ISX "whistling" and shut down

[JimT]

Just reread the thread again. Before going too far down the rabbit hole you should verify there's no restriction in fuel flow coming from the tanks. Even a partial blockage there could be starving the pump as it call for more fuel, rail pressure drops off, truck shuts down, pressure equalizes and it starts back up.

Unless you have some evidence that debris got passed the primary and secondary filters I wouldn't think that it made it into the rail. Even after the filters there is a mesh screen on the fuel line banjo bolt coming into the gear pump. A screen which should have be inspected when the pump was replaced.

Since you just mentioned the excessive rail pressure loss, on top of the recent replacement of the gear pump and priming pump, lets focus on that for a second. The pressure relief valve shouldn't be opening anywhere near 8700 psi. It should be somewhere above 40,000 psi. That's not the only way fuel flows back though. The injectors could be leaking into the fuel return line or the quell tubes going to the injectors could be leaking into the same return. Those tubes are crush fit to the injector so if they are removed they need to either mate back up to the same injector or be replaced. They need to be torqued down properly too. You could also have a leak at any connection point along the fuel rail itself. Go through and retorque everything to spec.

Finally, if there's no restriction in supply and if the primary and secondary filters are not running dry then that leaves everything from the point the fuel exits the secondary filter to the engine for a leak. You could still be sucking in air somewhere before the gear pump. Or there could be a leak in the high pressure common rail circuit. Really the only thing to do at that point is to methodically go through the diagnostic tests outlined in quickserve to pinpoint the cause. Guessing can only go so far.

[Rawze]

A red engine is not a blue or yellow, or black engine. Never assume that it is similar!.

Also, fuel rail and injector leaks are often into the return line system, and not directly into the cylinders ... but injectors can leak into the cylinders too.

Here is what you should be doing as far as testing the fuel rail for holding pressure properly ... AND LEAK TESTS SHOULD BE DONE AT 30,000 PSI, NOT JUST SIMPLY AT IDLE PRESSURES!!!.

There is a proper set of procedures for it and a video on how to do it here...
http://rawze.com/forums/showthread.php?t...2#pid69262

[CoroView Shop]

Hi there, thanks for the replies.
Once I realized that the injectors also return pressure to the tank, it made sense that it may not cause a hard start/smoke condition. Thanks for that info!

Also, the highest pressure we could achieve is about 17000psi at about 2000 rpm, which is also all it commanded. We don't have Insite unfortunately, and are limited to having access to live data. Commanded pressure never got higher than 17000psi either. Could that point to an issue? ECM calibration or?

I'll watch the video when I have a moment (thanks!), but at this point the boss would like to remove injectors and have them tested rather than spend the $ to get test equipment for one engine. The rest of our fleet is either Cat or Detroit (sorry for swearing!)...

Thanks again, you all have been very helpful!

[Rawze]

(05-09-2024 )CoroView Shop Wrote:  Hi there, thanks for the replies.
...
I'll watch the video when I have a moment (thanks!), but at this point the boss would like to remove injectors and have them tested rather than spend the $ to get test equipment for one engine. The rest of our fleet is either Cat or Detroit (sorry for swearing!)...

Thanks again, you all have been very helpful!

doing injector leak tests does not require any type of special equipment and costs absolutely nothing on a common rail ISX!. It should also be done with them installed into the head, not taking anything apart!. - It is a simple test using Insite (watch the videos). ./. and it also sounds very much like your boss is a complete moron!!!>.. tell him I said that too!.

Its sounding more and more like the shop you are at has BEYOND ZERO TRAINING on cummins engines. It sounds more and more to me like that they need to tell all customers with red engines TO GO SOMEWHERE ELSE!!!.

Its one thing to come on here and learn how to do things right. Training even by the OEM's is garbage at best.. , however its totally another to have a repair shop purposefully make BAD DECISIONS, DENY REALITY, AND IGNORE PROPER PROCEDURES, ETC.. SIMPLY BECAUSE THEY DO NOT WANT TO INVEST IN IT .. and then their customers have to suffer the consequences of a shops sheer stupidity as a result.

What was the name of that repair shop?? .. so that I can tell EVERYONE ON HERE, AND EVERYONE THAT I KNOW, TO STAY AS FAR AWAY FROM THOSE MORONS AS POSSIBLE!!!>


and by the way ... YOU NEED TO GO FIND ANOTHER PLACE TO WORK AT IF THEY ARE THAT INCREDIBLY STUPID!!!>