Annual Update re Mexican Diesel Fuel

Briansue, the reasons I do not wish to post the procedures on this website, or any other website, are:

1.
I have the experience to ask the right questions of an owner, so that I can determine which is the best course of action. If an owner simply starts doing things off a pre-printed list, without having an understanding of the impact, he or she could complicate the situation rather than solve it.

2.
I need to protect the sources who have supplied me with the necessary technical information, for a number of reasons, not least of which is the fact that the EPA has specifically prohibited manufacturers from making public some of the procedures. The EPA is concerned that owners with too much knowledge may make modifications which increase emissions. I therefore have keep to a minimum the number of copies in circulation, and to first question an owner in order to determine that the problem is genuine - that it is not just a fishing expedition to find out the sources of my information.

3.
It is VERY important that there be a central database where all of the experiences can be tracked, so that the procedures can be improved, and mistakes can be avoided. This happened last season when a question by an owner led indirectly to a simplified way of dealing with Poor DEF Quality messages on 2012 and later GM products.

4.
In some rare situations, owners need access to email, and an Android based cellphone, as well as a specialty wireless item that has to obtained from the USA. I have to ensure that all of the correct items are present before explaining what needs to be done. Again, this is rare, but every situation needs to be assessed before deciding on the best approach.

5.
Bottom line, if I try to explain it in simple terms, all of the procedures are aimed at getting exhaust gas temperatures up to a level which will burn sulfur compounds out of the DPF (and the SCR in 2011 and later model years). The ideal way is to induce a regeneration cycle, which the EPA says owners must not be allowed to do, so the vehicle has to be "tricked" into starting a regeneration cycle well before limp mode. Sometimes, for 2007.5 through 2010 model years, a 15 minute high speed drive, above 74 mph, is sufficient, and is an easy thing that any owner can try without complicating matters.

Ed White,

Is there some way you can post the procedures people might need to use to do whatever they might need to do if they get stuck in Mexico? Clear codes? Regenerate? You say they can contact you but if you have the procedures maybe you could post them here and people could do a Copy & Paste to their computers so they will know what to do if they get stuck out somewhere that they cannot make contact. I assume the procedure could be long and maybe different for various makes and models. Maybe there are links you could post where folks could find more info.

Please don't take this the wrong way - no disrespect intended - but any post on any forum is hearsay until supported by some credible source - such as a Duramax/Isuzu website (company site - not owner forum) so folks can find facts. When I post I try to provide Copy & Paste web addresses where facts can be found.

The example posted by The Texan is hearsay of course, as it references someone who "had a friend" who is purported to have experienced a certain situation.

That having been said, it is absolutely certain that anyone having their vehicle towed out of Mexico, to a dealership, with emissions related codes, is likely going to have to pay for repairs, which, incidentally, are extremely easy to do and should be CHEAP. All that is required is for the dealership to initiate a "Service Regeneration" or a "DEF Quality Test" right in their parking lot. In about 35 minutes the problem is 100% gone, codes cleared, no damage to emissions components. There is NO NEED WHATSOEVER to change any components, and the total amount of technician time required to initiate the procedure is less than 10 minutes.

Despite the hearsay nature of The Texan's example, I can confirm a similar "hearsay" example that did occur for an owner on the Mexican Mainland. In that case, I did end up speaking with the owner AFTER the incident. Unfortunately, he was unaware that he could have contacted me to deal with the issue, so he contacted a Mexican GM dealership. Sadly, because there are no Duramax powered pickups sold in Mexico, the technicians have no training, and no diagnostic procedures or tools. Worse still, they can not access parts using the vehicle VIN. It is very bad news.

Eventually, the Mexican techies did find out how to initiate a regeneration and returned the truck, working again, to the owner. I do not know how much he paid for the service, but labor rates are not high in Mexico.

The main reason I do these postings every year is to help those folks who inadvertently, or deliberately, enter Mexico with their diesel pickups post 2007.5, and subsequently need help with emissions related issues. I am not going to pass judgement on their decision to enter Mexico. I will help them to clear those error codes and deal with the use of Mexican fuel. I do this because I know that NO DAMAGE is done to any emissions system component by using Mexican diesel for less than 40,000 continuous miles. It is therefore unfair to cancel a warranty for the use of Mexican diesel, although an owner should pay for the Service Regeneration to fix a problem.

Maybe you know more than the GM engineers and GM dealers, but here is just one instance of a GM owner losing his warranty for use of Mexican fuel........

Re: PEMEX

When I see UBA diesel, specifically the yelling and screaming with joy that it is being sold in México (DF) then I'll start paying attention when it may increase its coverage in the rest of the country.

Pemex is wired by a dozen federal mandates to provide UBA to DF before anywhere else in the country. Yes the border areas can widen a little but you ain't gonna hear about UBA being available in Culiacan, or Coatzacoalcos, or Chetumal before DF gets theirs. It's all about smog.

Regarding the above questions and input:

1.
To The Texan, while it is true that the ECM (onboard computer) registers one or more emissions related codes when there is sulfur poisoning of the emissions system, some of the codes are TEMPORARY, and are erased automatically once the system returns to normal after a regeneration.

I am especially familiar with the programming of the GM systems, much more familiar than anyone at your dealership would be, so I can share with you that the only codes which sometimes remain in the ECM are P2022 and P20EE, neither of which identifies high sulfur fuel as a cause of the code. P2022 indicates that a NOX detector returned a less than specified level of NOX (oxides of nitrogen) in the exhaust, and P20EE indicates that the DPF (diesel particulate filter) returned an error code. A technician seeing these retained codes during a routine read at the dealership, when no engine warning light is lit, would just assume there had been a non-standard event which corrected itself, and he would routinely erase the codes.

There is no code of any type on any of the Big 3 vehicle emissions systems that specifically checks for the presence of sulfur, so it is impossible to tell, after the fact, that LSD was used. If you would like to check the accuracy of this statement, ask your Dealer exactly HOW they can tell that LSD has been used, and what code specifically identifies that LSD was used.

That having been said, I repeat that I do not counsel people to take their trucks to Mexico. I only want to share factual information so that owners can make their own decisions based on those facts.

2.
Regarding the Tiffin with the clogged DPF, I suspect that the author of the letter lacked all the necessary information and/or was given incorrect information by the dealership. Most service reps at dealerships have absolutely NO IDEA how the emissions systems work or how the components interact.

Without having all of the necessary information, I can say that it was not uncommon in 2007.5 through 2010 model years for problems with clogged DPFs to occur because the regeneration cycle was not properly burning out all the sulfur. As a result, over numerous cycles, carbon built up in the DPF and clogged it. SULFUR COMPOUNDS ALONE DO NOT CLOG A DPF - SULFUR COMPOUNDS REDUCE THE EFFICIENCY. I therefore doubt that the Tiffin owner's DPF was clogged with sulfur, and my question to the dealer would be "What scientific tests were done to identify sulfur in the clogged DPF?". I know what the answer would be.

In fact, if the DPF was damaged by sulfur, no warranty would apply, whether or not the unit was in the USA.

As for traveling to Mexico with the Tiffin, I do not have enough information to make a judgement about the risks. Generally speaking, for vehicles prior to the 2011 model year, when urea injection and an SCR were added to the emissions system, no problems occur while in Mexico and owners will not notice any issues or problems. Some will see occasional blue smoke and/or get a temporary engine light and/or Poor Quality DEF warning, all of which go away after the next regeneration cycle.

Also generally speaking, vehicles under load, such as when pulling a large fifth wheel trailer, or transporting a large motorhome body, will have high enough exhaust temperatures to continually burn off sulfur compounds and no fault codes will be seen.

As for whether some "get away" with using Mexican fuel, and some "may not", that is EXACTLY what happens. The vast majority, based on data I've collected since late 2007, experience no issues whatsoever, but there are some every year who come close to going into limp mode, or do go into limp mode, before the fault codes can be cleared. For those folks, I have a database of information built up from the feedback from other owners, along with my technical knowledge of the programming of the system and its components, and I haven't had a case yet where I couldn't solve the issues for the owner. I don't like to see people stranded when I have the knowledge to help fix a problem.

In the Tiffin motorhomes magazine Roughing It Smoothly Volume 10 #4 there is a letter in the tech section on page 70 from a guy with a small Tiffin Breeze with an International engine I believe . . .

http://tiffinmotorhomes.com/owners/magazine

He says his particulate filter clogged using US fuel and they had to take it out and send it somewhere to have the sulfur burned off. He was asking if there is an additive that will burn the sulfur off. Not known. He wants to go to Mexico and is concerned.

So if US fuel can clog a filter causing it to clog so badly it has to be sent somewhere to be burned off - what will the Mexican diesel fuel do to his filters??? His was probably covered by warranty in the US but if someone puts Mexican diesel in and has to have it burned off how much will it cost with a voided warranty due to using the wrong fuel???

I know nothing about any of this. But there could be more than one side to every story. Some people get away with using Mexican diesel but others may not. What are the risks and the costs should things not go according to plan???

This forum is not the place to ask. The manufacturer of your engine is the place to ask - not the dealer - not the mechanic - not the guy at the gas station - but the actually home office of the manufacturer of your engine. Or you can play Russian roulette with your very expensive engine.

Ed, do you have a solution to the fact that EVERY one of those error codes are logged into the computer and are the basis for denial of warranty? I specifically asked that question of our dealer when we bought our truck, and he showed me a GM notice to dealers, that if there was any information logged into the computer showing the use of LSD fuel, that all powertrain warranties were to be denied......How do you skirt that one?

Pemex is claiming ULSD by the end of 2014. Believe it when you see it.