New Monarks!! Awesome! New knock!?! NO!!! - Page 3 - PeachParts Mercedes-Benz Forum

scoodidabop · #31 08-15-2009, 12:10 AM

Quote:

Originally Posted by UriahT

Hmmm...
Since all injectors are supposed to be identical, as are all cylinders, it doesn't make sense that swapping 4 and 5 should make any difference, really. It should just change the cylinder that the injector pinging is in.

Perhaps you have an injector that is spraying poorly after rebuild or at the wrong pop pressure, combined with a busted prechamber in either the 4 or 5 cylinder. Or low compression in one of those cylinders, which can exacerbate a nailing injector.

But first get those injectors pop tested.. it will probably solve all your problems. It's easy enough to make your own pop tester, but if not:

http://www.boschservice.com/ServiceLocations/DieselServiceCenter/Diesel+Service+Center.htm

Dang. None of that sounds good.

I think I'll have time to go to the Bosch place next week. Thanks for the link.

scoodidabop · #32 08-15-2009, 03:41 AM

Quote:

Originally Posted by barry123400

First I would substitute the injector or move two on the engine to verify it is the injector. It can be a pump out of calibration on that cylinder as well.

Especially if someone was timing the injection pump sometime and did something they should not have. The suspicion or possibility arises anytime the number one cylinder has issues.

Could this be a possibility even thought the engine seemed okay before the new injectors were installed?

I've got one new injector on the way from mercedes source, so I'm going to try that before I do anything else. I won't really have time to go to the Bosch shop until Thursday.

Ugh. This is KILLING me. I REALLY want to drive this car!!

alphadeltaromeo · #33 08-15-2009, 06:49 AM

I'd personally review this thread...which you probably have done:

A Question for the Injection "Masters"

I found it rather informative indeed.

Andy

houtxfdcapt · #34 08-15-2009, 08:30 AM

what part of Houston are you around the most. the two biggest places I know of are off of Navigation, and on the North side off of shepherd just south of little york. I have taken plenty of 'gas' injectors over there but they are a diesel injector business.

oldsinner111 · #35 08-15-2009, 08:44 AM

BGKast rebuilt mine with Monarks.I've run 10,000 miles so far on wvo/30% diesel.No problems,power is awesome,deadly fast on pure #2.

scoodidabop · #36 08-17-2009, 12:36 PM

Well guys it doesn't look good. I took my injector to a Bosch shop and they tested it for me. It tested at 135 bar with an excellent pattern. What should my next move be? Is there anything I can do to mend this engine (short of a rebuild)? A friend of mine at work is a good mechanic and can help me rebuild if it comes down to that. Where can I source rebuild parts and what all do I need to do it?

I need to change the oil. I will inspect the oil pan at that time. I'm hoping there's not a bunch of metal in there.

scoodidabop · #37 08-17-2009, 12:38 PM

Quote:

Originally Posted by houtxfdcapt

what part of Houston are you around the most. the two biggest places I know of are off of Navigation, and on the North side off of shepherd just south of little york. I have taken plenty of 'gas' injectors over there but they are a diesel injector business.

I went to the shop on shepherd.

Cervan · #38 08-17-2009, 01:21 PM

just move the injector around, until it finds a happy cylinder and then drive the stupid thing.

1lowdiesel · #39 08-17-2009, 03:36 PM

Quote:

Originally Posted by scoodidabop

Could this be a possibility even thought the engine seemed okay before the new injectors were installed?

I've got one new injector on the way from mercedes source, so I'm going to try that before I do anything else. I won't really have time to go to the Bosch shop until Thursday.

Ugh. This is KILLING me. I REALLY want to drive this car!!

i would say it's possible. usually with bad flowing injectors the problem will not be as severe. now that you have better flowing injectors, the pump might be feeling the effects of it.

any reason besides the tapping that you haven't driven it? mine taps a bit but has great power and fuel economy.

barry123400 · #40 08-17-2009, 05:37 PM

The injector checked well in a static condition. It operates in a dynamic fast condition or enviroment. Sub it with another average used injector. As you stated this problem was not evident on the old nozzles. Actually you already proved the new injector nozzles are not equal when you exchanged number five and four. Had they been equal the noise would not have dropped eighty percent. That number five may still be defective but pass the pop and pattern test.

Someone posted earlier on your thread that if the monark nozzles flow heavier might be an issue. That would indicate they would have to launch fuel a little earlier as far as quantity per injection is concerned. Not later in time just more fuel initially when starting to open if nozzles are larger. It kind of amounts to the same thing though.

Or as Cervan already mentioned try various injectors in various positions to see if nailing stops. When you have any injector out check the pre chamber for ball condition etc.

Maybe checking the injection pump timing is not a bad ideal just in case someone set it up with more advance than normal or needed now. Not really a likely senario though as the nailing is confined to one cylinder. I would exhaust every simple possibility first.

Then I would engage the milli volt method to modify the pumps element timing for that nailing cylinder. Not recommended although it works as people do not tend to really think of what they are doing. If something is missed in the process or not allowed for it might not work correctly.

You also want to record any changes in depth in case you want to restore an element to its old position. Again people have not been consistant enough to use this system in my opinion. You could look up the milli volt method to get some ideal of what is involved in the archives. It will work if the absolute need is established properly and methology is correct. At this point the need is not even established.

sasquatchgeoff · #41 08-17-2009, 06:32 PM

Quote:

Originally Posted by scoodidabop

Well guys it doesn't look good. I took my injector to a Bosch shop and they tested it for me. It tested at 135 bar with an excellent pattern. What should my next move be? Is there anything I can do to mend this engine (short of a rebuild)? A friend of mine at work is a good mechanic and can help me rebuild if it comes down to that. Where can I source rebuild parts and what all do I need to do it?

I need to change the oil. I will inspect the oil pan at that time. I'm hoping there's not a bunch of metal in there.

It could be that the lowered compression for #5 was such that the old injector condition in that cylinder was complimentary - in other words, low compression can cause nailing to surface in otherwise refurbished cylinders. I have personal experience with this concept in that I just did a top-end rebuild and have witnessed the horror of pre- or post detonation. In my case, my valves are tighter, my injectors are close to perfect, where before the rebuild two of the injectors would not even hold pressure (according to my Bosch shop). If purging my injection pump of air did not resolve my situation at least temporarily, I would seriously suspect that less than perfect compression in one of my cylinders would be the culprit for the intermittent nailing.

Just because one cylinder has lower compression does not mean a complete rebuild is in order. Like Cervan suggested, find a solution that eliminates or greatly reduces the nailing and drive it like you just robbed a 7-11. With ULSD as the prevailing fuel (even that in OR is B5) nailing will be at least some time or another a part of our reality. Cetane booster and diesel additives are a certainty in this age.