"dadas" Sound When Hard Accelerating

[NRX]

Guys. My car makes a "Dadas" sound when hard accelerating in 2nd or 3rd gear and loses power to wheels for a fraction of a second and regains power. This happens more frequently now. When this happens I feel as if I drove over a big pothole, My body moves forward as when you hard brake and the car shakes. This can be experienced mostly when I push the gas pedal to the metal. There is another thing. The sound and the loss of power can be felt intermittently when driving in 4th gear as well, but the magnitude is rather small. This can be felt when driving a bit slowly in 4th gear ( but not that slow to be required to fall back to 3rd gear) The feel is more like a hesitation, and I can feel a bit of a sway in the car. BTW the RPM does NOT drop when this happens.

I changed the gear box oil but the problem is still there. My car is a FB13 with a Manual gearbox.

Appreciate your replies.

[harshansenadhir]

lower arm bushes are gone and tire moves forward and backwards?

from which side you hear the noise?

do this test, keep the car stationed, apply parking brakes and put the gear to neutral. Then try to push/roll each of the front wheels backwards forward using your foot to see whether there's a play. or else, ask a friend to watch while you release the clutch in first gear and reverse gear to see whether there's a significant movement of each of the front wheels.

also check the engine and gearbox mounts for cracked/loosen mounts.

[HardHat]

sounds more to me like a slipping clutch

Edited February 18, 2013 by HardHat

[Dinukap4]

About the dadas sound must be from Engine Mounts ? Does it make the same dadas when you stop the engine ? And I think you have a clutch issue or pressure plate as if it was a miss from the engine the RPM will drop, how does it take off in 1st gear ? Is it normal or does it chatter ? I'm quite cirtain there are some hot spots on the pressure plate,

Edited February 18, 2013 by Dinukap4

[Bora.Mora]

Check your engine mounts....

[NRX]

lower arm bushes are gone and tire moves forward and backwards?

from which side you hear the noise?

do this test, keep the car stationed, apply parking brakes and put the gear to neutral. Then try to push/roll each of the front wheels backwards forward using your foot to see whether there's a play. or else, ask a friend to watch while you release the clutch in first gear and reverse gear to see whether there's a significant movement of each of the front wheels.

also check the engine and gearbox mounts for cracked/loosen mounts.

Harshan. I did a wheel alignment few months back and they checked the whole front end prior to alignment, there wasn't any play or such. It's been only about 500Kms since then.

I can't identify from which side the sound comes from. I feel like it's coming from the center.

[NRX]

About the dadas sound must be from Engine Mounts ? Does it make the same dadas when you stop the engine ? And I think you have a clutch issue or pressure plate as if it was a miss from the engine the RPM will drop, how does it take off in 1st gear ? Is it normal or does it chatter ? I'm quite cirtain there are some hot spots on the pressure plate,

Since few days back taking off from the 1st gear in an incline after a cold start has been a bit tricky. There aren't any sounds though. Put the gear in to 1st and when releasing the clutch, it engages at the last couple of centimeters of the pedal travel. I think it is what some people call as "Clutch eka uda thiyenne" . Sometimes the car almost stalls. But other gear changes are not affected as I feel. And this goes away when the car has been warmed enough.

[terrabytetango]

Broken engine mount I think, the "dadas" sound is the engine shifting and settling.

[NRX]

Broken engine mount I think, the "dadas" sound is the engine shifting and settling.

Terra, Can the loss of power attibute to a broken mount ?

[H.C]

I think your car may have two diagnosis. Sound is most probably a broken mount and may be it needs new clutch too. Is it a carb one?. If so, sudden nock kind of felling with sudden accelaration may be related to inadequate fuel delivery to carb.

[Rumesh88]

I think your car may have two diagnosis. Sound is most probably a broken mount and may be it needs new clutch too. Is it a carb one?. If so, sudden nock kind of felling with sudden accelaration may be related to inadequate fuel delivery to carb.

To me it is the latter. The engine is missing a beat when the pedal goes down.

[Dinukap4]

Since few days back taking off from the 1st gear in an incline after a cold start has been a bit tricky. There aren't any sounds though. Put the gear in to 1st and when releasing the clutch, it engages at the last couple of centimeters of the pedal travel. I think it is what some people call as "Clutch eka uda thiyenne" . Sometimes the car almost stalls. But other gear changes are not affected as I feel. And this goes away when the car has been warmed enough.

Engine mounts/ Trani mounts and Pressure plate Fingers have has lost its flexibility/Pressure Plate has hot spots. some of these issues .

[H.C]

Yes Rumesh, I had a similar nock when sudden acceleration in my Honda Eg8 and culprit was some earlier makabas has seald off the fuel lines to power valve which delivers aditional fuel to the carb in sudden acceleration.

[harshansenadhir]

Harshan. I did a wheel alignment few months back and they checked the whole front end prior to alignment, there wasn't any play or such. It's been only about 500Kms since then.

I can't identify from which side the sound comes from. I feel like it's coming from the center.

you said when the sound comes, car sways. This sway back and forth or sideways (left/right). if the sway is sideways, then there should be some play in the wheels. If it's back and forth, most likely the mounts.

[Rumesh88]

Yes Rumesh, I had a similar nock when sudden acceleration in my Honda Eg8 and culprit was some earlier makabas has seald off the fuel lines to power valve which delivers aditional fuel to the carb in sudden acceleration.

Correct H.C. It can be either the power valve or the accelerator pump. I've already PMed NRX to check whether the pump is working. Of course the power valve operation cannot be confirmed without dismantling the carb.

[NRX]

you said when the sound comes, car sways. This sway back and forth or sideways (left/right). if the sway is sideways, then there should be some play in the wheels. If it's back and forth, most likely the mounts.

Harshan, it's more likely a sway sensation. not really a big sway. This does not make any sound, just the sway feeling (sideways) and the feel of the hesitation for power. This feels only when the car is cruising in a higher gear, not when I push the pedal to the metal for a quick acceleration ( That's when the Dadas sound and the jerk forward thing happens)

Edited February 19, 2013 by NRX

[ZyKo]

Hey NRX,

had the same problem in my peugeot 406 and it turned out to be a worn out engine mount. Also the knock sensor was busted. Not sure if you have one of those in Fb13 but worth checking out. The sound is probably the mount. Pain to drive when the engine slows and starts to rev up and move again