Thread: Fuel Trims Q

Car 1996 Nissan 200sx SE-R (208,xxxK) Code was tripped on warm up with 50F outside temp
codes PO115 ECT
PO125 clsd loop fuel ctrl insufficient coolant temp
Date from PO115
engine rpm 0
Load value 0%
Coolant temp -40 f (lol it was like 50 outside)
Short term fuel trim1 0.0%
long term fuel trim1 0.0
Short term fuel trim3 -100.6%
Long term fuel trim3 -100.6%
Vehicle speed 0
fuel system 1 open
fuel system 2 N/A

My question is why do i have a Short/long term fuel trim3 on a one bank engine, and only one fuel system? Is that just my scan tool showing extra unneeded data? I'm 99.9% sure the -40f ECT is the problem, that will be replace.

Or is this car so smart that trim1 is cylinder 1,2 and trim 3 is rich on cylinder 3,4 and it knew all this with one 02 sensor i dont think so?

Sounds like the coolant temp sensor, your o2 sensor isn't even being used at this point, and the temp sensor is the reason why. looks like you have some erronius data hat is confusing you

Update Fix the PO115 code. New CTS installed.
Got a new one code P0400, Already found the problem. A nipple from the EGR vacuum solenoid ripped off, going to try and superglue it back on because the solenoid still works. Cheapest EGR vacuum solenoid I found was 72.99(new).
I get the right FT on a update later but i think it was,
STFT and LTST both jumped to +/-7.0% because of the vacuum leak into the intake.

p0400
rpm 887
coolant temp 183
STFT -7.5%
LTFT -9.2%
vehicle speed 0 mph
fuel system clsd
load value 27.8%

super glue the nipple on the EGR solenoid cuz i don't wanna spread 73 bucks on a sensor that still works.

PS i may have a p0500 code because Nissan can make a instrument cluster that works pass 5 years