I just bought a 1993 4runner with 224K miles, and it seems to be running great - quick start, smooth idle, smooth acceleration, nothing leaking underneath - but I've been noticing a very strong rich gas smell coming from the exhaust ever since I drove it home on the highway for about an hour. The smell was not present when I bought it. At first I thought it was coming from the engine bay because I could smell it in the cab, but I realized that was because I was starting it, rolling down the windows, and then reversing down my driveway through the exhaust haha.

The smell does NOT go away no matter how long it's been running, although you can only smell it in the cab if you stop moving and have the windows down. I haven't polished off a tank of gas yet so not sure about MPG.

There is no smell in the engine bay and no visible leaks without removing the plenum. Just to be sure, I checked the fuel pulsation damper on the back of the engine and it is dry.

That pretty much leaves the EVAP system, right? The charcoal canister and the purge valve? I read somewhere if you "top off" the gas tank it can flood the canister, so maybe the seller did that (tank was full when i bought it). Check related vacuum lines for blockage? Anything else I should poke around? Thank you!

 

It would help us a lot to know not only the year, but the engine (22RE, 5vz-fe, etc).It matters. For example, the unit at the rearward end of the fuel rail on the 22RE is the pressure regulator, the pulsation damper is at the front of the rail.

Did you pull a spark plug and check it's condition? Is it black, covered in carbon, or a nice, clean, pale tan?

Yes, over-filling, or topping off, the fuel tank can cause troubles with the evap canister. Have you checked the canister for liquid fuel?

Have you checked that valves for the evap canister are functioning correctly? The FSM has a good test procedure.

Let us know what you find. Help us help you
Pat☺

 

Hey Pat, thanks for responding so quickly! I thought '93 4runners only came with the 3VZ-E 3.0L V6? That's what mine has.

All I've done so far is check and make sure there wasn't anything obviously leaking in the engine bay, specifically that the FPD wasn't causing the leak. I was just trying to collect a laundry list of things to check when I get some free time this weekend .

I'll pull the spark plugs and take a look. Didn't think to check those. Do you have to remove the plenum for that? Guess I'll find out lol. Will also check the charcoal canister for fuel and that the valves are working. Thanks!

 

Well, I had a few moments tonight after work so I pulled the canister and found that the purge vacuum line had burned through about a foot down and wasn't connected to to the TVV. Guess that's my first project!

http://htftp.offroadsz.com/marinhake...74layoutan.pdf

 

I may well be wrong, I often am, but I believe the 93 may have come with a 22RE. And after 30 years, a different motor than from the factory isn't out of the realm of possibility. That's why people put the information like that in their sigs. A glance tells everyone a wealth of information that way. Makes life easier for everyone

Glad you found that bad vacuum line. May I suggest a better routing on the new one?
You might want to verify all the vacuum lines for routing using the sticker on the inside of the hood, upper left corner when it's open. Make sure they're all in good shape, no cracks, breaks, burns (ahem), or stuff like that. Alternatively, just go through, and replace all the vacuum lines with new. That way you KNOW they're good.
Also, the large tube from the AFM to the Throttle Body has a known problem with the flexible corner pieces developing cracks, so verify that hasn't happened. The pieces are readily available from most stealerships, at a surprizingly reasonable price.

Good luck! Have fun. That's why we get these trucks after all
Pat☺