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frank1 · 09-20-2010, 10:22 PM

i have a 99 8.3 in a gulfstream svb with a electronic fuel injection pump,i think its a model 44 pump -my past knowlage is that when cummins went over to electronic injection they also went with 24 valve-mine looks like a 12 valve .so do/would i have a 12 valve with electronic fuel injection.or ??????

CC38EL · 09-21-2010, 04:35 AM

I think that if you can see the top of your engine, it may have a 24v on the valve cover if it's a 24 valve model. I'm trying to find a picture to send you.

Other than that, if you have the engine serial number, you can call Cummins and ask for the specifics of your particular engine.

Gary RVRoamer · 09-21-2010, 03:39 PM

The current ISCs have 24 vales and as far as I know have always had 4 valves/cylinder since the mechanical 8.3 became the ISC. Check with Cummins if your does not seem to have that many.

Roadking · 09-23-2010, 03:53 PM

I'm no expert here, but this is what I've learned from other folks, some of which were Cummins technicians and appeared to be very knowledgeable...maybe experts.

The C8.3 is a mechanical engine and the ISC is an electronic 8.3 liter engine. The first electronic ISCs came out in about (edited) early spring 1998. The C8.2 inventory was still available in 1998 and may have been used in 1999 model year coaches.

The model 44 pump you reference perchance may be the VP-44. The VP-44 is a mechanical injector pump and was installed on all mechanical ISB engines and this injector pump was also used in the mechanical C8.3 engines. .

Both the C8.3 and the ISC's use an "electric" lift pump that pumps the diesel from the tank to the injector pump. This pump is an elaborate 12VDC electric motor that produces about 7psi.

There were two versions of the ISC. The first version of the ISC used a system call CAPS ... Cummins Accumulated Pressure System. The ISC CAPS was replaced in about mid 2003 by a system I believe was called CARS. This is the Cummins Accumulated RAIL system... which is a common rail injector system which I believe is still used in the new 2009+ engines with the expensive EPA mandated exhaust controls.

One noticeable trait of the CAPS system is when initially starting the engine cold, about 10-20 seconds after then engine has started the engine will make a very noticeable change in the sound. This is occurs when the ECU switches from the default starting mode to the proper computer controlled running mode.

Roadking · 09-23-2010, 04:11 PM

I'm not positive about this but I believe the ISC has a red valve cover and the mechanical C8.3 has a black valve cover. Also, the ISC's released in 1998 had a new 24 valve head. THe C8.3 was a 12 valve engine.