Rough Cold Starts

[Kloopofadown]

My poor car has started having problems about 2 weeks ago. It will start right up but it runs very rough at about 150-300 RPM (that's a guess because my Tach is kaput) and if I open the throttle a little, it will die. It will usually run like this for a few seconds then die. I start it again and it runs normal as if nothing ever happened.

The only other thing that happened about 2 weeks ago is that it got cold outside (40-60 degree weather). I've replaced the Engine coolant Temperature sensor and changed the oil to 5W-30 with no difference.

I'm pretty sure this is not the season for those symptoms for which Mitsu issued the infamous kludge boxes. (Isnt that around spring?)

What is wrong and what should I do to fix it?

I do have a logger and if you need any more information let me know.

 

[TurboChrged93]

Double check that coolant temp sensor that feeds the ECU information. That is a common problem. If that is malfunctioning the ECU does not no how much fuel to add during a cold startup and will always take about 3 tries til it starts. If you have a logger when you do have it running see if it's corresponding with your factory gauge.

 

[Kloopofadown]

Ok, my laptops battery no longer works so I have a power converter that shuts off when you crank the engine so there's no way I can even look at what the temp reads when it starts. I'll put the software on a different laptop on Thursday or Friday and see what it says. It's a circa 91-93 JDM engine(as if that means much) that was previously mated to an auto tranny. The harness and connector for the ECT on it was different from my old engine but I chose to attach the new connector and use the new ECT which has a smaller probe on it. I went and bought the "right" ECT and it didnt make a difference. ( already told you that in a way)

Oh and does the polarity of the ECT matter? or does it just work on resistance.

Could this "not knowing how much fuel to add" cause it to not want to rev? I cant run at low speeds in second gear until I get out of the parking lot ###(edit- because) it will just bog down.

On another note, the oil pressure sender that was on this Auto JDM engine is allot smaller (by half) than the one that belongs on there. My oil pressure gauge doesnt work so I think it's the kinda sensor used for idiot lights.

On a side note, I can smell it running rich from the drivers seat before it has fully warmed up.