<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Stylin':
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tom and Patty:
I find the lift pump issue interesting. Calif has had USLD I believe since August. In mid October we relpaced our lift pump on our 45K miles '00 ISC because it was starting to leak. Coincidence? </div></BLOCKQUOTE>
The short answer is starting to look like yes. </div></BLOCKQUOTE>
Cummins* Communication on Lift Pump Failures/ULSD
*Customer Assistance Center
Columbus, Indiana, USA
The alert that we sent to the field related to possible fuel system leaks has so far proven to be unneeded.
We were concerned that some early leaks we saw, especially related to PT fuel pumps, might portend more leaks but this has not happened.
We have always had the odd fuel leak and this still occurs.
If a pump fails during warranty we will replace it.
We did recall early ISB engines with VP44 pumps installed in emergency vehicles, for lift pump replacement, with a new pump that incorporates a bypass circuit. We did this so that lift pump failure would have less chance of stopping the engine and stranding an emergency vehicle. This does not extend to non-emergency vehicles.
Lift pump failures that precipitated the recall were not related to leaks or low or ultralow sulfur fuels.
There are many rumors circulating about the effects of sulfur being in diesel fuel or sulfur being taken out of diesel fuel. Diesel fuel without sulfur is just as good, in all respects except one, when compared with today's fuels with sulfur.
Diesel fuel, in the United States, must for the first time meet a lubricity standard. The producers adjust the lubricity before they distribute the fuel. No further additives are needed to ensure proper fuel system lubrication.
The only negative effect of taking sulfur out of fuel is that the fuel becomes more expensive, somewhat negating the inherent cost advantage of running diesel engines when compared to other fuels. As we are certain you know, sulfur doesn't jump out of the fuel on command. It has to be removed using specialized equipment and chemical processes that add to the expense of producing the fuel.
We have seen a very few instances where the reduced aromatic content of the fuel has resulted in slight leaks from fuel systems. This is not expected to be an issue with many engines.
Basically the change to new fuel should be pretty easy for folks with the engines built prior to 2007 and for customers with the engines built in 2007 it will be necessary, for the short time it takes fuel stations to consume the remainder of the old fuel (maybe a month or two), to be certain they are not fueling with the older fuel.
There is an effect on diesel engines from the use of low or no sulfur fuel which we expect to be positive. The blowby gasses that normally pass through the engine crankcase will contain less or none of the chemically reactive sulfur and its compounds. This will tend to keep the engine oil cleaner during operation and allow important engine components like bushings, bearings and piston rings to live longer.
Diesel fuels containing sulfur or no sulfur each have the same specific heat, about 20,000 BTUs per pound. For that reason they give the same amounts of work for the same amount of fuel. That means the fuel economy per gallon will not be affected.
Over the years we have seen fuel economy decrease, somewhat, as diesel engine designs have been modified to meet the lower NOX limits imposed by government. This has been totally unrelated to sulfur in the fuel.
With lower sulfur fuels it is possible that some exhaust after treatment devices (catalytic converters) may be used to better effect, making it possible to further decrease harmful exhaust emissions.
If you use diesel fuel that does not meet the new federal low sulfur requirements that are going into effect for 2007, in a 2007 vehicle that requires the new fuel, it will produce particulate matter that will cause rapid plugging of the exhaust particulate trap. We don't anticipate producing engines for such vehicles until 2007.
Note – this communication has been edited to remove personal and/or non-relevant material from the opening and closing. Nothing has been altered in the portion included. The alert mentioned in the opening sentence was the Bulletin issued in August 2005.