Help! Fuel leaking from exhaust

[TrackRunner]

Hey everyone. I started up the rig today and was checking over everything when I noticed that I had a leak in my exhaust:

http://i171.photobucket.com/albums/u318/trackrunner00/Exhaust-Leak.jpg

I wouldn't have been so alarmed, but the smell of raw fuel was pretty heavy. How can that much fuel get into my exhaust system? I've had really bad gas mileage (11-13mpg) and I'm hoping this may have something to do with that. To give you an idea of the maintenance I've done recently to try and combat the poor gas mileage I've compiled a list below:

So far I have replaced:
Front 02 Sensor
MAF sensor
Fuel Filter
Fuel Pump
Air Filter
Spark Plugs
Plug Wires
TPS Sensor
PCV valve
Timing Belt
Water Pump

and I've cleaned:
IAC valve
Throttle Body

Also, I noticed that by the time I had driven home, the leaky area had dried up, so it seems to be more of a problem when I'm first starting the truck. If you have any thoughts on getting this problem fixed I'm all ears! Thanks guys

[reggie 00]

are you 100% its gas?
I would think that condensation coming out of the exhaust would smell like gas too. at least it did the one time i thought the same thing , but i tasted it and realized it wasn't.

Have you checked your cat? a clogged cat will cause bad gas mileage.
seems you done everything but that.

If you have a laser temp gauge, if i remember right one side of the cat will be significantly hotter than the other.

[TrackRunner]

I'm not 100% sure it's gas, I just presumed because the smell was so strong. As a test maybe I will drive away from the puddle it creates, light a match, and see how flammable it is...

I will check the cat as soon as I can. Thanks for the reply :thumbup:

[reggie 00]

As a test maybe I will drive away from the puddle it creates, light a match, and see how flammable it is...




That would be too cool.

[Bob98SR5]

track,

my first question when i saw your pic was "who welded your muffler?" it looks like the pipe going into the muffler inlet is not even welded. it looks new too. can you speak more to your muffler? when it was installed, what kind, etc? and were your mileage issues predating the muffler install?

where in LA are you located?

also, you should attend the Pismo event on Oct 12 - 14th. its a great way to meet all of us So Cal guys.

bob

[TrackRunner]

Bob,

The muffler was installed at major muffler on santa monica blvd. I still have the receipt, and was planning on going back after seeing the leak and telling them to get it done right. It looks like that definitely needs to happen. I purchased the muffler online from hottexhaust.com It is the Magnaflow 24" overall center/center muffler with 2.5" inlet/outlet. It was installed about two months ago. My poor mileage has been an ongoing problem though, and was an issue before the muffler install.


where in LA are you located?
I'm in the Brentwood area.

I'm definitely interested in the Pismo event. I'm going to see if I can get my gf to take the weekend off. If she can I'm in!

Jon

[Bob98SR5]

Jon,

Definitely take it back. lost back pressure from an ill-fitted/welded muffler is not a good thing. you probably noticed a decrease in 'ooompf' when accelerating from a dead stop, right?

when did you start noticing the poor mpg?

regarding the poor gas mileage, looks like you did all the right things. can you tell us more about your truck's gearing and tires? upgrading tire size definitely makes a huge hit on mpg. that said, your mileage should not be in the 11's.

...unless you really push that SC you got under the hood there :hillbill:

Pismo: this event will be ginormous. you really need to make this trip. Chris (slosurfer) has put together one of the best events i've seen planned this year, which is also very well sponsored. there's a wealth of knowledge making this trip, so perhaps we can also help you in person.

Bob

[MTL_4runner]

I seriously doubt that is gas because if that much gas was coming out I doubt the engine would even run. More than likely that is just condensation in the exhaust getting blown out of the unwelded section of your new exhaust.

Now the heavy gas smell could be a clue to your bad gas mileage though. When you replaced all those parts, did you only use new parts? are they all OEM? can you pull a spark plug or two and post a pic? have you tuned your S/C mapping properly? What do the fuel maps look like?

[Stevo3]

Im not getting the condensation like your getting, but i sure the heck and getting the fuel milage like your experiancing. Im gettin like 13 - 14 mpg TOPS. Have no clue why this is. Even ran several tanks in pressure only.

And my fuel maps are set to when im in low boost : about 12 - 12.5 AFR and high boost is 11.5 - 12 AFR. But as i said i kept in pressure on a few tanks. So im lost, and near removing the fuel kit and ftc.

[MTL_4runner]

Im not getting the condensation like your getting, but i sure the heck and getting the fuel milage like your experiancing. Im gettin like 13 - 14 mpg TOPS. Have no clue why this is. Even ran several tanks in pressure only.

And my fuel maps are set to when im in low boost : about 12 - 12.5 AFR and high boost is 11.5 - 12 AFR. But as i said i kept in pressure on a few tanks. So im lost, and near removing the fuel kit and ftc.


I did notice that everyone that is getting poor gas mileage on a supercharged motor seems to be using the URD piggyback fuel upgrade kit while the people running the 7th injector seem to be getting near normal or slightly higher than normal MPG results. I almost wonder if it would be worth trying to splice in a later model (99-02) ECU to try and get back to more manageable fuel consumption levels. You might also see what Gadget had to say on people getting bad gas mileage with his URD setups and if there was some common causes for that as well.

[TrackRunner]

When you replaced all those parts, did you only use new parts? are they all OEM? can you pull a spark plug or two and post a pic? have you tuned your S/C mapping properly? What do the fuel maps look like?

The MAF sensor, TPS Sensor, and PCV valve were all OEM. I purchased the 02 Sensor from URD. Spark plugs are Denso IK22's, plug wires are NGK. Fuel filter, timing belt, and water pump were all replaced by my mechanic. He used to work for Toyota so he hopefully used the correct parts.. The fuel pump is a new Walrbo 190.

I will pull a couple of spark plugs and take a picture when I get a chance. I pulled them out with my mechanic about a month ago and they looked good though. They were also pretty pricey so I hope they are still okay.

As far as my fuel map goes, it isn't as dialed in as I would like it. I recently (read: two weeks ago) got my Runner back from the shop after getting the supercharger rebuilt by magnuson (under warranty! woohoo!). My previous map was very rich with the new charger, so I ended up loading the base map that shipped with the URD fuel kit. It helped a good amount, but I still had to pull quite a bit of fuel in the boost portion of the map. I was hoping that this was the cause for my poor gas mileage, but after all was said and done I'm still getting crappy mileage.

If you look at my fuel map (http://i171.photobucket.com/albums/u318/trackrunner00/Fuel-Map-1.jpg), you can see that once you get into the boosted portion the numbers are much lower than in the vacuum section. My truck is either 14.7ish afr all the time or 11.5ish WOT. I can be boosting at 8psi and unless I floor the skinny pedal all the way, I will remain in closed loop. I've been waiting patiently for a revised ESC1 that works for the later model 4Runners (w/ fed. emissions) so I can avoid this situation.

Quick question. I re-gapped my plugs from .043 to .034 a while back. I've read that plugs gapped to small can cause bad gas mileage. Do you guys think that .034 is to small maybe? I had mileage problems before re-gapping, but if it's too small it definitely isn't helping anything!



I did notice that everyone that is getting poor gas mileage on a supercharged motor seems to be using the URD piggyback fuel upgrade kit while the people running the 7th injector seem to be getting near normal or slightly higher than normal MPG results.

I thought it worth mentioning that I had bad mileage before the URD kit was installed. lucky me! But what really sucked was I bought the URD 6 larger injector kit one month before the URD 7th kit came out. I really wish they had told me it was on it's way because I would much rather have gotten the 7th kit. Oh well, it is what it is.



Im gettin like 13 - 14 mpg TOPS. Have no clue why this is. Even ran several tanks in pressure only.

I've tried staying out of anything above 0Hg myself, doesn't help me either. What was your mileage before the URD kit? What was your mileage before the S/C?

[TrackRunner]

lost back pressure from an ill-fitted/welded muffler is not a good thing. you probably noticed a decrease in 'ooompf' when accelerating from a dead stop, right?

Hahaha, I had read that the straight through design of the magnaflow muffler caused a loss in torque/gain in HP, and I had just chalked it up to that. I'm looking forward to getting some of that low end back!



when did you start noticing the poor mpg?

a few days after I bought it. I just figured it needed some good maintenance and a replaced sensor or two.. how wrong was I!



can you tell us more about your truck's gearing and tires?

The truck came from the factory with 265/70r16 tires and 4.10 gears. I called Toyota and gave them my VIN just to double check on that. I just put 265/75 MTs on her two weeks ago, but that hasn't adversely affected my mpg compared to what I was seeing before the change.



...unless you really push that SC you got under the hood there :hillbill:

Some tanks of gas go faster than others.. :angel:



Pismo: this event will be ginormous. you really need to make this trip. Chris (slosurfer) has put together one of the best events i've seen planned this year, which is also very well sponsored. there's a wealth of knowledge making this trip, so perhaps we can also help you in person.

Do any of you guys have a link for more information on the event? I'm almost positive I will be able to make it, unless something at work comes up.

Edit: Never mind on the link. I found it :)