[DDiSLover]

Originally Posted by a4anurag

Fill-in 1-2 psi more than recommended cold tyre pressures (Found on the drivers side door). I fill in F=33psi and R=31psi i.e. warm tyre pressures.

I know controlling one self on a DDiS engine is difficult but it HAS to happen if FE is important. Do get the MAF checked and update.

Anurag.

Originally Posted by csateesh

The rear tyre pressure is 31psi as I found 32 and above to be bouncy especially on the "tall" speed bumps.

Here's what I do - Fill 34 and 32 which is warm tyre pressue and the same evening or subsequent morning I reduce it 33 and 31 using something like this

The one I use though is a slightly better one

Hope this helps to solve your problem

Hey guys,

I'll try keeping the rear wheels at 32psi warm and see how it turns out.

Thanks a lot for all the effort you guys are putting in to help me out! Really appreciate it!

[humyum]

Originally Posted by a4anurag

I don't know whether it is correct or no but why don't you try plugging another Swift's (same model as yours) ECU and drive around. Even after so much trial FE is not improving then may the brain of the car isn't working. May Be! Just a thought.

Anurag.

It's not really that easy to do that. The Key fob is programmed with the ECU because of the immobilizer, U ll need to reprogram that with the new ECU, the injectors are keyed in with the old ECU, with a changed one, U ll need to reprogram this too. If the ECU is faulty, there ll be an error code, if not, changing it just won't help.

[a4anurag]

Originally Posted by humyum

It's not really that easy to do that. The Key fob is programmed with the ECU because of the immobilizer, U ll need to reprogram that with the new ECU, the injectors are keyed in with the old ECU, with a changed one, U ll need to reprogram this too. If the ECU is faulty, there ll be an error code, if not, changing it just won't help.

So much work Oops! Thanks for enlightening me sir.

Where could the problem lie then? Even after so much R&D, FE doesn't increase.

Anurag.

[humyum]

Originally Posted by a4anurag

So much work Oops! Thanks for enlightening me sir.

Where could the problem lie then? Even after so much R&D, FE doesn't increase.

Anurag.

No problem Anurag, I somehow have doubts on many things in his car, Clutch, tyre pressure, a stuck brake pad somewhere or wheel bearing which is on its last legs, a bad wheel alignment and if not all of this, I would somehow doubt the driving style ( Hey no offence, I am not a perfect driver myself).

I somehow simply cannot fathom a DDIS giving 13 kmpl, I mean, in my drive it like you stole it runs too I have never ever got anything less than 16. If I was in Bangalore, I would have test driven his car and exactly told him the problem, but sigh, since I am here, I ll have to rely on his descriptions.

[a4anurag]

Originally Posted by humyum

I somehow simply cannot fathom a DDIS giving 13 kmpl, I mean, in my drive it like you stole it runs too I have never ever got anything less than 16.

+1.

13 kmpl on a DDiS is like crazy-ness. Even if the car is redlined also it would give 13 kmpl but the owner won't do it so the problem had to be something related to the car that is not getting detected.

Anurag.

[DDiSLover]

Originally Posted by humyum

No problem Anurag, I somehow have doubts on many things in his car, Clutch, tyre pressure, a stuck brake pad somewhere or wheel bearing which is on its last legs, a bad wheel alignment and if not all of this, I would somehow doubt the driving style ( Hey no offence, I am not a perfect driver myself).

I somehow simply cannot fathom a DDIS giving 13 kmpl, I mean, in my drive it like you stole it runs too I have never ever got anything less than 16. If I was in Bangalore, I would have test driven his car and exactly told him the problem, but sigh, since I am here, I ll have to rely on his descriptions.

Originally Posted by a4anurag

+1.

13 kmpl on a DDiS is like crazy-ness. Even if the car is redlined also it would give 13 kmpl but the owner won't do it so the problem had to be something related to the car that is not getting detected.

Anurag.

Hey guys,

I don't red-line my car at all these days. There was a time about 4-5 years ago, when I just got my license, when I used to red-line! Now I have become a much more soft driver. I hardly push my car above 2k rpm, barring a few overtakes (even then, I shift at around 2.5k, at most 3k!) Like you said, there seems to be something else wrong somewhere. I have been trying to figure out the issue for a long time now and I am running out of ideas.

Tyre pressures are in check, I can assure you about that.
I got the Clutch overhauled at around 70k kms (if I remember correctly). Could you give me some symptoms of a bad clutch?

How can I check if a brake pad is stuck or if the wheel bearing is nearing its end-of-life? There aren't any weird sounds coming from any part of the car as of now.

I'll get the wheel alignment re-done, although I am pretty sure it isn't the culprit. I have been facing these issues since before I changed to alloys, and I have got my wheels aligned a few times in the past 20k kms.

[swiftnfurious]

Originally Posted by DDiSLover

...I got the Clutch overhauled at around 70k kms (if I remember correctly). Could you give me some symptoms of a bad clutch?...

I think the rpm will shoot up without resultant surge in power. Also some jerkiness while changing gears can be treated as symptoms.

Originally Posted by DDiSLover

... How can I check if a brake pad is stuck or if the wheel bearing is nearing its end-of-life? There aren't any weird sounds coming from any part of the car as of now...

I don't think that could be a problem; it would have been diagnosed while service.

Did you get to talk to Lokesh again? May be you can check with the feasibility of an ECU change as well. FYI, Surakshaa has even a pick & drop facility (for extra bucks) for convenience.

[a4anurag]

Originally Posted by DDiSLover

Could you give me some symptoms of a bad clutch?

Hour is the pick-up and in-gear acceleration? Use the Speed vs RPM relation to find out the fair idea. A high revving engine but the speed is less the clutch could be at its end.

80 kmph @ 5th gear = 1900 rpm
100 kmph @ 5th gear = 2300 rpm

Originally Posted by DDiSLover

How can I check if a brake pad is stuck or if the wheel bearing is nearing its end-of-life?

Jack up the car and rotate each wheel by hand and see if it rotates smoothly or you get a jerky movement, any metal rubbing sound. When a wheel is rotated, it should come to a stop normally and not forcefully. If the wheel bearing are gone then there will be a should "hhuumm" continuously and will increase with speed. IMO change all wheel bearings if not changed since purchase.

Originally Posted by DDiSLover

I have been facing these issues since before I changed to alloys, and I have got my wheels aligned a few times in the past 20k kms.

Does the car travel in a straight line or does it pull to any side? Wheel alignment may not be that an issue but does have an affect on rotation efficiency.

>> Check the MAF and if possible injector cleaning.

Anurag.

[DDiSLover]

Originally Posted by a4anurag

Hour is the pick-up and in-gear acceleration? Use the Speed vs RPM relation to find out the fair idea. A high revving engine but the speed is less the clutch could be at its end.
80 kmph @ 5th gear = 1900 rpm
100 kmph @ 5th gear = 2300 rpm
Jack up the car and rotate each wheel by hand and see if it rotates smoothly or you get a jerky movement, any metal rubbing sound. When a wheel is rotated, it should come to a stop normally and not forcefully. If the wheel bearing are gone then there will be a should "hhuumm" continuously and will increase with speed. IMO change all wheel bearings if not changed since purchase.
Does the car travel in a straight line or does it pull to any side? Wheel alignment may not be that an issue but does have an affect on rotation efficiency.

>> Check the MAF and if possible injector cleaning.

Anurag.

The in-gear acceleration is pretty good. In 5th gear, it does 80kmph at around 1900rpm and 100kmph @ 2300. So i guess clutch issues are ruled out. Ill check for the wheel rotations. I haven't noticed any sounds coming from any part of the car. I will check it in any case.

Originally Posted by swiftnfurious

I think the rpm will shoot up without resultant surge in power. Also some jerkiness while changing gears can be treated as symptoms.
I don't think that could be a problem; it would have been diagnosed while service.
Did you get to talk to Lokesh again? May be you can check with the feasibility of an ECU change as well. FYI, Surakshaa has even a pick & drop facility (for extra bucks) for convenience.

I shall give Lokesh a call now itself. Will let you know what he thinks.

Thanks guys!

[dass]

Originally Posted by DDiSLover

I'll get the wheel alignment re-done, although I am pretty sure it isn't the culprit. I have been facing these issues since before I changed to alloys, and I have got my wheels aligned a few times in the past 20k kms.

What size are the tyres? You may have already mentioned somewhere but I am thinking the wrong up/down size of tyres also can lead to lesser mileage. Did you try shell diesel anytime?

[DDiSLover]

Originally Posted by dass

What size are the tyres? You may have already mentioned somewhere but I am thinking the wrong up/down size of tyres also can lead to lesser mileage. Did you try shell diesel anytime?

I have Apollo Acelere 185/ something tyres. What is the recommended size? I shall check and post back.

[a4anurag]

Originally Posted by DDiSLover

I have Apollo Acelere 185/ something tyres. What is the recommended size? I shall check and post back.

LXi/LDi/VXi/VDi - these came with 165/80 R14 - Bridgestone S248, JK Tornados.

ZXi - this variant came with 185/70 R14. No ZDi in that period.

Currently the ZXi/ZDi come with 185/65 R15 - with MRF ZVTV's.

Anurag.

[dass]

Originally Posted by DDiSLover

I have Apollo Acelere 185/ something tyres. What is the recommended size? I shall check and post back.

I was recommended 185/70R14 for my Dzire VDI and I think the same should be for the Swift too. 33PSI all round and mileage has been over 20kmpl always. If its not the tyres, then it has to be the fuel apart from the other technical stuff that the other guys have posted here. Try out shell for couple of fills, its only Rs. 6 more than normal now.

I just realized, mine is the new Dzire so the specifications may be different.

Anurag has posted the actual sizes, if your tyres are up for a change, is it prudent to go back to stock size?

[swiftnfurious]

Originally Posted by dass

What size are the tyres? You may have already mentioned somewhere but I am thinking the wrong up/down size of tyres also can lead to lesser mileage...

Originally Posted by DDiSLover

I have Apollo Acelere 185/ something tyres. What is the recommended size? I shall check and post back.

Originally Posted by dass

...Anurag has posted the actual sizes, if your tyres are up for a change, is it prudent to go back to stock size?

I have been running on 185 70 R14 profile (from day 2) and never had issue with the mileage. A lot of experienced people say NOT much difference can be caused by a tyre upgrade - may be 1 or 2 kmpl at the max. Even then it can't be that low as @DDiSLover mentioned.

Plus, at ANY cost, please do NOT downsize to 165 profile tyres - that's suicidal. The car just would NOT stop as you wish over 80+ kmph speeds.

[DDiSLover]

Originally Posted by dass

I was recommended 185/70R14 for my Dzire VDI and I think the same should be for the Swift too. 33PSI all round and mileage has been over 20kmpl always. If its not the tyres, then it has to be the fuel apart from the other technical stuff that the other guys have posted here. Try out shell for couple of fills, its only Rs. 6 more than normal now.

I just realized, mine is the new Dzire so the specifications may be different.

Anurag has posted the actual sizes, if your tyres are up for a change, is it prudent to go back to stock size?

Hey Dass,

My tyres are in pretty decent nick and they should last for at least another 10k kms. I do not intend on going back to the stock 165/ tyres as they are terribly skinny and I remember my car's handling and braking being much much worse than they are currently. Just as @SwiftNFurious mentioned, I am not willing to sacrifice safety for mileage.

While I have hit 160kmph in the current setup, I remember my car trembling when I touched 140kmph on the stock tyres (in closed roads and safe conditions of course!) and also the car becoming almost uncontrollable under hard braking.


I just hope we can find out what is wrong and fix it, before its too late. I did some calculations and I reckon I spend about 5k on fuel per month, driving about 800-900 kms.