Fail gas mileage.. getting expensive.

[Two Fowty]

My 90' s13 sohc is getting horrible gas mileage, as in like.. 220 miles a tank. My spark plugs, wires, distributer cap and rotor are all fine. I mean they aren't brand new but they look fine, and I've tried a new set of wires, still crap. I have 34 lb injectors, which are 3x stock (i didnt put them on). Could those be the culprit? I was told by the guy at autozone that that is the reason, but I was told by a mechanic that my ecu should compensate for it and it shouldnt affect my mileage..

Just seeing if I should get new injectors. Cause brand new ones are like 600 at autozone. Screw that. Also, my idle isn't steady. Ranges from 600-1000. Not sure if that's connected.

[s13_chris]

In your avatar section it says you have two 240's. Pull stock injectors off 1 of the 240's and put it on the gas hog. Or go to a junkyard and pull some stock ones.

[Two Fowty]

The car i currently drive is a 89', with the engine from the 90. The 90 has the engine from the 89' which was blown when i bought it. I guess that doesn't mean the injectors are bad. Totally didn't think of that.

[Lonismos14]

or if not ill sell you my injectors and the fual rail for real cheap lmk.. went turbo dont need it just wasting space in my trunk

[pacotaco345]

Dood my car gets terrible mileage... I've maybe driven it 100 miles since the last fill up (trip doesn't work) and I'm already at half a tank. Given I'm not the nicest driver but come on!!

[AZ89two4Tsx]

Lol, you're wondering why your car gets bad mileage when it has injectors that are 3 times the size of stock? Really?

Not to mention, it's a single cam, which means the mileage will be fair to poor on a good day.

[Two Fowty]

Lol, you're wondering why your car gets bad mileage when it has injectors that are 3 times the size of stock? Really?

hence me saying this in my original post :

I was told by the guy at autozone that that is the reason, but I was told by a mechanic that my ecu should compensate for it and it shouldnt affect my mileage..

[240dx]

Dude common. You cant just throw in gigantic injectors and call it a day. Your washing your cylinder walls with fuel. The excess fuel seeps past your rings and into your oil. Stop driving the car until you get some sort of fuel management and stock injectors. god daym brah

[Two Fowty]

again, I didn't put them on.. apparently no one can read.. I'll just try out the fuel injectors from my blown engine.

[dana541]

has to be those injectors,they are could also be the cause of the strange idle.the stock fpr probably cant feed those things enough and the ecm is trying to compensate with timing and such.

i only get around 270-290 miles per tank with my single slammer with mixed driving(if i keep my foot out of it) It also runs extremly well.new fuel pump,new injectors,fully functional and clean emissions system,new fuel filter,new plugs,new cap and rotor,new plug wires,fresh rebuild.so im convinced that my mileage is pretty much as good as it gets.

[nifares240]

could be other things beside your large injector. poor maintenance on tire pressure, slipping clutch, a lot of junk in the trunk which adds considerate amount of weight. but really, there's no reason to run that injector size and i know you didn't put them in. swap for stock ones.

[Jdmstyles]

thats horrible lol. Swap the injectors out please.

I get 340 miles to the tank on my single cam.

[Chris28]

Your mechanic is dumb. The ECU isn't a supercomputer, how the heck is it supposed to know when you put 3x times larger injectors in?

Put the stock injectors back in and for the love of god change your oil. You're lucky your rods aren't knocking by now.

[nissanman04]

The ECU will compensate in closed loop mode (idle, cruising, light throttle) since it adjusts fuel based on the O2 sensor. Once you give it some fast throttle input or open the throttle a decent amount, it will ignore the O2 sensor and rely on the fuel map values (open loop) which is where the injectors will start dumping fuel since the programmed pulse width will release 3x the appropriate amount of fuel. You should also notice some sluggish performance as well if the injectors really are this much bigger.

[NISSAN240SX12]

i dont get great gas mileage in town maybe 20 mpg. but highway is like 30 mpg.

[240dx]

again, I didn't put them on.. apparently no one can read.. I'll just try out the fuel injectors from my blown engine.

It doesnt matter is jesus himself put those injectors in brah.they still need to be managed or swapped for stocks

[LOVERboy]

send me your injectors and ill send you the injectors that you suppose to have .... and see if it will help ....... ill even be nice ... ill pay the shipping cool?!

[Two Fowty]

alright, pulled out the ones, that were supposedly 34lb injectors, and they looked exactly the same as the ones i pulled from my blown engine, except they were black. The shape and appearance was identical though. I tried them out anyways. Car started up then stalled instantly. Did that twice, then just cranked. I pulled them out and there was bubblyness coming from the 2nd cylinder.

EDIT: swapped old ones back in.. car started up right away, but i go look at it. and the last injector is leaking fuel, from where it connects to the fuel rail. what now.
Modified by Two Fowty at 4:41 PM 11/24/2009

[240dx]

you sir, need another set of stock injectors. The ones from your blown motor seem to be dirty or clogged. You need a buy a set of stock ka injectors. many people on nico here probly just have them kicking around and you could get them for cheap. If the original injectors are leaking from the fuel rail most likely the o-ring is shoddy.

[Two Fowty]

new injectors are like 600 bucks at autozone, im 17 and done have paypal or anything so i couldnt order from here or i totally would. Autozone doesnt carry the o rings, so idk what to do.. i took the injector out and now im just sitting here

EDIT: went out, took out the last injector that was leaking, wiped it off.. put it back in.. got it all hooked up.. started it up, runs fine.. no leaking..
Modified by Two Fowty at 4:58 PM 11/24/2009

[cbt240sx]

I have bought two sets ($30 each set) of used injectors from ebay. The current injectors have been on my sohc for about 2 years. Havent had any problems so far. You just gotta keep your eyes out for a good deal. 600 dorra, jeebus!! http://shop.ebay.com/?_from=R4...ories

Setup that paypal. What you waitin fo mang??

[Lonismos14]

Dude 34 lb injectors ur lucky u didnt blow the welds on the intake!!!

[hbpignosePA]

? what does paypal have to do with it?

hit up CL for someone parting a car out; or the regional sections

theres gotta be someone who has some close by

[locoluna825]

I also only get 220 to a tank of gas on my SOHC. I bought a set of remanufactured injectors for $130. I know for a fact my car runs real rich (does yours run rich OP?) and has had a strange idle problem forever now.

keep trying to make it stop running rich, tried timing it to stock specs 15 ATDC, I ONLY run 91 octane gas from shell in the car. Also tried advancing it 7 and 10 degrees while running 91 only. still runs rich i only notice the slight power gain. The car does not throw an engine light currently.

I have yet to try sefoaming the engine, change the FPR, fuel pump, O2 sensor and the resistor for the injectors.

On bright side, on the freeway i can get almost 400 to a tank. If it is all freeway driving.

[Gcustoms]

pleeease tell me the guy put them on as part of a turbo kit. if not i expect you to go to his house, ring the doorbell, and slap him upside the head

3x normal injectors without any good reason is so pointless... omg.

[Space Monkey]

I have yet to try sefoaming the engine, change the FPR, fuel pump, O2 sensor and the resistor for the injectors.

You would be amazed what an O2 sensor can do for your gas mileage. Also try disconnecting your battery for a few minutes and connecting it back up. Reset to ECU and it will "re-learn" your driving style.

[fastass]

ill trade you even my injectors for yours.

[wrightme43]

Do you have a Orielly auto parts near by? A little less than 90$ for the one I bought from them a few weeks ago. New not reman.

[locoluna825]

Also try disconnecting your battery for a few minutes and connecting it back up. Reset to ECU and it will "re-learn" your driving style.

Been there done that to many times...