Unburned fuel 'spots' on tailgate?!

[TechnoWeenie]

So, I noticed on my tailgate that I have black spots that look like oil stains, but smell like fuel.. They won't come off..

I also noticed my back window pretty caked with soot, although there is no excess smoke while driving, just a small puff of black smoke when starting...

In addition, on occasion, I'll get a real strong fuel smell, but there doesn't appear to be any leaks.

I'm thinking that the timing is advanced too far, or the pump is set too high...

Now, to complicate things, for the first time since I've owned this truck, it wouldn't start in the morning (80*).. and I had to crank it for a couple of minutes while goosing the throttle to get it to start, and it hasn't done it since (about a week). I was thinking about the fuel lines/filter, and have already purchased a spin on replacement, just has to go on.

So, any insight on these issues?

Side note : I do have an exhaust gas head gasket issue, however, other than topping off the coolant every week, there haven't been any issues. There is no oil/coolant intermixing, only excess pressure in the coolant system.

 

[Brett09]

Side note : I do have an exhaust gas head gasket issue, however, other than topping off the coolant every week, there haven't been any issues. There is no oil/coolant intermixing, only excess pressure in the coolant system.

As you mentioned you have excess pressure in the coolant system. It sounds like you have lost compression in one or more of the cylinders and the raw fuel is just going down the tail pipe. With diesels no compression = no ignition. The head gasket is where I would start if it was my truck.

 

[alburms311]

84 M1009. I am having this issue as well, partly. I see small spots on the tailgate and some reach the back part of the roof. Cant really tell/smell what fluid it is though, and it only seems to happen when I go on longer than normal trips(50+ miles above 60mph, usually when I'm taking it to or returning from a local show). The back window doesn't have soot on it as the OP stated, nor do I use any coolant, smell fuel, or smoke. I do have a pinion seal leak, but I don't believe that is what is traveling that far up, and I cant trace it on the bottom of the truck. Other than this new issue, it starts, runs great. Any other thoughts?

 

[blackhueys]

I had the same issue, long trips and above 60 mph what I found on mine was the vent for the trans was leaking and the under truck air movement was pulling and curling it up onto the tail gate. my trans level was good and the only thing I did to fix it was added some trans additive yes I know those are only supposed to be a temp fix but never had the issue again in over 3 years. I cant remember exactly what I used but it came in a small red tube about the size of a chap stick tube it was not cheap around 20 dollars for it but like I said no issue since. I feel that since the issue started right when I got the truck and it came from a national guard unit that the truck was not used hard for awhile and everything was a bit dried out seal wise the additive i put in helped renew the seals since I am sure the truck was not used much. I bought it with 54000 on it in 2010 so low miles and it was sitting for awhile. I did read on line that these transmissions will blow out the vent tube when the front seal starts to go or is gone already not a easy job as you would need to pull the trans and remove the front pump assy for repair so that's why I tried the cheaper fix first. hope this helps.

 

[dependable]

So, I noticed on my tailgate that I have black spots that look like oil stains, but smell like fuel.. They won't come off..

I also noticed my back window pretty caked with soot, although there is no excess smoke while driving, just a small puff of black smoke when starting...

In addition, on occasion, I'll get a real strong fuel smell, but there doesn't appear to be any leaks.

I'm thinking that the timing is advanced too far, or the pump is set too high...


So, any insight on these issues?

Side note : I do have an exhaust gas head gasket issue, however, other than topping off the coolant every week, there haven't been any issues. There is no oil/coolant intermixing, only excess pressure in the coolant system.

Whoah there ! (in the voice of Foghornleghorn, the cartoon rooster) you think adding antifreeze due to leaking head gasket not an issue? Do you think that is sustainable and will not get worse? Engine damage likly if you don't fix this. I would suggest sorting out basic mechanics before you get too theoretical. Unless you or previous owner changed pump settings, they are probably the same as when they rolled off the line.

 

[alburms311]

Thanks, I hadn't thought about the vent tube but that makes sense. I'll look for the chapstick stuff in town this weekend while Im out and report back if any change.