Havig a bad day. CM2350 fuel pump failure.

[Hammerhead]

(09-24-2017 )Ragindirt Wrote:  Thanks, guess I could be a little more informative in my ?. So I have always referred to my engine as a isx 15, given my vin and order parts. Going to start working on her more myself ( and yes do know mechanics, race bikes, car, and NG mechanic ).

So being new here and reading trends, watching videos, (which resulted from a bad shop experience); I just started doing an ERG tune. Fuel mileage started going down before I parked her late summer. Taking some needed down time.

Have 700 plus on her, looks good under valve cover, can't remember if it had two cams or one). Been months since an overhead, which I just watched between beers.

So question is, do I have an 871 or the 2250. Went to KW the other day to get a part and asked the guys what what series "oh it an isx 15" 'well no shi#t but what class'.

Looks like Kenworth site says new series came in 2010!

Guess I'll run over with the engine serial number, and fuel pump number and find out which pump I have. Talk with someone who knows.

Your blinders have just been removed, so to speak...of course KW doesn't know if it's an 871 or 2250, to them an ISX is an ISX generally. Hence the "bad service experience" you mentioned, they just aren't that educated...because the manufacturer doesn't really want them to be. Undereducated people are controllable, uh oh, no he didnt!
Around here, you ARE speaking to people who know...

The designations come from the engine ECM model numbers.
Any ISX build date of 2008 is a CM871.
You will have two cams.
You DO NOT have to panic about your fuel pump.
The 871 uses an electronic lift pump for priming and a gear pump driven off the injector cam that produces under 400psi of fuel pressure. This is not a threadhold that is difficult to contain. The 871 and older engine produces the many thousands of psi fuel pressure internally in the injector at the point of injection, which is driven by the drivers side cam, thus not really having containment issues of extreme pressures.

The 2250, 2350, & X15 DO NOT have the drivers side cam to drive the injectors with the mechanical forces necessary to create the extreme injection pressures. The injectors are fed via a Common (fuel) Rail, hence the nickname Common Rail Engines. In order to supply enough pressure to properly inject the fuel, these motors use a front gear train driven XPI (brand) fuel pump that produces upwards of 40,000psi and feeds the injectors a full time supply in this range. The mechanical forces required to produce this kind of pressure, at the volume required to continuously feed 6 injectors is incredible, which is why these pumps are failing and have such short life spans.

Next time you have your 871 rocker cover off for any reason, look at the size of each of the cam lobes on the drivers side injector cam. Now just using a little common sense, ask yourself "how intelligent the engineers of the XPI fuel pump were when they use 2 lobes about the width of each VALVE lobe to produce the 38,000psi regulated injection pressures for ALL 6 injectors, when each one of those massive lobes on the injector cam drive 1 injector?"
Now with the blinders removed and your eyes adjusted to the light you are starting to get the picture we all talk about here, sad isn't it?
Now if you really want to beat your head against the wall, go ask your KW this same question. If he's anything like my guy, he'll just surf his shoulders and ask "What's the problem?" Welcome to the dark side...

If you are ever working on a common rail engine's fuel system, take head the warnings on them. 40ish thousand psi of fuel pressure WILL injure you!