Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 10th August 2009, 10:26   #1
BHPian
 
Join Date: Jul 2008
Location: Chennai
Posts: 274
Thanked: 40 Times
Default Indigo DICOR - Idling issues??

After the third service, I noticed a drop in the FE of my Indigo Dicor from 12.5kmpl to 11.7kmpl

Yesterday I noticed a strange thing - When the vehicle is stand still and clutch pedal pressed down, rpm is close to 1000 mark. This is the case even if the gear is in neutral. However, if I take my foot off clutch pedal with the gear in neutral, rpm drops down closer to 800 mark.

Can this be a reason for the increased Fuel consumption as most of my driving is in peak hour traffic and I have to operate the clutch frequently.
cnaganathan is offline   Reply With Quote
Old 10th August 2009, 17:43   #2
BHPian
 
Join Date: Jul 2008
Location: Chennai
Posts: 274
Thanked: 40 Times
Default Pix attached

Here are the pictures I took. The first one shows rpm with clutch pedal pressed down while the second one is when the clutch is released. Both were shot with gear in neutral.
Attached Thumbnails
Indigo DICOR - Idling issues??-clutchpressed.jpg  

Indigo DICOR - Idling issues??-clutchreleased.jpg  

cnaganathan is offline   Reply With Quote
Old 10th August 2009, 18:03   #3
Senior - BHPian
 
greenhorn's Avatar
 
Join Date: Apr 2007
Location: TN-14
Posts: 6,838
Thanked: 1,318 Times
Default

was the AC on ?

could this be due to the AC/electricals load ?
greenhorn is offline   Reply With Quote
Old 10th August 2009, 18:41   #4
BHPian
 
Join Date: Jul 2008
Location: Chennai
Posts: 274
Thanked: 40 Times
Default

Quote:
Originally Posted by greenhorn View Post
was the AC on ?

could this be due to the AC/electricals load ?
A/C, electricals both were on fully in both cases. I tried both cases (clutch pedal pressed and released) with electricals and A/C switched off too - still the rpm when clutch pedal is pressed was higher than when it is released.
cnaganathan is offline   Reply With Quote
Old 11th August 2009, 10:56   #5
BHPian
 
athalaga's Avatar
 
Join Date: Jul 2009
Location: Bangalore
Posts: 112
Thanked: 17 Times
Default

Quote:
Originally Posted by greenhorn View Post
was the AC on ?

could this be due to the AC/electricals load ?
Exactly my question too greenhorn.

the idle speed must not change if you are in neutral and the clutch is depressed, (the idle speed does increase when the AC is turned on).
Now that you say its not due to the AC I have one more query.
Is this the case everytime you try it or is it just your tacho variability.
athalaga is offline   Reply With Quote
Old 11th August 2009, 15:10   #6
BHPian
 
anky's Avatar
 
Join Date: Apr 2006
Location: Mumbai
Posts: 395
Thanked: 92 Times
Cool Dicor same issues + more

Hi I have an lx dicor ( indigo) 2007 model I to notice the difference when cluth is pressed , I too have noticed the drop in FE to 12.5 and noticed the engine drinks coolant more faster than it should and the engine getting noisier than what it was 1 yr back.Power windows sometimes get stuck ... but on the whole the dicor engine is far better than the tdi and has great pickup and torque...Not trying to make any point just thought I share my expirence too...
anky is offline   Reply With Quote
Old 11th August 2009, 17:35   #7
BHPian
 
Join Date: Jul 2008
Location: Chennai
Posts: 274
Thanked: 40 Times
Default

Quote:
Originally Posted by athalaga View Post
Is this the case everytime you try it or is it just your tacho variability.
This is not tacho variability. I have tried at different times - when the engine is just warm and has run a few minutes, when the engine is hot after a short run and the engine is hot after a long run. It is always like this. And as I mentioned earlier, this is the case only after 3rd service was done.
cnaganathan is offline   Reply With Quote
Old 11th August 2009, 17:52   #8
BHPian
 
im_srini's Avatar
 
Join Date: Sep 2006
Location: Portland
Posts: 956
Thanked: 368 Times
Infractions: 0/1 (5)
Default

Assuming everything else being the same, the only difference would be that in one case you're spinning the gears within the gearbox & in the other, you're not. With the clutch fully depressed the engine's isolated from the transmission, so the only load on it would be the A/C & alternator.

In neutral, with your foot off the clutch, the engine's still spinning the gears inside the gearbox. So the extra drag could be reducing the idling RPM a bit. Maybe you could check if they forgot to fill the gearbox with oil (been known to happen !) in case it was drained for replacement. Before your service, what were the idle RPM like, was it 800 or 1000 ?

In any case, from the pics, the difference appears to be very small...

Last edited by im_srini : 11th August 2009 at 17:56.
im_srini is offline   Reply With Quote
Old 18th September 2009, 10:45   #9
BHPian
 
Join Date: Jul 2008
Location: Chennai
Posts: 274
Thanked: 40 Times
Default Wierd behavior - noticed a new one

Well I noticed a new wierd behavior two days back and verified it again today. Here is how it goes:
- Accelerate car to 60 kmph (4th gear) and then shift to Neutral
- Keep feet off all pedals and let car glide along.
- idle rpm stays close to 1000 (the way it is when idling with clutch pedal pressed)
- As speed drops to below 45kmph, rpm starts rising and when peaks at close to 1250 when speed drops to 35kmph!!
- Thereafter tacho stays close to 1000rpm till the vehicle come to a complete halt - irrespective of whether clutch is pressed or not

Questions:

1. Is this normal behavior? Has someone else observed this in their car too?
2. If this is abnormal what could be the issue - clutch, an ECU sensor or the ECU itself?

Some points to note:
1. Some Clutch components (IIRC - Release bearing and Pressure plate) were replaced FOC under warranty at 8k kms when I complained of a Hard clutch.
2. I do not remember such behavior prior to 3rd service.
3. Switched over to Mobil 1 Synthetic oil during 3rd service
4. Car has run 21k kms in 13 months and is handled by me mostly with an occasional drive by my driver.
5. Most of the run has been in city - peak hour.
cnaganathan is offline   Reply With Quote
Old 18th September 2009, 11:53   #10
Senior - BHPian
 
DerAlte's Avatar
 
Join Date: Mar 2007
Location: Bangalore
Posts: 8,076
Thanked: 2,876 Times
Default

@cnaganathan, you should be a Test Engineer for the auto manufacturers, since you seem to think of Test Cases which they might never have thought about! :

The ECU controlling the injection quantity at any point of time has at least about 20 different conditions to reckon with to calculate the injection quantity. Ironically, it does not know which gear, if at all, has been engaged - though it does know the clutch has been depressed, but not how much. There are conditions where the ECU has to predictively increase the injection to help the driver, like Uphill Start Assist in higher end vehicles. Such behavior is non-intuitive for most users, but normally has a technical basis. Maybe you could measure the RPM when trying to start the car uphill WITHOUT pressing the acc pedal (only on half-clutch)?
DerAlte is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Idling issues in my Fiat Palio Radnam Technical Stuff 25 25th April 2012 09:25
2002 Honda Accord 4 cyl idling issues! aditya.86 Technical Stuff 10 21st June 2011 20:32
Tata Safari Dicor LX 4 X 2 or Safari Dicor EX 4 x 2 Digitalmafia SUVs, MUVs & 4x4s 55 1st June 2009 17:31
Opinion wanted - Dicor VX 4X4 vs Endeavour XLT 4X4...updated Now Booked Dicor VX 4X suman SUVs, MUVs & 4x4s 80 1st April 2009 14:11


All times are GMT +5.5. The time now is 20:52.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks