ISX high pressure system leak down test

[Margeetus]

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thought i would add to this i have had good luck on cm2350's starting and running with 5 of the 6 injectors capped to help narrow them down
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Wow, the 1 cylinder ISX! 8-) I didn't have to go down that far.

I started off capping cylinders 4&5, as I had recently replaced #6 and re-ran the leakdown test and fuel pressure stayed around 30k psi for the full test. It was weird, the fuel pressure was right around 29,000psi while running, but actually increased to a bit over 30,000psi when I shut it down. Maybe the fuel pump stroked and the injectors didn't fire right as I shut it down?? Kind of strange behavior.

I then reconnected #5 and it was still sealed, so #4 was my leaker. I replaced #4 and the beast is running happily now! Thanks Rawze for the great information!

I find it amazing that 1 leaky injector was causing it to run this bad. I understand that it would be down on power, but it was dropping down to almost nothing and had horrible vibrations... The ECM must be doing something to the other injectors to try to compensate, or making it run so bad that you have to stop and fix it? I had watched rail pressure previously with the bad injector and it wasn't running low or anything. There wasn't any strange knocking noise or anything like that I could hear. Anybody know what exactly is going on with a leaky injector?

Thanks,

Margeetus