeorus

This is a prechamber engine normal this prechamber is fixed quite well in the head! In my engine i have done this severale times!

If you are in an emergency you can take out all nozzles, emty the engine for water, and run the engine on the starter with the nozzles out!

But in general i agree. If you can easyli have the nozzles cheched
do that!

And in general dont do it!
 
I have done this test on site before, all you need to do is clamp the sleeve down with the bracket that holds the injector in, cut off the fuel supply by cable tying the manual stop control on the pump and turn the engine over, though to be fair all you will see is a spray pattern you wont be able to test the opening pressure which is very important.
 
I think I would be more concerned about the personal safety risk than the risk of injector sleeve leaking water into the cylinders. I believe the preshure of the diesel injection system can easily fire the fuel through your skin and into your blood stream. I know some of us believe we have diesel pumping through our veins!

DO SO AT YOUR OWN RISK!
 
volvopaul said:
................. cut off the fuel supply by cable tying the manual stop control on the pump and turn the engine over, though to be fair all you will see is a spray pattern you wont be able to test the opening pressure which is very important.
Click to expand...

Err, if you pull the manual stop lever, how will you get a spray pattern at the injector- have you not just shut down the fuel supply to the injector?
 
NorthUp said:
Err, if you pull the manual stop lever, how will you get a spray pattern at the injector- have you not just shut down the fuel supply to the injector?
Click to expand...

Yes you still get a small amount of fuel there but not a full pressure, its just a way of testing to see if the injector actually opens, there is still fuel in the pipe that will be pushed through at a certain pressure by the cam plate.

I did this to test before removing all the injectors and taking them to a bosch agent.
 
volvopaul said:
Yes you still get a small amount of fuel there but not a full pressure, its just a way of testing to see if the injector actually opens, there is still fuel in the pipe that will be pushed through at a certain pressure by the cam plate.

I did this to test before removing all the injectors and taking them to a bosch agent.
Click to expand...

I know you are right. Some yers ago was changing fro CAV to Bosch pump on an engine and it did not start even if all the marks were correct. I removed the drive belt and rotated the pump shaft. I could clearly feel the pump cycles! When i mounted a plastick hose on syl one pipe i discover that the level was rising in next cycle acording to marks. I had to make a new alignement mark!

Then i rememberd that the solinoid was in stop. Still there were fuel comming! Remember that an engine needs maybe 5% of maximum fuel just to idle!
 
Hi everyone,
Thanks for all your input, the next stage will be to take the belts off of the engine to make sure it's not a water pump bearing or an alternator noise then if the noise is still there I will take the injectors out and get them checked and overhauled. This would save a lot of messing about and will answer the question of whether the noise is mechanical or combustion related.

Regards
Slobbit

PS, anyone know of a good and reasonably priced injector workshop around coastal Hampshire or West Sussex
 
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