J30 Gas Mileage?

[Jakw]

Have you ever used Seafoam, Negus? A can in the gas tank will clean the injectors. A half can run through the throttle bodies (both sides) will clean up the intake manifold. And then another half can in the crank case will clean...well, everthing else. I actually haven't run it in the crankcase yet, but I can surely vouch for the other two. On another forum I frequent, this stuff has been known to stop shakey idles, improve gas mileage, and generally just make things run smoother.

You can get it at just about any auto parts store (Checker, Advance Auto Parts, etc...), so pick up a can or two and see if you don't get a little bit better mileage.

[brandonjustice93J30]

Advance auto down the street from me had the laser plats for $9.85 last year. I dont know what they are now.

[yodawill2000]

Hey JakeI'm about to use the BG intake cleaner .Did you just take off the tubes off the throttle bodies and dump it in ???

[yodawill2000]

thankz yoda,

what about the O2 sensor? if i replace that, u think that would help aswell?

Anybody know if a bad o2 sensor would throw a code ??I would think it would.

[gr8scott72]

Anybody know if a bad o2 sensor would throw a code ??I would think it would.

If it's bad enuf it will. Alot of the time your fuel mileage will take a crap before you ever see a code for the o2 sensor.

[Jakw]

Hmm...there was a writeup on 3zc about getting seafoam through the intake. You can suck it through the brake booster, but I think that only cleans the driver's side of the manifold. Basically, you need to find a vaccuum point for the seafoam to be sucked in through. Make sure you feed both sides, however you do it, and it for sure helps to hold the throttle open a bit while you're doing it.

[gr8scott72]

Hmm...there was a writeup on 3zc about getting seafoam through the intake. You can suck it through the brake booster, but I think that only cleans the driver's side of the manifold. Basically, you need to find a vaccuum point for the seafoam to be sucked in through. Make sure you feed both sides, however you do it, and it for sure helps to hold the throttle open a bit while you're doing it.

You won't have to hold the throttle because when you have the vacuum line open, the engine wants to rev higher than idle. You do have to feed the seafoam slowly because it bogs the engine down as it ingests it.

You are correct about the brake booster only getting to the driver's side. I still haven't found an easy-to-reach vac line that feeds both side on the J.

[NegusJT]

i have never seen or heard of seafoam but i will look for it next time i am in autozone and i never new autozone or advanced carried NGK

n i am thinking the same thing about the O2 sensors. from my experience it wont give a code unless they r really shot.

[NegusJT]

when should the O2 sensor be replaced?is the right and left side the same part or are the side specific?

when should the timing belt be replaced, i read it was 105k but i thought i read on here it was 60k?

[brandonjustice93J30]

auto zone doesnt, but advance does...I'm not sure about O'Reilly's or not

I went on a search a couple years ago when I needed plugs and didnt want to wait on shipping.

[yodawill2000]

Negus

The original 93 belt was good for 60K.In 94 the went to a Kevlar belt thats good for 105K

[brandonjustice93J30]

and at 210000...I'm over ready for my 2nd belt change...lol

[NegusJT]

i c,

now i wonder, if i take my 93 j30t to the dealer, will they put the kevlar belt in or the other one??? hmmmm.......ooh, and u know the dealer is charging 1600 for timing belt out here.......they said they do, timing belt, front main seals and water pump..........i was like well damn, how much just for the timing belt, and they wont do just the timing belt.

[NegusJT]

ooh, what about my O2 sensor question........any info on that?

wow, 210+ and u only on your second one........?? how did u manage that?

[yodawill2000]

Im doing my own soon.The whole kit is about 350 from Joe at everythinginfiniti.com

http://www.trademotion.com/par...34382

Scroll down to the Timing belt kit.

It makes sense to do it all while your in there.It would Forcefully inhale if the water pump went out a month after you replaced just the belt
Modified by yodawill2000 at 6:47 AM 3/14/2008

[brandonjustice93J30]

well....still may be on it's first for all I know...I've never replaced it.I dont have anything near $1600 right now for something that isnt broken.

I figure if I have to drop that much into the car right now...I'd take the $1600 and put it as a down payment on a newer car. 93 with 210+ isnt worth much over $1k-2k with the body damage.

I'll drive it til the belt breaks since it's not an immediate safety issue where I'm going to not be able to stop or steer the car, and then junk it.

Unless I get a good deal on the job like the tie rod, struts, and brakes.

[yodawill2000]

Dude ..You can get just a belt on ebay for uber cheap and replace yourself.

You gotta be tech inclined !!Your a Tech !!!

[brandonjustice93J30]

Yeah, yeah, yeah, I know.

But I've heard so many horror stories from belts being replaced incorrectly and finding time to work on the car is rare with it becoming warm and needing to do work on the house instead.

[yodawill2000]

Yup ..Im gonna take it Nice and slow and dang sure turn the motor over manually via the crank before I try to start it.Pulling the plugs should allow me to do that.. I hope.

[NegusJT]

just put some new spark plugs in there, pray for me guyz.....lol

and i used some seafoam in the oil and tank........

gotta go for emissions soon anywayz........

[driverdriver]

Make sure the spark plugs are the same as the OEM Nissan NGK's. For whatever reason J's don't run right on non OEM plugs.

[brandonjustice93J30]

I'm running fine on NGK Iriduim IX's...Or at least it seems fine to me...

But I'm going to spend the extra bit on the laser plats next round and see if I notice any difference.

[Gerardjg]

I drove from Daytona beach to Jacksonville FL and back on friday 216 miles round trip No traffic either way. I set the cruise at 70 and made 90% of the trip without touching the pedals. I filled up before I left and again at the same pump when I got back, It took 8.79 gallons or 24.5 MPG

[Gerardjg]

Hey JakeI'm about to use the BG intake cleaner .Did you just take off the tubes off the throttle bodies and dump it in ???

I Used the BG aerosol intake cleaner and loosened the clamp after the filter box slipped in the little straw and sprayed the whole can in while revving at about 2 grand. Lots of sputtering and smoke. So I guess it worked. It did change the oil and clean the plugs when I was done.

[NegusJT]

well i took my first lloooooooong trip with my j30. nice ride too.......was goin through the foothills, so it was kinda hilly with a bunch of winding roads. i set the cruise on 75 and just coasted. even through the hills and windy roads. needless to say i averaged about 70-80mph and ended up with approx about 25mpg. and that was allllll hwy. sooo.......now i wonder, why do i get like 13-14mpg in the city just daily driving. i mean, i am certian i am not flooring it at every green light.

hmmmm?

[rdorman]

I recently replaced (relocated) a bad knock sensor, cleaned the MAF, sea foamed the plenum and throttle bodies (on the car) and replaced my air filter. Gas mileage went up almost five miles per gallon in conbination driving... 18.7mpg. If you have a bad knock sensor, fix it!

[Jakw]

13-14 is pretty bad in the city, negus. Where are your shifts? You don't need to floor it to affect mileage, but that still seems low. Keep it under 3,000rpms if you can. I usually stay under 2,500.

Have you cleaned everything up (MAF, throttle bodies, seafaom the plenum and some in the tank, etc.)? Any codes from the ECU?

[gr8scott72]

13-14 is pretty bad in the city, negus. Where are your shifts? You don't need to floor it to affect mileage, but that still seems low. Keep it under 3,000rpms if you can. I usually stay under 2,500.

Have you cleaned everything up (MAF, throttle bodies, seafaom the plenum and some in the tank, etc.)? Any codes from the ECU?

Ok GRANDMA, get out of the way! Geez!

When I shift, it DROPS to 2500, not FROM 2500 down from there. I don't think I could stand to drive like that. Why even have the J30 if even the Hyundais and Kias are going to drive faster than you?

[brandonjustice93J30]

I'm constantly shifting between 3k and 5k, sometimes bouncing off about 7k if I'm in the mood. And for the most part I still get about 18 mpg city if I drive that way.

If I'd try to stay below 2500-3k on a daily basis...I'd feel like I should be driving a 3cyl 50hp metro.
Modified by brandonjustice93J30 at 4:16 AM 3/26/2008

[Jakw]

Lmao, yes, yes. I drive like an old man.My transmission has 215,000 miles on it, to the best of my knowledge. That's not something to beat on. And I'm waaay broke, so any gas I don't have to buy is good news for me. Broke like I donate plasma for groceries. At least until May when I move.

As for why I even have it...well, because I can't get anything but lowball offers or people that walk away when I tell them the mileage on the body. Trust me, if I could trade it for a Honda or Toyota or some other gas-saver in equally good shape, I would. Then I could actually put some pressure on the pedal without paying the price at the pump.

Yes, it's fun to get on it once in a while, but meh, I still see it as an old luxury car. To me, it's not a 'sport sedan', as I've heard it called but some (nala). It's a delicate old lady that needs to take me from CO to WI in two months, and I can barely afford to fix anything if it breaks.

Btw, I just filled up. 24.5 mpg with probably 80% highway and a little aggrivation in the city.