SR20DET sputtering / jerking help!

89Hatch240sx

89Hatch240sx

Slurpy? DUDE!?
Driver
So I kinda have 3 things ive narrowed this down to just off simple logic.

when I start the car it fires right up. No hesitation nothing and it idles perfect at 850 rpms. The problem I seem to be having is when I am driving at a constant rpm lets say 2700 rpms the car will jerk and studder until i give it gas. then after it spits and shudders I will rev it will stop.

Then after I come to a stop the rpms will dip down pretty hard go under 500 rpms for a second then i will lightly give it some gas it will want to bogg harder until i go 1/2 - 3/4 throttle.

now here is the weird part after she gets to full temp it will run fine but that's only after its fully warmed up. Now im starting to think it can be 1 of 3 things. Mafs (but it doesn't make sense why when fully warm it works) TPS, or maybe the walbro?

Note I am in Indiana right now and I rarely drive my car. yesterday i took my car out in the snow so it was pretty damn cold outside.

any ideas? could it be a bad cas?

any tips will be greatly welcomed! need my car running 110% as I will be moving back to Florida in Feb so she needs to be ready for the 1500 mile drive.




*if you want to know whats on the motor. my avatar has all parts that are currently on it. also I am running a SOHC MAFS*
 
I would first check ecu for codes
If no codes come up
Then its maybe wirin or a slighly bad sensor
Only before its up to OP temp
Could be many things...
Try the coolant temp sensor
But check codes first:bigthumbu
 
mongooze said:
Get the right plugs. Ngk 7s I think. Gap to. 025 no bs that fixed like 3 SRs
Click to expand...

part number is bkr6eix or bkr7eix

But that all depends on the amount of boost he is running. Doubt it would be the plugs unless they are foul. It's a fuel problem.

I'll just throw some common shit out there:

Rust in your tank clogging up your fuel system (so common)

Bad FPR
 
Last edited:
dude seriously ive had SRs with stock boost or little over stock like 10psi and i gapped them to 25 and it fixed it, please just gap them to 25 and try it.

no bullshit i fixed adams car this way and my death hatch ask bill me n him chased problems and once i gapped em ran like new.
 
ok now the problem has escalated! i cant see spark plugs being involved in any form or shape now...

I pulled my ecu to do a diag test... well the light dont come on. i turned the screw left and right NOTHING. i had keys turned to acc power. nothing.

now when the car starts it will idle fine then rpms will drop then stall.

im over 70% sure this is a MAFS problem. I am running a SOHC mafs. never had probs but since its stalling and sputtering im assuming its the mafs.

also i dont have a o2 sensor right now (guy who had sr before me jb welded it off. fuckin dumbshit i know. the SR is in TOP condition over 155 psi across all 4 cyl.

the car will drive 100% a ok as long as i am gaining rpms if i coast at set rpm it will bog and lose power and jerk....

so now im thinking its MAFS.

what you guys think?

---------- Post added at 01:56 PM ---------- Previous post was at 12:28 PM ----------

also my gas pedal sometimes has a dead spot in it.... could this be TPS? im bout ready to say fuck it and buy brand fucking new TPS and MAFS from nissan...
 
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