[gpa]

Originally Posted by travelwriter

I recently got some work done on the AC. When the AC is on and the car is idling at a traffic signals, the compressor switches on (which is usual) but of late what is happening is it switches on and then off immediately, then on again and so on.

This type of compressor behavior (compressor engaging and disengaging constantly) generally occurs when refrigerant has been overfilled in the system.

I specifically remember the mechanic at my M.A.S.S saying that the refrigerant should be topped up to the right levels else the compressor will kick-in (on and off) frequently which will lead to overall loss of cooling. This was when I had asked for a top-up of gas during the 50k kms service of my Alto.

[travelwriter]

Originally Posted by gpa

This type of ...of my Alto.

Thanks, Gpa. I just hope there is no link between this phenomenon and the lower mileage. I still am not able to figure out the reason for the drop in mileage. Could it be just that it nearing 4 years of age?

[Gansan]

^^Age actually depends on the number of KM completed by the car, rather than months!

[rajeev k]

Originally Posted by gpa

compressor engaging and disengaging constantly
I specifically remember the mechanic at my M.A.S.S saying that the refrigerant should be topped up to the right levels else the compressor will kick-in (on and off) frequently which will lead to overall loss of cooling. This was when I had asked for a top-up of gas during the 50k kms service of my Alto.

Check the position of your temperature control switch, the one with the blue, yellow and red colour band.

[gpa]

Originally Posted by travelwriter

I just hope there is no link between this phenomenon and the lower mileage.

This is surely not the reason for a drastic decline in mileage but get the problem fixed and then see if you continue to have poor FE figures. 32k kms is surely not a time when you should be having mileage problems.

Some additional areas you could check are:

* Check for binding brakes
* Change the bunk where you fill fuel since they might be shortchanging you
* Clean/replace spark plugs after adjusting the gap
* Clean/replace the air-filter
* Replace engine oil and oil filter
* Adjust valve (tappet) clearances

[Sutripta]

Originally Posted by gpa

This is surely not the reason for a drastic decline in mileage

Hi,
A compressor running with a higher head pressure (for whatever reason) will surely have an effect on FE figures. (Remember what used to happen when the alternator AVR blew?)

Regards
Sutripta

[RM2488]

One of my friends has a 2005 Alto Lxi. He has the strangest issue I have ever seen, and he's asked me to come up with possibilities before going to a workshop.

The engine starts up fine. The moment the first gear is engaged, and the clutch is released, the stick automatically shifts back into neutral. If, however, the stick is held there, forcibly, it allows you to drive- very jerkily I might add. This is true of all the "forward gears"- 1,3,5. Driving it in 2nd, 4th, or reverse does not require holding the gearshift in place. Any ideas?

[R2D2]

Originally Posted by RM2488

One of my friends has a 2005 Alto Lxi. He has the strangest issue I have ever seen, and he's asked me to come up with possibilities before going to a workshop.

The engine starts up fine. The moment the first gear is engaged, and the clutch is released, the stick automatically shifts back into neutral. If, however, the stick is held there, forcibly, it allows you to drive- very jerkily I might add. This is true of all the "forward gears"- 1,3,5. Driving it in 2nd, 4th, or reverse does not require holding the gearshift in place. Any ideas?

The Alto's gears are operated and changed by a set of cables under the gear selector. As your pal to get the selector and cables checked for correct operation and check the cable slack/play.

[rajeev k]

Originally Posted by RM2488

The engine starts up fine. The moment the first gear is engaged, and the clutch is released, the stick automatically shifts back into neutral. If, however, the stick is held there, forcibly, it allows you to drive- very jerkily I might add.

This is because the gears are not engaging properly and on transmission of load they are separating off and this phenomenon is known as gear slipping. The reason for which is to be got checked off. Running by holding it in position is not a proper way as the jerks indicate and can cause serious damages. So get it checked up asap.

[R2D2]

^^^^
Agreed with you but before delving into the gearbox synchronisers we should check the gear shift actuators and cable, which is a simple check - if it turns out ok then we can move on to other more detailed internal inspections.

[im_srini]

Originally Posted by RM2488

One of my friends has a 2005 Alto Lxi... The moment the first gear is engaged, and the clutch is released, the stick automatically shifts back into neutral. If, however, the stick is held there, forcibly, it allows you to drive - very jerkily I might add. This is true of all the "forward gears" - 1, 3, 5. Driving it in 2nd, 4th, or reverse does not require holding the gearshift in place.

Hi, how forcibly is your friend having to hold the gear lever to prevent it from slipping back to nuetral ? Is it just a light touch or does the gear lever have to be held in with some force ? Did the car go in for any complaints or servicing of the gearbox prior to onset of this issue ? Did your friend drive over a speed-breaker or something & hit the floor of the car ?

As others have mentioned, please have it checked as soon as possible to prevent any damage to the gearbox, many of the parts within are quite expensive.

Originally Posted by R2D2

The Alto's gears are operated and changed by a set of cables under the gear selector. As your pal to get the selector and cables checked for correct operation and check the cable slack/play.

The old Alto does not have a cable for gear actuation, the gear lever end is attached to a metal rod that's connected to the gearbox, there's a secondary rod that's basically used to maintain the position of the gear lever relative to the gearbox. Only the Alto K10 uses cables for gear actuation.

Originally Posted by rajeev k

This is because the gears are not engaging properly and on transmission of load they are separating off and this phenomenon is known as gear slipping. The reason for which is to be got checked off. Running by holding it in position is not a proper way as the jerks indicate and can cause serious damages. So get it checked up asap.

The output gears (except reverse) in the gearbox are constantly in mesh & rotate on the output shaft. When you shift, the fork for the appropriate gear moves collars (a fork & collar is shared between two gears) splined to the output shaft, its these collars that provide a positive connection between the spinning gears on the output shaft & the output shaft itself (thus transferring torque). Synchros allow speed matching so that the collars can slip on to the spinning gears easily.

Originally Posted by R2D2

Agreed with you but before delving into the gearbox synchronizers we should check the gear shift actuators and cable, which is a simple check - if it turns out ok then we can move on to other more detailed internal inspections.

The gear actuating rods that move the forks in & out have detents in them, into which sit spring loaded small steel spheres (like the ones used in ball bearings), these spheres prevent the fork rods from moving about once a gear is selected. Will post pics from the parts catalog, that should make things easier to visualize. The issue appears to be only with 1st, 3rd, & 5th - hence my guess is that the issue is due to the gear actuation mechanism rather than the individual gears & synchros.

[RM2488]

Originally Posted by im_srini

Hi, how forcibly is your friend having to hold the gear lever to prevent it from slipping back to nuetral ? Is it just a light touch or does the gear lever have to be held in with some force ? Did the car go in for any complaints or servicing of the gearbox prior to onset of this issue ? Did your friend drive over a speed-breaker or something & hit the floor of the car ?

It is difficult to say how much is too much force. Though not a lot of strength is required, I would not say it is negligible. The car did have the clutch plates replaced a couple of months back. As far as I know, there hasn't been any damage, but I could be wrong- multiple people drive that car.

Originally Posted by im_srini

As others have mentioned, please have it checked as soon as possible to prevent any damage to the gearbox, many of the parts within are quite expensive.

The car is parked until some diagnosis can be made, so no problems there.

Originally Posted by im_srini

The issue appears to be only with 1st, 3rd, & 5th - hence my guess is that the issue is due to the gear actuation mechanism rather than the individual gears & synchros.

Would you say a Maruti Suzuki A.S.C. would be better than a really well-equipped local garage? I personally don't have experience with Maruti (Ford isn't so good though), but my friend doesn't really like their work. And what, exactly, should he ask them to check?

[im_srini]

Originally Posted by RM2488

And what, exactly, should he ask them to check ?

This is what the service manual says needs to be done...



The following are images from the Alto Parts-Catalog & Service-Manual:

Gear actuation.











Gear detent mechanism.



Gear cluster.







Was the transaxle dropped for the clutch change ? Its possible the gear shift linkage was not correctly connected back after the job. Its unlikely to be the detent mechanism since its usually not touched for anything. I think the real clue is that the box isn't able to hold 1st, 3rd, & 5th only - hoping mechanical engineers on the forum can have a look at the gear cluster pics & list the most likely causes...

[RM2488]

Ah, this is leading somewhere. The highest possibilities are the five mentioned in the first image, right? Should be good enough for a diagnostic.

[Aroy]

After replacement of the AC compressor, your AC will be cooling better. Alas better cooling is always at the expense of FE. Normally the FE difference between AC & non AC driving is about 2 km/l. On highways it may reduce to 1 km/l and in heavy traffic to 5 or even 6 km/l.