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Idle lopes when compressor comes on


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jeffj
User

Jul 30, 2013, 10:19 PM

Post #1 of 23 (1663 views)
Idle lopes when compressor comes on Sign In

  
98 Nissan Altima GXE
105,000
The check engine light is not on


The RPM's drop down to 450 to 500 and the engine seems like it is going to stall. It only does this briefly when the compressor kicks on. The RPM's go back up to 750 to 800 a second or to later. What could be causing this issue? I was thinking it could be the Idle Air Control. How can I determine whether it is related to the IAC or something else?

The valve is comprised of a AAC and FICD. Can I test these two components? I have a digital meter. I was planning on cleaning all the components of the IAC first. I'm thinking the FICD might be bad and not increasing the idle when the ac kicks on. If so, can I just purchase the FICD solenoid, or do I have to buy the whole IACV assembly?


(This post was edited by jeffj on Jul 30, 2013, 10:54 PM)


Discretesignals
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Jul 31, 2013, 4:45 AM

Post #2 of 23 (1635 views)
Re: Idle lopes when compressor comes on Sign In

Does it surge any other time besides when you turn on the ac? You could try cleaning the throttle body to see if that helps. Also check for vacuum leaks and cracks in the intake ducting hose.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Jul 31, 2013, 4:47 AM)


Tom Greenleaf
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Jul 31, 2013, 4:56 AM

Post #3 of 23 (1631 views)
Re: Idle lopes when compressor comes on Sign In

Just a thought: Does A/C work properly and no unusual sounds from compressor? It seems to recover but might be suffering from an excessive load from compressor? Anyone mess with the refrigerant charge before this?

T



jeffj
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Jul 31, 2013, 5:29 AM

Post #4 of 23 (1621 views)
Re: Idle lopes when compressor comes on Sign In


In Reply To
Just a thought: Does A/C work properly and no unusual sounds from compressor? It seems to recover but might be suffering from an excessive load from compressor? Anyone mess with the refrigerant charge before this?

I don't think anyone has touched the ac before. The only time the vehicle has been in the shop is for an occasional oil change and to replace the cv axles. I don't hear any weird noises, but that definitely is a possibility.



Tom Greenleaf
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Jul 31, 2013, 10:56 AM

Post #5 of 23 (1604 views)
Re: Idle lopes when compressor comes on Sign In

OK - the thought was that if the engine can't overcome a reasonable load without your symptoms a compressor or even PS pump is a real load. If A/C gets overcharged the compressor is working way too hard up to near stalling and can if excessive - usually something people do that don't know that too much is not going to make it better sort of thing.

Still check integrity of vacuum and intake parts as DS suggested,

T



jeffj
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Jul 31, 2013, 11:56 AM

Post #6 of 23 (1599 views)
Re: Idle lopes when compressor comes on Sign In

 
It only idles rough with the ac.

I cleaned the IACV. I thought it was only going to take 30 minutes, so I figured I would just clean it. That was a mistake. It took me 4 hours to take it off and put it back on. I had to use a mini box wrench to get one of the bolts out. It didn't help at all.

I think I may have some compressor issues. The ac is blows really cold. It makes a slight noise at idle, however. I did here a chirp noise when it cuts on. The belt tension is fine. It looks like it is putting to much of a load on the engine when it starts. I held the engine to 2000 rpm and cycled the compressor and still got a significant drop in rpms. When the compressor cycled on, it appeared to shake. I'm thinking the compressor has mechanical issues. The only other thing I can think of is that liquid slugging is occurring. The TXV would have to be stuck wide open for this to occur. What are your thoughts? I haven't put my gauges on yet. I will do so tomorrow. I ran out of time. I don't want to replace the compressor unless I'm certain it is damaged.


Tom Greenleaf
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Jul 31, 2013, 12:36 PM

Post #7 of 23 (1596 views)
Re: Idle lopes when compressor comes on Sign In

Great to take A/C pressures as if that sucker is working way too hard for whatever reason best to get to that before it explodes. Let us know your temps, at what RPM and the pressures,

T



jeffj
User

Jul 31, 2013, 1:36 PM

Post #8 of 23 (1590 views)
Re: Idle lopes when compressor comes on Sign In

 
If the pressures are normal, do you think it is an mechanical issue (starting the process of seizing)? Do you have any more suggestions for diagnosis?


Tom Greenleaf
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Jul 31, 2013, 2:19 PM

Post #9 of 23 (1589 views)
Re: Idle lopes when compressor comes on Sign In

Still guesswork that compressor is taking up too much force to work. Pressures, noise if belt if chirping are a clue that it might be about to choke/sieze up then it will be a real pest to be certain and worse if that is the reason to wait for it the give out,

T



Hammer Time
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Jul 31, 2013, 2:47 PM

Post #10 of 23 (1584 views)
Re: Idle lopes when compressor comes on Sign In

I seriously doubt this has anything to do with the AC. The system is cold and the compressor is quiet. The idle speed does recover. It just doesn't do it as fast as it should and that is usually a sign of the IAC getting tired or sticking.



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Tom Greenleaf
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Jul 31, 2013, 4:11 PM

Post #11 of 23 (1578 views)
Re: Idle lopes when compressor comes on Sign In

Jury still out without more testing. It only happens with A/C use and it was mentioned it chirps the belt? It's still odd that it recovers, blows cold but would also think it would shut down if pressures were too off. I would think if idle control was totally at fault it would do it with other power robbing events like even parking in a tight spot not mentioned yet that it just can't maintain proper idle except for A/C??

T



Hammer Time
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Jul 31, 2013, 4:14 PM

Post #12 of 23 (1574 views)
Re: Idle lopes when compressor comes on Sign In

There are no other power robbing accessories that apply that much load that instantaneously.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Jul 31, 2013, 4:30 PM

Post #13 of 23 (1569 views)
Re: Idle lopes when compressor comes on Sign In

Its probably chirping the belt because the belt isn't tensioned enough.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jeffj
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Jul 31, 2013, 5:19 PM

Post #14 of 23 (1564 views)
Re: Idle lopes when compressor comes on Sign In

 
The weirdest thing just happened. I removed the key and the engine continued to run for another 5 to 6 seconds. This has never happened before. I have read that this year Nissan had an issue with oil leaking in the distributor and causing erradic idle problems. I wouldn't think it would keep the car running like this though. What could be causing this?




I really do not want to replace the compressor unless I'm sure it is the issue. What type of diagnostics can I do? I tried holding the rpms around 2000 to 2500 rpms and engaging the compressor. The compressor would cause the rpms to drop 500 rpms and stay constant. If I disengage the compressor, the rpms go back up 500 rpms.


jeffj
User

Jul 31, 2013, 6:31 PM

Post #15 of 23 (1559 views)
Re: Idle lopes when compressor comes on Sign In

 
I just tried the same test on my toyota camry. It actually did the opposite. I held the rpms at 2000 and it would go up with the ac on and drop back down to baseline. I'm not sure if it has the same setup, however.


It could be just a faulty FCID solenoid I suppose. I will try to ohm it out tomorrow.


Discretesignals
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Jul 31, 2013, 6:57 PM

Post #16 of 23 (1552 views)
Re: Idle lopes when compressor comes on Sign In

Toyota and Nissan use two different types of idle air control systems for those years. The Toyota uses a rotary air valve and the Nissan uses plunger electromagnetic style.



COMPONENT INSPECTION
IACV-FICD Solenoid Valve
Disconnect IACV-FICD solenoid valve harness connector.

- Check for clicking sound when applying 12 V direct current to terminals.
- Check plunger for seizing or sticking.
- Check for broken spring.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Jul 31, 2013, 7:08 PM)


jeffj
User

Aug 2, 2013, 11:09 AM

Post #17 of 23 (1524 views)
Re: Idle lopes when compressor comes on Sign In

I downloaded the FSM for the vehicle and checked the FICD. It is working properly. I also checked the pressures and the were within range. 30/150. Is there anything else it could be? I was going to replace the compressor, but I am now doubting that is the issue based on the responses in this thread.


frankiedonnn
User

Aug 2, 2013, 11:24 PM

Post #18 of 23 (1507 views)
Re: Idle lopes when compressor comes on Sign In

Vacuum leaks can also cause engine to lope and leaking e.g.r. valve plugged p.c.v. valve.Listen for any hissing and use soapy water spray on manifold and vacuum hoses to spot any vacuum leaks.


Hammer Time
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Aug 3, 2013, 2:57 AM

Post #19 of 23 (1503 views)
Re: Idle lopes when compressor comes on Sign In


Quote
and use soapy water spray on manifold and vacuum hoses to spot any vacuum leaks.


Curious minds want to know. Exactly how does that work?

How does sucking soapy water into the engine show you a leak?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



frankiedonnn
User

Aug 3, 2013, 5:47 AM

Post #20 of 23 (1498 views)
Re: Idle lopes when compressor comes on Sign In

 tyre.

In Reply To

Quote
and use soapy water spray on manifold and vacuum hoses to spot any vacuum leaks.


Curious minds want to know. Exactly how does that work?

How does sucking soapy water into the engine show you a leak? Because it will show up the leak by its bubbling action similar to checking for a puncture in a tyre plus you are listening for hissing at the same time



frankiedonnn
User

Aug 3, 2013, 5:50 AM

Post #21 of 23 (1494 views)
Re: Idle lopes when compressor comes on Sign In


In Reply To
tyre.

In Reply To

Quote
and use soapy water spray on manifold and vacuum hoses to spot any vacuum leaks.


Curious minds want to know. Exactly how does that work?

How does sucking soapy water into the engine show you a leak? Because it will show up the leak by its bubbling action similar to checking for a puncture in a tyre plus you are listening for hissing at the same time.




Hammer Time
Ultimate Carjunky / Moderator
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Aug 3, 2013, 5:58 AM

Post #22 of 23 (1493 views)
Re: Idle lopes when compressor comes on Sign In

You're confusing a pressure leak with a suction leak. You aren't going to see any bubbles from a suction leak, in fact it would work in the opposite and remove bubbles.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jeffj
User

Aug 3, 2013, 6:31 AM

Post #23 of 23 (1489 views)
Re: Idle lopes when compressor comes on Sign In

I thought about spraying carb cleaner on the intake. I know these cars are prone to leaks on the 4th cylinder intake gasket. I would have thought that I would see erratic idling if there was a leak in the manifold or vacuum system. The idle is rock solid until the ac is depressed. I think the fast idle control device helps, but it does not help enough. When I disengage the ac, the idle bumps up by 50 rpms and then returns to normal idle.






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