Nissan Fb 14 Engine Run High

[chathuu]

Hi Guys..

Im new to this,

i have trouble in my Nissan FB14 cos the engine runs fast at idle mode.

RPM indecates 2000-3000 @ idle. (RPM meter working)

when driving it does 8-10Kmpl (Avg).

Seems it would be better fuel consumtion.

What is the reason or is it normal..?

[Uditha88]

Check n clean IACV Valve.

Get MAF sensor & throttle body checked.

8-10 is normal based on Driving condition, Driving style and lot more factors.

But idle speed in neutral is not normal.

[The Don]

  On 9/9/2014 at 3:52 PM, chathuu said:

Hi Guys..

Im new to this,

i have trouble in my Nissan FB14 cos the engine runs fast at idle mode.

RPM indecates 2000-3000 @ idle. (RPM meter working)

when driving it does 8-10Kmpl (Avg).

Seems it would be better fuel consumtion.

What is the reason or is it normal..?

Does the engine settle at around 750-1000 after the initial fast idle mode?

[Rumesh88]

@Chathuu

If I may extend The Don's point above, please note the idle speed when you start the car in the morning (cold start) without AC on. Then note the idle speed when the engine reach its working temperature (ie temperature gauge in the mid range) again without AC. Also note the idle RPM value in your current ECO certificate and revert back with your readings.

[chathuu]

tnx guys for your opinions. i will try those.

[chathuu]

  On 9/10/2014 at 9:09 AM, The Don said:

Does the engine settle at around 750-1000 after the initial fast idle mode?

@ The Don

Its not settle down.

[Sierra Charlie]

  On 9/12/2014 at 6:52 AM, chathuu said:

@ The Don

Its not settle down.

Think you should get it looked over by a specialist. There are well reputed specialists that won't cost you an arm and a leg. I too feel that it's something to do with the IAC valve since I too have the same issues. Like you, I didn't know what's wrong until I had someone have a look.

[The Don]

  On 9/12/2014 at 6:52 AM, chathuu said:

@ The Don

Its not settle down.

Like some have said the issue could be a number of things. The following is not an exhaustive list.

1. MAF sensor

2. The idle controller

3. Vaccume leak

4. Throttle body carboned out and the butterfly valve not closing properly

5. ECU

First thing to do is to clean the throttle body, clean the sensors in question, reset the ECU and run for a few days and check if the problem resolves itself. If your mechanic has a scanner, scan for errors as well.

[chathuu]

  On 9/12/2014 at 4:40 PM, The Don said:

Like some have said the issue could be a number of things. The following is not an exhaustive list.

1. MAF sensor

2. The idle controller

3. Vaccume leak

4. Throttle body carboned out and the butterfly valve not closing properly

5. ECU

First thing to do is to clean the throttle body, clean the sensors in question, reset the ECU and run for a few days and check if the problem resolves itself. If your mechanic has a scanner, scan for errors as well.

Thanx lot..

[The Stig]

What I find weird is that your fuel consumption is normal for this car. But if it runs at 2-3000 rpm always the consumption should be much lower.

It could be a faulty tachometer, you never know. Try using an external tachometer and see if the rpm readings are accurate.

Edited September 15, 2014 by The Stig

[The Don]

  On 9/15/2014 at 3:44 AM, The Stig said:

What I find weird is that your fuel consumption is normal for this car. But if it runs at 2-3000 rpm always the consumption should be much lower.

It could be a faulty tachometer, you never know. Try using an external tachometer and see if the rpm readings are accurate.

Stig, 2-3000 rpm is when idle. As soon as the car starts moving it becomes irrelevant and comes down because of the load on the engine. This is called an idle surge.