2006 175hp hpdi #2 cyclinder blown

[bullduck]

The # 2 cylinder blew on my yamaha 06 175 hpdi.There was no warning indicator cruising at 47mph 45to 4800 rpm and she shut down.Broke the engine down to find #2 piston cracked and burnt...checked head gasket for leak no leak ,checked the oiler oiler not clogged ,had water pressure roughly 12 to 16 psi.Its obivious, it overheated extremly quick, what could cause this.Im waiting on parts and im not going back together with it until i have a better idea what caused it to fail......all 5 other cylinders seem fine .Could the oiler check valve for the #2cylinder get stuck.Or cooling ports clog in the head.Also honed #2 cylinder minor pit in bottom of cylinder closer to crank .I think it ran lean so now my question is why and is it common?Is there a web page with specs for that engine dealing with tolerable fuel flow and idle psi on the water, oil flow ect.....

[bullduck]

anyone else have this problem?

[99yam40]

I would be looking at the injectors if only one cylinder had a problem.
Pull them all and send of for testing and cleaning and more testing to be sure if that was a problem.
mark or label them so you know which one came from which cylinder.
all filters and screens need to be cleaned or replaced.
Monitoring fuel pressures should show something, but the specs should be in the Yamaha service manual maybe or if you look through Rodbolt17's posts you maybe able to find some info

[bullduck]

thanks also the operating temp is 120 140 would it be wise to pull thermostats out

[99yam40]

thanks also the operating temp is 120 140 would it be wise to pull thermostats out

Never!! I repeat never just remove thermostats as they restrict the water flow and make sure water circulates to all parts of the motor properly.

You can remove and test to make sure they are functioning properly or just replace with new. I like to test even the new ones just to be sure

[bullduck]

found the problem

okay after rebuilding my yamaha 175 hpdi...i tookit to the lake to find my high pressure pump had crapped out.This being the reason my number 2 cyclinder fried the exhaust side...i took the inline filters out of the pump to find they were not clogged so i broke the whole pump down...to find a spot washed out on a distribution plate was the reason she wasnt pumping.which is part of the housing so if any one could tell me where to get the 700psi pump from for less than 1800 bucks it would be greatly appreciated

[99yam40]

The pump may be bad now and not getting up to the proper pressure, but I would think it would have affected more than one cylinder as it went out. Any low pressure furnished to the rail and injectors will affect them all the same.
Have all injectors tested and cleaned would be my thought. Check with the guys that do the cleaning and testing as they rebuild pumps too most of the time

[bullduck]

I would think it would effect them the same way also...But the pump being washed out where it was. The pump on the 175 is a single to 2 injector rails versus the 225 250 ....have dual high pressure pumps 1 for each rail.The singles have 3 ports just before hitting the rail ports, and in the 3, the center washed out where the high pressure fuel enters the chamber that distributes the fuel equally, into 2 injector ports via a baffle, or pressure plate that rests againts the port that washed,or high pressure output. o-0-o o-(0>)-o so im thinking the pressurized fuel went the path of least resistance, and considering the right side on the output, looked far worse than the left,and on top of poor pressure due to cavitation, it leaned out the left bank or #2 #4 and #6., #2 is the hottest on that bank #4 and #6 catch the water as it passes by to #2 I wasnt wide open so i didnt get an rpm drop running 43...4500 rpm and from what ive read those engines run lean in that rpm range anyway. It got number 2 really quick seized the #2 piston bogged engine down so fast it didnt have time to set temp buzzer.which is why it went off about 2to3 minutes after i shut down the ignition what do you think?

[bullduck]

all back together

OK switched injectors number 6 to number 2.checked double checked torque spec ....replaced filters.....replaced high pressure pump new piston and rings wrist pin ect....breaking engine in section wide open throttle for no more than 5 minutes at a time. Now im right back where i started number 2 cyl blown once again can the exhaust tuner cause 1 piston to blow

[Finisher]

WOT??...... The overheat sensor could have gone off after the failure because the piston scraping against the side of the cyl with no oil creates friction/ heat. Have you checked and re checked that you have bled your oil pump correctly. There is a very specific way to do that insuring you get oil to all cyls with no air. Other than that I agree with the other posts an injector would be a very valid reason. High pressure pumps go bad but tend to not allow you to run up in the 4500 range. Look into proper lubrication

[bullduck]

bled the oiler via service manual.Also took each hose off every cyl, blew through them makeing sure there where no restrictions.it being a precision oiler there arent any monitors for each individual line how is that precision?but on the other hand the piston doesnt just get oil at the piston from the one line .IT also gets oil through the intake port and some mixes directly with gas to lube injectors.And the piston would use that also.And it isnt a slow heat the overtemp alarm once again didnt sound.Its happening so fast the piston is breaking down on the exhaust side like its running lean.I need the diagnoses software and cant find it yey yamaha

[Finisher]

It seems like you have narrowed the field down. You said you have replaced the high pressure pump and swapped the injectors and #2 still blew. The oil pump has clear lines on the end of the hoses you can visually see. Just because the lines of the oil pump are clear doesn't mean it is getting oil. Since you blew them out priming that line will take a bit. Hpdi motors are very fickle on how the oil pump needs to be bled. Assuming however it is not oil, have you changed your water pump impeller recently? checked your water pickups for growth? is that head getting hotter than the other side with a temp gun? I am not sure the software is going to give you the answers your looking for. It will tell you your temp and high pressures but it does not tell you a whole lot regarding lean/ rich.

[bullduck]

will do and thanks for the advice man this thing is given me fits. im an auto mechanic/technician but nothing ive ever worked on, is this sensitive, and touchy.But i do know it ran fine for 5years so if i can get it right it should atleast last another year or 2.Also do you know if you can bore the cylinders out on these engines they sell oversized pistons for them?And where could you reprogram the ecu to run a bigger piston.

[bullduck]

does the high pressure pump have to be calibrated ?

[Finisher]

You can bore them and use a Weisco piston. You can also send it out and have it re-sleeved if you know a good machine shop. The high pressure pump does not need calibrating but it does need to be filled with gearlube.