Knocking Noise in engine

I have a knocking noise in my 05 2.7L 647. I have had timing chain tensioner replaced along with all lifters, injectors, oil pump and injector pump. Some times the noise is worse than other times. It is random as it can be noisy hot or cold. Has anyone had a vacuum pump make this noise? I'm kind of out of ideas. I've pulled the drive belt to eliminate any components. If I use Lucas diesel conditioner the noise seems to lessen. I replaced the injectors as they failed the leak off test. I'm to the point I will just drive it until it blows. I have lots of power and fuel economy is around 20 mpg.

Have you had your oil pressure checked? There is a port on the driver's side of the engine that I used to hook up a permanent gauge to mine. Alternately, there is a test cap for the oil filter housing that allows oil pressure testing. Don't know what minimum specs are for the Sprinter, but my son's '87 190 2.5 TD service manual lists them for his. Probably close for ours, so if you need 'em, give a holler.

The oil pressure was checked before and after the oil pump was installed. I don't remember what the shop told me what the pressure was. I do know that they said it was within specs. The new pump is less than 6 months old. I will have to check the oil pressure myself since there is an extreme lack of competency here in FL. Best place to find a crook though.

Also have a high pitched hum coming from the EGR at idle (at least that is when I can hear it) and when I push my finger on the top of the valve where the label is, the noise goes away. Has anyone heard of that happening and if so is it normal or am I stuck with getting a new EGR?

Contact DocktorA

Icarus

You performed a leak off test? Explain how this is performed please. Also, can you do an injector kill test and see if it changes or goes away when each injector is shut off.

Type2teach wrote up the leak-off test.

I usde the clear plastic tubing in 4" sections as described in the thread about the leak off test and followed it to the t. After cranking for 10 seconds I measured the fuel in the tubes. #1-1.25" / #2-1.50" / #3-1.75" / #4-1.35"
#5-NO FUEL. #1&5 HAD BEEN REPLACED LESS THAN A YEAR AGO. #2-4 WERE ORIGINAL. All parts came from my local dodge dealer and had new bolts,seals and anti seize compound. LUCKILY THEY WARRANTIED INJECTOR #1 FOR ME.The switch out was easy and painless. I had all 4 replaced and the engine running within 30 minutes. Since then I have gotten the MB Star (knock off) That works well except for injector classification. Working on that now. I did an injector shut off and on a couple of the cylinders there doesn't appear to be a big difference. I can also run the cranking compression test. 2 cyls are just slightly different than the others. I did this late at night to test the unit. I'm hoping to try everything again this morning and write down the results.
The injector shot off test has never made the noise change or go away. It sounds high and in the front of the engine.

jcweller1 said:

I usde the clear plastic tubing in 4" sections as described in the thread about the leak off test and followed it to the t. After cranking for 10 seconds I measured the fuel in the tubes. #1-1.25" / #2-1.50" / #3-1.75" / #4-1.35"
#5-NO FUEL. #1&5 HAD BEEN REPLACED LESS THAN A YEAR AGO. #2-4 WERE ORIGINAL. All parts came from my local dodge dealer and had new bolts,seals and anti seize compound. LUCKILY THEY WARRANTIED INJECTOR #1 FOR ME.The switch out was easy and painless. I had all 4 replaced and the engine running within 30 minutes. Since then I have gotten the MB Star (knock off) That works well except for injector classification. Working on that now. I did an injector shut off and on a couple of the cylinders there doesn't appear to be a big difference. I can also run the cranking compression test. 2 cyls are just slightly different than the others. I did this late at night to test the unit. I'm hoping to try everything again this morning and write down the results.
The injector shot off test has never made the noise change or go away. It sounds high and in the front of the engine.

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OK, I still can't get the injectors to classify. This MB STAR knock off is programmed wrong with preset parameters. Anyway I did do the injector shot down test again and I got slight noise variations in cyls 3 & 4, and a major change in cyl 5. The rattle part of the noise when away. I ran the test a few times to make sure. I also ran the fuel rail pressure regulator and sensor test. I told me I had a fuel pressure sensor that was out of parameters and failed the test.
This may explain why the noise comes and goes. If the sensor is working properly or close enough to the tolerances then the noise is lessened, but if it is working out of the parameters, then the knock would be worse because the rail pressure would not be correct and neither would the injector spray pattern causing a knock. Just a theory.
I will gladly receive any input from anyone.

Oh I for got, I posted about a high pitched whistle coming from my EGR valve and have had no comments on that subject. When it whistles, I can put my finger on the top where the decal is and push down with very little pressure and the noise goes away. Any thoughts?

jcweller1 said:

...This may explain why the noise comes and goes. If the sensor is working properly or close enough to the tolerances then the noise is lessened, but if it is working out of the parameters, then the knock would be worse because the rail pressure would not be correct and neither would the injector spray pattern causing a knock. Just a theory.

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Sounds like a reasonable enough theory to be probably worth purchasing and installing a new part. That said, the DAD has the capability to monitor fuel rail pressure with live data. Your unit should do that too. Does the condition happen regularly enough that you can do a test drive with someone?

jcweller1 said:

I will gladly receive any input from anyone.

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Then I guess I'm included.

jcweller1 said:

Oh I for got, I posted about a high pitched whistle coming from my EGR valve and have had no comments on that subject. When it whistles, I can put my finger on the top where the decal is and push down with very little pressure and the noise goes away. Any thoughts?

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I remembered that the EGR control gets a PWM Pulse Width Modulated signal. That is confirmed in post #1 here about halfway down.

"PWM is the pulse modulated signal wire for the EGR
MAF is the signal wire from the MAF"

https://sprinter-source.com/forums/showpost.php?p=166801&postcount=1

and here





The PWM frequency can cause an irregularly manufactured coil or unit cover to mechanically vibrate with a resultant noise. By pushing on the unit you are either binding the loose parts or changing the lever point so the noise goes away. Often AC powered solenoid coils will have what is described as a "60 cycle" hum which I find an interesting term because it is actually a 120 cycle hum as the sine wave passes through "0" volts twice for each cycle.

Anyway, sometimes coils or covers make noise. I wouldn't worry about reliability. If the noise is driving you batty then maybe try tapping the cover lightly with a ballpein hammer to change the position. Personally I wouldn't worry about it.

Thanks for the continued feedback about your scan unit. vic

jcweller1 said:

The rattle part of the noise when away.

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It's hard for me to tell w/o hearing if the knock/rattle, etc. you're hearing is normal, or abnormal and if abnormal, what might be the cause. Maybe you could post a video w/ sound?

Some additional information. It may help if you have the capability to access the signals. vic

To give you all an update. Yesterday when I started the engine the noise was like a dry start engine and then it got lighter in sound till the next stop sign. For the next 7 miles it rattled so bad you would swear a lifter or 2 were coming apart. I got to work and let it idle for about 3 minutes as I was loading for a trio to the dump, and low and behold the noise was almost gone. It was so quiet in comparison that I had to check to see if everything was OK.
I then took off down the road and it was quiet for about a quarter mile then started all over again. This more or less rules out a hard part causing the noise. I think I will try the fuel pressure regulator as it did fail the test. I know these fuel systems are sensitive. I will try to post a video. Tried with my iPhone yesterday but the file was to big to email to myself. So I will record a better one and download to my PC then upload to the forum.

Thanks everyone. your input is very valuable to me.

Jim

Just a thought - I wonder if the harmonic balancer retaining bolt could be loose allowing the timing chain drive sprocket to shift around? If timing were varying, then I would expect some combustion noise differences. A note of caution here, only turn harmonic balancer clockwise (when looking from front).

I'll give the balancer bolt a check.
I did the injector shut down test again last night and when I shut down #5 (the one I didn't replace but is just about a year old) the rattle stopped. Aside from feeling a dead hole, the rattle was gone. I did this about 10 times just to make sure. This tools is fun.

I also ran the tests on the fuel rail again and the Rail Pressure Offset Test said that the rail pressure sensor generate excessive pressure and that it is faulty. So it looks like I may start with replacing the rail pressure sensor.

Never got around to taking a video clip of the noise. Still may do it and post it.
Thanks all!!!

Since the same rail pressure is seen by all injectors, maybe that's not the source of the noise? IIRC, the leak-off test showed no leak on #5. But, maybe injectors can fail in ways that test can't measure? If your tool can test that injector in other ways, I'd try. Or, just simply swap that injector with another to see if the noise follows the injector or stays with the cylinder/piston.

Wow, you seem to be bouncing around a lot. First it sounds like lifter rattling. But the noise goes away after killing #5 injector, this tells me you could have a problem in the lower end or the injector itself is overfueling causing a "fuel knock" Just curious.

Have you checked your oil level? What Oil do you use? Is it synthetic or base? What weight is it? Cylinder number 5 is the last one to get oil.

Also, there is a test we can perform at a dealership for checking injector leak down (or leak off) while the engine is running. I have seen a couple of cases where injector leak down is fine while cranking.

Also, according to how you've explained the leak down test, not having strong enough battery voltage could give you a false passing test simply because the engine wasn't cranking fast enough in that 15 seconds. Did you have a larger battery charger on it while cranking or at least charge the battery for a while before running the test. It's possible with all of the key on, engine off time messing with this brought the battery charge down too low. But still high enough to start.

Anyway, the engine running injector leak down test is very similar to the cranking test, only the vials are larger and of course you do not disable the engine from starting.

I have consistently found a soft code for the past few day with my MB Star.
It shows the fuel rail pressure sensor is over pressuring the rail.
It would make sense. I ordered a new Fuel Rail Pressure Sensor and should
have it tomorrow. Results will be posted tomorrow night.

The rail pressure sensor simply indicates pressure, it doesn't control the pressure. The ECM uses the fuel pressure solenoid (IIRC, a new one for OM647 means a new rail too) to control the pressure based on feedback from the pressure sensor. Again, the fuel pressure is seen by all injectors, so all should be making noise if that's the problem.

Well I did replace the fuel Pressure Sensor and you all were right, it made no difference. I did replace #5 injector withe #1 injector yesterday and haven't had the time to run the injector shut down test yet. However the noise seems to have moved more to the front of the engine. Maybe it is in my head. We shall see.

In answer to the questions about my oil type, I use Rottela 15W40 as it is hot in FL all the time. The oil level is just shy of the full mark for expansion. I have had it right at the full mark in the past and got a light for high oil level. Had to drain some out and all was OK.

This morning the rattle didn't seem as bad as yesterday. This is the way it goes all the time. Sometimes it is really bad and other times not too bad at all. Once I take the time to do this injector shut down test I should have some kind of confirmation as what my next step should be. I have checked the harmonic balancer bolt and taken the drive belt off to make sure that there wasn't an accessory problem. No difference.

A note: This haunts me all the time. When the lifters and all the other parts were replaced the head was machined. Now according to DR. A this head can't be machined. It was 15 thousands warpped and he said that the tolerances were to tight for milling and that if the head was warpped, the cam journals would be warpped as well and that this may be an issue. It would seem if a head is not serviceable that the machine shop would know this, however this is FL.......need I say more. I have put so much $$ into this van that I'm married to it.

I will post the results of the injector shut down test ASAP.

Thank you all for you feedback

jcweller1 said:

In answer to the questions about my oil type, I use Rottela 15W40 as it is hot in FL all the time.

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Maybe you already know, but Rotella was reformulated and is no longer OK per MB. Was 228.3 approved, is now 228.31 approved, which is a MB "must not use" spec oil.