Do you have a MightyVac or a vacuum gauge that measures in inHg? If not, might suggest you consider getting a MightyVac. Handy tool to have for some diagnostics and other things. You can get the plastic version from an auto parts store for like $30-$40 I think. I think Autozone even loans them if you don't want to buy one. It will probably help us with the diagnosis.

 

Ok, don't have a mighty vac or anything like that, but I can come up with one if need be.

Got under the truck and snooped around. From what I could tell, the vent at the front of the tank runs to the back of the tank. It T's into the rear tank vent, and then that hose goes to the vapor canister.

The hose labeled "Air" coming out of the canister goes up toward the filler hose, into where the gas door is. Can't see the end of it without having to take something apart, so I couldn't locate exactly where it ended.

The hoses looked about as you would expect to see on a 23 year old, 337k mile truck, lol. Except for the front tank vent hose, I replaced that with a longer hose a few years ago to aid in gas tank removal and installation.

 

Red, I do need some more info from you to look at the correct wiring diagram for your truck. But I think we have enough to do some leak testing on your system in the meantime. I started thinking about other causes for your problem outside of the EVAP system, but the fact you smell raw fuel just keeps bring me back to EVAP. To do some proper leak testing, you’re going to need to get a MityVac and also a way to seal different points off. My suggestion is you get a pack of rubber type vacuum line caps. I keep a pack of all different sizes in my tool box and use them for a lot of things. I’ve seen a MityVac type tool on the counter cover at Autozone as a loaner, and I’ve seen them for sale also. You’re only going to be dealing with max of 15 inHG of vacuum and that’s so little that you can’t test real well without the tool (with a gauge). Now I have actually heard of guys looking for leaks with cigar smoke, but that’s not what I would call the best way to go.

After we do all the leak testing, we can look at circuit tests. If everything passes the leak and circuit testing, then I think we are definitely looking at a bad (contaminated) VAPOR CANISTER. As I think I stated before, if that gets fuel or water in it, it’s basically toast. I’ll you that I had to replace my VAPOR CANISTER and it even passed leak tests. I was using a smoke machine and some of my other diagnostic equipment and the only way I was able to call that as the problem was because everything else passed. I ran every test there is. I saw no way the rest of the components could give a false pass, and the VAPOR CANISTER was the only thing that possibly could. So I replaced it, and it fixed my code and the problem (fuel smell also after filling up).

Your EVAP is set up different than mine and I don’t want to say your VAPOR CANISTER is the problem without testing the whole system. Yours could be a leaking EVAP line or something else.

Some info I need to know so I can pull up the correct diagrams/tests for your truck:
- Do you have a PCM control unit (located under glove box), or a VCM-A control unit (mounted on passenger side fender in engine compartment?

Unfortunately this long distance stuff is pretty slow. Could you also post a pic of where the line goes into your throttle body? I’d like to see that if possible.

 

I'll get a mighty vac and we can start working on that this weekend.

My ecm is mounted on the passenger fender well, right on top of the radiator surge tank.

I'll get you a pic of the throttle body connection later this afternoon.

 

Good deal. I was bouncing back and forth between the two diagrams and there are differences on what shares the feed wire. Just a little bit of knowledge I picked up on today. The 95 was a split year. You probably know that because of the OBDI/OBDII that year. Technically, you have a VCM (VCM-A to be exact). The other models had PCM's (little more than tomato tomato). Important for the future if you ever need to do some circuit research or you could go in a totally wrong direction. I wonder if the PCM was only OBDI? Do you know?

 

Yeah, I'm well aware of all the weird stuff with 95 trucks. Mine is obd II, but my first code scanner wouldn't read it. Bought a little more expensive one, and it reads it just fine.

As far as vcm vs pcm, you're above my pay grade lol

 

Ok, here's some pics of the evap to throttle body connection.

The first two are of the hose going into the throttle body.




This one is showing the port relative to the throttle blade. With the throttle closed, it's right underneath the blade, slightly to the outside of it (Towards the front of the vehicle.)


Sorry for the potato pictures, it's kinda a tight spot, and that's the best a Note 8 can do.

 

So, I pulled off the "air" hose on the vapor canister, to see if it was clogged. It was just fine.

So next, I pulled off the "tank" hose. And promo got drenchd with a bunch of liquid gasoline. Is this normal? My understanding is there should just be vapors in there.

 

If there is any liquid at all in your vapor canister (fuel, water, beer) it is toast and needs to be replaced. Then the question from there is how did it get in there? I think you need to find out definitely where the end of that "AIR" hose is going and what (if anything) it is attached to.

 

Well, there was liquid fuel right when I pulled the hose off. But I took the canister out, and turned it upside down, and there's no fuel.

The air hose goes up by the gas fill door area. It's not blocked, I can suck and blow freely though it

Edit: the end of the air hose is just open up by the gas fill port. I can feel the opening while putting compressed air
​​​through it.

Edit #2 finally got a cel and code P0305. Cylinder #5 misfire. I've gotten that one befoe when it was running bad, and I was too heavy on the throttle. The fuel trims from when the code was set seem high, the STFT was 19.5%, the LTFT being 25%. Am I correct to assume that indicates the computer seeing a lean condition, and telling the engine to go rich?