compound high idle issue
 

I've got an early 22RE with an issue that has progressed and taken me down a weird path. I took it to a mechanic today who gave me what sounds like it could be a reasonable diagnosis, but I'd like someone to read all this crap and tell me if my entire world is about to fall apart or what :att:

For the past few weeks, truck has been idling high. It started around 2K rpm at idle, and aside from that things seemed fine. I talked to a friend and we were gonna take a look at it when he was in the area soon. I kept my driving to a minimum, as a precaution. I searched the forums and googled around, and it looks like a lot of people describe this problem as an issue with the IAC valve / sensor or the throttle body and suggest spraying some carb cleaner or something on it to clean it up.

Slowly, the idle got higher. Around 22~2300 RPMs I noticed a new issue, the engine temp was heating up a bit. Normally the temp needle (I'm no guru, can't tell you the actual temp) sits around the middle of my temp, but now when I start it, it slowly rises as I drive until it's maybe 75% up. Not into the danger zone or anything, but high enough that I noticed. As soon as it hits the top point around that 75% mark, it instantly falls back to normal, and only does this from a cold start in the morning. Between searches and friends we determined that I might also be in for a thermostat replacement. Now only drove it as absolutely necessary.

So just a couple days ago, I start hearing an intermittent noise sort of like a combination of rubbing belt squeak and something else sort of rattly. Idle is now nearly 3K. Couldn't figure out what it was until I took it to a mechanic today. We noticed that the bottom pulley on the engine that turns the alternator is wobbling back and forth as it spins. The noise is definitely coming from the pulley, all right. So, the mechanic tells me that my harmonic balancer (dampener?) is shot and we need to switch a new one in, and my alternator belt is also sitting low in the groove, so maybe a good time to replace that as well.

My gut says that all of this makes sense, and regardless of whether this fixes the high idle, the replacements are a good idea.

Oh, and I noticed my check engine light flickered on and off while it was running (only once) so I decided to check the codes. I have a single-digit old 22RE, and it threw code 5 (O2 sensor) and 11 (A/C idle sensor I think?). The mechanic says we can o-scope the O2 sensor to see if it's actually bad or not; his preferred method.

Anyway, he mechanic thinks that replacing the pulley/harmonic balancer+belt might fix everything, and the reasoning I got was:
- The ECU might be increasing the throttle to kick up the alternator output because it sees low voltage.
- The wobbly pulley, as it is unbalanced, controls my water pump, and might be related to the thermal issue.

Ok so my questions are:

1) I want a second opinion; does all of this make sense / sound legit? Just because it sounds logical to me doesn't mean it's right.
2) How much labor (time) do you think I'm in for? The mechanic mentioned being not sure if we were gonna have to take the radiator out to get the pulley out or what, and I'm sure that affects time spent. Hopefully someone who sees this has done this before. He's not a toyota-specific mechanic, so if I can offer him any tips I can probably save time and money.
3) Is there anything else I should know or be asking?

The radiator should be removed. It's easy and quick to do so why risk it. I'm guessing he'll either put a breaker bar on the crank pulley bolt and jump-start it off or use an impact gun. Once the bolt's off the pulley slides right off, maybe with a few taps from a mallet. The alternator belt is tensioned by loosening the 2 bolts and pulling the alternator further away from the engine.

Labor should be under 2 hours even with the radiator removal. Coolant gets drained to replace t-stat anyway.

Please let us know if this resolves those issues.

While I don't know a lot about the 22re, I'm 98% sure that you DO NOT have an "electrical load idle-up" (see, e.g. http://www.cygnusx1.net/Media/Supra/...taTech/h26.pdf) More plainly, the ECU has no way to increase idle based on alternator voltage. (I'm not sure how replacing the harmonic balancer/pulley/belt would even address that anyway. Is the belt slipping, so the alternator is running slow?)

Having said that, a wobbling harmonic balancer is bad. If the crank bolt has loosened and the balancer slid out on the shaft, not only will it damage the balancer, but the crank too. But if your only problem is that the annular rubber ring has failed, replacing the balancer is what you need to do. And replace all the belts while you're in there.

If you have a sticky thermostat, replace it. It will only get worse, and then you'll have a real problem.

So what IS causing your high idle? I really don't think it's the harmonic balancer (but it sounds like you have to work on it anyway). I would examine the actual throttle mechanism on the throttle body. The throttle cable pulls a lot of "stuff" around, and something as simple as dirt may keep the throttle plate from closing all the way when you let off the gas. If you can make the idle drop just by pushing on the linkage with your finger, you've found it.

I agree with the above.

These engines have mechanical throttle cables from the accelerator pedal to the throttle body and the ECU has no way to move the throttle plate by itself.

:safari:

Thanks for all the replies. I'm seeing used pulleys online for around 50 bucks, and the belt should be around 10 bucks new, right? any suggestions on sources? it looks like auto zone has new pulleys perhaps? get? avoid?

In addition to a general inspection of the external linkage, you also want to have a look inside at the throttle plate (crusty, gummy) build up here will cause issues but it's pretty rare the springs don't overcome it. There is also a device called a dashpot on manual transmission vehicles (basicly a metered diaphragm) that slows the closure of the throttle plate between shifts, these become eratic if the aren't getting air properly. And finally the idle.adjustment screw (big flat vertical screw, on your left when looking at the throttle body), this should have a good oring on it it will vibrate around or leak air if not.

Are you SURE you need a new harmonic balancer and pulley? While it is possible that you've failed the rubber ring (so you need a new balancer), it is also possible that you've allowed the balancer to slide out on the crankshaft. If that's the case, you might have damaged the shaft, in which case a new balancer won't make any difference.

For what it's worth, a little shopping turns up a new $67 balancer/pulley assembly. http://www.lowrangeoffroad.com/toyot...r-2-types.html While an "OEM" balancer may be better, given what (might have) happened to yours, I would be willing to pay the extra $17 to avoid a used unit.

Of course, you're talking to guys (and gals) who would do all the work themselves. We have the luxury (?) of waiting until we see the damage before we order the parts.

I can try and get a picture up here, or a video of it running, if you want.

I would say check the TB flap for mechnical sticking first. Check for vacuum leaks too. Block all air ports for the IAC to make it behave as if the valve is closed. Wrap some duct tape around the intake elbow at TB, they crack and would let in unmetered air. Can't see it from the top.
If the harmonic is wobbly, it is maybe only loose from a previous fix, like seal or what not. Try to tighten that nut. Correctly tension the alt. (wobbly should not affect waterpump either, the belt doesnt care as long as it is not slipping.
Your temp overshoot "can" be normal. Turn off the heater valves. Does it still do it? Drill a tiny bypass hole or buy the fancy one 4crawler recommends.

Great point. The oring is failing and the screw is backing out bit by bit. They do this.
The idle adjustment is the big flathead screw, half an inch, adjustable from the TOP not the front!. The front adjustable is the "zero" position of the TB flap itself. Do not adjust unless sticky flap or preparing to adjust the TPS sensor.

Okay, so, quick but unfortunately not a full update, mechanic has replaced the harmonic balancer, the seal near it (?), and the alternator belt for good measure as the old one was sitting pretty low in the pulley and we were worried about it. the culprit for the high idle was the idle stop screw (which I swear we checked :oops:). it's back around 1K. if I notice it slipping to higher revs, the ring is something I can replace and don't need a mechanic for, even if I'm an idiot, right? :cool:

I think the temp creep is still happening (need to drive it a little more, I just got it back)... should I go for the thermostat next?