Clio 172 speedo issue
Discussion
I've had my Cup 172 for 3 months now, and within 2 weeks of owning it when driving in heavy rain I'd see the speedo needle waver slightly or it would drop down to zero and then back up to whatever speed it was doing. At the time I was fine with it because it was only in very heavy rain and not any other time.
Now in the last 2 weeks it's been happening more frequently in dry weather and a few times now the speedo has stopped working altogether for a few minutes and then all of a sudden will perk back up again. The really worrying thing now though is that the engine will quite vioently vibrate when this happens which shakes the car
I'll try to explain what its like in more detail, the feeling is quite odd. It is one vibration, just a single shake to the car, at which point the speedo will either stop working altogether or dip to zero and return to the correct speed. It also feels like its gone full throttle by itself for a moment, not enough to actually increase the cars speed, but it feels like a kick of power from behind. Also the more it happens the more convinced I am that I can feel a change in the resistance in the accelerator pedal - though I'm sure that's not possible.
All the time the speedo isn't working the engine runs fine, except for the initial vibration.
Could this vibration be a misfire that is confusing a sensor somewhere relating to the speedometer?
Now in the last 2 weeks it's been happening more frequently in dry weather and a few times now the speedo has stopped working altogether for a few minutes and then all of a sudden will perk back up again. The really worrying thing now though is that the engine will quite vioently vibrate when this happens which shakes the car
I'll try to explain what its like in more detail, the feeling is quite odd. It is one vibration, just a single shake to the car, at which point the speedo will either stop working altogether or dip to zero and return to the correct speed. It also feels like its gone full throttle by itself for a moment, not enough to actually increase the cars speed, but it feels like a kick of power from behind. Also the more it happens the more convinced I am that I can feel a change in the resistance in the accelerator pedal - though I'm sure that's not possible.
All the time the speedo isn't working the engine runs fine, except for the initial vibration.
Could this vibration be a misfire that is confusing a sensor somewhere relating to the speedometer?
Edited by MSTRBKR on Tuesday 13th April 00:31
Thanks for the reply. That's good info, I didn't know the sensor was there. It doesn't sound very accessible though if its duff! Though I'm afraid to say I think it might be an engine problem judging by the vibration and power kick and it's confusing the sensor causing the flutuations in the needle.
Maybe I should get petrol from somewhere other than tesco. I only go there because its more convenient but I've heard the stories about their fuel. I've had this problem running it on both 95 and 99 octane, but I'm now running it strictly on 98+ to see if it stops doing it once the ECU 'learns' the new fuel (I hear it takes 100 miles and I've just passed that mark).
Happy to say it didn't do it at all today on a 12 mile run to work. Let's see on the way home.
Maybe I should get petrol from somewhere other than tesco. I only go there because its more convenient but I've heard the stories about their fuel. I've had this problem running it on both 95 and 99 octane, but I'm now running it strictly on 98+ to see if it stops doing it once the ECU 'learns' the new fuel (I hear it takes 100 miles and I've just passed that mark).
Happy to say it didn't do it at all today on a 12 mile run to work. Let's see on the way home.
Well I haven't checked the wiring yet as suggested above as I've been very busy. However, we had rain last night and I haven't driven it in the wet for some time and the problem was back. It hasn't done it since we've had this nice dry weather, but this morning it was definitely accelerating by itself for a split second and the speedometer stops working as per. It will then start working again almost as soon as I go down to 4th gear and begin to slow down.
I'm going to check the wiring as suggested above tomorrow.
Someone also has the same problem as me here http://www.renaultforums.co.uk/showthread.php?t=69...
I do have an aftermarket head unit in the car but it was doing this before that.
I'm going to check the wiring as suggested above tomorrow.
Someone also has the same problem as me here http://www.renaultforums.co.uk/showthread.php?t=69...
I do have an aftermarket head unit in the car but it was doing this before that.
I'm not 100% sure, but the cups have a speedo cable plugged into the box, pretty much the same as on the ph1 172 and the Mk1's.
On the Mk1's, a duff cable has been known to cause very odd running problems as it's earthed at the clock end & dodgy earths are often the cause of issues similar to yours, as well as the speedo having a mind of it's own. So I'd think about replacing the speedo cable.
Hope that's of some help to you, if I'm wrong & it doesn't have a speedo cable, my advice has been completely useless
On the Mk1's, a duff cable has been known to cause very odd running problems as it's earthed at the clock end & dodgy earths are often the cause of issues similar to yours, as well as the speedo having a mind of it's own. So I'd think about replacing the speedo cable.
Hope that's of some help to you, if I'm wrong & it doesn't have a speedo cable, my advice has been completely useless
Had it serviced lately ? What plugs have been fitted ?
So many problems like this can be caused by basics, as said previously by things like battery connections etc. Non spec plugs are notorious for causing all sorts of problems with instruments jumping, missfires, autobox gearchange issues etc etc. Incorrect resistances of plugs cause spiking of multiplex systems blah blah blah
So many problems like this can be caused by basics, as said previously by things like battery connections etc. Non spec plugs are notorious for causing all sorts of problems with instruments jumping, missfires, autobox gearchange issues etc etc. Incorrect resistances of plugs cause spiking of multiplex systems blah blah blah
Earth lead to gearbox is another common problem that can cause this sort of thing, wiring inside sheathing in front of gearbox rots, Speed pulse generator on gearbox also known problem area, corrosion on connector as well as internal problems. Injection computer uses road speed info, which it takes from this generator, if this is lost it could well cause a fuelling/ignition problem, giving the jerking that you describe. Check the output using Clip/scope for loss of output.
It had it's last service at 72000, now on 77800 - but the previous owner did it about a year ago.
The battery connections all appear fine from a visual check.
I've just got back from a 160 mile run and again the problem was certainly affected by wet weather. As soon as we entered a heavy shower it would go nuts. The car was rained on over the weekend while it was parked and for 10 miles or so tonight when driving back it was playing up, then after 10 miles it stopped. I suppose whatever is being affected by the water dried up.
This is causing havoc with the trip computer as well. mpg is dropping when the the speedo stops working, I assume because it thinks it's idling. I hope it's not dumping extra fuel into the engine.
First of all I need to establish where the sensor actually is. I think I can see it on the top of the gearbox casing between the engine and bulkhead, it's angled backward slightly. Then I'm going to get a replacement sensor if they are <£20 as that may cure it without delving into testing wires etc. I don't have any testing equipment and haynes don't make a manual so finding wires to test is tricky to say the least.
I really appreciate the help though, it may help if I decide to take it in to a garage.
The battery connections all appear fine from a visual check.
I've just got back from a 160 mile run and again the problem was certainly affected by wet weather. As soon as we entered a heavy shower it would go nuts. The car was rained on over the weekend while it was parked and for 10 miles or so tonight when driving back it was playing up, then after 10 miles it stopped. I suppose whatever is being affected by the water dried up.
This is causing havoc with the trip computer as well. mpg is dropping when the the speedo stops working, I assume because it thinks it's idling. I hope it's not dumping extra fuel into the engine.
First of all I need to establish where the sensor actually is. I think I can see it on the top of the gearbox casing between the engine and bulkhead, it's angled backward slightly. Then I'm going to get a replacement sensor if they are <£20 as that may cure it without delving into testing wires etc. I don't have any testing equipment and haynes don't make a manual so finding wires to test is tricky to say the least.
I really appreciate the help though, it may help if I decide to take it in to a garage.
Edited by MSTRBKR on Monday 3rd May 23:56
You have probably sorted it by now.
if not then the speedo sensor is 100% at fault, a quick way to determine this is to disconnect the wiring from the top of the sensor by just pulling the multi plug connection out.
its very easy to get to and you dont have to jack the car up etc, just peer down the back where the exhaust manifold is and look to the right it may have a heat shield round it.
I have exactly the same problem on my 2002 172 ph2 exactly same running fault when the speedo drops out the car runs poor.
The ecu must be reading from the speedo input and if the sensor is faulty it will give it a hissy fit, however a faulty sensor that is disconected fools the ecu in to thinking all is ok and your car will no longer jerk and run like it has bad fuel etc.
this is obviously a short term fix and the car will run 100% all be it without a speedo reading. this is primeraly to identify that the sensor is at fault which can then be replaced for approx £25 for a new sensor from renault to restore the speedo back to working operation.
Hth
Nick
if not then the speedo sensor is 100% at fault, a quick way to determine this is to disconnect the wiring from the top of the sensor by just pulling the multi plug connection out.
its very easy to get to and you dont have to jack the car up etc, just peer down the back where the exhaust manifold is and look to the right it may have a heat shield round it.
I have exactly the same problem on my 2002 172 ph2 exactly same running fault when the speedo drops out the car runs poor.
The ecu must be reading from the speedo input and if the sensor is faulty it will give it a hissy fit, however a faulty sensor that is disconected fools the ecu in to thinking all is ok and your car will no longer jerk and run like it has bad fuel etc.
this is obviously a short term fix and the car will run 100% all be it without a speedo reading. this is primeraly to identify that the sensor is at fault which can then be replaced for approx £25 for a new sensor from renault to restore the speedo back to working operation.
Hth
Nick
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