boost boy, read, my problems.

[ca18det240hatch]

Dee, i mean no offense, maybe i should have been more clear, i was running stock computer, stock maf, and stock injectors up until yesterday, and getting terrible mileage. No mods whatsoever, besides the walbro 255. I changed my FPR to a adjustable one a week ago, just to see if the walbro was forcing fuel past the stock one. Still bad mileage. So then, i figured, leaky injector or something similar, so i burned a chip for my ecu for rb20 maf and 440cc GTi-R injectors and installed them as such. Same problem still.... terrible mileage and STINNNNKY exhaust. so really....ive narrowed it down to oxygen sensor.....what you think?

dont mean to come back at you or anything, i just wanted to make clear what i said in the other thread, but its locked....

thanks dee.

[ca18datsun510]

have you changed your coolant temp sensor yet?

if not your engine could be staying in cold start mode.

[boost_boy]

Dee, i mean no offense, maybe i should have been more clear, i was running stock computer, stock maf, and stock injectors up until yesterday, and getting terrible mileage. No mods whatsoever, besides the walbro 255. I changed my FPR to a adjustable one a week ago, just to see if the walbro was forcing fuel past the stock one. Still bad mileage. So then, i figured, leaky injector or something similar, so i burned a chip for my ecu for rb20 maf and 440cc GTi-R injectors and installed them as such. Same problem still.... terrible mileage and STINNNNKY exhaust. so really....ive narrowed it down to oxygen sensor.....what you think?

dont mean to come back at you or anything, i just wanted to make clear what i said in the other thread, but its locked....

thanks dee.

I understand you better now and I'll help as much as possible. Check the codes on your ecu to see if it's diagnosing a fault. Look for leaks and not just at the intercooler piping, but at the intake manifold as well. Poor grounds can cause these conditions, but it is unlikely. If you would like me to unlike your old thread, just reply here and I'll do as such or we can continue on here. If your ecu flashes code 13, then the second poster is correct in the fact that you have a fault around your water temperature sensor, connector or circuitry. If your car isn't hard to start, then you can rule out the water temperature sensor as this will cause flooding if it is bad.

And rest assured "big dog" I'm not taking your response as a come back, but that you desperately need help from others that can possibly help you and hopefully we can.

Dee

[ca18det240hatch]

thats what gets me, new temp sensor, code 55, no damn codes.

altho i did the thing where you put it in mode 2 and hold the throttle at 2000rpm and i dont get blinks on my lights, they turn off and on once in like a minute, not more than 9 times in 10 seconds......oxy sensor?

[r34 gtr]

i will send you my old stock ca one if you want to try it. it worked last time i checked, and its relatively new. i dont have a use for it, so if you email me with your address ill send it out.

[capowered240]

Sounds like the o2 sensor is probably bad.

[ca18det240hatch]

thats ok r34,ill buy a brand new one locally.

thanks tho, appreciate the offer.

would a bad oxygen sensor cause driveability issues in boost as well?

[r34 gtr]

no, the stock ecu only uses the o2 sensor in closed loop mode, so it wont make any difference when you stomp it. it only uses the o2 sensor for adjustments when you are cruising at a constant speed/rpm.

hows the valvetrain? got any vslves that could potentially be sticking? and how about the wiring job? have you started checking pins on the ecu plug with plugs in the engine bay for continuity?

my car used to run just terribly. it would get less than 10mpg no matter how you drove it. ecu threw no codes. i went through the harness and found out that my o2 sensor and some other sensors were only getting a couple of volts because i had hooked them up to an unstable voltage line. i went back and connected them to a proper switched 12v source and saw between 30 and 40mpg when cruising, and mid 20s around town. i went from getting about 100 to 500 miles on a tank. just some food for thought.

[ca18det240hatch]

so basically i should make sure that my oxygen sensor is for sure getting 12v from that brown wire?

[r34 gtr]

sure why not

[ca18det240hatch]

can you tell me what sensors you checked in total and how you checked them. I would reallly like to get to the bottom of this.

[r34 gtr]

you will need: a multimeter, a friend, some bare wire (like bailing wire), eccs wiring diagram w/ ecu pinout, spare time.

just check them all. why not? who knows if the ones i had a problem with are causing yours. wrap the bare wire around the leads on the multimeter so you can cram them into the connectors, set her to ohms, and check away. might want to check your switched 12v wires and grounds too. just dont set it on ohms when you check the voltage lines or youll be needing a new meter.

[ca18det240hatch]

ahahaha, yah ok, ill start checking this weekend. Motor is coming out again in teh winter so i can redo my rings, as 140 psi is not acceptable.

[r34 gtr]

might as well beat on it all summer/fall and see if those numbers dont improve.

[ca18det240hatch]

i dont think i can beat on it anymore than i have. at 14 psi im getting blowby out of the valve cover....

[r34 gtr]

well, sounds like you could use some sort of tune up there. its just blowby though, and you know what the cause is so who cares. go rag on it until it breaks, which will hopefully be the day before you plan to disassemble it anyway. thats what happened to me. it even made it home!

[Masterdebater]

pshh who needs o2 sensors? or even knock sensors??!!toss em out lol im not running any and get good gas mileage.but for some reason i cant get down the timing down so no top end for me lol

[r34 gtr]

might want to invest in those little deals. both are somewhat important

[Masterdebater]

yea i know loli need a whole new harness...