Part – V(B)

Preamble

Likewise in this section, we’ll look at some more techy bits which fox most of us some times or the other………..
----------------------------------------------------------------------------- 9) EU-I Starting troubles

For a petrol ICE to 'Start' satisfactorily, it needs to be assured of the following - in that descending order :

1) Regular use of a well branded Petrol Additive or the eqvt new generation 'premium' Petrols.

2) Engine in correct tune by way of - i) Distributor 'Dwell Angle' setting, ii) Ignition Timing, iii) Idling rpm setting AND iv) Correct 'CO' setting as recommended by the OEM for your Model. (i) is not applicable to 'Electronic Distributors as in Zen/Esteem.

3) Correct setting of the 'hot-restart/1500 rpm ckt' for cars like Zen/Esteem.

4) 'Adequate' Fuel Supply to and 'just adequate' from the Carburettor to the Cyls. A Blocked Petrol Filter can upset the apple cart. Faults within the Carb such as a high 'Float-Level' or its other Auxiliary Circuits can 'flood' it. On the other hand, fuel lines from Tank to the Carb/return can get choked with progressive wax deposits in old Cars - like the Human Heart's. Replacing such Piping with new ones is the only solution, as they cannot be cleaned satisfactorily.

5) With Ambient Temperatures below 15*C, one may have to take the 'Choke' to some extent, the first thing in the morning. Please read and follow your Owners Handbook in this respect.

6) Availability of a healthy Spark 'inside' the Cylinders AND Correct 'Ignition' Timing. Needless to say healthy/correct gap-set Spark Plugs go a long way on this front - not to mention damaged HT Leads otherwise. Faulty Ignition Coil mounted Ballast Resistor 'by-pass circuit' of the Starter Solenoid Switch can also compound the problems. However, this is not applicable to Cars like Zen/Esteem.

7) Plenty of fresh air - a blocked Air Cleaner Filter can spoil the show too.

8) Correct/Minimum 'Cranking Speed' - for the lack of which a weak Battery or a worn-out Starter Motor can be responsible.

9) Upset Valve timing due to a worn out timing belt.

10) Worn out Engine it self - resulting in 'compression ratio' below the OEM specified limits.

Beyond a point, the situation can be out of reach of an average DIY person or a Friendly Neighbourhood Mechanic, as it needs some Special Test/Engine Tuning Instruments as well. If you or your FNM have had a good run at it already - usefully or otherwise - I'd suggest you now seek professional help from a Garage of repute.

10) When to change the Valve Timing Belt

This is a tricky one. Mpfi or Carb has nothing to do with it. Most OEM's specify a change ~ 60-80 kkm, coz a snapped Timing Belt can cost one dear by way of possible damages to the Cyl Head/Valve Gear - not to mention getting stranded in middle of no where and await a tow-up to the nearest garage.

On the other hand, TB's being slow moving items, remain of the Vendors' shelves for long and replacements are usually past their shelf life - leading to noises which were earlier on not there !

So the best bet would be to have the TB Covers removed and have it inspected closely for any fraying/cracks. If so noticed, get it changed by an OE part - other wise carry on for another 5 kkm to re-inspect.

11) Taking off on a Gradient

The skill to tackle such a problem that one faces frequently can best be 'demonstrated' live by an experienced driver, rather than a class room lecture. Nonetheless, I'll try :

i) Using the Hand Brake to assist is the right thing to do. In fact out there in the West, it's mandatory to shift the Car to neutral and engage the Handbrake when coming to a stop, such as on traffic lights. The reason being -a) you don't roll fwd/bkwd and 'kiss' the guy ahead/behind you, b) If some one hits you from behind, you don't take-off and start a chain reaction.

ii) Likewise when you have to stop on a slope, engage the HB fully first and then shift to neutral and take your foot off the clutch.

iii) Now comes the tricky part - to take off smoothly on an upgradient w/o the engine stalling or the Car rolling back. In fact it's quite as easy as learning to swim, once you get the 'hang' of it. Here's what you do -

a) With the HB still fully engaged, you get into the first gear and rev-up/let the clutch go slowly till the Car 'attempts' to move even with the HB engaged - which will be apparent by the engine tending to stall somewhat.

b) NOW you 'co-ordinate' the clutch release + more accelerator AND 'progressive' handbrake release - in such a manner that the Car smoothly moves fwd w/o stalling or rolling back. It's a skill easily acquired by getting the 'feel' of things and not getting nervous about it.

iv) Remember always that it's you who's driving the Car and not the other way around. It'll do exactly what you command it to do - knowingly or unknowingly.

For the beginner-drivers, there are Pages under Infobank on our Sites titled 'Driving Essentials'. Pl Surf these, as I am sure you'll pick up a lot many things to make you a better driver.

12) ‘Torque-Steer’

'Torque-Steer' in auto lingo afflicts practically all FWD Cars where the two drive-shaft lengths are inevitably unequal - due to the Power-Train layout.

In most such Cars, the RHS/DS is longer in length compared to the LHS one. Since the 2-DS's are made using the same 'shaft' material for reasons of mass-economy, their 'end to end torsional-stiffness' varies - being inversely proportional to their lengths - per elements of applied mechanics.

In other words, the longer/RHS-DS has lower torsional stiffness than the LHS one. Therefore, in the event of high torque/acceleration, the drive torque takes a fraction of a second longer to get transmitted to the RHS wheel, compared to the LHS one - tantamounting to it being 'effectively braked' for a while compared to the LHS one - hence the steering drag to the right.

This problem can be pretty annoying in high performance sports cars and to overcome it, designs are now available where the two drive shaft lengths are made equal. However, in mundane cases like ours, there are two possible solutions :

i) Grin and bear it, knowing what's causing it, or

ii) Make the RHS wheel 'toe-in' a shade higher than the LHS one - but ensuring that it's still within the OE tolerance specified. This should minimise the drag under hard acceleration, if not eliminate it.

Having done so, it'd be advisable to keep a close watch on any uneven/rapid wear of the two front tyres. If observed, take corrective action accordingly.

For more info on the subjects, you're invited to Surf the following URLs -

http://www.indiacar.com/infobank/fundamentals.htm
http://www.indiacar.com/infobank/fundamentals2.htm
http://www.indiacar.com/infobank/fundamentals3.htm

http://www.indiacar.com/infobank/torque_bhp.htm
http://www.indiacar.com/infobank/torque_bhp_part2.htm

13) Side Drag in Cars

Any or more of the following can cause ‘Side-drag’ in a Car :

1) Unequal 'cold' tyre pressures - either up front or rear.

2) Asymmetrical tread patterns/different brands - particularly up front.

3) Unequal wear up front - leading to difference in overall wheel dia's of > 2mm.

4) 'X' rotation of Radial Tyres - which should preferably moved up and down on the same side only.

5) Difference in RH/LH 'Wheel Bases' of > 5mm, due to whatever reason - severe bumps or faulty post accident repairs being most common.

6) Faulty Wheel Alignment - by way of - i) Toe-in, ii) Castor, iii) Camber and iv) 'Offset'.

7) Significant 'unequal' loading - especially upfront - say driver weighing 50 kgs and the passenger weighing > 75 kgs - more so in Cars lighter than say 750 kgs.

8) Heavy 'Crown/Camber' of the road surface - generally leaning excessively to the left.

9) Strong 'cross-winds'.

For further info on (1) and (9) above, you're invited to Surf the following URLs -

http://www.cybersteering.com/cruise/driving/tyre_pressure.html

http://www.indiacar.com/infobank/fundamentals.htm

14) Slow-speed Steering Wobbles

There could be more than one cause for such slow speed wobbles - viz :

1) ‘Out of true’ Wheel Rims.

2) Dynamically out of balance Wheels/Tyres.

3) Out of true Brake Discs.

4) Sticky front Brake Caliper Assys.

5) Worn out Steering Ball Joint Linkages.

6) Damaged 'Knuckle Joint'

7) Damaged Wheel End Axle Assy.

8) Internally damaged Radial Tyre Casing.