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I have 2001 nissan altima auto,4 cyl ,85k and the idle is at 1400-1300 rpm during startup, it goes down to 1100-1200 rpm after warmup,,normally it should be in 800-750 rpm,, i cleaned the idle air control valve and adjust the idle screw and also i replaced PVC valve but no changes,,,any suggestion is greatly appreciated,thanks
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[quote=”Boyet” post=155296]I have 2001 nissan altima auto,4 cyl ,85k and the idle is at 1400-1300 rpm during startup, it goes down to 1100-1200 rpm after warmup,,normally it should be in 800-750 rpm,, i cleaned the idle air control valve and adjust the idle screw and also i replaced PVC valve but no changes,,,any suggestion is greatly appreciated,thanks
Is there a idle learner procedure on this car to makes the rpm down to specification ? I heard its apply to 2002 and up model only
Might suggest ..
1) Clean the MAF sensor with the proper solvent
2) Clean the throttle body, with the proper cleaner
3) Reset the Mixture Ratio Self – Learning Control
Following the steps below …
A ) Start engine and warm it up to normal operating temperature.
B ) Turn ignition switch OFF.
C ) Disconnect mass air flow sensor harness connector, and restart and run engine for at least 3 seconds at idle speed.
D ) Stop engine and reconnect mass air flow sensor harness connector.
E ) Make sure Detected Trouble Code (DTC) P0102 is displayed.
F ) Erase the DTC memory. (This could be done by disconnecting the car battery for 12 – 24 hours or with a scanner)
G ) Make sure no codes are stored in the ECM.
H ) Run engine for at least 10 minutes at idle speed. If you disconnect the battery in step 4 below, you may omit this step H4) Disconnect your negative battery terminal for 12 – 24 hours
5) After reconnecting the battery ..
A ) Start the engine and allow it to come to operating temp.
B ) Drive the vehicle ( highway driving ) for at least 25 miles in order for the ECU to relearn.Thanks for the quick response, can i erase the code by using obd2 scanner instead of disconnecting the battery and do i need to drive the 25 miles continuously without shutting the engine off for this procedure? Thx
Yes, you can clear the codes by using a scan tool.
I always do a full reset ( MAF and ECU ) twice a year once in winter and then for summer.
Start and warm up the car, then go for a nice drive
The learning procedure is best done by a continuous drive at varying speeds for 20 – 25 miles.
This allows the computer time to relearn and remap the mixture ratios.Ok,let me clarify myself… If i follow the procedure from 1 to H and using scanner tool to clear the code,,,do i need to proceed number 4 (disconnect the battery for 12 hrs) after? thanks again
Ok,let me clarify myself… If i follow the procedure from 1 to H and using scanner tool to clear the code,,,do i need to proceed number 4 (disconnect the battery for 12 hrs) after? thanks again
No, but considering your going through the motions to reset the MAF Mixture Ratio, it would seem logical to reset the ECU and have a clean relearn process.
I have never tried it without doing a ECU reset, so I can only assume according to the instructions it can be done the way your asking.[quote=”Boyet” post=155546]Nope , no engine code, this high rpm started when The car is only 45 k miles 8 yrs ago, now it’s 88k[/quote]
Well, as I was taught start with the simplest and move from there.
I would inspect the idle cam and see if, when the motor is at operating temp, the cam is at its lowest point in its travel.
It may be binding or a faulty connection.
It may be the Idle Control Valve holding it back.Follow the throttle cable to where it attaches to the throttle body linkage.
Having a tough time finding an illustration..
Hope this works for you.I saw the middle leverage moved slightly from cold start to warmup, can I adjust the screw (with the red arrow) ,to see if the idle goes down? also btw I got p0420 engine code , this came out suddenly(not sure if because I cleaned the idle air control valve?) thx
(the upstream o2 sensor maybe the culprit? still original part 88K miles) thank you
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