its pretty pathetic i drove a penske rental daycab prostar with the cummins the jake was so powerful. i got my crappy maxxforce back and thought i was still in the cummins and put the jake on. lol it didnt do anytihng. i just got in the habit of not riding peoples ### as much so i dont have to keep tapping my brakes. they replaced a driveshaft yoke and said it fixed the bad shaking. i got up to speed and it did the same shaking. lol mechanics.
The engine brake is pathetic. The 2008 model engine is actually an "exhaust brake" and basically useless. The 2010 models do in fact have an "engine" compression brake that is also made by Jacobs. The effectiveness of the brake drops off dramatically as the rpm comes down. Keeping the engine rpm as high as you can will increase their braking power.
The same thing we used to do before drivers became so reliant on Jakes that they put them on every truck ever built...become a truck driver.
I drive a 2012 mf and came from a 9200 with a isx. I like the prostar. The isx was more peaky, mf seems to be better everywhere else. I am getting around 6.3 mpg on average running Appalachian mountains and northeast
How many drivers have had problems with the Maxxforce 13 engine running away. It is getting more common. This seems to happen when the high pressure turbo starts pumping oil into the intake and the engine will begin to rev even after the key is turned off. This happens when the oil that is in the engine continues to get pulled into the intake by the spooling turbo, it gets compressed like fuel and the engine will continue to run by igniting the oil as the ignition source. The engine will rev in excess of 3000 RPM's or until the engine will literally come apart. If this has happened to you, please respond?
Jake brakes work from off of engine oil preasure. Actuators flood the jake heads with oil, opening and closing certain valves during a piston's cycle, creating a vacuum. Negative preasure in the cylinder heads act on the engine giving it a braking effect. The key to all this is oil preasure and that's depending on engine rpm driving the oil pump. As once described to me by a mechanic friend, it's a brilliant system designed by Jacobs. Exhaust brakes needs the same principle idea. High preasure from high RPMs to make effective engine brakes.
A Person could save money by not ordering the engine break on the maxxforce and just drag a stick on the ground, it would be just as effective!
I just moved from a 2010 prostar w cummins to a 2013 with maxxforce13. So am I reading this right that the engine brake really is just dragging a stick? Company shop couldn't fix, waiting for dealership to open (during a holiday week, right!) Another big difference is that if cruise control is set, engine brake does NOT engage at all. Very different from the cummins, which kicked in 5mph over cruise setting. Between these two differences, i'm getting overspeeds and over rpms, which eventually someone will notice and scold me for (mega-carrier company driver). Question: can these things be fixed (ie be more like the cummins I'm used to!) or do I just need to adjust my expectations? Thanks!
