Rough cold start

[ChiTDI]

New battery (1 week), new plugs (month old), but a difficult start this morning. I could smell poorly burned fuel, engine wouldn't catch after repeated attempts. Finally it fired on a couple/three cylinders and a few seconds later fired on all six. Smooth from then on, and warm starts were flawless. Engine runs well, but we did have 3" of blowing snow and rain during the night.

Places to look when I get the car back tonight?

 

[rg200amp]

What kind of car?
What kind of oil?
How many miles?
How long is your commute?

 

[Nyquist]

Did you put wires on and change the fuel filter? Where do you get your gas?

 

[ChiTDI]

Fuel filter was changed with plugs. '02 Toyota Avalon w/108k miles, GC 0w30 for the last 50k, and the normal commute is about 8 miles.
There are no ignition wires, that I'm aware of, but the coils were a thought I had as a potential problem source.
Gas has been from the same location with regular FP+ use.
The other possibility was a short to the starter from the battery terminals. They were clean and mold free at the posts, but I didn't look past them towards the starter unit. That area could be subject to wind blown precip.

 

[Nyquist]

If it were the starter it wouldn't crank at all. You would only hear a click.

Check for fuel pressure if you have the proper equipment. If that comes back Ok, then look to the coils' output.

If you can figure out if it is a fuel or spark issue it will help tremendously. Since it sounds temperature related, I'm leaning to something like spark.

 

[rg200amp]

Did you clean the throttle body, Mass air flow sensor, PCV valve, IIAC valve(if equipped)

 

[ChiTDI]

Haven't touched the MAF, but the throttle body, PCV system, and air idle controls I have cleaned. It's a sludge prone engine so I have to stay on top of that.
I'll see if I can get a fuel pressure reading tonight or tomorrow morning when it's cold. Have to go borrow those gauges and hoses. I don't think there's an extra injector for cold starts, maybe I'll hit up the library.

 

[Mau]

Distributor cap and rotor? not sure if your car has em.

 

[mechtech2]

It could have been from the moisture and wetness that got in or around some component.
See if it happens again.

 

[The Critic]

This was discussed before. Here's a link to the thread.

 

[ChiTDI]

Great responses, thank you.
PM startup was normal, as was the 20 degree AM start today.
I'll watch for symptoms and in the meantime, I'll prepare for Mokanic's procedure on the IAC electrics.
Thanks again guys.

 

[M1Accord]

Originally Posted By: Nyquist
If it were the starter it wouldn't crank at all. You would only hear a click.


This is not always the case. My Corolla (18 years old) had a bad starter that won't start until many tries, sometime taking up to 30 minutes and with different copies of the key. At first I thought it was the ignition component but a guy at work suggested that it could be the starter. Once the car is warm, it started much better but may still requires a few tries. I had Pep Boys changed out the starter and it works every time now just like a new car. Electronics problems aren't always as black and white as we would like them to be.

 

[ChiTDI]

Symptoms reoccurred, this time leaving from a stop. Reoccurred next day coming to a stop.
Fuel pressure checked out, vaccuum steady, coils checked within resistance limits, so I replaced the Idle Air Control Motor.
No symptoms, car runs like a top with a clean throttle body.

Thank you guys. Again.