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My Poor Omni

Hey all–

First, I’ll tell you what I know: it isn’t getting enough gas to keep running, and sputters out when the choke is off. It smells like gas, and has, on occasion, dripped gas, especially when the weather turned warm. Here’s some additional information that may or may not be related (and may or may not be helpful): there is a open tube, with a connection flange that looks like a fitting for a rubber hose, mounted on the passenger-side firewall that I have seen gas dripping from once. I traced that tube back to the gas tank, where it appeared to connect to the top of the tank. I can not make gas come out of the tube when I pump the accelerator (even if the car is running), so I would assume it to be some sort of vacuum connection. However, I can’t figure out where the other end of whatever connected to it went. Any clues?

What year? What engine? I’m thinking that is the fuel tank vent and either goes to the fuel cannister or the carb. Post back with year and engine and I’ll look up the fuel tubing routing.

It’s a 1988 with a 2.2 L four cyl. There’s a tube next to the suspect tube that runs between the vapor tank and the fuel tank.

The Omni was made from 1978 to 1990. What are the year, engine and mileage of yours?

I’m going to take a wild guess and suggest that the tube you’re alluding to was a vent from the gas tank that was supposed to allow fumes from the tank to go into a charcoal canister to be captured and be breathed in from the canister and burned by the engine. My wild guess is that the connection from the tube to the canister, and perhaps the canister itself, have long since disappeared. Gas may have gotten pushed into the tube by overfilling and expansion of the gas in the tank due to temperature rise and/or agitation probaly pushed some out, causing the drips you saw.

Having that system disconnected is probably manifesting itself as a vacuum leak in the engine intake.

Here is a picture of the fuel evaporative system line routing. Might be a little hard to read, but it gives you an idea of what lines should go to the cannister.

Thanks for the responses. While I try to follow the diagram provided, here’s some pictures of the tube involved, in case it offers more insight.

I can’t make out the schematic clearly. It looks like at least two of the lines to the module to which the Electronic Spark Control System Vacuum Connection goes are intact, and I’m guessing that the line below the one in question is the vapor line from the tank to the charcoal canister, so the open one must be the vapor line from the fuel pump to the module. I’m assuming that’s some form of diaphragmatic vacuum controlling/switching module. It may incorporate the purge valve. Others can correct me if I’m wrong Check the module itself and see if it has all three of its lines.

I’m wildly guessing here guys, so go easy on me.

Regardless, I’m going to play ‘Captain Obvious’ and say that the line looks like it should be connected to SOMETHING.

Anyone out there with a similar Omni that could follow that tube and maybe post some pictures?

It’s not the Omni that is poor…

I have my doubts if there are 100 of these still running anywhere! You might try and find a Mopar forum that might have more folks with Omnis. You are to be commended for keeping this one going. I can’t remember the last time I saw one.