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Old 3rd April 2010, 08:27   #1
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Default Santro Mileage woes

Hi People

Recently i got my Santro (2007, 24 k on odometer) serviced. During servicing, i got the oil change, cleaned the spark plugs and yes cleaned the throttle body with spray. But the fuel efficiency has gone drastically down.

Just wanted to clarify, is that because of the carbon which was removed from throttle body as i understand to certain extent carbon in engine helps to gives better fuel efficiency??

Inputs will be appreciated

Thanks
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Old 3rd April 2010, 11:24   #2
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This drop in mileage is definitely due to the throttle body cleaning with spray. it is advised to dismantle and clean the throttle body. This is done by the A.S.S on request and labor charges are extra.

UM
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Old 7th January 2011, 15:35   #3
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Default Mileage drop on my santro

I raised this earlier on a new thread to have specific discussion about the problem (undectable so far) we have in our Santro. Unfortunately that thread got deleted so raising on this thread. Please go through the details below and let your suggestions come in. Many thanks in advance.

Some history:
We have a Jan 2005 Santro with 131k km's on the ODO. Car is used in Punjab and we have open roads with very less traffic signals and jams. So till about 115k km's we were getting a mileage of 18/19 w/o AC. Then the power steering pump of the car started creating whining sound and we got the pump bearings+seal+oil changed. This was done at the local mechanic as HASS wanted to change the entire PS unit. Apart from this, we have never had any component failure in the car. It's serviced regularly at HASS in Chandigarh. Engine oil, filters, gear oil etc has always been changed as per schedule.

Problem:
At about the time the steering pump bearings were changed, mileage in the car reduced to 14/15 from earlier 18/19

Work Done So far:
After detecting the drop in mileage, at about 122k km's I got the following things done:

1. A major service. Engine oil, oil filter, air filter, fuel filter, gear oil, spark plugs, coolant, brake fluid etc were changed. Injectors and throttle body was cleaned. TB was opened and cleaned.
2. Since the car was on original clutch at 122k km, got the clutch changed. Again due to open roads of punjab, original clutch lasted this much.
3. Doing the above did not solve the problem, so went to HASS and got the engine scan done with OBD. This did not detect any problems whatsoever. All sensors are working fine and according to them, everything is okay

After all this the car is still on 14/15 mileage. Driving the car does not give any clue of any problem whatsoever. There is no loss of pick-up, no jerks, no missing, new clutch seems to be okay. Infact driving it gives the feeling that it's almost a new car with no problem at all. That's the reason we don't want to sell it but use for another couple of years. It's in perfect shape mechanically and otherwise. Also we have not done any mods to the car, it's on stock size tyres.

So we are not able to detect the reason for drop in FE. And it was a sudden drop not gradual which can be associated with the age of vehicle. We have another Santro in family which returns a mileage of 18/19 in similar conditions.

There are two wrong symptoms though which might help lead to the issue.

1. If the car is started on a clean floor, I can see soot coming from car's exhaust. It's not pure carbon, but black water. I checked it on hand, it's water, not petrol or engine oil. But then coolant level in car does not drop, neither does oil level. So where is this water coming from?
2. The engine oil of the car is turning black more quickly than it should in a petrol car. After oil change, within 2k km's it's brown and in 5k km's it black. It's not normal for a petrol car.

But I am not sure what these problems mean so need advice on what to check/ fix. I know this is a long shot but as a next step I intend to the following:

1. Do a compression test. This may not lead to anything as the pick-up seems okay.
2. Get head gasket checked. What are the exact symptoms that it might be bad?
3. Get Tappet adjustment checked. HASS folks at the time of engine scan said that this does not need to be checked as if bad, tappets will create sound. So they did not check on it. Can this be the issue for low FE?

Will the above help, other than this, I do not have any idea of what to do. Can there be a possible timing problem (like off by nano seconds)? My local very reliable mechanic tells me that changing PS bearings can not have this much drop in FE. Even if it's tight (let's say heavy to move) it will have very little impact on FE. Wheel alignmet, balancing etc is also done recently. Driving car does not tell that anything is wrong just that it's expensive to run (and more polluting as well).

Please let your suggestions come in on what could be the possible causes of this and what should I do?

Last edited by amit1234singla : 7th January 2011 at 15:39.
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Old 8th January 2011, 17:51   #4
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Default Re: Mileage drop on my santro

In continuation of the above post and after reading through clutch wear thread this morning, I decided to check if the new clutch is slipping and resulting in lower FE. I took the car to an open road and came to a stand still. Slotted in 3rd gear and released the clutch slowly with minimal revs. Car stalled. I did it again but now with moderate revs, again car stalled. Third time but now with decent revs, again car stalled. Then applied the handbrake firmly and tried to move the car in 1st gear with moderate revs, car did not stall but it dragged ahead with rear wheels locked.

I think with the above, the new clutch is fine and is not slipping. Am I reading it right? This was just to rule out the remote possibility of clutch slipping. Also, I think with the car dragging ahead in handbrake mode and rear wheels locked tells me that engine is generating enough power. I will still do it but I think compression test may not tell anything.

Lastly, I observed closely today on the road that many petrol cars have water drops coming out of exhaust. I think that's due to the winters. Cold air touching hot exhaust resulting and air moisture getting converted into water (might be wrong on the logic). May be that's normal in my car as well?

I am myself ruling out the possibilities of what's wrong!

Last edited by amit1234singla : 8th January 2011 at 17:58. Reason: spelling error
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Old 8th January 2011, 19:11   #5
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Default Re: Santro Mileage woes

Did the engine oil start changing colour faster after the major work carried out? If you are using mineral engine oil, try switching to a semi-synthetic or a fully synthetic oil. Also try replacing the engine oil after 2-3K instead of waiting for the normal 10K interval. If it's the carbon deposits in the engine which are now loosened, a frequent oil change may help get some of that sludge out of the engine.
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Old 8th January 2011, 20:11   #6
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Default Re: Santro Mileage woes

Quote:
Originally Posted by honeybee View Post
Did the engine oil start changing colour faster after the major work carried out? If you are using mineral engine oil, try switching to a semi-synthetic or a fully synthetic oil. Also try replacing the engine oil after 2-3K instead of waiting for the normal 10K interval. If it's the carbon deposits in the engine which are now loosened, a frequent oil change may help get some of that sludge out of the engine.
Can't say if the engine oil started changing colour faster after the major service was carried out as the car is used by my dad in Punjab and I live in Noida. I did not check the oil condition on earlier oil changes. Till 122k km's car was on mineral oil (Servo filled by HASS). I changed to castrol megnatec on 122k km's major service. FE drop happened at about 115k km's. If the issue can be due to carbon deposits would going for a decarbonization help? It was last done at 100k km's. Also I don't know if decoke and engine flush at this stage would be recommended (131k km's).
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Old 8th January 2011, 23:20   #7
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Default Re: Santro Mileage woes

131k kms, your car fared very well for you. But after it crosses 1lac kms lot of things need to be done.
1. clutch, it lasted more than 1lac kms, thats news to me.
2. Head job. Valve clearances.
3. Timming belt, a must.


PS: rev the car hard after it has attained an ideal temperature. If you see whitish smoke coming, a major overhaul is underway.
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Old 9th January 2011, 10:03   #8
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Default Re: Santro Mileage woes

Quote:
Originally Posted by SirAlec View Post
131k kms, your car fared very well for you. But after it crosses 1lac kms lot of things need to be done.
1. clutch, it lasted more than 1lac kms, thats news to me.
2. Head job. Valve clearances.
3. Timming belt, a must.


PS: rev the car hard after it has attained an ideal temperature. If you see whitish smoke coming, a major overhaul is underway.
Thanks. Clutch has already been changed at 122k km. Timing belt was changed at 80k km as per Hyundai schedule. There no whitish smoke at high revs, infact it's blackish, which I think is normal. Can you detail a little bit more on what all a head job will involve? Will it be like opening the head, change piston rings etc. But if the compression is good, will it still be required? I am yet to go for compression test though.
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Old 9th January 2011, 12:58   #9
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Default Re: Santro Mileage woes

Hi Amit

Perhaps the answer to woes with regards to the low mileage is Air Filter. The correct Air Filter Santro Xing which is imported and Black in color.

A$$ Hyundai people are foolish and normally they fit the Orange color air filter. No doubt that air filter gives you excellent pick up BUT drop in mileage. This Black air filter is correct one. Also this Black color air filter is Not avaliable in aftermarket can be only procurred from the Hyundai A$$. The black filter costs Rs350.0 where as the orange color cost Rs 150.0.

Amit
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Old 9th January 2011, 17:13   #10
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Default Re: Santro Mileage woes

Quote:
Originally Posted by amitpunjani View Post
Hi Amit

Perhaps the answer to woes with regards to the low mileage is Air Filter. The correct Air Filter Santro Xing which is imported and Black in color.
....
Amit
Thanks for your suggestion but I don't think this could be the case. For one, an aftermarket vs OE airfilter can not have a FE difference of 4-5 kmpl (assuming after market is also of a good brand like Purolater or Elf). We also have another Santro in family which is on same airfilter as this one and we get a mileage of about 18/19. Thanks again and please let the suggestions coming.
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Old 9th January 2011, 19:00   #11
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Default Re: Santro Mileage woes

Quote:
Originally Posted by amit1234singla View Post
...please let the suggestions coming.
Do the following step-by-step, checking after each step whether mileage improves:
  1. Start with fresh engine oil if the current engine oil is not clean. Use an API-SF (or max. SG) specification mineral oil of 20W-50 or 15W-50 grade, or at worst, 20 or 15W-40. Do not use semi-synthetic or synthetic oils with higher specs like SH or SJ of lower viscosity like 10W-40 or 5W-40 etc. Change air & oil filters at same time;
  2. With the engine warmed up completely to operating temperature, check for smoke coming out from the oil filler cap when you open it, or from the dipstick tube when you remove the dipstick. If there is smoke, you need engine work. If no smoke, then...
  3. Change all spark plugs and plug leads (wires);
  4. Clean fuel tank and change petrol filter;
  5. Use an additive like System-G @1ml/litre for one tankful, then 0.5-0.7ml/litre for the next tankful;
  6. If no improvement upto step 5, use an engine flush to clean out the engine, then re-fill with fresh engine oil as specified in step #1.
Would suggest you stick to the same petrol station from where you have filled earlier and got good mileage. Do not try out any other pump, since fuel quality would play an important role in reducing mileage.

Let's hear about whether mileage improves, once you've done the above.
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Old 10th January 2011, 10:25   #12
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Default Re: Santro Mileage woes

Quote:
Originally Posted by SS-Traveller View Post
Do the following step-by-step, checking after each step whether mileage improves:
  1. Start with fresh engine oil if the current engine oil is not clean. Use an API-SF (or max. SG) specification mineral oil of 20W-50 or 15W-50 grade, or at worst, 20 or 15W-40. Do not use semi-synthetic or synthetic oils with higher specs like SH or SJ of lower viscosity like 10W-40 or 5W-40 etc. Change air & oil filters at same time;
  2. With the engine warmed up completely to operating temperature, check for smoke coming out from the oil filler cap when you open it, or from the dipstick tube when you remove the dipstick. If there is smoke, you need engine work. If no smoke, then...
  3. Change all spark plugs and plug leads (wires);
  4. Clean fuel tank and change petrol filter;
  5. Use an additive like System-G @1ml/litre for one tankful, then 0.5-0.7ml/litre for the next tankful;
  6. If no improvement upto step 5, use an engine flush to clean out the engine, then re-fill with fresh engine oil as specified in step #1.
Would suggest you stick to the same petrol station from where you have filled earlier and got good mileage. Do not try out any other pump, since fuel quality would play an important role in reducing mileage.

Let's hear about whether mileage improves, once you've done the above.
Thank you SS-Traveller, let me try the above. Oil and filter change is anyway due now, so as suggested I will go for normal mineral oil of specified grade. Will do these step by step while monitoring the mileage. Might take about 2 weeks to do this all one by one. Thanks again.
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Old 30th August 2014, 08:46   #13
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Default Re: Santro Mileage woes

Bumping up an old thread.

Was planning to replace air filter on my Santro Xing. However, since regular Purolator brand air filter was not available at local spares shop, the owner suggested ZIP brand of air filter.

Does anyone have an idea about ZIP brand of air filters?
Apologies for the low quality picture as it was clicked at the shop with my phone camera.
Santro Mileage woes-img_0288.jpg


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