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Gas/DEF/Diesel Mistakes

PostPosted: Fri Apr 28, 2023 9:09 pm
by K of the C
Has anyone dealt with customers putting one of gas/DEF/diesel in the wrong tank? We've had 5 or 6 in the last year and was wondering how common this was since there's nothing (that I can find) about the procedure for it

Re: Gas/DEF/Diesel Mistakes

PostPosted: Fri Apr 28, 2023 11:38 pm
by Ichabod Farquar
GM has very specific procedures for addressing DEF in diesel fuel. There are actually three different approaches.

1 - Customer realizes mistake and no attempt has been made to power-up or start the vehicle.

2 - Customer realizes mistake but did power-up the vehicle but did not start the engine.

3 - Customer may or may not have realized the mistake and started the vehicle - or - tried to start it.

I don't know the bulletin number off the top of my head but #1 requires removing tank and replacing a few things. #2 requires a lot more. #3 is catastrophic and requires replacing entire fuel system. $10,000 for a Duramax is a good starting point.

Re: Gas/DEF/Diesel Mistakes

PostPosted: Mon May 01, 2023 1:10 pm
by AlanHomes
Have seen a few here. One was a fleet company owned vehicle. Driver knew he screwed up, started the vehicle anyway. Drove it here then quit his job.
The other was a private owner, knew he screwed up. Did not start the vehicle, called a wrecker and warned the driver not to start the vehicle, it was an easy hook and roll up on the bed. Tow driver started it anyway, tow company got a bill from the owner. Tow driver promptly fired.
Usually the mechanic will lift the body(s) off the frame and go at it, replacing everything affected.
Here's your sign.

Re: Gas/DEF/Diesel Mistakes

PostPosted: Mon May 01, 2023 8:41 pm
by Lutom
We've had a few here. They seem to be getting more and more common lately.

The doc ID I found for it is 4790235.

Re: Gas/DEF/Diesel Mistakes

PostPosted: Tue May 02, 2023 5:06 pm
by joecool17
We've had all of the above here at one time or another. Just last week a customer filled his new 2023 Denali K2500 Diesel with gas. He realized it when he went to hang up the nozzle and the pump handle wasn't the right color. Drove it here from 30 minutes away (mostly highway). Once he got it here he pulled directly into the service drive and it wouldn't start again. Also when he go out, he had a beverage in his hand. Later found out that it was the anniversary of his son's death who had committed suicide a few years back. We felt terrible for the guy. Our diesel technician was able to drain and purge everything. He probably had about half a day into getting it remedied. It now seems to run just fine. It all really depends on what they put in. DEF fluid is the worst. GM usually wants everything the DEF fluid touches changed. We once replaced an entire fuel system on a diesel Canyon. That was truly a nightmare, as that was a new and rare model. Took months to get everything necessary to do the job. It's always best if they realize what they did, to NOT START IT! Then it's as simple as draining and refilling.

Re: Gas/DEF/Diesel Mistakes

PostPosted: Tue May 02, 2023 7:35 pm
by WhoParted
Love when they do this and start the vehicles. $$$$

Re: Gas/DEF/Diesel Mistakes

PostPosted: Tue May 23, 2023 2:05 pm
by AlanHomes
Got another one in here, checked in a pile of parts for a fuel system rebuild. Owners insurance will pay, then probably kick them out or raise his rate.

Re: Gas/DEF/Diesel Mistakes

PostPosted: Fri May 26, 2023 11:52 pm
by Ichabod Farquar
Got another one in today. This one is gasoline in the diesel tank. Ran over 50 miles then "stopped" - will have to see next week how many thousands of dollars damage has been done.

Anyone seen a destroyed engine because of this?

Re: Gas/DEF/Diesel Mistakes

PostPosted: Mon May 29, 2023 12:08 pm
by AlanHomes
Have not seen one that was run with gasoline, imagine the pistons have holes in them. Trying to compress 87, even 93 octane with diesel compression will create critical issues. Post some photographs if possible. Ten dollars says the owner will cry warranty.
There was a friend from high school, his father had an Oldsmobile with the 5.7 diesel, what a disaster to begin with. Took it to the local Esso station, the pump jockey filled it with gasoline. Fortunately he caught it, called a wrecker, towed to the local dealer, drained and cleaned the tank .

Re: Gas/DEF/Diesel Mistakes

PostPosted: Tue May 30, 2023 2:26 pm
by AlanHomes
Ichabod Farquar wrote:Got another one in today. This one is gasoline in the diesel tank. Ran over 50 miles then "stopped" - will have to see next week how many thousands of dollars damage has been done.

Anyone seen a destroyed engine because of this?


Much of my experience dates back to the late 70's and early 80's with old school diesels, the 5.7 disasters, 6.2 and a handful of 4.3 diesels that would continue to run with incorrect fuel until they exploded.

Well, I learned something yesterday. The diesel (in this instance a GMC Canyon) that was towed in with a tank of gasoline mixed with whatever diesel was left stopped after roughly 30 miles. The mechanic pulled both fuel filters and ran the pump to drain the tank. The system only allows the pump to run for 30 seconds, pause for 30 seconds, pump again etc. It took more than an hour to completely drain the tank.

Added some fresh diesel, ran the pump again to help purge, installed fresh fuel filters, start vehicle, let it choke/puke, it shuts off on it's own, start again eventually it smooths out.

Mechanic has his laptop checking codes, parameters etc. Clearing them out, pressures look good, etc etc. I was looking for a paper clip to have it flash codes and count the number of flashes but that is another story.

I asked him, how does the vehicle know it has the incorrect fuel and shuts off? In a nutshell, diesel fuel and gasoline have different viscosities, in this case, the pressure sensor on the rail detects fuel that is too thin. It could have destroyed the injector pump, leading to a fuel system rebuild.