Engine vibrations at low revs at Puma 1.6 2002

[PumaNoob]

Wow, sounds like a real quandry mate, i have to say, i dont have a clue what it could be!!! Its quite hard to try and diagnose a problem when the car isnt in front of you!! Id say its worth changing the clutch, it would have been better if you changed it when the gearbox was off, but you know that now, but i dont think its the clutch plate thats the problem, although for what it costs, if you change it and its not that, at leaste you can eliminate that as the problem! I would have said the slave cylinder would be my 1st suspect, but youve already changed that, so next id be looking at is the rest of the system for kinks or leaks in the pipe. It could be a problem with the actual gearbox internals, have you checked there is enough gearbox oil in there, if its not got enough oil, or its been run without enough oil, it could have caused problems! Not sure if you know how to check it, but there is an allen key plug on the front of the box, the oil should be about level with the bottom of that hole. You can just put an allen key in and see where the oil comes up to.

 

[Gerhard]

Wow, sounds like a real quandry mate, i have to say, i dont have a clue what it could be!!! Its quite hard to try and diagnose a problem when the car isnt in front of you!!

Thank you for your support. It's hard to diagnose with the car being in front of you, too.

... so next id be looking at is the rest of the system for kinks or leaks in the pipe.

I there would be any kinks, I would think that the pedal should be harder to press. But I'll check of course. The tube is quite hard to see close to the master cylinder. I guess I'll have to dismount it latter. For now I put a big stone on the clutch pedal to press it down while the car is parked. Yesterday I washed the engine bay, so that I can see any leak there or from a drop of the level in the tank.

It could be a problem with the actual gearbox internals, have you checked there is enough gearbox oil in there, if its not got enough oil, or its been run without enough oil, it could have caused problems! Not sure if you know how to check it, but there is an allen key plug on the front of the box, the oil should be about level with the bottom of that hole. You can just put an allen key in and see where the oil comes up to.

A mechanical problem of the transmission I can almost exclude. The reverse gear is unsynchronised, so I would not know what could fail there? The oil level is something I didn't really suspect. But it is easy enough, so I'll sure check. Maybe there was some oil missing anyway and I lost a bit during the change of the slave cylinder. In my manual it says 10-15 mm below the refilling hole. Well, I guess it's not too strict.

 

[haGGard]

I have this exact same symptom. My cars a 1.7 and after an evening of VERY spirited driving my engine will now vibrate between 1000 and 1400 RPM. Its not a massive vibration but you can feel it most when pulling away from a standstill as obviously the revs are held in that position for a couple of seconds. Apart from that, the engine is fine. I cant feel the vibration at any other point in the rev range.

Do you think this could be a bent valve too?? :|

 

[PumaNoob]

@ haGGard : Are you having the gear selecting problem too, or just the vibrations? f its only vibrating at a certain point in the rev range, id look at bushes and such, if they go, or start to go, you normally get vibration at a certain speed, then after a certain speed, it goes. Just jack the car up and wiggle the wheels and see if there is any movement, and if you have a crowbar or something like that, just lever the bits up and down to see if there is any movement.
If you had a bent valve, youd feel like you were getting a misfire, because youd get no compression in 1 of your cylinders, if youve still got full power, then the chances are youve not bent a valve, youd normally hear a tapping noise too, as the valve cant close properly when its bent, so it would be tapping on the piston every rotation

@ Gerhard : Best to go with what is says in the manual mate, the way i check gearbox oil levels is just general to most gearboxes, it dosent matter if you overfill them slightly, as it will just come out where the driveshaft is when you drive, but if the manual says 10 - 15mm, just go with that!! When i wrote that its hard to diagnose a problem without it being in front of you, i was thinking exactly the same thing as you, it sounds like it would be hard to diagnose it even if it was in front of me!! :?

 

[haGGard]

Pretty sure theres no more tapping than normal, and power definatley feels the same. I thought it was a mount like you, and had a garage check it over but they couldnt fine anything wrong with it. Its annoying because it will cause the whole car to shake. I've kind of got used to it now though.

 

[PumaNoob]

Did they check the tracking too, thats another cause of vibrations?? I know you may have already thought of that, but just thought id mention it, as sometimes people are so busy looking for big things, they forget about the simple things!! Another thing worth checking, is if youve had your wheels balanced, the little lead weights can come off and give you a vibration, just a thought. Its probarbly something really simple that none of us have thought of yet!!
Sorry for cluttering your thread Gerhard!!

 

[haGGard]

Yeah sorry for the hijack.

Cant be tracking or wheel balancing as the vibration can still be felt when the car is not moving and the clutch is not engaged.

Anyway, thats enough from my mystery, back on topic :lol:

 

[Gerhard]

Yeah sorry for the hijack.

No problem.

Cant be tracking or wheel balancing as the vibration can still be felt when the car is not moving and the clutch is not engaged.

Anyway, thats enough from my mystery, back on topic :lol:

Maybe our vibrations are originating after all from the clutch? I doupt it very much, but you never know? I guess I will find out soon, I am decided to change the clutch. My little leak test with the stone on the pedal didn't show any leak so far. I still have to top up the oil level but it is not too promising I am afraid. I'll order the clutch this week and put it in next weekend. I keep you updated.

 

[PumaNoob]

But if he is getting vibrations whil its not even in gear, then it cant be anything to do with the clutch, because its not spinning when in neutral! If its in neutral, then we can rule out bushes, teacking, and anything to do with gearbox, as none of them are in use in neutral! Gerhard, do you still get the vibrations in neutral, or only when driving? I Think haGGards problem must be either a worn engine mount, or something out of balance with the engine. It so annoting when you have a niggling problem with your car, and you cant find the problem!!!

 

[Gerhard]

But if he is getting vibrations whil its not even in gear, then it cant be anything to do with the clutch, because its not spinning when in neutral

The pressure plate is always spinning with engine spees. However, it is difficult to imagine a severe sudden demage to it, making the engine vibrate. So you are right, I guess.

Gerhard, do you still get the vibrations in neutral, or only when driving?

I also have the vibrations in neutral. But for sure they are worst when releasing the clutch. So I guess I have to sort out the clutch first and see then. Thank you for all your input.

 

[PumaNoob]

The pressure plate is always spinning with engine speed.

Haha, ive just worked out how it works now!! So what i really meant to say was, does it still vibrate with the clutch pushed in!! Because then the clutch plate will be disengaged! But then if there is a problem with the clutch not disengaging properly, your back to square 1!!

 

[Gerhard]

I replaced the clutch this weekend, now everything is as it should be. The clutch releases normally and also the engine vibrations are gone. So full success.

Thank you to all for their input.

Gerhard

 

[haGGard]

Cant be same problem as me then, as my clutch was new last year :lol:

Glad you got it fixed now. To be honest my vibration has just become a characteristc of the car!

 

[Gerhard]

Cant be same problem as me then, as my clutch was new last year :lol:

I would not complete exclude the clutch. My old clutch was obviously used but not too bad in my opinion. Although it showed no sign of obvious damage, maybe there was still some hidden fault not related to usage. The same could apply to your clutch, maybe. From the characteristic of the vibration I did not at all suspect the clutch. They were only evident at low revolutions, so obviously not originating from an unbalanced clutch.

Good luck with finding your vibrations.