Only starts after block heater is plugged in

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Darkimag22

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Have a bit of a weird one that has me scratching my head (and wanting to beat it against a rock wall).

Long story short, 3 weeks ago I was in a rush and had a HUGE brain fart and filled up with 60l of diesel (I'll never live that one down lol). I drained everything, threw in new 91 octane fuel as well as a fuel system cleaner and thought all was good as it ran great. It was until temps began to fall past -10C that I started to have a no start issue. It will partially fire and then just die. If I plug the block heater in for more than 5 minutes it will fire up no problem at all. I have disabled the VSS so that shouldn't be an issue. After it has warmed up, most of the time it starts after 4 to 5 seconds of turning over...and the odd time it will instantly fire.

I replace the spider injection a little over a year ago so I don't think that is the problem. I am going to replace the fuel filter tonight after work...but it still doesn't make sense to me why it starts instantly after only 5 minutes of being plugged in. I don't think it is the fuel pump since I had the 2 fuel lines detached from the top of the engine (had to bleed the system to get all the contaminated fuel out of the lines) and it seemed to be pumping fuel fine.

Any suggestions of what else it could be/what I could try to fix this issue.

Still can't believe I was such a dumb a$$...
 

Drunkcanuk

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Don't feel bad, this summer I put diesel in a couple of generators at work, idiot laborers marked the fuel cube wrong.
For sure change the filter!!!!
As for the plugging in, that makes no sense, as as I assume, being from Canada (same by the way) it is the block heater cord. Which heats up the antifreeze in the block. Straight up coincidence I think.
 

Darkimag22

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I thought it was a coincidence as well the first time. I have now done this 3 or 4 times in the past week...same no start...same fires up instantly after being plugged in. I am going to order a fuel pressure testing kit if changing the fuel filter doesn't help.
 
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Schurkey

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Connect scan tool, verify coolant temp sensor accuracy. Overall, this doesn't seem related to the Diesel fuel episode. I think the truck has some problem unrelated to the Diesel fuel, the fact that it's happened some time after the Diesel incident is coincidence. If you've flushed the fuel plumbing, and run gasoline through the system long enough to purge the little remaining Diesel so that it's mixed-into the gasoline, I wouldn't expect it to gel or cause any other problems. But I've been wrong before. I had a "parlor stove" in a previous garage, which was mistakenly fed #2 fuel oil when it should have gotten #1. The fuel gel was unbelievable. Looked like the system (filter, tubing, "carburetor") was filled with vanilla pudding.

How did you get the Diesel fuel nozzle into the restricted, "Unleaded" fuel opening? Has someone pounded-out the "Unleaded" restriction? Incorrect nozzle on the Diesel fuel hose?

The block heater doesn't heat the fuel system directly; I wouldn't expect 5 minutes of heating the coolant to make a huge difference in engine temp...but although my vehicles all have heaters, they've not been used for years; and I've never measured temperature rise over time.

Good reminder to me to grab the ohmmeter and check to see if the heaters and cords are still usable. Typical block heater has something like 35 ohms resistance through the two flat blades of the cord and heating element...
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...and nothing from either one of the two flat blades, (doesn't matter which one) to the round "ground" pin.
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Darkimag22

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The UFA cardlock that I get fuel at has the same size of nozzle for both gasoline and diesel. It is a different color (red=gasoline, black=diesel) but I was in a rush and wasn't paying attention.

Everything else checks out so far. The whole plugging in and starts fine thing doesn't make any sense to me either but it now does it every time. Being plugged in for 5 minutes would do very, very little towards warming the coolant.
 
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Supercharged111

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I was thinking it would be illegal to have a Diesel fuel nozzle that could fit into an "Unleaded" fuel-filler restrictor. Apparently that's not the case. I guess I learned something here.

In Germany the green nozzles are gasoline. I don't recall if the nozzle sizes were different.
 

Orpedcrow

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I agree with both the coolant heater not warming the coolant much, and a faulty (or soon to be) coolant temp sensor causing a hard start issue.

How far away from the sensor is the actual heater element? Could it be warming the coolant around the sensor enough within that 5 minute time frame to see a different reading? (I’m from the south and have never even seen one lol)

Do you have an ohm meter to check the resistance of the sensor (before and after heating) or a scan tool to see what the computer is seeing as a value? ( I don’t remember the specific number but usually when the sensors go bad the computer will show a value of “-55f” I think)
 

Orpedcrow

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In Germany the green nozzles are gasoline. I don't recall if the nozzle sizes were different.
They aren’t standardized here in Texas, most places have a red handle for “ethanol free” while other have red for “may contain 10% ethanol”. Others are all black, others are green for gas and black for diesel

I even saw a red diesel and green gas at the same pump the other day. No heckin way I’m getting gas there lol
 
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