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Cold weather, hard to start...

16K views 28 replies 14 participants last post by  99taco00tundra 
#1 ·
Need a little help if you can.

2000 3rz 278k

Hard to start only in cold weather, no probs in the summer. Once warm even in cold weather itll start right back up like it should unless it cools down completely, ie 4-5 hours after last shutoff.

I have the 2 coil pack ignition, one is less than 2 years old (new from toyota when replaced), one is original, coil wires are under 2 yo again from toyota. Plugs are less than a year old, fuel injectors just rebuilt, pressure reg, new as well. Starter original, yellow top optima less than 2 yo.

Turn key and truck cranks strong, I just stay on the key till it starts, anywhere from 1-5 minutes of cranking. It cranks strong the whole time, acts like it wants to start after 10 seconds or so but just stays at a constant sputter, it will die if I dont stay on the starter, after a while longer it will begin to want to start more than not, but still not enough to let off the key, eventually it gets to the point where gently giving it throttle helps it fully fire and run. It runs rough for a minute then gets to the point where it runs/idles normal for a cold start for a 3rz.

Is my IAC sticking? Can I clean it, just replace it etc???

Im about to replace the 1/4 coil pack, the one that is original, im consistently getting p0301 and p0303 but the 3/2 coil pack and all the wires are under 2 yo. So i could understand maybe the cyl 1 misfire is the age of the coil, but the cyl 3 misfire when all else is relatively new? Leads me to think maybe the IAC is sticking. Would that cause the misfires? But why only on cyl 1 & 3?

Fuel pump has been ruled out as trucks runs like new once warm at all speeds in all conditions. Originally thought maybe fuel pressure was leaking down but ive done the injectors and regulator in the last month because of that and still have the issue (hard to start). Problem started last fall and has progressively gotten worse, now even harder to start in cold 25-40* and recently hard to start in warmer 40-60* temps when it used to only have problems in the colder range.

Thoughts?

Sorry if this is cluttered. Thanks.
 
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#3 ·
First, determine exactly why it won't start.

Is it fuel? Is it spark? Is it compression?

I think using a substitute fuel source like some starting ether or WD40 or even some spray contact cleaner should settle that question.

Spray some fuel in the intake, then try a cold start.

If it fires right off with substitute fuel, look at your fuel system for the problem.

If adding fuel doesn't help, then it's not the fuel system. Look elsewhere.

Have you checked compression yet?

I doubt that it's spark related. Usually an ignition system problem gets worse with heat, not better.

Try adding fuel and tell us what happens.
 
#6 ·
Wd40 had no effect. Guess ill ground the plugs and check spark and compression while theyre out, then resort to cleaning the IAC.
 
#7 ·
Really interested in this, as my 5vz is doing something similar thing in the morning especially on more humid days. Live about 20 miles north of galveston tx so it's humid.

Long time issue is on cold starts it will fire but run rough until i either tap the gas and it straightens out to a very good idle or i have to rev it up to around 2500 rpm and it will finally smooth out. I took off the TB and cleaned the IAC to a nice shiny finish. still happens at times.

This morning my truck was grumpier than ever. Wouldn't start. After 5th crank a stumble. 10th another stumble and it starts to catch, gas gauge drops to below e. 17th crank it fires rough and i push to 3500 and it smooths out to a fine idle, gas gauge starts to move up a little. Take off and it drives great gas gauge seemed to go up and down depending on if i was pushing the gas pedal or not, but i can't see the connection. Stop to drop my kid off at school and it starts right up, gas gauge goes back to where it supposed to be. I will go out after work tonight 10p and it will start right up like every other night???

Maybe together we can find the answer cause this shit is annoying. Not stealing your thread, but the problems sound similar.
 
#8 ·
Well cleaning the IAC seems to have had no effect. As soon as I can ill be grounding for spark, throwing in some new plugs for the hell of it, and checking compression.

FWIW, I checked the ignition packs for resistance and they were right in the middle of spec.

Cleaned the MAF too, that didnt do anything.

Driving me nuts, once its warm it cranks back up like new.

Camshaft sensor? Crankshaft sensor? Timing? If timing or any of those things were off wouldnt it show up all the time? Not just cold on start?

One more thing, could it be exhaust valve clearance? Valves have never been adjusted.

Good article: http://shadetreespeedshop.clvr.tv/my-car-is-hard-to-start-or-runs-poorly-cold-why/
 
#9 ·
I had/ have the gas gauge droppin as well hossmaster. And start ups are getting worse.

I got a P0300.

Got plugs, waiting on wires, and fuel filter. Then go from there.
 
#10 ·
My gas guage is unaffected. Fwiw, my iac has 278k on it and really wasnt that dirty, not enough to be suspect, but i cleaned it anyway.
 
#11 ·
clean or not... you did test for proper operation ?

What about yer EGR valve, check that ?





for the 5vz just 'cause...







use ether for start up... works better
well... if it's still available at the ap stores :dunno:

works better for airing up a tire too :D

maybe this brand... :p

 
#16 ·
no, he hasn't :(


yup... sounds pretty familiar


does it help when you give it some gas? when im startin mine and i give it some gas after a sec it will fire up
when it finally starts to sputter to life, it helps... but then entire time its TRYING to start the raw fuel smell is really strong.

the video was only a few seconds of like 10 minutes of cranking that morning.
 
#18 ·
http://www.toyotanation.com/forum/1470792-post11.html

stretched timing chain, bad crank sensor, bad cam sensor, bad wires, or bad ECU.... ?

With a high mileage motor it could very well be that the timing chain is stretched, or the tensioner is worn, allowing the cam and crank to be just on the edge of spec. With a stretched chain the marks will still line up, but the motor is not timed. This is why timing chains/belts must be replaced by mileage, not by inspection. They can look fine, but there is no way to tell if it has stretched just by looking at it. When you rev up the motor the cams catch up to the crank, and the motor runs.
 
#19 ·
there is a sensor on the back of the engine, its a coolant temp sensor for the ecu that, if it goes bad will tell the ecu that the truck is already warm and wont supply enough fuel to the injectors for a cold start. fix that and your problem will go away. my buddy just had this exact same issue on his and we replaced that sensor and it went away completly and now the truck starts better than it did when it was brand new.
 
#20 ·
its worth checking, yes, but when its trying to start, the raw fuel smell around the truck is overwhelmingly strong...
 
#21 ·
#25 · (Edited)
I just watched that video.

yeah.

Notice the way it sounds?

It goes "one two three GRUNT one two three GRUNT one two three GRUNT".

It's supposed to be nice and even.

Check compression. I'm betting you have one cyl that's O.K., and three that are lazy.

It's been my experience that 100 PSI at cranking speed is minimum to start, and I bet that's where you are first thing in the morning when it's cold.

Valves been adjusted lately? Swallow any water recently?
 
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