Gas Problem! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

hellllo · 06-12-2007, 03:15 PM

I've searched trying to find each symptom my car has relating to my gas problem, and haven't found answers.

Problem: I dont think its normal for SRs, but my car uses about 3 gallons of gas per 50-60 km's (about 10-12mpg). Its my first boosted car handed down from my bro and I really doubt turbo cars uses that much gas even redlining it.

What I've noticed:
-10-12mpg barely going into boost but letting the car idle for 5-10mins to get to normal operating temp when starting it, depending
-No strong fuel smell from the motor running
-Car hesitates in power sometimes while turning
-Car lost alot of power but its because of a blown turbo (car feels n/a)
-I see blue sometimes a hint of white smoke during every other idle
*blown oil seals on turbo = blue smoke, but maybe that hint of white smoke = unburnt fuel???
-RPMs fall down to 300-500 after every load when i brake or put the car in nuetral and slow down (either one, maybe both, can't recall)
-Compression test all 140, Leakdown test less than 8% leakage per cylinder

What I think:
-The car is basically a stock SR with FMIC, the car is running rich because of the walbro 255 fuel pump and bov is not recirculated, but can't be the reason for very very low mpg
-RPMs drop down maybe because of a bad brake booster causing a vacuum leak, or the atmospheric bov messing with the MAFS.

What I've found:
-Leaky injectors? is the closest thing I've found, but I don't know the symptoms of that besides the heavy white smoke in the exhaust. Could this likely be the problem?

I'm not going into the eng/mech field but into computers so I'm not too experienced in that but i do try. I've searched but I haven't seen any DIYs of how to test leaky injectors so if someone can help me out. Links or Writeups, very specific (from taking out the neg side of battery to when to start the car etc)

Thanks Zilvia members!

DP_Michelle G · 06-12-2007, 03:41 PM

1.clean your fuel injecters
2.recirculate your bov
3.get a fpr

those three things have alot to do with your MPG

hellllo · 06-12-2007, 10:10 PM

I know the idea of cleaning or fixing the injectors but is there a DIY link. Most people expect others to know the basics but I'm not one of them. Are taking out injectors and cleaning them simple as unscrewing them out individually from the fuel rail and unplugging the cord connected to it?

projekt_s13 · 06-12-2007, 10:51 PM

If you have a blown turbo why dont you get a new one since thats probably your problem. Turbos get the air needed to mix with the fuel to make combustion, so if the turbo is blown how does it do it properly?

I dont know much about blown turbos or anything but thats my best guess.

GRIPPY · 06-13-2007, 11:10 AM

To test for leaking injector seals take off your fuel rail and unplug your CAS. Then let the fuel pump prime the injectors. You will be able to see if fuel is leaking by.

steve shadows · 06-13-2007, 12:22 PM

Quote:

Originally Posted by projekt_s13

If you have a blown turbo why dont you get a new one since thats probably your problem. Turbos get the air needed to mix with the fuel to make combustion, so if the turbo is blown how does it do it properly?

I dont know much about blown turbos or anything but thats my best guess.

yeah get one from me

but hey i got you covered on a clean rebuild with a super 60 wheel and modified turbine housing etc.

eitherway the advice so far is pretty on.

DJ_Sunrise · 06-13-2007, 04:05 PM

I get 12mpg as well. I stopped my bitching and lived with it

FPR helped a little. New injectors going in this weekend, and tuning 2 weeks after. I'll let you know how it all goes.

Rob's S14 · 06-13-2007, 04:48 PM

try cleaning the throttle body. that should help with the car dropping down to 500 when you're idling. i had the same problem and that worked for me.

SSC299 · 06-13-2007, 05:33 PM

the idle will drop with too much or too little fuel as well. if your maf is sending the wrong signals you could be getting way to much fuel for how much air your're getting...which is probably because of your blown turbo. if the maf says you're getting air nd the turbo isn't delivering you have problems....check the maf. Might be on its way out. Just a thought. If all else fails replace your turbo (which you should do asap). Steve Shadows seems to have you hooked up with a good turbo option.

hellllo · 06-16-2007, 08:41 PM

Quote:

Originally Posted by SSC299

the idle will drop with too much or too little fuel as well. if your maf is sending the wrong signals you could be getting way to much fuel for how much air your're getting...which is probably because of your blown turbo. if the maf says you're getting air nd the turbo isn't delivering you have problems....check the maf. Might be on its way out. Just a thought. If all else fails replace your turbo (which you should do asap). Steve Shadows seems to have you hooked up with a good turbo option.

I'll check on that thanks. Haven't really driven the car since it really sucks on mpg, but I started the car today trying to find all the symptoms. There seems to be some sort of clicking sounds near the intake manifold, injector, fuel rail area.

vi3tdt2005 · 12-09-2007, 12:18 AM

1) Replace your plugs, make sure they're gapped correctly
2) Check your fuel lines, make *sure* there are no leaks anywhere
3) Check your fuel tank o-ring, replace it
4) Check your injectors and o-rings
5) Get a fuel pressure gauge. Make sure you do this before you get an FPR. A gauge costs ~$30; FPR costs at least $100, and you're going to need a gauge to adjust your fuel pressure anyway. Better to get the gauge first and then the FPR, rather than wasting $$$ on an FPR AND gauge and finding out that your fuel pressure is fine.

06-12-2007, 03:15 PM	#1
hellllo Leaky Injector Join Date: Feb 2007 Location: Wyoming Age: 36 Posts: 76 Trader Rating: (0) Feedback Score: 0 reviews	Gas Problem! I've searched trying to find each symptom my car has relating to my gas problem, and haven't found answers. Problem: I dont think its normal for SRs, but my car uses about 3 gallons of gas per 50-60 km's (about 10-12mpg). Its my first boosted car handed down from my bro and I really doubt turbo cars uses that much gas even redlining it. What I've noticed: -10-12mpg barely going into boost but letting the car idle for 5-10mins to get to normal operating temp when starting it, depending -No strong fuel smell from the motor running -Car hesitates in power sometimes while turning -Car lost alot of power but its because of a blown turbo (car feels n/a) -I see blue sometimes a hint of white smoke during every other idle blown oil seals on turbo = blue smoke, but maybe that hint of white smoke = unburnt fuel??? -RPMs fall down to 300-500 after every load when i brake or put the car in nuetral and slow down (either one, maybe both, can't recall) -Compression test all 140, Leakdown test less than 8% leakage per cylinder What I think: -The car is basically a stock SR with FMIC, the car is running rich because of the walbro 255 fuel pump and bov is not recirculated, but can't be the reason for very very low mpg -RPMs drop down maybe because of a bad brake booster causing a vacuum leak, or the atmospheric bov messing with the MAFS. What I've found: -Leaky injectors? is the closest thing I've found, but I don't know the symptoms of that besides the heavy white smoke in the exhaust. Could this likely be the problem?* I'm not going into the eng/mech field but into computers so I'm not too experienced in that but i do try. I've searched but I haven't seen any DIYs of how to test leaky injectors so if someone can help me out. Links or Writeups, very specific (from taking out the neg side of battery to when to start the car etc) Thanks Zilvia members!

06-12-2007, 03:41 PM	#2
DP_Michelle G Zilvia Addict Join Date: Aug 2005 Location: Anaheim/OC Age: 42 Posts: 666 Trader Rating: (0) Feedback Score: 0 reviews	1.clean your fuel injecters 2.recirculate your bov 3.get a fpr those three things have alot to do with your MPG __________________ BC RACING COILOVER REVIEW

06-12-2007, 10:51 PM	#4
projekt_s13 Post Whore! Join Date: Jul 2005 Location: Chico/Pittsburg, CA Age: 39 Posts: 2,801 Trader Rating: (5) Rides Gallery: projekt_s13 Feedback Score: 5 reviews	If you have a blown turbo why dont you get a new one since thats probably your problem. Turbos get the air needed to mix with the fuel to make combustion, so if the turbo is blown how does it do it properly? I dont know much about blown turbos or anything but thats my best guess. __________________

06-12-2007, 10:10 PM	#3
hellllo Leaky Injector Join Date: Feb 2007 Location: Wyoming Age: 36 Posts: 76 Trader Rating: (0) Feedback Score: 0 reviews	I know the idea of cleaning or fixing the injectors but is there a DIY link. Most people expect others to know the basics but I'm not one of them. Are taking out injectors and cleaning them simple as unscrewing them out individually from the fuel rail and unplugging the cord connected to it?

06-13-2007, 11:10 AM	#5
GRIPPY Join Date: Oct 2006 Location: Edmonton, Alberta Age: 39 Posts: 16 Trader Rating: (0) Feedback Score: 0 reviews	To test for leaking injector seals take off your fuel rail and unplug your CAS. Then let the fuel pump prime the injectors. You will be able to see if fuel is leaking by.

06-13-2007, 04:05 PM	#7
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 38 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	I get 12mpg as well. I stopped my bitching and lived with it FPR helped a little. New injectors going in this weekend, and tuning 2 weeks after. I'll let you know how it all goes.

06-13-2007, 04:48 PM	#8
Rob's S14 Zilvia FREAK! Join Date: Jun 2006 Location: Fountain Valley, CA Age: 43 Posts: 1,199 Trader Rating: (1) Feedback Score: 1 reviews	try cleaning the throttle body. that should help with the car dropping down to 500 when you're idling. i had the same problem and that worked for me.

06-13-2007, 05:33 PM	#9
SSC299 Join Date: Sep 2006 Location: Virginia Age: 38 Posts: 37 Trader Rating: (0) Feedback Score: 0 reviews	the idle will drop with too much or too little fuel as well. if your maf is sending the wrong signals you could be getting way to much fuel for how much air your're getting...which is probably because of your blown turbo. if the maf says you're getting air nd the turbo isn't delivering you have problems....check the maf. Might be on its way out. Just a thought. If all else fails replace your turbo (which you should do asap). Steve Shadows seems to have you hooked up with a good turbo option.

12-09-2007, 12:18 AM	#11
vi3tdt2005 Zilvia Member Join Date: Nov 2007 Location: Socal Posts: 201 Trader Rating: (0) Feedback Score: 0 reviews	1) Replace your plugs, make sure they're gapped correctly 2) Check your fuel lines, make sure there are no leaks anywhere 3) Check your fuel tank o-ring, replace it 4) Check your injectors and o-rings 5) Get a fuel pressure gauge. Make sure you do this before you get an FPR. A gauge costs ~$30; FPR costs at least $100, and you're going to need a gauge to adjust your fuel pressure anyway. Better to get the gauge first and then the FPR, rather than wasting $$$ on an FPR AND gauge and finding out that your fuel pressure is fine.