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Diesel Fuel Quality

The local shop is overloaded with repair work to replace the fuel injector pumps. The reason- California (and perhaps other states) in their wisdom to clean up diesel fuel emissions, has removed some bad guys from the fuel and, in so doing has also removed some good guys. One of the good guys removed is at least one of the lubricants that lubes the injector pump. The result is pumps that eventually get destroyed. Their are fuel additives available, the one the local shop owner recommends, he can't keep in stock. When he told me about the problem, he told me the best thing to do is to go to a local store (Walmart or KMart) and buy the cheapest 30 weight oil I can find and when I fill up the tank with diesel fuel, add two quarts of the 30 weight to our 90 gallon tank. Obviously, this means use one quart if we are only adding 1/2 a tank of fuel. He said their are no side effects of adding the oil, but there sure are if we don't. He could not speak to the fuel in other states, but said it won't hurt to be sure. You might wish to speak to your own local shop and act accordingly."

Leo Everitt quickly contacted his Cummins interface and replied with quoted words from Cummins which indicated that there is no problem with the lubricity of diesel fuels anywhere in the US affecting Cummins engines.

I reported my information again at the Richmond Rally, simply FYI, and Leo again replied with the Cummins statements. My immediate reaction in both cases was "something is wrong in this equation. If there is no problem with lubricity of the fuel in California, then why is there a rash of fuel injector pump failures in recent months in California." My plan of action at this point was to provide the Cummins data provided so quickly and accurately (as usual by Leo) back to my Cummins service company and inquire as to "wot's up". I did this and here was the response form McCormick Diesel Service in Lancaster, California:
"No reports of lubricity problems with fuel injector pumps has been forthcoming from Cummins probably because the problem is with the injector pumps, not the Cummins portion of the engine. The reports HAVE come directly from the injector pump manufacturers and alerts/notices have been issued by them"

I supply here the primary content of two such alerts which Steve McCormick supplied me (I have FAX copies of both):
United Diesel Service, Inc. (A Bosch Injector Pump Dealer in South El Monte, CA) October 1999:

Over the past couple of months, we have seen a dramatic increase of injection pump failures due to the quality of diesel fuel.

The problem appears to be related to low diesel fuel lubricity. We have extracted fuel samples from several sources and are awaiting the laboratory results.

In the meantime, we strongly recommend the constant use of a diesel fuel lubricity supplement to protect your fuel systems. We are not able to warranty failures due to poor fuel quality."

Fuel Injection Service Company of California (A Bosch injector pump dealer) July 10, 2000:
"We have seen a dramatic increase in "fuel quality" related failures of injection pumps over the past few weeks. Fuel samples extracted from failed units were sent for HFRR (High Frequency Reciprocating Rig) laboratory testing in order to measure the lubricating qualities of the fuel in question. The results just received indicate that the samples are extremely dry and abrasive, typical of kerosene or even jet fuel. The average wear scar diameter of the samples tested was 30% to 40% worse than the maximum allowable. Fuel Injection is strongly recommending consistent use of a diesel fuel lubricity supplement in order to protect your fuel system. Injection pump failures due to poor fuel quality ARE NOT WARRANTABLE."

Steve McCormick also indicated that the injection pump failures he has seen are not limited to Cummins engines (Ford and GM also), small or large, and are not limited to Bosch injector pumps.

So what's the bottom line? As for me, when I fuel up with diesel anywhere in California, I am using an additive. Either a special additive for lubricity (one is put out by STP but I have no knowledge of its quality) or to do as Steve McCormick suggested- in the absence of a special additive, use the 30 weight oil. Why Cummins is not aware of this I can't answer, but I am going with what the injector pump folks are saying. As far as Steve McCormick knows, California is the only state that has inforced the stringent process for sulfur removal which also removes the lubricity qualities. To his knowledge, none of the low sulfur fuel is exported to other states.

Best regards and happy motoring,
Don Fuller #1088


The DISCOVERY OWNERS ASSOCIATION, INC, was formed to promote the sharing of information and the camaraderie of fellow Discovery motorhome owners. Membership in the club is limited to owners of Fleetwood Discovery motorhomes.


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