Gas run in TDI scenario

[tdihopeful]

I saw an ALH on craigslist that was said to have had gasoline run in it. Says it needs work. Not considering buying it at the moment but thought I'd ask what potential damage would such a blunder cause. Could it be as simple as flushing the fuel system with correct fuel and starting it up? Would there be other damage to engine such as to lifters or pistons/rods from an inevitable pre-detonation? Would there be damage to the fuel pump/seals from gasoline? I imagine this would be a fairly well documented issue.

 

[ZippyNH]

Guessing if it's for sale saying it's had "gas run it" it was driven a bit...then the drain and fill was already tried before sale and it didn't fix it....
So safe to say there is damage done...

 

[Powder Hound]

In my mind, the usual scenario is someone mistakenly filled with gasoline instead of diesel, tried to drive out, then the engine stopped after a very short distance. We're talking a mile or less.

The usual worries about damage to the engine are limited to the injection system. Cleaning out the injection system will require draining the fuel lines as well as the injection pump, hard lines, and the injectors. The pump, hard lines, and injectors is a nontrivial exercise.

In my opinion, chances are pretty good that the most damage was done trying to restart. A failed battery, some friction damage to the pump and injectors, and a burned out starter motor may be present, depending on how determined the owner was. Damage could also have been done by an indy mechanic who just kept spinning the engine not knowing what else to do.

Details on the exact scenario of the running on gas episode along with all the things that were tried would be in order. It could be easy, or it could cost big bucks to get it running again. The devil is in the details.

Cheers,

PH

 

[jettawreck]

From past readings it seems most of the damage is as above when the amount of gasoline added was a majority of the amount in the tank. It's possible that less gas in the fuel would allow it to run/drive and do some extensive IP wear and internal engine damage.
Until you know the real story it's all speculation. It could be very minimal as it's been done a lot w/o any real long term isssue(s).

 

[Lightflyer1]

If the price was right and the rest of the car in good condition, I would give it a try. Less than $1k and I would have to think really hard about it. Any more than that or the car sucks, it isn't worth the gamble.

 

[Franko6]

The biggest issue with filling the tank with gasoline is the lack of lubrication that the diesel oil provides the pump. Be prepared to replace the injection pump and maybe the injectors. Retail, that's around $1400, but that would be the worst case scenario. It is unlikely the engine itself was harmed.

Many years ago, when the winter fuel was not as predictable, I would add up to 10% gasoline to the diesel with no harm. If the tank were to have been completely empty, or 1/2 full when gasoline filled, could make a big difference what occurred in the injection pump.

The question is, does it still run? Does the injection pump clatter? The first thing to go is usually the distributor shaft in the pump head. Even that is separately replaceable. $400 buys a good head. Mileage, body condition, engine condition, interior condition... Is the rest of the car worth the time and trouble?

If I were testing that car, I would 1. Drain the injection pump by removing the plug in the back of pump head. All the fuel won't come out, but maybe 1/2 will. Reinstall center nut. 2. Make a remote fueling setup, remove the 'IN' line on the fuel pump, Set up a small fuel tank to fill the injection pump. Vacuum the fuel from the system until you have at least 1 qt of diesel moved into the pump. With all the lines tight, use the return line removed from the #4 injector and a MiteyVac (me, I have an electric vacuum pump...) and pull the fuel into the pump. 3. Once the pump is primed, purge the air/ gasoline. from the injector lines. 4. Attempt to start the vehicle. A NO START is an expensive pig in a poke. Of course, if all this is done in front of the owner, and it does start, your purchase price goes UP!

As for me, I would offer junkyard prices. That's what a non-running car is worth. $400-$500, maybe. Or walk away.

If it doesn't pan out, I part out things like that. The engine/ transmission removed from the vehicle is worth more than the vehicle itself.

 

[buyingconstant7]

I had a 2006 Jetta TDI that I purchased as a project car that would barely run, unknown as to why. I found a full tank of gasoline in the tank. This guy clearly ran it until it crapped out and prolonged its misery because he would attempt to drive it for his commute everyday until it wouldn't start. I flushed the lines, new fuel filter. I inspected injector tips, they were fine. I inspected the glow plugs and they were BURNT. Clearly the combustion chambers got real hot. But I just did a simple fuel flush and filter and it's a happy car, my good friend owns it and has put 10k on it without an issue. I would hazard a guess and say that an ALH would be even less bothered by gas, but that failure prone injection pump may say otherwise. If this were a common rail, it would likely result in a $7,000 bill replacing the entire fuel system

 

[tdihopeful]

Thanks for all the information I am another step closer to being a TDI Guru! Thanks for taking the time to outline a procedure for testing and likely issues. The information provided here was pretty much all inclusive and thanks again.