Current Sonic Issues... idle and AC problems

[countrydrivin05]

Well I have been waiting to post on here but I am running out of ideas and the response of "its normal" is getting old. So here is what's going on and if anyone has had the same issue and it has been resolved I would love to know what you did.

Summary... I am having a problem with a rough idle while in "D" sitting at stop lights. As soon as you pop it into "N" it is smooth as silk. Having the AC on makes it much worse while in "D"

What has been done so far... First off I had a transmission fluid leak where my 2 of the seals on the trans were needing to be replaced. So that was major surgery because they had to separate it from the engine. Apparently they could not replicate the rough idle. But they did update my ECM to the latest verson which didn't change anything that I could tell.

On my 2nd trip for some AC work and my chrome interior door handle coming apart, they said my AC was only charged to .77lbs and a proper charge is 1.1lbs so they evacuated the system and recharged to proper amount... so not only does it cool really well now but I can feel every engagement and disengagement of the compressor clutch and sometimes it is rough... I have never felt the AC engage on any GM product I have ever driven. It still short cycles on and off every 5 seconds while driving with or without the recirc on and it was 83 and muggy today and it was quite annoying to drive with the AC on.

My mechanic found that my battery sensor was disconnected and was setting a code in my BCM... he reconnected it and cleared the code... but that has helped some but the idle is still rough and very rough with the AC on.

Oh and on a side note... to have the plastic chrome on the interior door handle replaced... they have to special order the entire interior door panel... you cannot just replace the handle so I am waiting for that to come in and be put on.

So before I go back... is there anything else I can look for or try? I don't know what else to do besides have them ride with me and go from there.

Right now I have just under 15K on the vehicle and it seems to be getting worse with age.

 

[lambertsonic]

Every car I have driven with a small displacement engine acted up like you described, when the Ac was on . This is exactly why I bought my sonic without Ac .

 

[countrydrivin05]

Update...

With STL's crazy weather I noticed yesterday when it was only 45'F out that I do not have a rough idle while in "D" with or without the AC on. It is only when we get into the low 80's and above is when I have the problem which was the case 2 days ago.

 

[Bogus]

No that idle issues is not normal. I have driven both 1.4T and 1.8L. These cars should have a smooth idle A/C on or off.

One thing you could do is check your spark plug gap. Since you have the 1.4 set them between 0.024 - 0.028. Over or under can cause problems.

 

[ChrisJ]

I notice my compressor cycling even going down the road depending on the conditions but I've never seen it cause a rough idle. It may cause it to be slightly rougher than when the compressor is not engaged but its not enough to matter.

One thing I'm curious about is you say they claimed it was only charged with 0.77kg so they evacuated it and charged it with 1kg. My problem with this is I don't believe there is anyway they could have measured the amount of refrigerant in the system before evacuating it.


The reason many may notice the AC in the Sonic more than some other GMs is it uses a fixed displacement compressor which means it may cycle on and off except for on hotter days. I don't know why GM chose this compressor over a variable displacement model other than I believe its a physically smaller and may be more efficient pump than the variable models. I mentioned the Sonic having a variable displacement compressor in another thread, this is incorrect.

No matter how you look at it, running a pump which can consume as much as 7 or 8HP off of a tiny little 1.4L or even a 1.8L engine will be noticeable when it engages and disengages.

 

[Bogus]

That all makes sense, but in my personal experience driving both engines with A/C on, I hardly even noticed the compressor kicking on unless I really paid attention for it.

 

[ChrisJ]

That all makes sense, but in my personal experience driving both engines with A/C on, I hardly even noticed the compressor kicking on unless I really paid attention for it.

I pay attention to everything.
Trust me, it kinda sucks (paying attention to everything).

 

[countrydrivin05]

Bogus... I know that all my spark-plugs are gapped at .028... I checked them last summer when I was having the same problems.

ChrisJ... The way they knew .77lbs was my initial AC charge was that is how much they were able to recover by evacuating the system.

If I am only having the rough idle when its warm/hot mainly during the summer, could I have a weak/bad coilpack? The reason why I bring this up is I know that my friend had a Beretta with a 3.1L V6 that because of where the coilpack was mounted on the engine when it got too hot it had the same issues. I know ours on the 1.4L is mounted right under the engine cover and its one piece... I wonder if it gets heatsoaked and has issues when its 80+ outside. When its that temp. outside it really gets bad right after getting off the highway sitting at stoplights on exit ramps and also during city traffic.

 

[ChrisJ]

Bogus... I know that all my spark-plugs are gapped at .028... I checked them last summer when I was having the same problems.

ChrisJ... The way they knew .77kg was my initial AC charge was that is how much they were able to recover by evacuating the system.

If I am only having the rough idle when its warm/hot mainly during the summer, could I have a weak/bad coilpack? The reason why I bring this up is I know that my friend had a Beretta with a 3.1L V6 that because of where the coilpack was mounted on the engine when it got too hot it had the same issues. I know ours on the 1.4L is mounted right under the engine cover and its one piece... I wonder if it gets heatsoaked and has issues when its 80+ outside. When its that temp. outside it really gets bad right after getting off the highway sitting at stoplights on exit ramps and also during city traffic.

That works for me then, but why did they evacuate it in the first place? Poor cooling performance? I'm assuming the rough idle is a totally separate issue?


Just make sure you use recirculate when its 80F or above, this greatly reduces the load on the system. I didn't beleive it my self until I experimented a few years ago and watched my highside pressure skyrocket on a 95F day when I turned recirculate off. This was on a different vehicle but it doesn't matter, same rules apply.

I'm not really sure what to think about the rough idle. What other details can you give, like is it when stuck in traffic for a long time, or when cruising or doesn't matter? Do you have a modified intake where the aircleaner is exposed to the engine compartment? Are you running a tune? Does it matter if its humid or dry out?

There are a lot of really smart people on this forum and I'm willing to bet if you give them enough details they can help.

 

[RS Turbo]

My problem with this is I don't believe there is anyway they could have measured the amount of refrigerant in the system before evacuating it.

Yes the Refrigerant is measured after removal in the recovery machine.... It is a recovery and recharge station. This has been used in the dealers for the last 15 years.

 

[countrydrivin05]

ChrisJ... No my AC was constantly cycling on and off every 5 seconds no matter what the temp outside was and regardless of recirc on or off.

The rough idle issue is somewhat separate but gets worse with the AC on.

 

[ChrisJ]

Yes the Refrigerant is measured after removal in the recovery machine.... It is a recovery and recharge station. This has been used in the dealers for the last 15 years.

Kind of a segue but do these machines also show how much oil if any has been removed? That was always my biggest issue was deciding on if I needed to add oil back in or not and how much.

Many don't realize how much of an exact science this stuff is, especially people who think the single gauge refill cans you can buy at the parts store are ok to use.

 

[ChrisJ]

ChrisJ... No my AC was constantly cycling on and off every 5 seconds no matter what the temp outside was and regardless of recirc on or off.

The rough idle issue is somewhat separate but gets worse with the AC on.

I'm curious, when this was going on did it throw any kind of warning light? Some 1990s GMs would throw a warning and disable the A\C if it detected excessive cycling.

 

[Bogus]

Where I used to live a couple months back it got over 100 degrees every day in the warm seasons and I never noticed this issue. Not that I can even attempt to diagnose your problem, just that it's not normal.

 

[countrydrivin05]

Nope ChrisJ... just was getting annoying because I could feel it every single time turning on and off so I was thinking it was either over/under filled and my hunch was right.

 

[Cinsue]

Summary... I am having a problem with a rough idle while in "D" sitting at stop lights. As soon as you pop it into "N" it is smooth as silk. Having the AC on makes it much worse while in "D"

I have the same issue with the rough idle.

It's so bad that I always shift into N at stop signs. This happens all year round and doesn't matter if the AC is on or not.

 

[RS Turbo]

Kind of a segue but do these machines also show how much oil if any has been removed? That was always my biggest issue was deciding on if I needed to add oil back in or not and how much.

Many don't realize how much of an exact science this stuff is, especially people who think the single gauge refill cans you can buy at the parts store are ok to use.

There is an Oil drain on it and usually it is checked after every recovery. Most of the time there is very little oil in this process. Oil is only recovered from replaced componants and then added back after measured. If a large enough leak that shows oil on parts most techs will add an additional 1/4 oz.

Remember there has to be a dramatic amount of addition oil to be a problem. Oil usually ends up everywhere but will pool mostly in the Dryer.

 

[Bogus]

I have the same issue with the rough idle.

It's so bad that I always shift into N at stop signs. This happens all year round and doesn't matter if the AC is on or not.

Wow that sounds bad. My idle is always smooth A/C on or off, hot or cold weather, hot or cold engine.

 

[ChrisJ]

Wow that sounds bad. My idle is always smooth A/C on or off, hot or cold weather, hot or cold engine.

I think they get it that its not normal.
They need a solution now.

 

[Bogus]

Got it. Just giving comparison so they don't continue driving around like that and do something about it.