Car is leaning out horribly and breaking up

[street_white180sx]

Hey wassup i got a serious prob, i had an exhaust leak that i repaired because my car was running too rich and the car was hardly boosting. so i fix tha problem now and my car is running lean and breakin up in every gear from about 3 to 3.5. The plugs are snow white in all cylinders. i jus recently changed the fuel filter to 300zx fuel filter about 2 months ago. Any suggesstions guys.

[smithers584]

you on the stock fpr?

[street_white180sx]

yea i am on stock fpr

[stevesr20]

bump for the man....

[smithers584]

i had the same problem, changed fpr to SARD and it helped but still broke up, finally changed coilpacks w/ a new harness and that worked. it was very misleading because my plugs were white so i chased fuel the whole time but then realized i had two problems. this is the second stock fpr i had go on me and both times it ran crazy lean but it wont cause it to break up. you might wanna swap that out and try some new plugs before coilpacks, also check the weak ass ground on the harness. i think you obviously have a fuel problem (fpr) unless you are on the stock pump, then that might be the culprit, and i think you are blowing out your ignition.

[street_white180sx]

i have a 180sx so the fuel pump is adequate for stock but i feel that its jus the pump. because i killed all the coils and they all show that they are firing. the thing is my car runs slightly better when its very cold like not driving for bout a few hours and then once it begins to warm up then it breaks up horribly again. like i wud break up at 3 grand then clear up at 4 or 5 then break up again at 6. i was goin to try a walbro wha u guys think

[Blues13]

Try changing the spark plugs and re-gap them smaller..

[street_white180sx]

If that corrects my problem i am guessin one or 2 of my coils are weak

[street_white180sx]

k i gapped my plugs to .20 took out my coils and ohmed them and i got 1.9 to 2.5 ohms across the coil. the car still ran horrible. i think i am leaning towards fuel because it looks like the car is runnin so lean its blowin out the ignition of spark causin me to break up. the weird thing is my car idles weird after bout 20 mins like its missing

[street_white180sx]

k i gapped my plugs to .20 took out my coils and ohmed them and i got 1.9 to 2.5 ohms across the coil. the car still ran horrible. i think i am leaning towards fuel because it looks like the car is runnin so lean its blowin out the ignition of spark causin me to break up. the weird thing is my car idles weird after bout 20 mins like its missing

[smithers584]

have you checked your fpr or the ground on the harness for the coilpacks? i have actually seen that ground on a couple different cars causing problems because its so weak. are you using anything for tuning?

.20 sounds a little small, i think .28 is optimal last i heard, but i could be wrong.

[street_white180sx]

well i pulled the plug for maf the car no longer is running lean so i am guessin the maf is no more good. but one thing tha has me puzzled i am gettin 10.12v on one of the pins for the maf and 0.112v on the other 2 i dont think this is normal. correct me if i am wrong.

[tailwaggin91]

Like smithers584 said, I'd check the coilpacks ground. My car wouldn't start for a while because (after wiring harness work) I grounded them to the valve cover instead of the back of the head.

[smithers584]

here are the values per FSM
Coil Packs: approximately 1 ohm
Injectors (you might wanna check):10-14 ohms
MAFS: at normal op temp and idle .8-1.5v, at 3000 rpm 1.4-2.0v. at pin 1 to ground. Also start car with MAFS disc. and one of the terminals should read to ground for batt. voltage. Also check the film inside the MAFS, you can clean them also, just make sure they are dry before reinstall.

[street_white180sx]

well i decided to change pumps wit one of my friends who has a skyline gts-t rb20 motor and i put the fuel pump in. the car ran better but still broke up. then this mornin i drove the car when the car was cool i boosted it and the car pulled the whole way through. no breakin up what so ever then like 3 mins later like when it got to operating temp it began to break up and got worse the longer i drove it. I switched out mafs wit my friend and no difference.

[RedtopTech]

DEF. CHECK maf YOU SHOULD HAVE BATTERY VOLTAGE ON ONE PIN, GROUND ON ANOTHER AND READ ABOVE FOR SPEC ON OUTPUT PIN. aLSO CHECK TPS AND I BELIEVE YOU SHOULD HAVE 1.4-4V. THROUGHOUT THE RANGE. AVE YOU CHECKED PCM FOR CODES? CHECK COMPRESSION BECAUSE SOME HEADGASKETS DONT LEAK TILL ATNORMAL OPERATING TEMP. aLSO I HAVE SEEN CASES OF THE "ENGINE CONTROL" FUSE PARTIALLY BURNING WHICH CAUSES HIGH RESISTANCE IN THE 12 VOLT SUPPLY TO THE PCM. cHECK THE RESISTANCE OF THIS FUSE "NOT JUST CONTINUITY".

[street_white180sx]

where is this fuse located redtoptech

[RedtopTech]

It Is A 10 Amp Fuse In The Main Fuse Box Under The Hood On The Right Side Of The Engine Bay.

[street_white180sx]

i checked the fuse the fuse is fine. i looked at my CAS and i noticed it has a wobble like its slightly bent. and when the car got warm and started to misfire i pulled one of the coils and noticed it was dead then would kick back in. can the degree wheel being slightly bent like that be causing this problem the whole time. I am bout to give up on this car man or i am gonna take it to the nissan techs next door at work. I work on fords all day and i roll a nissan.

[RedtopTech]

a bend in the tone wheel will def. cause missfire issues like yours. once warmed up the wheel can warp even farther. the sensor uses hall-effect, so it looks for one cut-out per revolution. If it doesnt see this the car will miss.

[street_white180sx]

Hey yo it was the the crank angle sensor degree wheel. Thanks alot guys for your help it feels good to boost again