Stilo
Apprentice
Posts: 1,536
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Post by Stilo on Jan 13, 2013 21:41:45 GMT 1
This is an oddball one which I'd like an opinion on.
My motor is a Grande Punto 1.3 Mjet 75bhp. It drives very very well except for two annoying issues which might be linked. Car is 2007, has 51000 miles on it and a full history.
Firstly, in a high gear at low revs, it shudders a bit around the 1300rpm mark. It feels like a misfire or like its going to stall. But if you go below 1300, its ok. It's most noticeable in 4th and especially 5th, but somethings you can feel it momentarily if pulling away. MAF and EGR were disconnected and made no difference. There's no stored fault codes and all of the live data looks spot on. So I don't think this is electronic, it's more like drivetrain.
Secondly, driving along at around 40mph, the ride is very choppy. The wheel rims are all true and. balanced. Shocks and ball joints are all ok. I replaced the tyres with 4 brand new ones which improved matters slightly. Ride at higher speeds are ok.
Someone I know commented that there could be a DMF issue, but my car doesn't have one. Could these be caused by a faulty drive shaft or worse, a wonky diff? When either fault occurs, it seems like its coming from the passenger side.
Advice / opinions anyone?
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Post by Rhubarb on Jan 13, 2013 22:00:21 GMT 1
Stop slogging it  Most likely a bit of wear in the inner joints of the driveshafts |
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Stilo
Apprentice
Posts: 1,536
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Post by Stilo on Jan 13, 2013 22:01:33 GMT 1
Stop slogging it Most likely a bit of wear in the inner joints of the driveshafts Any way of checking / testing the inners?? |
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Post by Karl on Jan 13, 2013 22:08:59 GMT 1
1300 rpm in 5th !
Drive it properly would be my advise
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Post by Rhubarb on Jan 13, 2013 22:13:11 GMT 1
Stop slogging it Most likely a bit of wear in the inner joints of the driveshafts Any way of checking / testing the inners?? Yep jack it up, bung it on stands and grab hold of the shaft next to the inner joint and check for movement...There should only be a fraction But seriously, stop slogging it, these FIRE engines need to be revved. Low revs and high gears puts too much strain on the transmission |
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Post by Karl on Jan 13, 2013 22:13:59 GMT 1
Best way to check the inner tripod joints will be to remove shaft and strip down
And check those needle rollers
I've had plenty of vehicles give shuttle shake acceleration
Trouble is its not always noticeable in a inner joint unless its shagged out with loads of play
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Post by Noberator on Jan 13, 2013 22:14:12 GMT 1
Is this shudder at 1300 rpm in fifth gear Will?  May be it's to high a gear for the revs and road speed.  Do the same symptoms appear in say fourth gear at 1300 rpm? |
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Post by Karl on Jan 13, 2013 22:15:01 GMT 1
Any way of checking / testing the inners?? Yep jack it up, bung it on stands and grab hold of the shaft next to the inner joint and check for movement...There should only be a fraction But seriously, stop slogging it, these FIRE engines need to be revved. Low revs and high gears puts too much strain on the transmission The fire engine is the petroleum version isn't it? |
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Post by Rhubarb on Jan 13, 2013 22:16:17 GMT 1
Yep jack it up, bung it on stands and grab hold of the shaft next to the inner joint and check for movement...There should only be a fraction But seriously, stop slogging it, these FIRE engines need to be revved. Low revs and high gears puts too much strain on the transmission The fire engine is the petroleum version isn't it? yep Old design now but a goodun |
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Stilo
Apprentice
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Post by Stilo on Jan 13, 2013 22:24:22 GMT 1
Yep this is a denzil, not the FIRE. My last Punto had the FIRE, she was the biz with an insane appetite for RPM!
Nobby,pProblem also occurs in 4th but not as bad. With the shudder, the rev counter flutters noticeably. Inner joints may be causing the bouncy ride, doubt if it causing the shudder though, would it?
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Post by Rhubarb on Jan 13, 2013 22:28:35 GMT 1
My mistake sorry, didn't notice it's a derv..
But you're still slogging it, and yes that and/or worn inner joints will cause a shudder
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Post by Noberator on Jan 13, 2013 22:38:24 GMT 1
Yep this is a denzil, not the FIRE. My last Punto had the FIRE, she was the biz with an insane appetite for RPM! Nobby,pProblem also occurs in 4th but not as bad. With the shudder, the rev counter flutters noticeably. Inner joints may be causing the bouncy ride, doubt if it causing the shudder though, would it? A faulty DMF would but you say it hasn't got one I thought they where fitted from 2005-6 onwards? |
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Stilo
Apprentice
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Post by Stilo on Jan 13, 2013 22:59:56 GMT 1
A faulty DMF would but you say it hasn't got one I thought they where fitted from 2005-6 onwards? Definetly no DMF, confirmed by local Fiat Dealer. The 90bhp model has them alright, mine is the 75bhp and doesn't. None at all BB. Engine itself is tight and sweet. Plenty of go and no clanking or rasping from the chain. |
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Stilo
Apprentice
Posts: 1,536
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Post by Stilo on Jan 14, 2013 14:53:26 GMT 1
There's live data on the return rates (or something similar) from the injectors and again they appear ok.
Am going to look into the inner CV joint when I can.
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gasmonkey
Tea Maker
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Post by gasmonkey on Jan 14, 2013 21:14:29 GMT 1
1300 rpm in 5th ! Drive it properly would be my advise Karl has a point. Years ago, Ford used to state in their vehicle handbooks that the vehicle should not be driven below 1500 RPM in any gear. It was good advice and should apply to all vehicles in my opinion. Puts far to much stress on engine and transmission. Used to change alot of 5th gears on Vauxhalls, almost always due to customer driving too high a gear at too low a speed. My sister found out the hard way that 5th gear, 40 MPH, 1100 RPM = expensive. |
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