I swapped an s4 t2 jspec motor into my 88se last summer using na wiring harness. I have an rtek1.5 and a 255 walbrootleg from ebay. Those are my only changes regarding fuel delivery. Well na maf but that would make me slightly leaner i think. I have bounced driving back and forth between a s10 blazer chevy lumina and my rx7. It hasnt been intil fairly recently that all i have been driving is the rx7. I quickly began to notice that i am getting honestly 120 miles per tank. This is **** at 4.25 per gallon. 52 dollars for a couple of days of driving isnt remotely practical. I then bought a narrowband af meter and spliced it in to the o2 sensor. I am constantly richer than donald trump at idle and throughout the power band except for a spilt second wen i let off the throttle. So today i put in a new 02 sensor and n332 ecu and am still rediculously pinned on the rich side of the af meter.

My plan and whats on the way.......

swap in another set of 550cc high imp injectors, upper intake manifold, tbody and tps from running t2. The only thing i can think of is that someone in japan put in a different set of higher flow injectors and my tps and throttleboddy are miscalibrated somehow. That almost doesnt even make sense. what else can i do aside from raising boost can i do to lean this gaswhore out? I am at a happy 5.5 psi with a smiling se transmission, rear, axles and driveshaft.

Everyone chime in please. Any feedback is appreciated .......

thanks in advance,

john ny

 

thought id let you know i get worse. might make you feel better =]

 

Your AFM is what is funking you up.

It won't run leaner... it will run radically rich with a N326 AFM instead of a N318 AFM.

Just think... to get any boost at all you are forcing the AFM open even further, so the ECU thinks more air is getting in there, so it gives it more gas.

Half assing something will always bite you in the ***.

Toss in that you say your TPS is not set correct and there you go... between those two I bet you are loosing 5-10 MPG just there.

And your bump was deleted... bumps are forbidden here in the 2nd gen tech section.

 

Thank you for the adv icemark. Even creative bumps? I will get on the n318 afm train immediately.

john ny

 

As Icemark has already mentioned, this is part of your problem.


It really gets annoying when people bitch about gas mileage...
Seriously, the car isn't going to get that much better gas mileage even in top, tuned shape.
If you're worried about gas mileage, get a Metro.
You've already replaced your stock engine with a turbo one, and that makes it a serious modification in most books.


This doesn't mean jack ****.
The narrow-band O2 sensor has a very hard time discerning between SLIGHTLY rich and OBSCENE rich.
Your conclusions might be totally wrong.


-Ted

 

I am bitching about gas mileage because something is wrong with my car. If i wanted a metro i would not be on this sight politely asking for help. I have heard people getting 240 miles per tank with a turbo engine, again i am getting 110-120, To me, this seems like an issue that can be corrected.

Maf on its way, thanks again icemark.

john ny

 

They only way you'll hit 240 miles per tank is if you do significant freeway driving.
Do you even do that?

Be careful on WHO claims this kinda mileage.
Your 1988 model has a 16.6 gallon maximum capacity.
US-spec Kouki FC models have a larger 19.x gallon maximum capacity.
If you own a Kouki FC with the large tank and then divide by 17, you get a more modest 14mpg.

The FC turbo will do a solid 15mpg when in top shape.
Extrapolating mileage on your smaller gas tank would put it around 210 miles.
When I used to run the stock ECU, I used to be happy getting 200 miles on a full tank.
On average, I used to get around 180 miles on a full tank; I do almost all exclusive city, stop-n-go driving.
With my Haltech tuned rich, I was seeing anywhere from 120 to 150 miles on a full tank - dreadful, but totally my fault.
After leaning the maps out, my last tank was 170 miles, so it's getting there.

You did an engine swap.
I bet you fucked it up.
That's why you're getting that bad gas mileage.
Is your O2 sensor even connected and working?
It sounds like the car isn't hitting closed-loop mode and this kills gas mileage by about 20% - 30%.
Does your car smell like gas?
Do you have a fuel leak?
Have you pulled your spark plugs?
Are they BLACK?
Take some pics and post it here.


-Ted

 

right, even if your afm is messed up, you should still be in closed loop in cruise. does your a/f meter cycle back and forth when cruising?

 

Are they all new 02 sensors?

 

I did the swap and followed directions given to me by people who have successfully done it using the na harness.
car does not smell like gas ever.
Just replaced o2 sensor which is hooked up properlyi believe. What is a quick test to tell if it is functioning. "Put volt meter here and it should be this" or "the resistance at this pin should be blah" That is the kind of answer i am looking for, sarcasm ok too. I dont mind sifting through it as long as there is an answer or directions in there. As far as the fuel leak, i park the car on asphault and would have noticed it eating away the sealer (my s10 did this).

spark plug i will pull at some point soon and post pictures.

Doesnt the ecu automatically switch into closed loop? if not how can i test for this?

thanks in advance rted.

john ny

 

Heh.. I think that was me.

To the new guy, I drive 14+ afm. Never engaging the secondaries or boost during these lean conditions and I drive from north of my state on I5 down to South of my state to visit my parents @ 55-60 mph at 5th gear. I get around 240 mi per tank. These I beleive are top conditions for gas milage. I also perform maintence on my car daily, so it's in realitively good shape.

Rotaries just were not designed for gas milage

*Edit*
Note also, taken a few pounds of my gross wieght with emissions removal, ac removal, dtss removal, aftermarket parts etc.

 

The new guy with 3 less posts and a half a year longer membership to this site unserstands your optimum conditions.

he is also trying to address his regarding 115 miles per tank.

so......... Doesnt the ecu automatically switch into closed loop? if not how can i test for this?
and
What is a quick test to tell if it (o2 sensor) is functioning?

john ny

 

After my turbo conversion I had an issue with my boost sensor always registering full boost. I was getting similar gas milage as you. You can make sure your ecu is getting the appropriate reading by checking the voltage at pin 2B on the ECU, it should be between 2.3-2.5 volts with the vacuum hose disconnected and the ignition switch in the ON position. Check out page F33 in section 4B of the Factory Service manual for ecu pin identification. Go through the procedure on page F77 of the fsm for testing procedure of the actual pressure sensor also.

I do about 85% highway driving and I average 200 miles a tank rarely boosting and cruising around 75mph the vacuum portion of my Rtek fuel map is leaned out a lot though. I have been able to get 230 miles on a tank before running out(literally), but that is 100% highway and at 60mph. On the streets it can be be as good as 160 miles per tank down to 100 miles per tank if i just go boosting all around town.
City driving mpg is pretty bad, all depends on how heavy my right foot is, it is on a diet until gas prices come down.
There are many gas mileage threads if you are interested search.

Hope this helps, good luck.

 

Check the signal from the O2 sensor wire (and ground).
Cheap O2 sensor / narrow-band gauges are all over the place - this makes it easier to watch.
Summit Racing sells 3 different types under $50.
You can try a DMM, but it has to react pretty fast.
The signal is pulsing under closed-loop.
Voltage level is going to be under 1.0VDC.


-Ted

 

Get a moped and/or a motorcycle to drive to and from work/school and use your 7 on the weekends...

 

Just as a side note, the guy IS asking for help not ten tons of **** for just asking, I know alot of you guys are here helping and what not, but honestly giving the guy grief about getting barely over 100 miles per tank wether 16 or 19 gallons is a little crass. I own FOUR T2's and NONE of mine from 400RWHP to stock 200 get that bad, 720/1600 cc in the high hp and it gets still 12-13 mpg combined city/hwy, so I dont think asking what could be wrong with 110 total is a out of character question.

 

Like I said before, I have seen 120 miles per full tank, so it DOES happen.

Also, his car is a SWAP - get that right.
It's NOT a "stock T2", so you cannot compare...

I think we can agree that the swap was fucked up?
RIGHT?


-Ted

 

Possible, can't rule that out hehheh.

 

Yea, it does seem absurdly low. I have a turbo swapped S4 vert (so even heavier than your car, lower compression ratio, and smaller tank), and I average around 220-240 or so miles per full tank (I usually run it down to E, takes approx 15 gallons to fill back up in a mix of city and highway, and over 300-320 miles of solely highway at approx 75 mph. For highway cruising I usually run about 16:1 AFR, and the car is still very rich as soon as it hits boost and idles around 12-13 AFR. If you're only getting 120 miles to a tank, regardless of what series tank you have there is a big problem.

I agree with Icemark that your first step should be getting the correct AFM (I have an N318 AFM laying around somewhere and I'm in NJ for the next few days, PM me if you want it) and a new narrowband O2 sensor for closed-loop control, although if you're tuning it yourself, a wideband O2 sensor and gauge will make your life much easier.

 

Used to get less than 100 per tank... then I found I had a vac leak in my fpr, the previous owner cut the oxy sensor wire somewhere down the line, and the 750's were in the primary slots

Heh sorry bout the new guy comment, I just refer to myself as new so I assumed you didn't mind being called new either.

 

i dont mind being called new. If i came off as harsh i am sorry. I want to thank everyone for their help too. Afm should be here within a week at most. I will address the tps tbi issue soon because those parts arrived. I will get 200 miles per tank. I just have to address more specific issues in my "fucked up swap" that i followed directions perfectly with. Afm issue origionally had n333 rebuilt one on the car. it pooped the bed and left me stranded. Put old one one from non turbo motor and started driving the car daily. It is a stock t2 i have 550 primaries and secondaries and am running 5.5 lbs of boost. It has to be a mechanical issue like 720 injectors installed in japan or my maf, something along those lines because i wired the car and did the work. I was very particular during the whole process. "Comence helpattack....."

john ny

 

ok here is a little update....... In addition to breaking up with my fat cheating ***** of a girlfriend, i replaced the maf and am now getting 170 miles per tank with 87. My uim, injectors, tbi and tps have arrived as well. I will put those on when i can function.

john ny