I recently opened a post to clarify my understanding of a situation on my car where I smell fuel after hard accelerating (i.e. under boost). I thought it was coming from the BOV, but have been educated that I was wrong. My car also has a couple of other quirks that I just never put together and now wonder if there is some relation.

First off – it’s a 93 Touring with 120k miles, no accidents, 3rd owner, full history since new, all recalls done (just checked the Mazda 800 line), mildly modified (see sig), recent engine (6,000 miles) and original turbos.

When I first got the car back from the motor builder, it ran fine with the exception of cold idle. When I tried to drive it down the block while it was not completely warmed up, it would stall whenever I let off the throttle from like 3000 rpm or so when I got to a stop sign or light. Once it warmed up to operating temps, it was fine.

When I took the car back for the 1,000 checkup, the Power FC was fine tuned and he readjusted idle values. I still have the cold idle/stall problem, but it is not as prevalent as when I first got the car. As I’ve driven the car more I’ve also noticed that when I’m in heavy stop and go NY traffic the idle when the car is hot is higher around 1200-1500 then drops back to normal ~800 after about a couple of minutes of steady idling.

The only time I smell fuel is under hard acceleration when the car gets under boost. Even then, I only smell the fuel for a few seconds after I accelerate. Never at idle or just cruising.

I have also noticed a couple of seconds of light smoke now and again coming from the vents in my Mazdaspeed hood when I stop for a light especially when the car is cold. Like the first light a mile from my house when I’m heading to the highway. I’m not sure if it is related as it has only happened 3 times in the last month. Hmm. Actually I haven’t driven it that much so maybe it does happen a bit more frequently than my mind has registered. Point is that I had also once seen smoke when I wrapped my downpipe in August about 3000 miles ago. Not sure if some of that **** is still burning off, but I know that the smoke from the wrapping didn’t come out the hood vents.

So, given these facts (idle, fuel smell, area of smoke) - Does this point to any one problem more than the other? Does it sound more like a Fuel Pulsation Dampener vs. a Charcoal cannister vs. an injector leak vs. a fuel line leak? My builder did check all the lines and stuff when he did the motor and found them to be fine, but the car does have 120k miles on mostly original underhood components. I want to start looking at this on Sunday, but there are so many possible options that I want to see if you guys can point me to what sounds like the most likely cause. Thank you.

 

There is also another possibility which has happen to a few: LIM gasket. People have had to replace that which fixed gas odor problems.

Have your fuel system pressure tested. That will let you know if something is leaking there. After that, you can take a look at the other areas.

 

LIM? Hmmm... Good point. How does one pressure test a fuel system? Is that something I can do at home or is it a shop only procedure?

 

Ive been smelling fuel all the time out of my car.Now what exactly is a LIM? Ive checked for any fuel leaks and i found none so where the heck can the smell be coming from?

 

I have the link at home, but if you want to find it yourself do a search for fuel smell and user Mahjik. He took part of a real good thread that explained fuel system checks reasonably well.

LIM is lower intake manifold.

For whomever is interested, I'm still researching my problem. So far I have found that the aluminum purge control (one-way) valve needs to be replaced. $14 at Malloy. I hope that does it. After quite a bit of checking, it seems like the smoke is a small exhaust leak. Need to test some more after getting the part. I think my idle is something unrelated at this point.

Smelling fuel all the time is not good. Spend some time reading that thread and a couple of others it should point you in the right direction.