newTOyotas

Today we had a pretty bad snow storm and on my way to work I ended up getting 'sucked' off the road and after some fancy stunts I came to a stop. The truck still seemed to be running fine altough one issue was a left front tire that was no longer on the rim. I happened to do this right in front of a friend's house so he said he'd put the tire back on the rim and drop the truck off at work just down the road in a bit. I pulled the truck in front of his garage and even at that time the truck seemed to run as good as always and there wasn't any up/down idle going on. I went out after work and started the truck and it idled like it always has. A few minutes later I came back out to hear the idle going from aprox. 1500 rpms to 2000 rpms back and forth/over and over. I drove the truck 11 miles home and it drove like it always did other than when I came to stops I noticed it was definitely idling all over the place, up and down between 1500-2000 rpms. I don't think I did anything to the truck to knock off a vacuume line but I can't be 100% sure. I was wondering what else could cause a truck that gets packed with snow/ice to start acting this way? The only thing that is different than a truck that ran perfectly is my stupidity of not keeping it on the roadway, nothing mechanical was changed and I still find it hard to believe that I pulled a vacuume line off although I won't completely rule that on out.

Any suggestions on what else to check besides a vacuume line? Is there anything else that may have gotten frozen somehow and could show these types of symptoms?


Just a little more info in case one of the yota gurus stumbles across this post....
The coolant level is full, there is no coolant leaks at all, and I didn't overheat the truck at all considering I'm already aware of how problematic these 3.0s seem to be as it is. There was some snow packed in below the fan area but I spent plenty of time getting 95% of the snow out from everywhere under the truck, front to back.

MudHippy

Nope, just a vac leak is all I can think of. You've undoubtedly got all that ADD junk going on under there. I'll bet one of those vac lines got pulled loose.

ET

same thing was going on with my 3vz 4runner when the water pump was going out.

newTOyotas

Hmmmm.....
Like I said, the truck never showed any signs of this until I inadvertently took it off-roading for a few seconds this morning. It has never lost any coolant and I decided to mention that since it seems that toyotas could have problems keeping a constant idle if low on coolant for some reason(??)
Is anyone familiar with any lower vacuume lines that may run under the truck? This is the only area that came in any contact what-so-ever with material from the ground (snow).
I hope I can get this figured out considering what a pile of crap this truck now sounds like every time you come to an intersection.

I have noticed that the truck starts up when cold as it always has and idles at or around 1500 rpms all while making the typical 'suction' sound as if it is trying to suck all of the air out of the universe (which also seems to be normal behavior) but once it gets to that point where the idle would normally drop down to ~500-600~ rpms, it then goes straight to the troll under the dash jabbing the gas pedal over and over again mode.

Sucks that it is so damn cold here right now and I doubt it will even be above freezing for another week or two.....maybe more.
Looks like there is more than enough vacuume lines under the hood to circle around the earth at the equator at least 3 times. (why?)

newTOyotas

MudHippy, you'll have to excuse my lack of knowledge when it comes to foriegn cars/trucks, but what exactly is the "ADD junk"? Even if you don't feel like explaining it, at least point me in the direction it is under the hood and I will try finding (hopefully) a line that has been pulled free/damaged somehow.

Thanks!

Kiroshu

You may want to take the time a nose around the engine compartment alittle bit. During your "off-roading" you may have knocked a vacuum line loose or a connector or the main intake tube.

Tps?

Got Coolant?

Air flow meter unplugged?

newTOyotas

Thanks for the reply.
main intake tube> If this is the incoming air ducting, from the air cleaner/etc housing to the TB(?), then it is all in place. I actually propped the lid (air flow meter/top?) away from the air filter base and filter and took those both inside for a bit. I didn't unplug what I would consider to probably be the AFM and it was definitely still attached if that is what I thought it was.

Not sure about the throttle position sensor yet. I will have to check that some time soon to confirm.

Engine coolant is definitely full and hasn't used/leaked a drop upon owning 1 1/2 months which is something I am sure to keep track of regularly, including twice today already.

I am going to have to search for a dreaded vacuume leak more than likely

Thanks for the input, I do appreicate the help.

chrishf12

He is talking about Auto Disconnecting Differential (ADD) if your truck has manual hubs than you do not have ADD. Otherwise It has a vacuum system that disengages the front differential from the CV axles when the vehicle is not in 4 wheel drive.

newTOyotas

Ok, yeah my truck has manual hubs that you have to get out and walk around the truck if you need 4wd.

newTOyotas

Well, since the weather is about -5 right now with the windchill and the wind is blowing 15-20mph I won't be able to do much standing out in the driveway. I will try to keep poking around here on this site in the hopes of coming across a thread that someone has been through exactly what I am going through right now.
If anyone has anything to suggest or add, PLEASE do.
I am convinced that it is something going on in or around the throttlebody that won't allow it to idle correctly but everything about this little truck is so confusing to me. I'm sure I could learn to have a little more respect for a TOYOTA in general if only I could understand what the heck they were trying to do with some of the alien contraptions jammed under the hood covering what I think is a simple internal combustion engine.

Oh well, hopefully someone will stumble across this thread and understand exactly what I am explaining and rattle off an exact cause for the symptom of an idle that quickly goes up and down repeatedly (forever, on and on) after the first few minutes of intitial(cold) startup(during those first few minutes it idles normally).

If I ever figure it out, I will take a minute to post what I had to do to correct it.

Toreador

My truck idles very high when it's cold. My truck also idles high after driving hours long distances at 4K rpms- as in, after I exit the highway, and sit at a light, my rpms stay way up. Why does my trucks idle speeds always fluctuate? I've seen it stay at 2300 by itself.

newTOyotas

FWIW, my truck idles high/low/high/low/high/low/high/low/high/low over and over and over and over. It's not just a high idle here and there, or a low idle here and there. One second high, the next second low, the next second high, and then back to low, over and over and over and over and over.........
I'm sure it is a sensor or something but I guess I'll have to figure it out somehow.

Toreador

i can't trust any mechanic in this town.

newTOyotas

I'm really not even sure what I did that has the truck idling at ~900 rpms~ right now and smooth, but I ended up turning the 'idle' screw all the way in and noticed immediately that the truck stopped revving up/down/up/down/up/down but still seemed to be idling too high. I took out my WD-40 and sprayed the 'dashpot' (I believe that is the correct name), the TPS in the area where the throttle shaft intersects it, and whatever the little black plastic 'plunger' looking contraption is towards the front of the throttlebody and the truck starts up and idles consistantly at 900 rpms. Hopefully now it doesn't give me anymore trouble since it's too darn cold here outside not to have the luxury of getting into a warm vehicle.

I'll find out soon enough I guess.

newTOyotas

It still doesn't want to idle correctly.
I'm lost.

What can cause an idle to pulsate back and forth(up and down), over and over and over on these damn trucks? I have a hard time believeing this is caused by a vacuume leak since the leak would always be there, no?
It has to be a sensor of some sort.

newTOyotas

Does anyone know if there is a test that can be performed on the coolant sensor for the ECU?(ohms or voltage ranges)
I realize it may be a fairly cheap part to buy, but on a truck that is 16 years old, I'm sure I will end up destroying a bunch of stuff trying to change it. I also hate to buy parts if I don't need them and go through the hassel of changing them if they don't correct anything. It seems the coolant sensor for the ECU would be somewhat a pain to change without screwing up other things because of it's location (on the rear of the intake?).

newTOyotas

I'm sure this will be yet another unanswered question, but can anyone offer any tips on how to unplug the TPS sensor without removing the engine?

newTOyotas

I finally got the TPS unplugged. I am not sure where the feeler gauge is suppossed to be installed. Doesn't really matter I guess since my TPS doesn't seem to be operating correctly. I can't get it to read 'infinite' (open?) in any position no matter how far it is swung in either direction. As it sits right now, my meter reads 5.73k and even at the furthest point it won't 'drop' any lower than 1.89k.

Does anyone know if the Japanese instructions for maint. on these trucks has been sucessfully translated to an English/American format that actually makes sense? Reading pretty much any task explained in the FSM shows that the language barrier obviously never was overcome.

Moustache

newTOyotas - Hey man, i had to join after reading your thread. I chased my tail with this EXACT same issue for almost 2 months. It drove me to the brink of insanity.

My first advice would be, Pull each coolant line from the Throttle Body and inspect the hoses and metal fittings.

The coolant fitting on the front of my TB was rusted shut but went un noticed by 4 different shops and a Toyota Dealer.

Here's a photo of my old TB


Got a new one from someone in Canada and it now runs great.

FYI i replaced ALL of my vacuum lines, TPS, cleaned the TB and none of it helped until i caught the clogged line.

Hope this helps!

Moustache

I believe there is a sensor inside the TB that detects how warm/cold the engine is, changing the fuel mapping to a "warm loop" as soon as the engine warms.

If your lines are clogged, this sensor may not be getting enough warm coolant to trigger the warm loop. Being winter does not make this issue any better.

I'm not possitive on this but i have done ALOT of research on this issue. just my .02