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Interesting thread. We have a 2006 Toyota 4Runner and it just started doing the same thing (shaking only when the A/C is turned on). It's definitely A/C related but no idea what's going on.
Interesting thread. We have a 2006 Toyota 4Runner and it just started doing the same thing (shaking only when the A/C is turned on). It's definitely A/C related but no idea what's going on.
In 2014, I got a new engine put in from a 2005 Kia Rio. The engine had 25,000 miles on it, I've put about 5-6 thousand on it since then.
I had created a thread back then to figure out if a different engine was worth it. In the end, it was actually cheaper for me to get a "new" engine than plunk down a whole lot of money for a new car. Engine got me from Maine all the way across the U.S. to the west coast without issue. That was about 3800 miles, taking a southern route due to winter and not wanting to take a Kia Rio across the Rockies.
Got to the west coast. About a week later, got an oil change. About one mile down the road, for the first time ever, when I was sitting at a red light, the car started shaking in idle in drive with foot on brake.
Fast forward to the last 2 months:
Because I did my work from home and did not have to drive that much, I didn't get anything done until recently.
In the last 2 months I have had the following done:
New engine mounts, from Kia. One was broken, one was almost broken, one was fine. Changed all 3 anyway.
New a/c compressor, and had it filled with freon and charged.
New battery. (Had a new battery last year, but apparently it was bad and had to get a new one, still under warranty, thankfully.)
New alternator. Mechanic replaced 3 belts (alternator belt, power steering, and a/c - is what he said.)
Drums and bearings in rear brakes.
Throttle body was cleaned out. Also was realigned by different mechanic when first mechanic did not align it properly. (Is what was said - have no idea what that means - I'm not a mechanic.)
IAC valve was cleaned out.
New air intake "boot" that was ripped.
New air filter.
New spark plugs - they said my old ones were bad.
New brake booster (because shaking happened when foot on brake, even in park and neutral although shaking was nowhere near as bad when in park or neutral since engine is not under load in park or neutral.)
New air hose (whatever it's called that is somewhere near the brake booster area - not sure official name.)
Ok, so got all of that done over the last 2 months. The brake booster, new air hose (near that area), and new spark plugs were just done this week.
Now when I drive, if I'm at idle at a stop light, car is back to normal. Because it's a 2004, of course it's going to have a very, very slight shaking - it's not going to be nice and quiet like a new car.
Mechanic took it on a test drive, got it all warmed up, and said "difference was night and day" and that can now drive and be at stop lights with foot on brake in drive and no shaking.
That much is true. But he didn't test it out fully, going through the scenarios I told him about before any fixes.
So I test drove it after they told me it was fixed, and I put it through the situations I had bad shaking before.
Drove and stopped at stop lights, in drive, foot on brake - no problem.
Went through a drive through to get a large drink, and to test car when idling for a long while, not just at a stop light.
Just a few minutes into waiting in this line, I tested various ways:
Car in drive, foot on brake
Car in neutral, foot on brake
Car in neutral, ebrake on
Car in park, foot on brake
Car in park, ebrake on
And in each one of those above, I tried with the a/c on and without the a/c on.
Car in drive, foot on brake - seemed okay.
Car in neutral, foot on brake - car did not like that. It started to shake badly.
Car in park, foot on brake - car shook, sounded like it would die, and I sat there and watched the RPMs drop while idling.
Car in neutral, ebrake on - seemed fine, but put a/c on, get some shaking.
Car in park, ebrake on with a/c on, car shaking.
So, driving it on city streets and coming to red lights, in drive, foot in brake, that part was fixed. But under load, with a/c on, something is going wrong. I've had 3 mechanics look at this car. One stated it was engine mounts. (That was back in 2015, and since I had just moved, didn't have the chunk of change to change them, plus do work at home, as stated above. Total miles driven since then is only about 500, about 300 of them being last year when I had to do a drive cycle to pass inspection after changing dead battery.)
The 2nd mechanic cleaned the throttle body, changed the engine mounts. We had tried after market engine mounts first, nothing changed, and mechanic said he didn't like how "loose" they were. So we ordered Kia mounts, which cost a bit more, and he seemed satisfied, but the shaking did not go away. He then did a check for vacuum leaks using a smoke machine. He said he found no leaks, and he said because he had already spent so much time on the car trying to find anything in the engine causing this, and could not find anything, he just didn't want to keep working on it.
Third mechanic discovered that there was a leak in a hose, and that the brake booster was "leaking" (not sure what word he used) from the diaphragm. (Or something like that...they mentioned those words "diaphragm" and "leaking" - but it is possible that I'm messing up exactly what they said so if that's incorrect, that's on me, not mechanic.)
As stated, he replaced the brake booster, replaced that air hose that he said he could clearly see "no tools have been anywhere near that clamp in a long time", and they did the spark plugs since the others were bad.
Does it have anything at all to do with the spark plugs? Is it something with the compressor they just changed? Is there something faulty with wiring? Is there somehow some issue with battery and alternator?
When I brought it back to the mechanic, I explained what happened. He wants me to bring the car back on Tuesday to inspect further. I'm just looking for ideas on what it could be. He mentioned something about "selinoid" (however that is spelled, and whatever that is) could be "leaking" or something like that.
Any ideas?
It is totally inconceivable to me that the car needed even 50% of the work that has been done to it.
It's a KIA, it's not like it has a lot of power in the first place. The only thing that I've kind of noticed, off and on, is sometimes there seems to be a very slight hesitation when going from a stop to moving. Very slight, and not all the time - it's only once in awhile.
Quote:
Originally Posted by Don in Austin
It is totally inconceivable to me that the car needed even 50% of the work that has been done to it.
Just looked that up. Also looked up what TPS means.
The engine isn't shaking when I'm going faster than idle. Even if going 30, it doesn't shake, it's only when idle.
Will ask mechanic about both of those. Parts wise, neither is expensive. Labor is another story.
Edit: I forgot to add that when in drive at idle, I hear a chirping noise, but when I put it into neutral or park, the noise immediately goes away. No clue what that is.
I had an early 90's Ford Tempo with a 4 cylinder. It would do the same. Turned out it was the spring loaded belt tensioner on the A/C pulley was getting weak, and was causing the compressor to "surge". The chirp sound you mentioned sounds like a slipping belt at idle.
New compressor, I doubt it is bad, but it may be overcharged some also. I am amazed at how many ASE certified mechanics that work for dealers do not know how to properly charge an MVAC system.
I had an early 90's Ford Tempo with a 4 cylinder. It would do the same. Turned out it was the spring loaded belt tensioner on the A/C pulley was getting weak, and was causing the compressor to "surge". The chirp sound you mentioned sounds like a slipping belt at idle.
New compressor, I doubt it is bad, but it may be overcharged some also. I am amazed at how many ASE certified mechanics that work for dealers do not know how to properly charge an MVAC system.
Hmmm. I'll ask. He said he charged it twice because it wasn't cold enough the first time...maybe you're on to something.
Yeah, over time, I've come to realize that a lot of so called mechanics can't seem to do much other than oil changes.
As for the chirping, yeah, that just started after this repair.
Since all belts were supposedly just changed (minus timing belt, that was either from the 'new' engine so it would only have 30,000 miles on it by now, approximately, or it was new when they installed the 'new' engine because the whole reason I even had to get a new engine is because the timing belt broke). All other belts were said to have been replaced.
When I got the alternator done, they replaced that belt, as well - they did that at no charge to me for reasons - although it was still under warranty, as well. After it was fixed, I heard the belt squeal a couple of times, and when I brought that up, I was told that after driving for a bit, they had to readjust it due to whatever they said. Don't recall ever hearing that before - and I've been in a car (not mine) 2 times when an alternator went out - don't ever remember anyone having to go back to get a belt adjusted. I did ask them to check all belts, all hoses - so I will ask them to do it again, just to make sure.
Quote:
Originally Posted by tickyul
I would check for any remaining vacuum leaks and confirm that the IAC is moving
during idle/off-idle operation.
Well, one mechanic checked for leaks using a smoke machine, which is supposed to be the better way to do it, but he clearly missed one hose that had a leak....will have to ask current mechanic what other hoses he checked.
As for the IAC, I'm wondering if I should just get it replaced if they can't figure anything else out. From what I've read, the IAC valve is supposed to be for the life of the car, but keep in mind that I did live in Maine for awhile. The engine that I got from the 2005 KIA Rio was from Massachusetts, so also a New England car. The crap they put on the roads in winter do a lot of damage to cars. Mine does have rust, and some things have to be changed after 15 years - I'm not sure why some posters are shocked by that - but maybe when they say "life of the car", no one actually expects us to keep a car that long.
Still, I'd rather they double check everything - and I'm really curious about that a/c compressor area because that was one of my first thoughts when taking it on my own test drive after I was told it was fixed.
At least this mechanic is trying. The "i unno" response is what I'm getting from everyone else, and/or they don't even want to spend the time trying to figure it out. I'm not sure why that is. They would get paid, so why don't they want to do the work. Or maybe it's because they don't want to have to say 'i unno' and reveal that they can't figure everything out.
I wish that YouTube mechanic, Scotty Kilmore, lived in this area. I'd just take it to him.
Far be it for me to speak for Don.. But I agree with him.
Sounds like you got someone or someones who loaded up the parts cannon.
I'm not going to weigh in on what I think it is or isn't, because I can't see the vehicle, so I don't know.. I will say pay close attention to what EckyX said, because I was nodding along with his post. I think he's got at the very least, the proper starting point. I think that's a very logical place that a mechanic should start from. Idle is dropping.. Why? Then you test and eliminate/identify the impossible. And whatever remains, no matter how improbable, must be the answer. Then you TEST again to verify the answer. THEN you replace parts.
But, let's look at some of your list..
Bad motor mounts.. If you've put 5k miles on this.. I find it VERY unlikely they went bad in the past 5k miles. Either they were bad when the motor was swapped, or they weren't bad. If it's the former, I'm concerned about who put the replacement motor in.
New A/C Compressor. Why? Was it not blowing cold air? Very concerned about this. If they tried the Compressor to stop the shake.. I'd be pissed. That is not a 'parts cannon' fix. Compressors are VERY expensive. I can forgive someone swapping a $2 light bulb to see if it's bad. I can't see someone swapping a $700+ (And I'm probably being generous here) compressor without knowing that thing is bad.
Battery.. Bad batteries happen, but they're astoundingly rare. What did you notice that would be a bad battery?
New alternator.. Again, why? Was the battery not charging? Did the alternator fail and kill the battery?
IAC and air intake stuff.. No argument on that. If the boot was torn, it needed to be replaced, and cleaning is good even if it's just preventative maintenance.
Drums and bearings.. Again.. Confused about this, unless this is just.. It was time. As I recall, you had pretty high miles on the original engine, so.. This could be normal maintenance, unrelated to the current situation.. and if so. I can see that.
Spark plugs were bad.. Pray tell on this.. If someone swapped the engine.. Plugs would be new.. And even if they weren't, the old engine had 25000 miles. Barely would have had those plugs broken in. This smells. Normally I wouldn't argue this one, but.. The math just doesn't work on this one.. Again, either whoever swapped the engine screwed up or there wasn't anything wrong with the plugs.
Brake Booster.. Sounds like the parts cannon being fired. This COULD have been a cause, but you find out if it IS the cause and replace if it is.. You don't replace it as a guess.
I'm just.. Massively concerned about how many parts have been changed.. And with.. Seemingly no good reason, other than perhaps the mechanics are trying to fix a pain in your ass by lightening your wallet.
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