Engine RPM changes

ABHAY SARMANDAL

MEMBER
2006 HONDA CITY
1.5L
4 CYL
2WD
AUTOMATIC
60,000 MILES

I have the car listed above it is the CVT model. When car is "N" engine speed keeps on fluctuations from 900 to 2000 rpm without A/C, same happens with A/C and also while driving. Engine scan does not show any error. They have cleaned throttle body, 10 % improvement only. If one applies the brakes fluctuations starts immediately. Unable to diagnose issue.

Please help thanks

9 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

This sounds more like a MAF problem. When the sensor wires gets dirty is will give the computer a false reading but not enough to create a trouble code. I would try cleaning the sensor first and if that does not work you will need to replace it. Diagram (below).

https://www.2carpros.com/articles/mass-air-flow-service

and

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

I would check the engine for vacuum leaks as well.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please let us know what happens so it will help others.

Cheers, Ken

Image (Click to make bigger)

SPONSORED LINKS

Was this

answer

helpful?

Yes

Tuesday, September 12th, 2017 AT 12:30 PM

ABHAY SARMANDAL

MEMBER
5 POSTS

Thanks, I had given my car to honda service center, they did scan but no errors, they removed throttle body and cleaned, problem remains, they are saying issues is with CVT gear box which needs to be overhauled and cost is Rs 60000 which is quite expensive, unable to understand role of CVT in engine ideale speed. When you brake car rpm shoots up

Was this

answer

helpful?

Yes

Tuesday, September 12th, 2017 AT 8:00 PM

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

Yes that can do it becasue the transmission grabs and releases I hear those CVT transmission are problems and it explains the idle fluctuation.

Please let us know what happens so it will help others.

Cheers, Ken

Was this

answer

helpful?

Yes

Wednesday, September 13th, 2017 AT 10:57 AM

ABHAY SARMANDAL

MEMBER
5 POSTS

I visited honda sc, they informed me that they have cleaned TB as well as iacv (removed and cleaned) I have driven car for 15 km and did not had any issue as per them issue will appear only when engine heats up, I need to monitor, report indicated suspect TB and CVT.

Was this

answer

helpful?

Yes

Thursday, September 14th, 2017 AT 4:31 PM

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

Please let us know what happens after you pick it up

Cheers, Ken

SPONSORED LINKS

Was this

answer

helpful?

Yes

Friday, September 15th, 2017 AT 2:07 PM

ABHAY SARMANDAL

MEMBER
5 POSTS

Dear Ken,
Meantime is it possible to know what are components in CVT box, how do they control engine speed, if some diagram, connection etc will be helpfull. No one is able to give clean answer, eg there are varios modeds such as D, N, S, L when is in L engine speed is very low and overrides acceleration coming down the hill thanks

Was this

answer

helpful?

Yes

Friday, September 15th, 2017 AT 5:41 PM

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

I wanted to ask you is the speedometer working? The manual is talking about a speed sensor which would effect the transmission.

Was this

answer

helpful?

Yes

Saturday, September 16th, 2017 AT 2:47 PM

ABHAY SARMANDAL

MEMBER
5 POSTS

Speedometer is working perfectly find, I went to local mechanic he does not find any issue I am now in fix whether to sale or keep it whole idea of keeping car was that it is in excellent condition and I drive 150 km per month. New cars are very expensive and running cost such as insurance etc is exorbitant, I think there is honda tech group who have got information on honda cars honda sc indicated that it is failing in CVT stall test but details not given

Honda sc is saying that they have done CVT stall test and it is failing but details are not given

Was this

answer

helpful?

Yes

Saturday, September 16th, 2017 AT 5:21 PM

KEN L