Technical Howto identify issues: Lack of power

[mqsash]

Hi folks,

I live in Pune, India and I've got a 1.2ltr, 2001 Uno which has single point injection, and has done about 90k kms.
Off late I've noticed that while overtaking (usually in 3rd or 4th gear) the acceleration has deteriorated. This is most prominent when I've got 4-5 people in the car and the A/C is on (i.e under load conditions). Even climbing gradients under load the car feels very underpowered, when the accelerator is pressed the engine RPM do not pickup as it used to. But once they get above a certain level (no number here as i don't have a tacho) then the engine suddenly starts to deliver the power as expected.

Also the gas mileage has dropped of sharply.
I like to think it might be the clutch, but I am no expert in this field.
My mechanic was not sure about the acceleration issue, but said that the mileage issue would get fixed if I got the throtle body and spark plugs cleaned

So questions:
1 - How to I identify if my clutch is slipping - even if it maybe only slightly?
2 - Could cleaning the throttle body and spark plugs fix the issue ?
3 - What else could cause such an issue?

mqs

 

[rawill]

About the clutch.

Drive along the road at about 50kph put your foot on the clutch and rev the engine quite a lot, say 5000rpm. Drop the clutch quickly, if the clutch engages slowly, kind of like an automatic, and the engine keeps revving and not speeding up quickly that is a sure sign the clutch is a problem.

Check and see if the the cable has any clearance (or freeboard) you should have about 2 -3 mm of movement in the cable before it starts to engage the clutch. You should check this before you do the above check.

At the moment I have a Mitsubishi Mirage Spacewagon that has a slipping clutch. So for me a gearbox has to come out, what a nuisance.

Hope this helps.

Engine tune
Change plugs, check timing, check air filter is clean/replace, same with fuel filter. In other words all the normal maintenance and simple things before you go digging deeper. Is it running at normal temperature, does the thermostat need changed. This can affect fuel economy but not acceleration.

But, from what you describe I don't think you have a slipping clutch. It will be good to see what others say.

 

[alexGS]

Great advice there from rawill

I doubt it is the clutch slipping as you say the engine has no pick-up. If the clutch slips, the engine revs go up willingly with no increase in the car's speed.

Have the ignition timing checked - the vacuum advance capsule on the distributor should have the pipe disconnected and plugged - with the engine idling, the timing light should illuminate the flywheel notch at near the 5-degree mark on the bellhousing. When you re-connect the vacuum advance, the timing should advance by about 10 degrees. If someone has mistakenly timed it with the vacuum advance connected, the timing will be too far retarded - fuel consumption will increase and engine pickup will be poor.

'cleaning' spark plugs sounds like a waste of time - I remember that used to be done (with a sandblaster) but these days, spark plugs are much cheaper than they used to be.

Check/replace the air filter.

It might be a good idea to replace the fuel filter. I don't know where this is fitted on your model of Uno, but it may be restricting flow especially if you have a mechanical (mounted on the engine) fuel pump. The symptom would again be a lack of power under load.

-Alex

 

[yengulamit]

I am sorry for the off topic discussion. But mqsash, where in Pune do you get your car serviced. Also are the genuine parts for UNO available. I myself own a 999cc Fire Uno here in Mumbai. Please post some details about the same.

Cheers
Amit

 

[alexGS]

I am sorry for the off topic discussion. But mqsash, where in Pune do you get your car serviced. Also are the genuine parts for UNO available. I myself own a 999cc Fire Uno here in Mumbai. Please post some details about the same.

Cheers
Amit

Good idea - not off-topic at all It's hard for those of us in other countries to offer much specific advice. Indian Uno Owners, unite!

-Alex

 

[yengulamit]

Hey Alex thanks.
Well to go about it. I have owned the car for fairly about 11 years. At this instant i must admit that it has lost its charm . Very recently i was struck by a problem caused by engine missing. I went about it and got the distributor cap changed. but the problem continued. then i solved the problem by replacing all the spark plugs. Got it done from the Fiat service centre guys. But the guys there were advicing the carburettor(Webber) should be changed since its been 11 years and it has been opened for servicing only once. Also the drive is not smooth. the pick up is good but the engine starts coughing at low speeds. What according to you should be done considering the non-availability of parts in India.

PS: one of the local mechanics suggested that i give the carburettor a petrol wash. Is it advicable ?

 

[a73uk]

Hey Alex thanks.
Well to go about it. I have owned the car for fairly about 11 years. At this instant i must admit that it has lost its charm . Very recently i was struck by a problem caused by engine missing. I went about it and got the distributor cap changed. but the problem continued. then i solved the problem by replacing all the spark plugs. Got it done from the Fiat service centre guys. But the guys there were advicing the carburettor(Webber) should be changed since its been 11 years and it has been opened for servicing only once. Also the drive is not smooth. the pick up is good but the engine starts coughing at low speeds. What according to you should be done considering the non-availability of parts in India.

PS: one of the local mechanics suggested that i give the carburettor a petrol wash. Is it advicable ?

I would check the vaccum advance unit on the distributor, when it fails it causes those issues.

If it has failed it will draw air through the pipe to the inlet manifold, causing the car to run lean, this can be temporarily cured by blocking the vaccum pipe with a screw or bolt until you find a replacement.