[Ed]

My Insight was involved in an accident earlier this year and had parts of the air conditioning system replaced. It’s just started getting hot enough to use the air con in anger now and I’m experiencing an annoying problem that I never had before the accident.

When the air con is switched on you’ll feel it heavily load the engine for a few seconds then let go. This continues over and over again. On the open road this makes it really difficult to maintain a constant speed and ruins fuel economy. At slow speed it causes the car to jerk forward really quite badly when the load comes off. This happens when the system is set on full Auto and also Econ.

I’ve had the bonnet up with the engine and air con running, and basically the compressor and the fan cycles on and off, as it did before the accident, but it’s now accompanied by a kind of whirring sound like something’s under a lot of load.

I want to get the garage that fixed the car up to put this right, but it would really help if I had an idea of what might be causing it. My knowledge of how these systems work is pretty non-existent, so if anyone has any ideas of what’s causing this I would be really grateful to hear them. Thanks.

 

[Holicow]

My first guess would be a bad bearing in the compressor. This could cause the extra friction and power loss you describe. If it is, it will make itself known before long.

Did they put in a new compressor?

 

[Ed]

I don't think so, it dosen't look new. The bloke at the garage said I 'bent the air conditioning like a banana', but I assume he just meant the condensor.

 

[Holicow]

From what you describe, there is friction when the compressor cycles on. The bearing (or possibly some other internal compressor failure) is about the only thing I can think of that could cause that. When it is "off" the clutch disengages the compressor.

If the high pressure line was bent and obstructed, I wonder if that could cause an extra high load on the compressor? I think it deserves an inspection.

 

[Insightful Trekker]

Like Holicow stated it sounds like the compressor is causing an abnormal load. A pressure test would be indicated unless the "noise" you are experiencing leads in another direction (which is impossible to determine via a NG).

On overcharge condition (too much refrigerant in the AC system)can also cause high pressures and an abnormally high air conditioner load on the engine.

HTH!

 

[Willie Williford]

You might also check the AC belt tensioner adjustment and the tensioner bearing.

I've seen (body shop) mechanics "over tighten" serpentine belts numerous times.

I'm going under the assumption the repair work was done at a "body shop" and not a mechanical repair shop.

 

[Ed]

Thanks for the advice everyone. The car's going in for a service next week so I'll get them to check it out.

Willie - yep the work was done by a bodyshop, although they had to take it to the local Honda dealer to finish of the air conditioning (I think this was just to refill it with gas). They've done a really nice job on the bodywork, but I'm not too sure about the under bonnet stuff as I've also had problems with air in the radiator.

 

[Holicow]

Be sure to let us know what they find!

 

[Willie Williford]

You might also be aware that "most" air conditioner compressors put roughly a 20 percent load on the ICE.

At low rpm that problem is more signicant than at higher rpm where the ICE is produceing more power.

(Verified with an OBD tool monitoring (% load on engine vs RPM, vs Speed)

 

[Ed]

Willie - 20%, wow that's a lot more than I thought. I could feel the load on the engine during hot days last year, but it wasn't cycling on and off like it is now. As you say it's a lot more apparent when driving slowly.

Interestingly I didn't have the music on this morning and found the loading of the engine is accompanied by a kind of sucking noise through the air vents. Very odd!

 

[Armin]

leaks

Have them check the refrigerant system for leaks. I don't know if the load you feel is normal, but the fast cycling on/off is definitely not! This can be caused by loss of refrigerant. Maybe they didn't fill the system right when they fixed it, or maybe they missed a slow leak...

Good Luck!

 

[counselorkv]

I was in an accident and the same thing happened to me.....

I took it in to my trusty honda mechanic and he fixed it FREE, I think he just loves my insight and I give him business with my other hondas....

It was OVERCHARGED beyond belief!!! He said I could have ruined the compressor if I had run it any longer.

It works great now.... He just recharged it to the proper amount for the insight.

Don't let them talk you into a whole lot of repairs!!

 

[Jim]

ac noise

Hi Ed,

usually if there isn't a lot of ambient noise around, you can the refrigerant moving through a sealed system. Central air, window units, refrigerators, cars - almost all of them have some sound associated with the refrigerant. I didn't check the manual to see what the high side pressure is, but I wouldn't be surprised if it's somewhere in the 250 to 350 psi range. Well, the Insight does have scroll compressor... Guess I should check - but I wouldn't be too concerned about the "sucking noise".

The short cycle definitely indicates a problem.

Hope your dealer gets it straightened out.

 

[Ed]

The car’s now been into the garage and they’ve identified that there’s a problem (well at first they said there wasn’t, but I asked them to look again).

They’ve said that their best guess is that the ECU isn’t raising the engine revs, power or whatever when the air conditioning goes on, hence the feeling of power loss. They also say that it won’t be a gas leak as the air con simply wouldn’t operate. The car’s therefore staying in the garage for another day so they can run a test on the electrics.

Does this sound right to you folks? The car’s just in warranty, however I’m a bit worried that they’re going to find ‘nothing warrantable’ wrong with the car and slap me with some rather high (£70 an hour, or about $100) labour charges for the test.

After insurance excesses, services and MoTs the little car’s proving a right drain on my wallet at the moment, still with rising fuel prices I guess I shouldn’t complain!

 

[Holicow]

They’ve said that their best guess is that the ECU isn’t raising the engine revs, power or whatever when the air conditioning goes on, hence the feeling of power loss.

Thanks for the update!

There should be a signal to adjust the idle speed when the compressor turns on, but this is only at idle (throttle closed) as far as I know. It should not adjust anything at any other time, other than idle, and then just to keep the engine from possibly stalling. While moving, your foot does the adjustment since power to the wheels is less.


I am not convinced.

Of course, I could be wrong.

 

[Calpod]

My car does the same thing, when I come to a stop and the air is on, the engine starts shaking a lot, it has never stalled, but it feels as if it's going to come out of the engine compartment. The reason I didn't notice this before is I just to do freeway driving and I'd use the AC only at freeway speed.
It does not bother me now because I got used to having the AC off, and only using it while coasting.

At 100K miles I'm out of warranty

Anybody else with this problem?

 

[Ed]

Well the garage has run the electrical test and can't find any problem. They've now been advised by Honda technical support to start taking parts out of the car and testing them, so it's staying in for another couple of days. Maybe it's a bad compressor like some of you thought.

This reminds me of my old car which used to spend days on end in the garage trying to chase a water leak, or 'optional foot spa' as a friend put it. :roll:

 

[Holicow]

Thanks for the update...

That explanation didn't sound quite right, so I guess I'm not surprised.

Sorry you are having a protracted incovenience. Just remember, it's not the car's fault it was damaged. :wink:

 

[Ed]

The problem has now been diagnosed as a slow gas leak from one of the pipes connected to the condenser, which was damaged in the accident but hasn’t been picked up during repairs.

Apparently the level of gas had fallen to the point where the car couldn’t make up its mind whether to keep the air con on or not, hence the cycling on and off I felt. The garage has filled it back up with gas and I’m now trying to get my insurance company to stump up for the repair cost, as it should have been fixed when the car was repaired.

Thanks for all the advice everyone. And good point Holicow, although the accident was actually caused by um…. an elk on a blind bend slick with oil whilst I was dazzled by err…. Venus.