Starting problem...

[Maxil]

Earlier today I was driving around a bit, everything seemed fine. I turned the ignition off and did something for about 2 minutes, when I went to start up again, it tried to start almost normal but when it hit about 700 rpms or so it went right back down and shut off. I cranked again and it again it cranked up to about 6-800 rpms then chugged out again.

It did that about 3 times, I checked under the engine for anything loose but everything looked fine, I got back in and tried again and it cranked just fine. The rest of today, I have started it 3 or 4 times and everything seems okay.

What I do know is the battery is fine, it had good starting voltage, starter is not in question either. That is all I am sure of fow now.

This kind of scares me because I don't want to get left in the middle of nowhere. Has anybody run across this before? I would really appreciate some help getting to the bottom of this.

Thanks,
Maxil

 

[zcruiser]

I've had this happen on another vehicle, acted like it got flooded. After I cranked it a few times, left it and came back, it started up again. May be the sign of a leaky injector, but not sure. Just keep an eye on it.

 

[brian2sun]

^^That's pretty much what I was thinking too. If it is a leaky injector, it'll get worse and you'll know if you need to replace it. Most likely you'll get a cylinder miss code sooner or later.

Try cleaning your MAF. It's easy, free, and can't hurt (as long as you're careful not to damage the little wires inside). A dirty MAF can also create idling issues.

 

[Baja Runner]

I'd vote dirty IAC (Idle Air Control valve). Very common on these motors. The valve opens and closes to allow extra air in depending on coolant temperature. The valve gets dirty after a while, and needs to be cleaned, as it sticks in the wrong position. Usually when the motor is warmed up.

Its located beneath the throttle body, and needs to be removed for proper cleaning.

Here's a link.
Re: 3.4L V6 Hard Start "hot" Cleaned IAC (Pics) - YotaTech Forums

 

[brian2sun]

I'd vote dirty IAC (Idle Air Control valve). Very common on these motors. The valve opens and closes to allow extra air in depending on coolant temperature. The valve gets dirty after a while, and needs to be cleaned, as it sticks in the wrong position. Usually when the motor is warmed up.

Its located beneath the throttle body, and needs to be removed for proper cleaning.

Here's a link.
Re: 3.4L V6 Hard Start "hot" Cleaned IAC (Pics) - YotaTech Forums

Good advice^^. I should have said clean the throttle body, IAC and MAF.

 

[Maxil]

I appreciate the help folks, I will start the cleansing process asap. I did clean the maf last year so I m leaning toward TB or IAC. Does an injector cost much to fix if it is that?

Thanks,
Maxil

 

[Baja Runner]

I really doubt its an injector. You would probably have a miss associated with it... I've talked with a Toyota mechanic that only works on Land Cruisers, 4runners and Tacoma's and he said in the last 10 years he's only seen 2 bad injectors. (Take with a little salt cause I've seen more on the online forums).

A Denso injector is in the $100 range, and is not hard to change. I would give it a 2 out of 5 on the "hardness" scale..

I'd definitely clean up everything. You'll be amazed with the amount of black soot gets stuck inside the intake, throttle body and IAC mechanism.

 

[whodini]

I had a similar problem over the winter. I had changed my plugs and wires so I had to take parts of the air system off. Hooked everything back up and everything wad fine. A week or two later I got the problem you described. Turns out my hoses must have contracted or expanded from the change in weather temps and one of the hoses popped off. Put it back on everything was fine again for another week and it happens again. Ended up putting a hose clamp on to keep it on snug and it's been smooth sailing since.

 

[Maxil]

I had a similar problem over the winter. I had changed my plugs and wires so I had to take parts of the air system off. Hooked everything back up and everything wad fine. A week or two later I got the problem you described. Turns out my hoses must have contracted or expanded from the change in weather temps and one of the hoses popped off. Put it back on everything was fine again for another week and it happens again. Ended up putting a hose clamp on to keep it on snug and it's been smooth sailing since.

Hmm, I changed my plugs just 3 weeks ago, we may have a winner. However I still plan to clean everything else as well just in case.

Thanks

 

[whodini]

Hopefully that's all. I agree with everybody else as well might as well clean things up while you're at it. Cheers.

 

[Maxil]

Okay so here is where I stand now. I dismantled most of the air intake system, cleaned the MAF thoroughly, which wasn't really dirty anyway. I managed to get the TB loose, but the darn coolant hoses are on crazy tight so I did the best I could with the IAC.

During all of this, the battery was disconnected.

I cleaned the TB pretty good, it is much better. However, the IAC I wasn't able to take apart so I shot some air intake cleaner in the hole on the bottom of the TB which leads to it. I hooked everything back up including battery and...

Upon start, at first it didn't want to but then cranked. It slowly idled down, but very low, around 500 and even under that. Going over everything, I noticed I forgot to tighten the 4 bolts to the TB so I shut it off and did that. There is also a sucking sound coming from the intake that I have never noticed before, though I may be paranoid. I restarted but it still idled low so I turned it off and disconnected the battery again hoping it will reset the idle.

The Battery is still disconnected but I am going to reconnect and give it a try in a few.

Does this low idle sound bad or is it a result of forgetting to tighten those bolts?

Sorry for the long report but it has me worried a bit.

Thanks,
Maxil

 

[Baja Runner]

Sounds like you forgot to hook up a hose on the intake, and its causing un-metered air to get into the intake. AKA a vacuum leak.

Double check you have the all the hoses connected, and they are tight.

Sometimes after cleaning the throttle body and such, its hard to start right of the bat. It should clear out though in 30 seconds.

Yeah, not getting to the IAC won't really help much. You need to get some good needle nose pliers to get those coolant hoses off.

 

[Maxil]

Hehe, who would have thought 1 little hose not connected would have done all that. After I wrote my last message I went and tracked down that sucking sound, I must have accidentally knocked off the hose that attaches right beside the coil pack on the passenger side. After I fixed that, redid the battery and it smoothed right out. It now idles at about 600 when in gear, but it is much smoother than before. Even though I didn't fully get the IAC I think it did some good.

Thanks for all the help!

 

[Baja Runner]

Sweet!

Well, I got to be a pro at cleaning my IAC through the years I cleaned it every year because it would get all gunked up. It always caused warm start issues.

See how it goes though and report if it still didnt fix the prob.