1mzfe high idle?

[lksdrinker]

***woops I posted this in the wrong section...is there a way to move it?***

Hi guys, noob to the site here with a question...sorry for the long post.

My dad and I have been working on his 95 avalon with the 1MZFE for the past few months now. Long story short we went to do a timing belt/H2O pump change (the odo is at approx 225K right now) and also fixed up the suspension (changed struts, bushings etc). Everything went basically fine until we broke one bolt when taking off the water pump. Tried getting it out with no luck. So we buttoned everything back together and threw the new pump on there minus one bolt. Surprise surprise once we started it up she leaked like crazy. So fast forward a few months....we pulled the engine, spent countless hours trying to retrieve the busted stud from the water pump and finally had some success. We finished it all up, got the engine back in the car and got everything running well with no leaks!

But now the only problem is that the car is idling at around 1500-1600 RPM. We've re-tightened the intake manifold and plenum, checked for vacuum leaks mutiple times, double checked the routing of the vaccum hoses, etc etc etc. We pulled the idle air control valve and cleaned it really well....and the resistance checked out ok. PCV valve seems ok and we get the same results when we swapped it for a new one.

When we turn on the A/C the idle drops to about 1250 RPM. Same thing happens when we jump TE1 and E1 on that 'diagnostics' port....and that doesnt change even after leaving the jumper in for more than 5 seconds.

Now the only thing which is not checking out is the resistance on the vaccum switching valve (or whatever its called?!) which is connected to the EGR vavle. The resistance was a bit high compared to the listed values in my haynes manual. We did the vaccum test on the EGR vavle and that checked out ok. We're going to try calling the boneyards around here on Tuesday to see if chaning out the vaccum switch helps...but for some reason I'm doubting it.

So any ideas on how to track down whatever is causing this high idle? Am i incorrect in thinking there is no 'idle adjustment' on the 1MZFE?

[tacosteelersman]

Just a thought Check the throdle cable on top of the intake and be sure there is slack in the cable there are two nuts one for the adjustment on one side of the bracket and one as a jam nut on the other side if the bracket..Adjust as needed..Good luck .. Dave

[lksdrinker]

Originally Posted by tacosteelersman

Just a thought Check the throdle cable on top of the intake and be sure there is slack in the cable there are two nuts one for the adjustment on one side of the bracket and one as a jam nut on the other side if the bracket..Adjust as needed..Good luck .. Dave

good idea, but we tried that with no luck.

Today we noticed that if the throttle is held for a few seconds then released the idle drops to about 800 RPM or so for a split second before bouncing back up to ~1500RPM.

[mmejia]

I know you said that you've checked all the vacuum lines, but it really sounds like something like that is the issue. I would say double-check the vacuum lines on the intake/throttle body and see if that helps any.

[lksdrinker]

Well we have been trying everything. We've double, triple, quadruple checked for vacuum leaks and found nothing.

We pulled of the IACV and cleaned it again. Tried putting 12 volts to it and nothing happened. We finally got it to internals of it to move after some prodding and prying to break it free. Then we continued soaking/cleaning that thing out. and now when we put 12 volts to it we get the plate to move and its working as it should. So I think the high idle was just a very dirty IACV....so dirty that just squirting carb cleaner alone was not enough to break it loose.

Got everything put back together and she idles a bit lower. Drove around for a bit and after 2 or three trips the idle seems to be back to normal at about 750 RPM. Sometimes you need to blip the throttle to get the idle down from around 1K.....but seems like we've got it figured out now!

The other problem that we now think we have is with the A/C idle up valve. It does not seem to make the engine idle higher with the A/C on. We checked the resistance of the wiring and found it was a bit high but not enough to really worry about it. So we put 12 volts directly to the A/C idle up valve with the A/C on and the valve operates as it should. So then we tested for 12 volts at the connector to the valve (from the ECU) and with the A/C on we arent sensing any voltage at the connector.

We didnt really bother chasing any wires or looking for fuses yet.....its cooling off and A/C wont be a necessity for the coming months. But this is still something we would like to figure out. Any ideas?