MBN it has a miss or does it? Any ideas?

First off I know that the MBN engine was the worst ever created by CAT. I have done a large amount of research on the engine and various "fixes" to the problems. When it comes time for a rebuild I will be pulling the engine and replacing it with a 6NZ. Till then I have a problem that I have been chasing for quite some time now. I have all the CAT mechanics stumped, so I am hoping that someone else has had this problem. I am going to give everything the engine is doing regardless of whether or not I think its realated. Engine has 1,341,000km or 827,800 miles on it.

I have a rough idle and running problem. It doesnt do it when it is stone cold. It sounds like a miss but isnt. I have had all the injectors pulled, inpected, replaced two worn ones, and had them all resealed. Didnt solve it. I had a cut out test performed at various engine temps to try and get results, when it going through the cut out test it feels like the problem that I have, only over exagerated. No engine codes have popped up from the cut out test. I had the injector trip codes turned up to try and get one to pop a code, nothing. Fuel pressure is steady 108psi but will shake significantly when you hit the throttle hard, probably about a 5-7psi "shake". it did not travel like that before.

When the engine is hot and I come to and intersection and stop, after about 5-10 seconds, it feels like something physically shifts in the engine and it begins the shutter, jump, or whatever you want to call it, but still feels like a miss. Exhaust temp rises quickly to 900 and on a hard climb will occasionally hit 950 but not for long. Top end set was down 2 months ago. When the Jake is engaged it gets a loud snap in it around 1300, 1500 and higher rpm. There is a loud knocking at the front of the engine on the intake side near cyclinder #1, and when there is only a little load on the engine it sounds like a volkswagon desiel starting on a -30 degree day, basically a really lound knock, almost a grinding noise.

Oil pressure is normal, fuel pressure other then on heavy acceleration is normal, water temp climbs quickly, but more than likely because the rad is due to be replaced. Boost is normal, turbo was replaced 4 months ago. An oil sample is done at every oil change, every 25,000km or 15,432miles, they have all come back clean except of the last one, with had more tin in it. Since it is the first indication and is signifigantly higher than the last reading I am hoping that it was just a bad sample. I will know better when the next one comes back in about 2 weeks.


This may not be related, but, i noticed oil around the intake line to the compressor, I checked the wet tank and the compressor was shot. However, with the new one installed i have noticed that there is still oil coming out around the gasket for the intake line on the compressor.

I dont quite have the money yet to swap out the engine so I am hoping that some one can solve my problem so that I can extend this thing a little longer.

 

it doesnt smoke when it is just idling, but have noticed a lot more black smoke on acceleration