PenRay Report post Posted July 24, 2012 Has anyone replaced the stock fuel lift pump on a 2000 Cummins ISB 5.9? I have this engine with a banks power pac and I am pretty sure the lift pump is bad. As I do not want to chance causing a injector pump failure I am thinking of replacing it with a FASS DDRP 02 pump. It is listed for a dodge appl. but the shop says it will work on the motorhome. Any sugesstions? Share this post Link to post Share on other sites
hermanmullins Report post Posted July 24, 2012 PenRay, Are you sure your pump is bad? Have you changed both of your fuel filter? My 400 ISL would snort and buck under a load and while in Oklahoma I replaced both filters and now it purrs like a kitten under load. (Just remembered that in my life time I have had two Fuel Filter problems with my coaches and both times it was in Oklahoma. Hmm) Share this post Link to post Share on other sites
PenRay Report post Posted July 24, 2012 I have change all filters. I have a warning light installed. When I turn on ignition but not starting engine the light should come on then cut off as it is a eletrical pump and pressure should build up with ignition swith on. As soon as I start the engine the light goes out. In my mind this tells me the lift pump is bad and that the injector pump is pulling fuel when engine started. The symtom I initally got was the mototrhome just seems low on power. I have not driven the Coach but maybe a mile or two since noticing problem so I think the injector pump is still good as it pulls fuel and no codes have shown up. I just want to be safe rather than let it go and mess up injector pump. Does that sound like I am on the right track? Share this post Link to post Share on other sites
hermanmullins Report post Posted July 24, 2012 Pen, sound like you are on the right track. However before you start R&R parts check with your local Cummins Service Center. Tell them what you have and what you have done and ask them if you are correct. Good Luck. Herman Share this post Link to post Share on other sites
dickandlois Report post Posted July 24, 2012 Pen Ray! I have changed the lift pump. I also have a pressure sensor that lets me know if the fuel pressure drops due to filters issues of lift pump issue. When new the pump pressure is between 15 to 20 psi. This is how the LED reacts when starting the engine. I currently have new filters and lift pump. Ignition switch on--- The LED lights and stays on even with the pump 30 second run cycle. Key on and bump the starter the LED goes out and it stays off. The LED flickers when one of the filters restricts the fuel flow or the pump output pressure has dropped. This is when I know to change filters. I then start the coach and take a test drive, should the pressure LED come on during a heavy load (I load the system by stopping at the bottom a a sizable grade) If the light stays out pump pressure is OK. If it lights, its time to replace the pump.. Pump cost is about 160.00 plus filter cost and labor if you have the work done at a shop. That price sure beats the price and labor charge of an injector pump. Over the years the setup has been dead on and I have not burned up the injector pump. The pump is cooled by the fuel going through it and the excess is returned to the fuel tank. Hope this helps. Rich There was a change in the Cummins lift pump number when the ultra low sulfur fuel came on the market. Edited 7-24-12, P.M. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 24, 2012 Rich, Is your fuel pressure sensor OE, or did you install it? Is it on fuel pressure out of the pump or is it a vacuum gauge showing restriction in the filter(s). I am not familiar with the warning light system that Pen Ray has-- would be helpful if he or someone else can confirm how it is supposed to work and then see if his is operating as it should or not. Most lights I am familiar with on diesels at start-up indicate glow plug/intake heater grid activation, not fuel pressure. Brett Share this post Link to post Share on other sites
dickandlois Report post Posted July 25, 2012 Brett, the sensor is after market not OEM. With the number of injector pump failures on the ISB engines due to low fuel flow /pressure, it has proven to be a great asset and safety net. The sensor is installed between the output of the last fuel filter and the injector pump: Bosh-44. When one of the filters restricts the flow of fuel the light (LED) starts to wink on and off as load increases. Changing the filters clears the problem most of the time. When that does not work and there are no fuel leaks in the suction side of the fuel system (weeping), its time for a replacement lift pump. I'm on my second one, as the OEM unit started to leak when the Ultra Low Sulfur Diesel came on the market and the second one had pumped enough fuel to put around 50K on the coach and and many of those miles where running in hilly country. I qualify as a Ridge Runner not a Flat Lander. Rich. Share this post Link to post Share on other sites
PenRay Report post Posted July 27, 2012 Rich. That is how mine works also. Now when I turn ignition on and bump the light does not come on. I believe the pump may have just failed even though I can not confirm 100% without putting a gauge on the pump. I have decide to go ahead and change out the pump. I was looking at the Fass Pump but decided after talking with and injector shop I trust to go with a Airdog FRRP. Mounts the same as stock pump but is a little larger to provide higher quanity of fuel to injector pump. I am planning on installing it in the morning so I will let you guys know how it works out. I feel better safe than sorry. Ray Share this post Link to post Share on other sites
