To Clean Or Replace IACV (Update)

[zach7685]

Seeking advice as to replace of clean IACV

[Towncivilian]

What prompted you to ask this question?

I would remove the IACV and clean it thoroughly with throttle body cleaner and replace any O-rings when reinstalling.

[zach7685]

Need my car and shop said that's what it was. went out on Thursday and it wouldn't start.

[zach7685]

Ok i got my car back but it seems to keep forgetting the iv-ac programming

[Towncivilian]

Did you try idle air volume learning? EC-58

[zach7685]

yes

[Towncivilian]

Is it performed successfully, but then must be performed again after restarting the engine? That makes me wonder if a fuse is blown somewhere that supplies power to the ECU when the engine is off.

[Mikey178]

Quick question on the iacv, where is this located under the hood? I've had the code consistently and have not noticed any performance issues but if there is a way of cleaning it, I would like to try that first. Thanks in advance.

[Towncivilian]

It is located below the throttle body. It is a cylindrical blue or black component secured by two Philips screws. Be sure to remove the negative battery terminal before disconnecting its wiring harness, and replace any O-rings while the part is removed. Use throttle body cleaner spray only.

Mine has 139k miles and I have not had a need to clean it yet. My idle is perfect.

[zach7685]

I Recommend cleaning it.

[zach7685]

Ok after replacing the IVAC 3 times 2 aftermarket one OEM it idles fine. Currently it has an aftermarket metal part and OEM electronics. In the mornings the car will start and die within 2 seconds. If i rev it to 3K rpm for 4 -8 seconds it will drop low then idle normal. No codes No light. ideas?

[Towncivilian]

You're really having trouble with this idle, huh?

Fuel filter recent? No vacuum leaks? Throttle body plate clean (both sides)? Idle air relearn successfully performed?

[zach7685]

Yes Yes Yes I'm Losing my mind They think ECU but i have no other issues and they pulled it and said it looked fine

[Bluewulf73]

Hey zach7685,

I've been having irregular idle and stalling issues with my Pathy (98 LE) once it warms up. None of the stalls have ever caused a CEL to come on so I'been at my wits' end for a while.

The IACV is located under the upper intake manifold. To check it and clean it properly you would need to remove the manifold.

I did so because I was experiencing stalling issues. So I followed the recommendations to clean the MAF the Throttle Body (TB).

After cleaning the MAF, nothing changed so I cleaned the TB and it made things worse. The vehicle idled very high (1500 RPM) and would not return to normal. So I tried the re-learn procedure. It would not take. I continued my research and concluded that the next thing to check/clean would be the IACV. I took a day and with a buddy's help, we were able to remove the upper intake manifold and check the IACV and its solenoid.

It appeared to be working fine (When powered, the solenoid moved) so I cleaned it and lubed the spring and adjustment port.(there is an air-flow adjustment screw on it, make sure you DO NOT MOVE IT) My buddy was able to help me screw everything (vacuum tubes, etc) back onto the manifold but then I had to put everything else back on my own, resulting on it becoming a full 8-hour day job. The hardest part was making sure all the hoses went back on properly. One ( 3", 90 degree elbow under the EGR valve) took me a whole 30 minutes to wrestle onto both nipples, sheesh...

While I had the manifold off, I changed the plugs (easier that way) and re-tightened my valve covers(the Phillips screws holding them on to the head were only finger tight). After everything was back together, I tested the car and nothing changed except for the car running a bit smoother thank s to the new plugs. The high idle was still there, the stalling was still there...oi!

So, I decided to take it to Nissan to have them give it a full inspection and try to ascertain the problem with the idle. Nissan inspected it and told me that there were several issues with the car but the important one would be fixed by replacing the IACV solenoid. They pretty much promised my wife (we were thinking of givin' up on our Pathy and replacing it ) the issue would be fixed with the solenoid replacement) so we had NIssan work on all the problems found. (Solenoid, rear links, belt replacements, etc., to the tune of $4000.00 CAD)

After changing the IACV, they told me that the car would still not take on the re-learn procedure so they would investigate further. A week later, they re-cleaned the TB and MAF, finally had the IACV take on the re-learn procedure but could not get the car to stop stalling when warm.

I told them that I read on a forum the issue might be caused by a faulty PCM. They then said if that is the case, it would be an expensive fix. They think it could be the TP sensor (black and blue sensor affixed to the TB, facing the front of the car) Apparently that too is an expensive part.

They put a call into Nissan Canada for guidance and still could not come up with the answer or fix so they asked me to drive it and monitor to see it if continued to happen. I am currently driving it and it has happened four times since the car left the shop. I've driven it approximately 150 km and it still stalls intermittently, while idling at red-lights, etc.

I will be taking the car back to them this Wednesday and asking them to fix it without us putting more money into it.

Reasoning behind this is that my wife asked them if the solenoid replacement guaranteed this issue would be fixed. The service-man said yes, hence why we put the $4000 into the truck. Don't think we can get away from it since I don't see that guarantee on paper.

Anyway, I hope you don't have to go through what I am, but unfortunately, I have read about a couple of very expensive yet unresolved cases involving the IACV and stalling issues on R50 Pathy's.

Juan

[GRNMACHINE]

Any updates? Sorry to hear

[zach7685]

None here.
Though I haven't tried anything

[Bluewulf73]

Any updates? Sorry to hear

Pathy is still at the Nissan shop. Since the AICV change did not fix issue entirely, they have told us they're going to try changing the TPS, free of charge installation, only purchasing the part. If nothing changes, the part is free as well.


I think that if nothing changes, and there are no safety issues with running it as is, I'll run it to the ground. If safety issues exist, wife'll want to get a new car (slushbox Versa or CVT Sentra ) She refuses to learn to drive a manual.

I have to say, even facing the prospect of losing out Pathy to some electronic gremlin , the Nissan in Richmond, BC has been phenomenal in trying to figure this out, with excellent customer service. So, a big thanks to them.


Lets hope this fixes it. The next thing to try is over $1200.00 CAD so it if don't, it could spell the end for our beloved Pathy.

Juan

[zach7685]

http://www.youtube.com/watch?v=IEoz0VhonB8 Here it my issue. Now it wont always start even after a just being driven. In the video im turning the ac on and off. The car randomly skips at idle and sometimes misses while driving. Only light on is for the iacv which I replaced. Iv also had the shop relearn the air volume.

[Bluewulf73]

Hey zach7685,

Sorry to see what's happening. The idle always changes when the A/C compressor turs on or the fans kick in. It was difficult to understand what was happening, other than when you started the car and it immediately stalled.

From what I understand, it takes about 50km for the car to properly re-learn the Air-fuel mixtures and can still have trouble for a few km's after the AICV has been changed. If you've already changed the IACV, take it to whomever changed it and have them check the engine over for a vacuum line they might have forgotten to replace, etc. Also, check your plugs, wires and cap/rotor. If any of these have not been replaced for a long time or were removed at any time recently, they might not be back on properly.

In my case, changing the IACV didn't fix everything. So, they told me it was the TPS (throttle position sensor) a $110.00 part. I agreed to them changing it if they paid for the labour AND the part if it did not fix the issue. As I mentioned the next part would be $1200.00. Nnuh-uh!

A while later and the issue has come back. I have noticed, however that it is most prominent around 20km after I refuel which leads me to believe my issue might be a clogged fuel filter and/or pump. (I don't hear any bump whine or any weird noises)

I didn't and still don't get any codes when the Pathy stalls. (never got a code for the IACV, TPS, MAF, or anything else - well expect for the one caused by running the car without the MAF)

I have a filter, now to research pumps. I will get these changed along with my dead suspension soon and will report back once it is done.

[zach7685]

FIXED! Found my problem, Two cracks in intake elbow. The second crack was only visible after removing the whole tube. Symptoms were stalling after starting and poor acceleration ivac lights and coil packs going bad.
check out these videos. My Fix for the time being was silicone.

Rev no load http://youtu.be/Ul30UhAZClI


Rev with car in drive (Parking Brake on) http://youtu.be/zm5GeU5KuEU Ps is this too much flex?


Rev after silicone in drive (Parking Brake on) http://youtu.be/5wtuvmCKYjo

[zach7685]

Bluewulf73 Just saw you post Thanks for the info