Ek3 Fluctuating Idle Rpm Issue

[HRV]

Hi,

If you have cleaned the IACV and TB and if its not still better, could you check the following ;

1. Check coolant level. If coolant is up to the correct level, make sure that you remove any air bubbles trapped. Open the radiator tap when its not too hot, put the AC into heater (running full) and run the car on idle until all air bubbles are gone, and then re-fill the reservoir to the correct limit.

2. Take your car to a battery joint, and do a load test and see if your battery is doing well. If the battery is weak (even if its cranking up etc), it may cause rough idle.

If you google about the issue, you could find more information about this.

[prvnrox]

Hi,

If you have cleaned the IACV and TB and if its not still better, could you check the following ;

1. Check coolant level. If coolant is up to the correct level, make sure that you remove any air bubbles trapped. Open the radiator tap when its not too hot, put the AC into heater (running full) and run the car on idle until all air bubbles are gone, and then re-fill the reservoir to the correct limit.

2. Take your car to a battery joint, and do a load test and see if your battery is doing well. If the battery is weak (even if its cranking up etc), it may cause rough idle.

If you google about the issue, you could find more information about this.

thanx bro.I'll definitely try it tomorrow morning!

[prvnrox]

thanx bro.I'll definitely try it tomorrow morning!

[prvnrox]

I tried it.turned the climate control knob into red and kept the engine in start while having the radiator cap open.kept it until the coolant over flow n then closed the cap.but no luck! ;(

[The Don]

If the IACV was not faulty, then the next suspect is the air flow sensor or a vacuum leak. Have you performed a diagnosis on the engine by plugging the car into a diagnostic system?

[prvnrox]

Yes I actually ran a scan at one of the garages near by and also scanned it at the BOSCH service center.no error codes were found.

[The Don]

Yes I actually ran a scan at one of the garages near by and also scanned it at the BOSCH service center.no error codes were found.

You should have taken it to the agent because the Honda diagnostic system should provide more detail plus the mechanics there might have encountered this problem before. I think the issue might be an intermittent fault which can only be diagnosed using a datalogger. If you can source another throttle body temporally with the throttle position sensor and IACV attached it might shed some light on the puzzle.

[prvnrox]

I actually took it to mahesh n Ajith both.tried two throttle bodies too (recon ones). But still the problem persists

[The Don]

I actually took it to mahesh n Ajith both.tried two throttle bodies too (recon ones). But still the problem persists

Did they try another ECU?

[prvnrox]

No.that's the last thing I gotta try.anyways I took it to another mech.so waiting to see the outcome.will keep the thread updated

[The Don]

No.that's the last thing I gotta try.anyways I took it to another mech.so waiting to see the outcome.will keep the thread updated

I had a similar problem with my Mitsubishi and it turned out to be the ECU in the end. It was a combination of old age, inferior quality capacitors. I also discovered that somebody had attempted a repair before. I replaced the ECU and problem was resolved. My issue was rpm fluctuating a lot and no check engine light and diagnostics came back with many error codes.

[kushan]

Hi,

If you have cleaned the IACV and TB and if its not still better, could you check the following ;

1. Check coolant level. If coolant is up to the correct level, make sure that you remove any air bubbles trapped. Open the radiator tap when its not too hot, put the AC into heater (running full) and run the car on idle until all air bubbles are gone, and then re-fill the reservoir to the correct limit.

2. Take your car to a battery joint, and do a load test and see if your battery is doing well. If the battery is weak (even if its cranking up etc), it may cause rough idle.

If you google about the issue, you could find more information about this.

Did you have this issue with your HRV, because I also have this issue sometimes, rpm fluctuates when I slowed/stopped near colour lights or to turn to another road, and the vehicle moves according to the sudden jerks. Did a EFI tuneup with the injector cleaning from BOSCH, their scanner couldnt pick the issue, and also at the test run (because its not happening always).

However RPM does not fluctuate between higher values like 2000 or higher, it was always less than 1000. when fluctuating normally it goes between 600 - 500 roughly.

[The Don]

Did you have this issue with your HRV, because I also have this issue sometimes, rpm fluctuates when I slowed/stopped near colour lights or to turn to another road, and the vehicle moves according to the sudden jerks. Did a EFI tuneup with the injector cleaning from BOSCH, their scanner couldnt pick the issue, and also at the test run (because its not happening always).

However RPM does not fluctuate between higher values like 2000 or higher, it was always less than 1000. when fluctuating normally it goes between 600 - 500 roughly.

Basically its your idle speed that fluctuates. This is controlled by the ECU using the Idle control valve (or IACV) and it takes input from the throttle position sensor, the engine speed sensor, the knock sensor, airflow sensor etc. Basically the entire system is controlled via actuators and vacuum so anything wrong with your vacuum lines or leaks in your throttle body can cause problems like this as well. That is because in idle the butterfly valve on the throttle body is closed and the engine is being supplied air through the IACV.

[kushan]

Basically its your idle speed that fluctuates. This is controlled by the ECU using the Idle control valve (or IACV) and it takes input from the throttle position sensor, the engine speed sensor, the knock sensor, airflow sensor etc. Basically the entire system is controlled via actuators and vacuum so anything wrong with your vacuum lines or leaks in your throttle body can cause problems like this as well. That is because in idle the butterfly valve on the throttle body is closed and the engine is being supplied air through the IACV.

So I have to check the IACV for this matter? or it can be a problem in ECU too right?

[The Don]

So I have to check the IACV for this matter? or it can be a problem in ECU too right?

Thing is this machan, when the diagnostic system itself does not report anything fishy these things become particularly difficult to figure out (though when you do it seems so obvious).

Usually first thing to do is basically take the sensors, throttle body off and clean them well. You need to clean the air flow sensor, throttle position sensor (some vehicles have 2 of these) map sensor (which senses pressure inside the throttle body) and obviously the IACV. In the process you should also verify that all of your vacuum lines are fine as well.

I think you have already done this.

Did you replace your IACV when you tried another throttle body? you should try that as well, and ensure the cavity the IACV settles into is not obstructed and free of carbon or aluminium oxide. Ensure that the IACV is clean as well.

If you've tried everything and the mechanics have run out of ideas, you will have to check the ECU as well. Easiest way to check it is to swap it with known working ECU (easier said that done!).

[HRV]

Kushan,

Sorry for the late reply. Yes m HRV had the same issue, got the TB and IACV cleaned up @ Stafford + fuel system clean up - and it cured it. So far it didn't came up for more than 1 year. Also BTW when you switch off the AC does it become smooth ?

But I have also noted that if there are air bubbles in cooling system, it starts to have an effect with the idle..

If you have already cleaned TB, IACV etc .Disconnect the battery or the fuse (Make sure you have the required security codes etc for Car DVD) , press brake for few seconds, reconnect battery , switch off all accessories, keep the car running at P for few minutes - atleast till the radiator fan cycles 2 times.. - This may smooth out the idle .

Edited July 27, 2012 by HRV

[kushan]

Thing is this machan, when the diagnostic system itself does not report anything fishy these things become particularly difficult to figure out (though when you do it seems so obvious).

Usually first thing to do is basically take the sensors, throttle body off and clean them well. You need to clean the air flow sensor, throttle position sensor (some vehicles have 2 of these) map sensor (which senses pressure inside the throttle body) and obviously the IACV. In the process you should also verify that all of your vacuum lines are fine as well.

I think you have already done this.

Did you replace your IACV when you tried another throttle body? you should try that as well, and ensure the cavity the IACV settles into is not obstructed and free of carbon or aluminium oxide. Ensure that the IACV is clean as well.

If you've tried everything and the mechanics have run out of ideas, you will have to check the ECU as well. Easiest way to check it is to swap it with known working ECU (easier said that done!).

No machan I they havent cleaned those sensors If I can remember correctly, What they did was cleaning the throttle body and the injectors, Will ask them to clean air flow, throttle position sensor and IACV. I have not replaced IACV (actually now only I knows abt this IACV). First I will go with those options and let you know the outcome.Then I will try other options like checking with another TB and ECU, if I have to.

Thanks machan for your ideas..

[kushan]

Kushan,

Sorry for the late reply. Yes m HRV had the same issue, got the TB and IACV cleaned up @ Stafford + fuel system clean up - and it cured it. So far it didn't came up for more than 1 year. Also BTW when you switch off the AC does it become smooth ?

But I have also noted that if there are air bubbles in cooling system, it starts to have an effect with the idle..

If you have already cleaned TB, IACV etc .Disconnect the battery or the fuse (Make sure you have the required security codes etc for Car DVD) , press brake for few seconds, reconnect battery , switch off all accessories, keep the car running at P for few minutes - atleast till the radiator fan cycles 2 times.. - This may smooth out the idle .

No machan, Stafford just cleaned the TB, not the IACV and Fuel system. Next time I will ask them to clean that as well. What you meant by Fuel system cleaning, is it the petrol filter? and will go up with your suggesstions by disconnectine the battery..

Thanks machan, will let you know the result

[MkX]

No machan, Stafford just cleaned the TB, not the IACV and Fuel system. Next time I will ask them to clean that as well. What you meant by Fuel system cleaning, is it the petrol filter? and will go up with your suggesstions by disconnectine the battery..

Thanks machan, will let you know the result

What is the condition of your Airfilter? When you last changed it?

[kushan]

What is the condition of your Airfilter? When you last changed it?

Its still in good condition, changed 3 months ago.

[prvnrox]

as per my knowledge throttle position has a particular angle.so u might as well not remove it.try another TB and see

[The Don]

as per my knowledge throttle position has a particular angle.so u might as well not remove it.try another TB and see

If the angle is set it wont get reset by removing it but you do need to be careful. In some cars it is actually adjustable. You can always mark it before it is removed so you can line it up when installed again.

[prvnrox]

did you get it solved? I did almost all i can do spent more than 100k on the gear box and every thing.only thing which i dint touch is the ECU.fed up now! let me know if any one of you find a solution please.i will post if i happen to do.

[prvnrox]

guys my idle rpm issue is almost solved now.but at times i get it but not as much as i used to get and its not so severe.the problem was the AC condenser.apparently the original AC condenser which comes for the ek3 is not big enough hence the compressor works continuously.this might give bad fuel figures too.i replaced the condenser and everything seems quite ok.relieved!

[The Don]

guys my idle rpm issue is almost solved now.but at times i get it but not as much as i used to get and its not so severe.the problem was the AC condenser.apparently the original AC condenser which comes for the ek3 is not big enough hence the compressor works continuously.this might give bad fuel figures too.i replaced the condenser and everything seems quite ok.relieved!

To be honest I'm a bit baffled by this. When the AC engages, the ECU or the AC Ecu sends a signal to the ICV to increase the RPM. But that should not be different if the AC engages more frequently or less frequently, I mean the idle should remain stable and predictable.