Cummins ISB no start

[DB2]

Hello all! We have an 07 Sterling SC8000 with a Cummins ISB that started then stalled and now refuses to start. All fuses and relays seem to be ok. Any insights ?

Thank you

 

[Bluox]

Make sure you have power to the ECM power wire usually wired to battery.
Bob

 

[Bluox]

Next check lift pump output if the lift pump fails that will take out the injection pump.
Bob

 

[DB2]

Yes we have good supply to the filter with the key on and power to the ECM. This one is HPCR so no injection pump per se.

 

[Truck Shop]

Not that familiar with the ISB, cam/crank position sensor? If it uses one.

Truck Shop

 

[DB2]

Thanks guys. ISB is basically a 5.9 24 valve with a HPCR injection system. Truck Shop those were suggested on a couple of videos we watched. Apparently if an injector fails it won’t build pressure to fire the others. The fast and dirty test is to cap off one line at a time and see if it will start. I’ll let you know the outcome.

Cheers

 

[Wes J]

Even a basic scan tool should be able to read the common rail pressure.

 

[DB2]

Yes. My mechanic was suggesting we should get one. Something to consider I guess. I prefer the old systems where you could troubleshoot without a computer.

Thanks for all the suggestions.

 

[DB2]

Meant to follow up earlier. Was actually the high pressure pump.

Thanks to all who replied !

 

[Birken Vogt]

Just a minor nitpick. The "IS"-whatever came around long before HPCR was ever a thing. Late 1990s I think for the ISC for instance?

Maybe it was the advent of full computer control of the engine that made it an IS. But the early IS still had an injection pump of some kind on the smaller ones.

 

[DB2]

Could very well be. The earlier model of the same model truck we have has a 5.9 with the VP44 pump. Not sure what that engine is referred to as.

Neither of them sit very well with me. Rather have a fully mechanical engine that isn’t so dependant on electronics.

 

[StanRUS]

Just a minor nitpick. The "IS"-whatever came around long before HPCR was ever a thing. Late 1990s I think for the ISC for instance?

IS = Interact System

 

[funwithfuel]

05-09 mounted lift pump between ECU and engine block. Service bulletin advises to mount away fro heat and vibration while still low enough to be gravity fed.
I'd check fuel delivery first.

 

[funwithfuel]

Do you have a fuel water separator? Have you checked the bowl. Have you drained some off the bottom of the tank. Water and common rail just can't mix. Conventional fuel systems would survive, somewhat, water intrusion, rails can't. Water is a death sentence from the fuel control valve, to the injectors and out to the safety valve. No part can survive. Hope that's not the case and you just have a single bad injector or bad cam sensor.

 

[DB2]

In the end it was the high pressure pump. Luckily we had a junker with the same engine. Never priced out a new one as my blood pressure runs high enough already.

But yes it does have a water separator and we are pretty diligent about servicing. Also our equipment gets filled from a slip tank which has a filter as well. Rarely do they ever get filled directly at a cardlock or service station.

Thanks to all who replied.

 

[12v92]

i had the same problem with a isb. i removed the high pressure pump and set it on the bench. i stood there for a few minutes looking at it and figured what the hell......it's no good now what can it hurt? i removed the charge pump from the front and disassembled it. seems a piece of debris must have gone thru it as one of the gears was split in two pieces and the shaft was broke.

i bought a reman pump for 800$ but i also changed the line from the filter going to the pump figuring this was where the debris must have come from.