sr20det cold start issue

SON240sx Automotive
1

setup
95 240sx with s13 sr20det blacktop swap
s15 t28, intercooler, exhuast, clutch, and so on
(no cams, stock)

The engine will not start when its been sitting overnight unless the throttle is cracked open a bit. After it fires up, it coughs, shoots some black smoke, then idles like a champ @ 1500 or so then drops down too 900 like its supposed to.

when the motor is cold hard to start
when the motor is warm or hot FIRES right up with no issue
no matter what temp it’s outside if the motor is cold it’s a bitch
to start

I have checked all wiring, found some threads on zilvia about a cold start ignition wire, everything is sound wiring wise.

Possible problems? coolant temp sensor? Does the coolant temp sensor need coolant in the system to work, or will it just read air temp?

Any ideas?

thanks in advance,

Dave

2

I guess the guys at Zilvia couldn’t help you either huh? LOL I saw the same post there, I check out Zilvia once in a while, I never post there, I’m not even a member there. Anyway…

It could be various things, could also be a fuel problem if it’s only on cold start up. How’s your fuel pump?

Have you done any mods like bigger injectors?

How about your crank position sensor?

3

Fuel pump brings gas right to injectors.
Stock sized injectors.
Crank position sensor is stock.

Once its started, the idle fluctuates alot (once warmer), and the coolant system isnt pressurizing. I have some work to do.

4

Sounds like your IAC could be malfunctioning. I dont remember exactly but I think its supposed to be cracked open during startup and if its malfunctioning the car wont start good. Check the S14 FSM for a good detailed description on how its supposed to work.

5

mine does the same thing… i have changed everything that could be changed trying to fix the problem. still the same shit… awhile back i was talking to a guy that had the same problem and what he was telling me there is a orange wire on the ecu that needs to see a 12v source. i havent lookd into it…