8.3 liter cummins
- Thread starter joker
- Start date
I have the same exact power train and I run similar RPM!s at 65 MPH.Don!t know if this is normal or not but I think it is.My 8.3 has 657,000 on it and still seems ok.I change oil every 9-10,000 miles,don!t beat it but don!t baby it either,keep the idling to a minimum and so on. I have met 2 guys who had over 750,000 miles on the engine with no major repairs. I also get an oil analysis done at Speedo every 3rd oil change. None of the measurements appear to increase so hopefully I can get another 100k out of it.
Your C8.3 is running at the correct highway RPM Joker. Any highway diesel should run at between 80-90% of its governed RPM at highway speed for maximum effeciency. Short of regular maintenance and LOTS of replacement shut-down solenoids, I never touched the Cummins engine on my old FL70, traded at half a million miles and still running strong. My dad had his 8.3 rebuilt a couple of years ago, mileage unknown. The full in-frame with turbo was only $6700. For some reason he just had to have the head gasket replaced with only 250K on the rebuild as it was drinking water. Still, I think the Cummins C8.3/ISC is the best engine out there for class 7 trucks.
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That shut down fuel soelnoid can drive you crazy.I have gone through 3 of them. You know it!s not working when you can!t shut the engine off,or it takes 4-5 starts for the engine to start,but the worst problem I had was when the solenoid was only opening about half way. The engine had very little power,could cruise ok but simply could not pull on any hill. It had all of the symptons of bad fuel or clogged filters. I changed filters twice suspected the turbo,but finally noticed the valve was only opening about 50%.Put a new one in and all was OK. Watch out for the rubber fuel line that comes off the filter and feed into the fuel pump. When this line breaks you will know it right away and if you don!t someone behind you will make sure you know. This is a easy repair,takes about 15 minutes, go to Cummins and get some of the tubing and carry it with you along with about a quart of fuel to prime the line.
Yes, I don't know why Freightliner used those plastic fuel lines near the engine which moves and vibrates a little bit and wears holes in them. I bent and moved the metal holder brackets a bit on mine to be sure the lines did not contact anything. That solenoid is another story, one yet to be answered. The "new" style, made physically bigger, did not last as long as the older small one did. At $250 a pop those things should be outlawed. My dad had his changed to the Ford 7000 style, which mounts the solenoid on the front of the fuel pump and uses a long actuator rod so it pulls horizontally. We will see if that makes it last any longer. It really does confuse you when the solenoid starts getting intermittent and doesn't pull the arm up all the way. I remember going through the fuel filter, injector routine the first time it happened to me. There are two electrical legs to it (three wires) a start and a run mode. When the run coil dies the truck will start but stall immidiately. When the start coil dies the engine will usually still start, but the arm won't come up all the way and the engine will have no power as it doesn't have full fuel flow. When it all dies you bungee cord the arm up, and open the hood and stop the engine by pushing the arm down. Fun! Bosch was a great mechanical fuel injection system though, it has a place in my heart. But the electronic systems eliminate it's three worst problems- throttle cable, return springs, and that friggin' solenoid. That spring loaded throttle arm can be a pain sometimes too.
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