Bad gas mileage and smell of fuel in rear?

[Dazzla]

Hey guys,

1995 240sx with KA24DE, automatic transmission, around 175k,

Problem: First of all, whenever I jack up the car, or if I'm working in the rear I can smell fuel. From what I've seen, it's not leaking anywhere, so I can't figure out why I can smell it. The smell is their even if the car has not been started for a few hours etc. Sometimes the smell is in the cabin too.

Second, I get about 400km a tank, and I've worked out that I'm doing about 8 or 9 kilometers per liter.

Obviously something is wrong, what could it be? I've got a rusted out exhaust if that helps. Engine wise the car is 100% stock except for a Walbro 255 fuel pump which I installed when the original died randomly a few months ago.

The car has been bumped a few times from the rear, aka fender benders but I'm not aware of any serious damage, my bumper is a bit scratched up and the title is clean lol

Any help nico? I wouldn't care much but I've heard some people get about 500-600km a tank on an Auto KA, I will be going SR in the near future, but I want to see whats wrong first.

[PapaSmurf2k3]

Did you replace your fuel pump O-ring on the tank when you did the fuel pump? That could be leaking and causing the fuel smell...

Does the gas tank have vacuum in it when you unscrew the cap for a fill up?

[Nali]

Your car is running rich because the stock Fuel Pressure Regulator is being over-run by the Walbro. You will need to buy an aftermarket Fpr to handle the Walbro.The smell is from residual fuel unburnt from the chamber coming out the exhaust and sleeping in and around the exhaust area.

FPR should fix ur problem./Thread

[Dazzla]

hmm that makes sense, but that doesn't explain the fuel mileage because I was getting the same fuel consumption before I installed the walbro. Its just the smell was not their before I'm pretty certain about that.

I didn't know you needed an aftermarket FPR if you installed a walbro, damnit lol

[PapaSmurf2k3]

Your car is running rich because the stock Fuel Pressure Regulator is being over-run by the Walbro. You will need to buy an aftermarket Fpr to handle the Walbro.The smell is from residual fuel unburnt from the chamber coming out the exhaust and sleeping in and around the exhaust area.

FPR should fix ur problem./Thread

I ran for a few years with a stock FPR + Walbro with no change in gas mileage. You'd have to be running pretty rich plus no cats to be able to smell the fuel out the exhaust.

FYI Everyone else, 8 to 9 km/l equals 18.75 to 21 MPG.

When was the last time you gave the car a tune up? Have you done a compression check? Have you had it emissions tested? What is your timing?

[Dazzla]

Car passed emissions fine a few months ago. I haven't checked the compression or timing.

The spark plugs, o2 sensor and everything seem fine. I've kept it maintained. The only thing I can think of is perhaps my exhaust. It rattles, and is completely rusted the hell out.

Other than that I can't think of anything that would be causing this. The car has gave me this mileage since I bought it 2 years ago. The fuel smell is pretty recent as far as I can remember.

[itsnever2fast]

18-21 mpg doesnt seem all that bad on a tired old 175k motor, lol clean your fuel system and check your plugs, might need a tune up, clean the maf and check that the 02 sensor is working properly clean your throttle body and check for vacuum leaks. check your fuel pressure and make sure it is in spec. im not sure what they had for diagnostics on the 95's but if you can get a scanner on it check your fuel trims.

[itsnever2fast]

and nali, as for throwing parts at it and seeing if it fixes it, not a good idea.

no personal insults

[Nali]

and nali, as for throwing parts at it and seeing if it fixes it, you are a moron.

You rude son of a b!!tch, didnt your mother teach you any manners, you need to get of the computer and go beg her for a lesson in respect. Disagreeing with someones opinion is one thing, calling someone a moron because of it is another.Why the hell did you even post that huh? Does it make you feel big? after stating your opinion you should have just kept your stupid mouth shut.

The FPR idea was based on my own experience and the experiences of others who have had their FPRs overrun by Walbros leading to them running horribly rich. I assumed this was what was happening here, based on the data presented.Its not like i pulled it out my arse.

Also adding an aftermarket FPR to the system cant be seen as a bad thing regardless of whether thats the cause or not.

Calling me a moron so randomly is a testament to your insecurities and lack of respect for others opinions.

Shut the fcuk up and keep the double posts to yourself.Frikkin douche-canoe./Rant!

[itsnever2fast]

Sorry, lost my job yesterday because of a guy that does just that. Costs people money. I take pride in an accurate diagnosis. And yes i should have kept my mouth shut. I am on a lot of vicodin right now too from my motorcycle accident, that might have something to do with it too...
Modified by itsnever2fast at 12:59 PM 8/1/2009

[PapaSmurf2k3]

You rude son of a b!!tch, didnt your mother teach you any manners, you need to get of the computer and go beg her for a lesson in respect. Disagreeing with someones opinion is one thing, calling someone a moron because of it is another.Why the hell did you even post that huh? Does it make you feel big? after stating your opinion you should have just kept your stupid mouth shut.

The FPR idea was based on my own experience and the experiences of others who have had their FPRs overrun by Walbros leading to them running horribly rich. I assumed this was what was happening here, based on the data presented.Its not like i pulled it out my arse.

Also adding an aftermarket FPR to the system cant be seen as a bad thing regardless of whether thats the cause or not.

Calling me a moron so randomly is a testament to your insecurities and lack of respect for others opinions.

Shut the fcuk up and keep the double posts to yourself.Frikkin douche-canoe./Rant!

Ah, I see you saw that post before I got to editing it. Definitely not cool on his part but he apologized.

And yes, you are absolutely correct. I have also heard of people running rich after a walbro swap. And getting an adjustable FPR IS a good idea... he could lower the fuel pressure and lean the engine out to where it should be (if it is running rich, for whatever reason) to get better mileage. Not to mention they are pretty cheap.

OP: you could also try doing a test on your coolant temp sensor to make sure its up to snuff. Check the terminals and make sure they aren't corroded. They are about $35 to replace (not bad at all).

[itsnever2fast]

yeah just having a s*** week and how he was so matter-of-factly about it for sure being the fpr it kinda triggered me.

[Fibre guy]

+1 for walbro making it run rich with stock FPR. Never smelled gas though.On a side note, the wifies s14 was in need of a tune up so when I pulled the sparkies they looked like little rounded off stubs. Replaced and insto MPG fix.

[SleepyHB]

lol at Nali, you and that picture cracked me up.

[hbpignosePA]

check the hardlines as well near the back of the car (under the diff etc.

they might be rusted through

you are up north after all.

[TroubleBound]

I had those exact symptoms t got bad mileage and i always smelled gas at the back of my car so i followed my nose to where it was strongest and jumped under the car to look for fuel lines. I know that you said you had gone around the car and didn't see anything leaking, but when my rubber fuel lines from my fuel pump running midway up the car were cracking the leak was too slow to see, the fuel was running up the line instead. It cost me like 5 bucks and 30 mins to fix it this is what it looked like: No more smell of gas anymore for me and i can actually notice the gas mileage increase.

Just throwin out an idea

[Nali]

lol at Nali, you and that picture cracked me up.

Thats the pic i use when im in my super defensive and counter attack mode.

It gives a really ominous feeling to the whole post.If ur into manga and anime you will know why, else it might not make much sense. But as long as the general idea is set.

[itsnever2fast]

i would also def look into the coolant temp sensor function as well, when the connection is faulted the pcm thinks it is -35 below zero so it runs rich to make up for the air density. there are 2 separate sensors, one for the cluster and one for the pcm...

[michael_grigoras]

would any one perhaps know where i could buy a completely new harness?? i have some corosion in the harness and i dont want it to eat everything away down to the sensors

[Nali]

OP did you ever find our what was wrong with ur car???

[michael_grigoras]

were exactly are th hoses for the gas on the car im having some trouble finding them