cekkk wrote:
So far the one concern I have is the fuel pump that was raised in the first replies. What was the problem, total failure, partial fuel starving?
This has been partially answered by previous posters.
I will add another aspect to the fuel pump debacle both Ford and GM are having with the original series CP 4.2 Bosch pump installed in 2011-2014 Ford 6.7L diesels and in I believe 2012 + GM Duramax 6.6L engines.
First, the CP 4.2 means it is a twin piston pump. There is also the Bosch CP 4.1 pump, a single piston pump, and it is used on a lot of VW and other makes of diesel cars.
Unfortunately, both pumps can have the same lousy results, completely destroying themselves sending shrapnel throughout the fuel system and expensive repairs.
There seems to be two primary causes for this.
First is the diesel fuel itself. These pumps rely on the fuel for lubrication, as it is their only source of lubrication.
Unfortunately, Bosch, from Germany, designed the pump to be lubricated by European diesel fuel.
Well European (and Canadian standards) are both higher than United States standards for lubricity in the fuel. Their standards are at a level of 460 HFRR, which is an indication of wear standards for the fuel metal on metal I believe.
US standards in the meantime are at the 520 HFRR level, which means it is really not good enough for these pumps. So you see many folks asking about lubricity additives.
Ford, in their owners manual, recommended their lubricity additive PM-22A for these motors. I used it religiously on mine.
EVERY FILL UP!Second is the pump design itself. A twin piston (or single, dependent on which version/vehicle you have) which runs about twice the RPM's of your engine. So at 2,000 RPM's in my previous Ford 6.7L engine, that pump was running at 4,000 RPM's.
A lot of the pump is aluminum. Central crankshaft running two connecting rods to twin pistons, one each side in the classic V arrangement.
And there is the major problem. There is
no wrist pin connecting the piston itself to the connecting rod.
So in some cases, the piston separates from the connecting rod and at 4,000 RPM's it starts to hammer itself to shreds every time they slam back together.
And you end up with shrapnel throughout the fuel system. And no warning that it is going bad until your check engine light comes on and the vehicle stalls.
One other related problem exists. Ambient temperature and fuel levels in your fuel tank. Most failures are recorded in the hottest months of the year, or just after those hot months have ended.
Add to that these pumps return fuel to the fuel tank which is much warmer than the tank diesel itself. So owners have been warned to NOT let the fuel level drop too low before refueling so as to avoid heating the fuel in the tank to too high a level.
Now after all that, appears from research I have read on that the failure rate for these pumps in both Ford and GM engines is about 3 percent of total vehicles.
Canada has had failures too, but it seems at a lower rate than in the US due to their improved diesel fuel standards.
Sure gives one confidence though. NOT!
This still does not change my original thoughts to the Ford 6.7L engine. I think it is a good engine, but both Ford and GM really got short changed by Bosch on the fuel pumps.
