Stumbling cold start ups in the mornings...

Im having a bit of a mysterious start-up issue on these cold mornings. This has been going on for awhile and i kinda am assuming its normal. When i go to start my truck (I4 2.7L) on cold mornings... for the two seconds that it catches fire and turns on its own it sounds and feels like a cold diesel starting, then after its 2 seconds of somewhat roughness, it idles out and begins its warm up fast idle. When it does this i look at the rear and there is no smoke from the tailpipe. It only does this when its been sitting in the cold for about 7+ hours. No other starting issues other than that. Runs strong, no other mysterious problems and no CEL. Other then the MPGs has gone down a bit, but i pass that off as the fuel companies switching to winter gas.

The only thing (if normal) is that the oil and any other related parts affected by cold temps takes a few initial revolutions of the engine to get them up and running.

So to clear up any questions about exact procedure...
I insert key and begin to crank over the engine, it will revolve about 3 revolutions with the starter then catches, right when it begins to rotate by itself it feels almost like its not burning completely on all cylinders and kinda spits and sputters (like starting a diesel when cold) for about 2 seconds. After that it straightens itself out and begins to climb to fast idle (warm up).

Does anyone elses 2.7L act weird when it gets cold out?

If there is a problem hear the only things that i can think of that would create cold starting issues is either 1. MAP Sensor, 2. IAC Valve, 3. Fuel Pump, 4. Temp sensor for the Computer System.

 

No one out there has had this issue before in colder climates? It did it again to me tonight. Went to start it up to let it warm up a bit and again it just started hard/rough and actually took a little more effort to start. When it did start you could smell a trace of raw fuel from the rear. Im considering maybe the Engine temp. sensor?

 

Can we ask for more info? Miles on plugs? Changed fuel filter? Cleaned the throttle body? Total miles on truck and what is the outside temp?

Too much info us just right?

KO

 

Truck currently has 111981 miles

Spark plugs replaced (NKG Toyota) 93175 miles

Air Filter replaced (NAPA Gold) 93175 miles

Valve Adjustment and Compression Check (By Toyota Dealer) 99988 miles

Entire Intake Manifold, Throttle Body and IAC removed and cleaned 101262 miles

Fuel Filter Replaced 101262 miles

PCV Catch Can installed 101262 miles

When this happens its in the teens... Last night the it was in the lower teens.

Its almost like it floods itself out. Like i said cant really put my finger on it but think it could be a sensor related to air/engine temp giving the ECM a false reading. Though no CEL.

 

My first thought as well. Intake air temp sensor issue. Start simple.

 

I thought about that, but i don't think i saw and sensor for the intake air temp, i think that's integrated into the MAP sensor. Ill look again today just to be sure.

 

I am having the same issue. Engine is the 3RZFE I4.
Were you able to resolve your issue?

 

What are your stft's in open loop? Do they go rich when spraying carb clean near intake or intake hose after maf sensor?

 

That's funny I have the same issue on my 2002 i4 2.7l w/ 208k miles I thought it was normal. Always happens in temps. 20s or below. I will take a video of the start up when it gets real cold out..

 

It ended up being my IAC valve. I took it off once and cleaned it. Then after a couple thousand miles it started sticking again. So I replaced it. Now in the coldest weather within sometimes one start revolution it fires up and goes right between 1800 - 2000 rpms and works it's way back down to warmup idle

 

My truck is a 2002 - I guess it has the IAC sensor built in to the mass airflow sensor?

 

It's actually under the throttle body. You have to remove the throttle body from the intake plenum to access it

 

Sounds like OP has his figured out, for other folks, could it be leaky injectors?

 

Called the dealer to order the Intake air temp sensor and they don't show it for my vehicle: 2002 2.7 3RZFE I4 - I guess it's part of the mass airflow sensor...

 

Is this the part? Shamelessly stolen from toyodiy.com:
22270 VALVE ASSY, IDLE SPEED CONTROL(FOR THROTTLE BODY)
22270-75030 1 $440.32
22270-75050 CALIFORNIA(LEV) SPEC 1 $440.32

 

http://www.ebay.com/itm/NEW-Idle-Ai...ash=item25c4edb3cd:g:QgsAAOSw8w1X6MBD&vxp=mtr

 

I can't off the top of my head remember the exact part number. However, if you look under the throttle body you can see the IAC valve. Looking at it you will see black plastic, on the black plastic is the part number you need. That's how I confirmed that that was the exact part number I needed before I purchased it. I was able to take a picture of it while it was still on the truck. So you do have some room to get at least a good veiw of it.

As far as purchasing. I would stick to genuine toyota parts for stuff like this. They seem to be made better and hold up better then other brands. My two cents here purchase at your own risk. I bought mine at toyotapartsonline and only paid around $245.00 shipped

 

You're mixed up.
IAC = Idle Air Control (Valve)
IAT = Intake Air Temperature (Sensor)

On 2002 the IAT is built into the MAF (Mass Air Flow meter). The connector should have 5 wires on it. Early Tacomas had a 3-wire MAF and a separate 2-wire IAT.

The OP (Original Poster) replaced his IAC valve which Toyota calls "VALVE ASSY, IDLE SPEED CONTROL(FOR THROTTLE BODY)"

The IAC valve is similar on most Toyotas around this era, so any do-it-yourself procedure explaining how to clean, test or replace should help you, if that's your problem.

 

It was a bad #3 coil pack..
Thanks for all of the replies though!

 

It was a bad coil pack and there was no MIL?