cas sensor limp mode ????

[gtrjon]

hey if your cas sensor was bad or going out on a r32 gtr could that cause the car to go into limp mode? my gtr randomly goes into limp mode sometimes and when in limp mode i cant rev past 2500rmp and when not on throttle wont idle it will sputter around 200 rpm and it will die. it repeatedly dies and turns off. just wondering if this could be my cas sensor? already replaced both masf sensors and re did all the masf wiring. i am thinking either cas or ecu. any imput?

[NismoS-tune]

CAS doesn't do that. CAS would just cause misfires or not run at all. You have a case of dirty MAFs, loose connection/damage element.

[gtrjon]

like i said both mafs have been replaced and the entire maf wiring has been re done

[DarkCaporaL]

Did you check your ECU for codes?

[sullivanracing06]

Pull codes

[gtrjon]

ran my ecu for codes and got code 55 which means nothing apparently. i ran my ecu for my o2 sensors and one wasnt reading. but i really doubt one bad o2 sensor could cause this much crap. would a fried ecu cause this?

[archaeic_bloke]

your ecu could be swamped with codes try this:

1) disconnect negative and positive battery terminal.. press brake pedal for 3 minutes to drain remaining power...
2) re-connect battery terminals
3) start up car, let it idle for 30 seconds for the ECU is in re-learn mode right now
4) press the throttle a little, rev it up and down (keep doing this as long as there's no problem)
5) if you havent had misfire of problems yet, get in a drive around the block
6) at the first sign of a problem. stop the car, shut it off, and see if u can pull any codes from the ECU


from the sounds of what you describe it sounds like MAF's... its possible sometimes that even though theres a problem with mafs the ECU doesnt pick it up for what ever reason.
if no new information results from this, then try swapping ECU's with another person.

O2 sesnor problem would be rough and boggy and misfire as long as your on vacuum, as soon as you hit boost the ECU reads the maf's and O2's arent looked at.

so when u describe the opposite, i.e. can't even get on to boost, we all think its MAF's.

check your TPS just in case, it should be 0.5 V at closed throttle and i think 4.5 at full open.

[gtrjon]

i can get into boost sometimes and when i am in boost it runs fine. its just getting there. but i am going to try and swap ecus with my buddy he just picked up a stock untuned one. i guess i might try to replace my mafs again. the tps is new as well. what would cause mafs to go out repeatedly?

[archaeic_bloke]

i can get into boost sometimes and when i am in boost it runs fine. its just getting there.

... you just answered your own question.. liek i said before, if you can get into boost and it runs fine once you're in boost.. 100% its your O2 sensors! replace them asap, car will run good again.


WHY!!! does everyone forget that the nissan service manual reccomends replacing O2 sensors every 60,000 km... its a part that needs replacing people! do the irght thing.

[gtrjon]

lol yes i bought new ones abt two weeks ago. but i tried to put them in last week and ran out of time. they were so hard to get at!!! any hints? there must be some tricks at how to change them?

[archaeic_bloke]

mine are pretty pretty easy to get to

take off all the intake piping... and follow the 2 wires that have connectors sitting near the ABE module behind the shock tower, those 2 grey connectors, one is square and the other is rectangle, those are for your O2 sensors.

get some penetrating lube/oil like liquid wrench or something and spray it on those bad boys, they are located in the top part of the turbo dump tubes. u should be able to see them from above

i can almost see mine just standing over my engine bay.

[gtrjon]

yea i can see them and i know where they are just hard to get my hands down there. any special tool to use other than a 17 wrench?

[archaeic_bloke]

you could try a stubby... it`ll be easier with a stubby for sure.

[gtrjon]

alright thanks man for all your help ill change them this weekend and let you know if it fixes my problems. I am hoping it should and hopefully ill pass air care lol i already failed once horribly

[gtrjon]

so i swapped my o2 sensors. it seemed to run better for about 15 min but than limp mode and the car repeatedly turning off. any other suggestions? replacing maf sensors again i guess? i am starting to think my wiring could be grounding out somehwere possibly?