Bad gas mileage, exhaust smells like fuel

[jspaeth]

After reading every single post reguarding SRs that are running rich, I think I have narrowed down my problem, but just want to hear some opinions.

Blacktop SR, FMIC, Greddy RS BOV, AVC-R, etc.

Basically, starting 2 weeks ago, I started having the following problems:


Bad gas mileage (used to be 23-25, now 15-18)
Car almost stalls when I depress clutch as coming to a stop
Exhaust fumes smell like gasoline a little bit


I am NOT getting black smoke out the tail, and the car seems to be running pretty well otherwise......

I DONT smell gasoline anywhere outside the car or in the engine bay at all.

Barring any fuel leaks or vacuum/boost leaks, I am leaning towards bad FPR or sticky/bad injector....


I am going to pull the spark plugs ASAP....if they are all uniformly wet/coated in fuel, can I rule out a (single) faulty injector?

Conversely, if only 1 of the plugs is particularly bad, can I conclude that the problem is isolated to that injector?

It's really annoying, I used to get 25 mpg, and now I am getting like 17 mpg...also, the semi-stalling on decel is annoying...

I will double check for air leaks or fuel leaks, but I don't think either are the cause. Car is building boost VERY quick (so I don't think there is a modest boost leak), and I have checked my BOV (which has stuck a tiny bit open before, but when it stuck open, I didn't build boost ANYWHERE near as fast as I am now)


Word

[EAT Motorsports]

After reading every single post reguarding SRs that are running rich, I think I have narrowed down my problem, but just want to hear some opinions.

Blacktop SR, FMIC, Greddy RS BOV, AVC-R, etc.

Basically, starting 2 weeks ago, I started having the following problems:


Bad gas mileage (used to be 23-25, now 15-18)
Car almost stalls when I depress clutch as coming to a stop
Exhaust fumes smell like gasoline a little bit


I am NOT getting black smoke out the tail, and the car seems to be running pretty well otherwise......

I DONT smell gasoline anywhere outside the car or in the engine bay at all.

Barring any fuel leaks or vacuum/boost leaks, I am leaning towards bad FPR or sticky/bad injector....


I am going to pull the spark plugs ASAP....if they are all uniformly wet/coated in fuel, can I rule out a (single) faulty injector?

Conversely, if only 1 of the plugs is particularly bad, can I conclude that the problem is isolated to that injector?

It's really annoying, I used to get 25 mpg, and now I am getting like 17 mpg...also, the semi-stalling on decel is annoying...

I will double check for air leaks or fuel leaks, but I don't think either are the cause. Car is building boost VERY quick (so I don't think there is a modest boost leak), and I have checked my BOV (which has stuck a tiny bit open before, but when it stuck open, I didn't build boost ANYWHERE near as fast as I am now)


Word


Codes? also do what you said and pull the plugs and see if its one or all , if all then try to get a fuel pressure gauge and go from there.

[jspaeth]

Haha....I know a decent amount about cars, but one thing I've never done is check codes haha....I will read about it on here and figure it out.

I don't have any check engine light, but then again, because I have a SR swap, I don't know if the CEL is hooked up

Haha whatever I will read up on it

The other thing......due to the fact that the bad gas mileage started at the same time as the bogging on decel problem, I am starting to second-guess myself......the bogging problem sounds like some sort of airflow problem.

Going to double check all boost/vacuum lines today.

Thanks for the input

[jspaeth]

Okay, so I just went outside and fired up the car....smelled all around, and no gasoline smell anywhere EXTERNAL...

Exhaust smells a little like fuel, and the dipstick smells a LITTLE like fuel (not too bad).

Check engine light is not on....double checked all fuel/boost/vacuum lines, don't see or feel or hear any leaks.

However I did notice 1 thing:

The person who did my swap (he has done 100s of swaps) hooked up the fuel system like this:

in,fuel rail,FPR,filter,out

From what I've read, the FPR goes to the outlet, so the in-out order is okay....however, the filter should be before the fuel rail, correct (seems obvious)?

Obviously, if it was completely backwards, it wouldn't work...I guess the filter isn't helping much if it's after the FPR!

Also, the outlet of the fuel filter (which is currently hooked up to the return line I guess) was sitting such that the hose was a bit kinked, so maybe that was raising the fuel pressure and making me run rich....

This seems like a reasonable possibility.

http://makingapril.com/greg/justin/Fuel3.JPG

As you can see, the FPR goes to the top of the fuel filter, then out to the return....I think this is wrong.

Also, which part of the fuel filter is the inlet...the top or bottom?

[cwtt]

in,fuel rail,FPR,filter,out

From what I've read, the FPR goes to the outlet, so the in-out order is okay....however, the filter should be before the fuel rail, correct (seems obvious)?

Obviously, if it was completely backwards, it wouldn't work...I guess the filter isn't helping much if it's after the FPR!

Also, the outlet of the fuel filter (which is currently hooked up to the return line I guess) was sitting such that the hose was a bit kinked, so maybe that was raising the fuel pressure and making me run rich....

This seems like a reasonable possibility.





The fact that the hose is kinked and you have the filter after the FPR is a huge problem. Fix both of those and then report back.

[unicoladron]

wait a minute...the person who did your swap did 100's of swaps eh..so there's HUNDREDS of sr's out there with their fuel filter in the wrong place....lol

good to hear that you at least found one problem.

[SHIFT_*grind*]

Yep, those are both pretty huge problems. :) Tackle those first and see where it gets you.

[jspaeth]

I am guessing that the guy who did my swap probably had someone else (an assistant) do some of the (supposedly) easier stuff....maybe that's why the filter is in the wrong spot.

Well, I had to drive 70 miles this morning, and unkinking the hose eliminated the bogging-on-decel problem, but gas mileage doesn't seem to be back to normal....typically, I get nearly 27-28 mpg highway and about 20-22 regular...I am getting like 18 on this tank, MOST of which is highway driving.

Also.....can anyone tell me....can I still be throwing a code even without a CEL?

Thanks in advance....not gonna drive the car much till this weekend when I go home....then I will put the fuel filter in right place, quintuple check for boost/fuel/vacuum leaks, and pull the spark plugs to see how they look.

This is so annoying....this is the one thing that has always bothered me about my SR....the car runs amazing and I am confident in the motor, but I always have wondered about the fuel.


Oh yeah, also going to try to pull the O2 sensor to see how that looks

[mizono]

Is your bov vented to the atmosphere? If it is you'll get horrible gas mileage. I had this problem before and the symptoms you have are the same I had when my bov wasn't recirculated.

[jspaeth]

I don't buy this for a second....my BOV is atmospheric, but it shouldn't make that much of a difference....for example....if you are driving on the highway, and not getting into it (constant throttle), your BOV never opens....

I understand your point....temporary rich conditions when you blow off, but this is negligible relative to the amount of time the car is operating...unless you have a crappy, leaky BOV, in which case I agree with you.....if the BOV closes properly, I think this is a moot point.

Thanks for the input though...

[SHIFT_*grind*]

I was getting 25mpg with my Turbosmart BOV, which you can't recirculate.

[jspaeth]

Exactly.....if the BOV closes properly, then the amount of time when it is open, resulting in temporary rich conditions, is negligible relative to the time that the engine is running....now, if you have a boost leak or open BOV always, that's another story......

[jspaeth]

I just got done changing my plugs.....NONE of them were fouled or wet, they all looked perfect..

Also, my compression in all 4 cylinders was 155 psi....

I am wondering if maybe the engine was "temporarily" running super-rich for the past week and a half (only drove like 350 miles or so) due to one of the fuel hoses being crimped, possibly raising the fuel pressure....

Anyone's opinions would be great.

Oh also, I just replaced my fuel filter, as it was in the wrong spot (on the return side of the fuel line)....I bought some injector cleaner for short term...I will be putting new, bigger injectors in in the spring, but I am guessing my injectors can't be in good condition, given that my fuel has been essentially unfiltered for the past 15 months.

gosh

[SHIFT_*grind*]

You could pull your injectors and spray some carb cleaner through them as well, might do better than just running fuel cleaner through your tank.

[Doluck]

Check your Maf.