# Engine idle speed Up and Down :¬



## jacm82 (Jul 23, 2016)

Hello !

This is my first posting on your message board. I bought my X-Trail 2011 SE AWD mechanics last week. 

With a warm start , the engine idle speed seems to start normally, & then suddenly goes up to 2.0 and down to 1.5, up to 2.0 and down to 1.5, up to 2.0 and down to 1.5 all day that long. 

what are your toughs

cheers from Chile


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## jacm82 (Jul 23, 2016)

Hello all, 

i try today the followings videos:

1. clean throttle body https://www.youtube.com/watch?v=XrcaDh4xDLs
2. Nissan Reset ECU in cabin no battery disconnect https://www.youtube.com/watch?v=B48cGRuya9k

and guest what??? got so clean that now is goes up to 3.0 and down to 1.5, goes up to 3.0 and down to 1.5, goes up to 3.0 and down to 1.5 all day long!!!

hope someone can help me

cheers from Chile

Jose Campos


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## molly (Oct 31, 2014)

Mine goes way down to almost nothing when I first start it, and then goes up to a normal range. But only when I start it, not when I am driving...Has done that from when I first bought it. I was hoping those new cam and crankshaft sensors may have changed that, but I guess not.
I hope someone can help you!


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## quadraria10 (Jul 6, 2010)

Hi Molly,
Thats a bit of a weird one. Throttle body cleaning, or of Mass Air Flow sensor may help. Try using a tank of premium gas. It might clean the injectors which could be the problem. Also how many kms on your present spark plugs. The original platinum plugs were rated for 160,000 kms. Replacement iridium plugs should be changed at 60,000 kms. Copper plugs should be replaced even more frequently. Its easy to check them, and if you look at any analysis chart you can tell something about the state of your engine and ignition.
Last thought, how old is your battery, or could it be a problem with your starter?


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## otomodo (May 23, 2008)

Premium gas has more octane only and octane prevents detonation.
High compressed engines use premium for that,regular gas explodes prematurely under abnormal pressure.

Maybe it has a leak between air filter and throttle body and MAF sensor can t operate normally.

envoyé du throne en grimaçant kclmop


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## quadraria10 (Jul 6, 2010)

My engine has never complained, and basically its the same as using a fuel system cleaner. Gives it an extra amount of pep every now and then. 
I was thinking a leak to, but its only on startup she said. But should be checked out.


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## molly (Oct 31, 2014)

Hey, thanks, guys! I don't know that I have had the plugs replaced since I bought it at 286K. It is coming up to 342K and due for another oil change anyway, so I maybe should get some new ones?? If so, what kind should he put in? No one ever seems to say anything about it, i.e. my mechanic, or even the Nissan dealer, however...Plus Nissan checked everything back at the end of April in their inspection, so it shouldn't be the starter... Battery looks older but my mechanic said it was still OK last time I asked.


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## quadraria10 (Jul 6, 2010)

Get these NGKs

NGK 4469 {#LFR5AIX11} Iridium IX

I got them off RockAuto, also available on Amazon or any Canadian Tire or NAPA store. They are great in the x trail.

You could do this yourself. Only requires a 10mm socket , a ratchet with an extension and sparkplug socket. No strength required everything should be hand tight.


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## molly (Oct 31, 2014)

Thanks, Quad! I'll let you know if anything changes...


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## otomodo (May 23, 2008)

As i always do before get the plugs out,a big blast of compressed air into the plugs sockets before taking it out.
With a cold engine ,i take the coils out and snap all the plugs. Sometimes there is a crust between the plug base and the block and unscrewing an 1/8 of a turn will break it.

With an old engine carbon will build inside and compression ratio will change.
That is why more octane in gas will make your(older) car run smoothly.
Why high mileage oil available for old cars?
Less detergent to clean the carbon build 


envoyé du throne en grimaçant kclmop


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## chadn (Jan 28, 2010)

molly said:


> Mine goes way down to almost nothing when I first start it, and then goes up to a normal range. But only when I start it, not when I am driving...Has done that from when I first bought it. I was hoping those new cam and crankshaft sensors may have changed that, but I guess not.
> I hope someone can help you!


Mine does this exact thing on occasion. Usually when about 1/2 warm. It starts fine, revs up to 2,000 or so, drops to 300 then back to 750. It doesn't do this when cold (stays at high RPM) or when fully warm. 

I'm not worried at all. I think it's just the air intake closing a bit too much right after starting when the engine isn't fully warm. 

There is an idle airflow relearn procedure that may help. It's a bit of a pain to do though.


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## Yeet (10 mo ago)

molly said:


> Thanks, Quad! I'll let you know if anything changes...


What did you do to solve the problem 6 years ago lol ? Got the same trouble and can't find how to fix it


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## rogoman (Dec 16, 2004)

jacm82 said:


> Hello all,
> 
> i try today the followings videos:
> 
> ...


There's is a procedure called the "Idle Air Volume Learning" which is a function of ECU to learn the idle air volume that keeps the engine idle speed within the specific range. It must be performed under any of the following conditions:
• Each time the electric throttle control actuator or ECU is replaced.
• Idle speed or ignition timing is out of specification.

Disconnect the negative battery terminal for 30 seconds to reset the onboard computer. Do not perform the relearn if the service engine soon light (CEL) is on and codes related to the mass airflow sensor, manifold absolute pressure, or incorrect idle speed are found. If everything is in order, we can begin.

First, bring the engine to normal operating temperature, 160-203°F or 70-95°C. Next turn off all accessories such as the air conditioning, rear window defogger, radio, and heater blower to prevent a load on the engine which would cause erroneous positioning of the throttle plate. Finally, make sure the front wheels of the vehicle are in the neutral position pointing straight ahead. We are now ready to perform the required relearn procedures:
----------------------------------------------------------------------------------

ACCELERATOR PEDAL RELEASED POSITION LEARNING 

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

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THROTTLE VALVE CLOSED POSITION LEARNING 

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

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IDLE AIR VOLUME LEARNING

CONDITIONS: Check Engine Light (CEL) with P0507 trouble code and high/pulsating idle, after disconnecting and reconnecting electrical to throttle position controller such as when cleaning throttle body.










TOOLS NEEDED: stopwatch or timer showing seconds.

1. When engine COLD, first perform the Accelerator Released Position and then the Throttle Valve Closed Position procedure as shown above.
2. Warm up engine at this point. Drive on the road for not less than 10 minutes; warming up the car in the garage doesn’t cut it! 
3. Put the car in Park, turn off all electrical powered stuff, wheels turned straight.
4. Turn key OFF and wait at least 10 seconds.
5. Turn key ON (not ignition) and start stopwatch at same time.
6. When stopwatch is at 3 seconds, press & release accelerator pedal 5 times fully and quickly within 5 seconds.
7. Wait 7 seconds or more and fully press the accelerator pedal and hold for approximately 20 seconds until the check engine light stops blinking and constantly stays on.
(note: If the CEL never starts blinking, then something is not working and you'd better start over again).
8. Within 3 seconds after the check engine light stays constantly on, release the accelerator pedal.
9. Immediately start the engine and let it idle. It may still likely be a high-rev/pulsating idle.
10. Let it run for about 20 seconds, then rev the engine a few times.
11. With foot on brake, shift into Drive. Idle should now go down under 1000 rpm. Shift to Park again, and the car should find its regular idle speed. Operation will be normal except CEL may still be on. It may disappear soon on its own, or you can do the following:

-----------------------------------------------------------------------------------

EASY RESET OF CHECK ENGINE LIGHT (CEL)

1. Turn key OFF and wait at least 10 seconds
2. Turn key ON (no ignition), wait 3 seconds, then press & release accelerator 5x hard and quickly.
3. Wait 10 seconds, then fully press accelerator.
4. After about 12 seconds CEL will go off then start blinking. As soon as it starts blinking, release the accelerator.
5. Wait 10 seconds, then fully press accelerator again.
6. Wait 10 seconds, then release the accelerator again.
7. Turn the key to off, then immediately start the engine. The CEL should be gone now.


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## Yeet (10 mo ago)

rogoman said:


> There's is a procedure called the "Idle Air Volume Learning" which is a function of ECU to learn the idle air volume that keeps the engine idle speed within the specific range. It must be performed under any of the following conditions:
> • Each time the electric throttle control actuator or ECU is replaced.
> • Idle speed or ignition timing is out of specification.
> 
> ...


Hi, I just tried everything that you sent twice but it did not work. I have the p0507 and my engine is pulsating from 1k to 2k rpm everytime I'm on Park and sometimes hesitates when on gear when the engine is hot. Do you have any idea how I could fix this damn issue?


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## VStar650CL (Nov 12, 2020)

Yeet said:


> Hi, I just tried everything that you sent twice but it did not work. I have the p0507 and my engine is pulsating from 1k to 2k rpm everytime I'm on Park and sometimes hesitates when on gear when the engine is hot. Do you have any idea how I could fix this damn issue?


Out of 1,922 fixes for P0507 in the archives of Identifix, almost 90% (over 1,700) were resolved by IAVL- or CTPL-related procedures. The remainder were all dirty/bad Throttle Bodies and a few bad ECM's. So it's very unlikely your problem is anything more than a calibration issue.

When you say "didn't work," I'm assuming you mean the IAVL didn't execute. There are two general bulletins about that. First, sometimes IAVL will not complete because of a MAF issue. This can be addressed by disconnecting the MAF for 10~15 seconds until the ECM throws a P0102 or P010C. This forces the ECM to stop using the MAF and allows recalibration to complete. If the engine is running too fast, this will also cause IAVL to abort without completing. On engines where either the injectors or coils can be reached, disconnect one (injectors are preferred if reachable). The "dead miss" will drop the idle speed and allow the procedure to finish. In both cases, just clear out the resulting codes when done.


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## Yeet (10 mo ago)

How do you know if the IAVL completed? Cause I did everything in all the procedures but in the end, nothing changed


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## Yeet (10 mo ago)

VStar650CL said:


> Out of 1,922 fixes for P0507 in the archives of Identifix, almost 90% (over 1,700) were resolved by IAVL- or CTPL-related procedures. The remainder were all dirty/bad Throttle Bodies and a few bad ECM's. So it's very unlikely your problem is anything more than a calibration issue.
> 
> When you say "didn't work," I'm assuming you mean the IAVL didn't execute. There are two general bulletins about that. First, sometimes IAVL will not complete because of a MAF issue. This can be addressed by disconnecting the MAF for 10~15 seconds until the ECM throws a P0102 or P010C. This forces the ECM to stop using the MAF and allows recalibration to complete. If the engine is running too fast, this will also cause IAVL to abort without completing. On engines where either the injectors or coils can be reached, disconnect one (injectors are preferred if reachable). The "dead miss" will drop the idle speed and allow the procedure to finish. In both cases, just clear out the resulting codes when done.


In the VQ35HR I have two mafs, and when I try to disconnect one my rpms still go up and down but faster. Should I just disconnect both even if the engine is "running fast (pulsating)"? Should I disconnect them while the car is running?


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## VStar650CL (Nov 12, 2020)

Yeet said:


> How do you know if the IAVL completed? Cause I did everything in all the procedures but in the end, nothing changed


Usually you'll get a noticeable dip in speed right before it completes, then a normal idle afterward. The advantage to doing it with work support on a scanner is that you can see whether it completed or not. One thing that wasn't mentioned above is that the tranny must be warm and not just the engine. You need to either drive it or do a low-grade torque converter stall to get the tranny warmed up, just sitting at idle won't do it.



Yeet said:


> Should I just disconnect both even if the engine is "running fast (pulsating)"? Should I disconnect them while the car is running?


The bulletin recommends just yanking one, but do whatever you need to do to bring the speed below 1K. Yes, it needs to be done with the engine running and kept disconnected until the ECM throws a "flatline" code for that MAF. The presence of the DTC is what should stabilize the idle. If a loose MAF doesn't do it, you may need to yank a couple of cylinders. If that kills the engine instead of stabilizing it, I'd say look into your Throttle Bodies. For the most part, that's the only other major cause of P0507.


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## Yeet (10 mo ago)

VStar650CL said:


> Usually you'll get a noticeable dip in speed right before it completes, then a normal idle afterward. The advantage to doing it with work support on a scanner is that you can see whether it completed or not. One thing that wasn't mentioned above is that the tranny must be warm and not just the engine. You need to either drive it or do a low-grade torque converter stall to get the tranny warmed up, just sitting at idle won't do it.
> 
> 
> 
> The bulletin recommends just yanking one, but do whatever you need to do to bring the speed below 1K. Yes, it needs to be done with the engine running and kept disconnected until the ECM throws a "flatline" code for that MAF. The presence of the DTC is what should stabilize the idle. If a loose MAF doesn't do it, you may need to yank a couple of cylinders. If that kills the engine instead of stabilizing it, I'd say look into your Throttle Bodies. For the most part, that's the only other major cause of P0507.


My injectors are not accessible since I have to remove the two throttle bodies and the air intake to be able to disconnect them. And when I disconnect one of the mafs, the ups and downs just go faster and it never goes under 1k rpm. Should I disconnect the coil packs instead after disconnecting one of the mafs? Should I be doing all this after the IAVL procedure?


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## VStar650CL (Nov 12, 2020)

No, you need to get the idle down in order to do the IAVL. The high idle is what prevents it from completing, but of course the MAF has to be hooked back up in order to do it. Making the MAF throw a code is supposed to reduce the RPM's, but if that isn't working, then like I said, do whatever you need to in order to get it below 1K. The IAVL will never take until you can reduce the R's with the MAF's still hooked up.


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## Yeet (10 mo ago)

VStar650CL said:


> No, you need to get the idle down in order to do the IAVL. The high idle is what prevents it from completing, but of course the MAF has to be hooked back up in order to do it. Making the MAF throw a code is supposed to reduce the RPM's, but if that isn't working, then like I said, do whatever you need to in order to get it below 1K. The IAVL will never take until you can reduce the R's with the MAF's still hooked up.


Its not dangerous disconnecting the coils while the engine is running? I'm afraid it could cause a voltage spike and blow the coil or the pcm...


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## VStar650CL (Nov 12, 2020)

No, it won't cause voltage spikes. You pull the connector off the coil, not the coil off the spark plug. If you do it for very long you could flood the disconnected cylinders or heat up the catalytic converters. That's why injectors are preferable if you can reach them. So with coils, do it for as little time as possible and then get them reconnected.


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## Yeet (10 mo ago)

VStar650CL said:


> No, it won't cause voltage spikes. You pull the connector off the coil, not the coil off the spark plug. If you do it for very long you could flood the disconnected cylinders or heat up the catalytic converters. That's why injectors are preferable if you can reach them. So with coils, do it for as little time as possible and then get them reconnected.


So just to make sure I understand everything, I need to perform the Accelerator Released Position and then the Throttle Valve Closed Position and then when its time to do the IAVL procedure, I need to drive the car for 10mins, then do the tingy with the pedal and the CEL, start the car when CEL stopped flashing, and instantly disconnect one of the mafs and some coils till the rpms decrease so the the IAVL can complete. Is that right? I just wanna make sure I do everything in the right order, so if you could explain with a little ''step by step'' comment that would be awesome! Btw thank you so much for all your reponses, really appreciated


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## VStar650CL (Nov 12, 2020)

Yeet said:


> Accelerator Released Position and then the Throttle Valve Closed Position


Those won't change, if you already did them earlier then there's no need to re-do them.



Yeet said:


> and instantly disconnect one of the mafs and some coils till the rpms decrease so the the IAVL can complete. Is that right?


No, if you already disconnected the MAF's and it didn't bring the idle down, then just hook them back up and forget about them. Just initiate the IAVL, then pull coils till you're below 1K. That's why this is _much_ easier to do with a scanner, because you can get the idle dropped first and then put it into IAVL learn mode with the press of a button. The manual procedure is very difficult to do when your engine is misbehaving, and there's no good way to know if it completed properly. If you have a Droid phone, you'll be entirely better off getting a copy of Torque Pro for $5 and an ELM327 adaptor for $15 and using the work support. If you have Apple there are other packages, I don't own one so I won't make suggestions. The point is, you're doing a lot of unnecessary tail-chasing trying to save $20..


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