Starbucks Junkie said:

It may or may not be linked, but I also find on occasions and only when attempting acceleration on a Gradient in 4th or 5th Gear that when the Gas pedal is pressed, the car engine Rev's but doesnt actually accelerate.

To counter this, I have to take my foot off the Gas Pedal and then re-press it and it starts to accelerate.

Could the extreme acceleration from 1st Gear pull away and this none acceleration be linked?

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Interesting. How many miles has the beast done? The first paragraph sounds like clutch slip.

It could possibly be connected to the 1st gear surge.... if the clutch is a bit slippy but you're at an engine speed range/lower end of a torque curve where the clutch can "grab" then it could give your symptoms that it's having a lunge, whereas it could just be working properly (at that point.. obviously not "overall").

If you're handy with a brake bleed kit, try bleeding the clutch. It won't fix a worn clutch but if there's a small/temporary improvement (bleeding helps whatever clutch is left) then that will point to a new clutch being the answer.

Ralf S.

Starbucks Junkie said:

This would mean I had to drive the car continuously in Sport Mode as i cannot guarantee when it's going to happen again.



It also happens so quickly that if I was to view the screen as and when it occurs again I might hit something as I have to break to stop the car from running away...



I was just wondering if anybody else has experienced this as I cannot be the only person.

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I'm not quite sure what your objection to using Sport Mode for a trip or two is whilst you investigate the problem, but if you really don't want to use you won't get to see the Turbo Boost gauge

Ralf S. said:

Good point... but you're being logical. This is car electronics we're talking about..

The ECU gets a signal from several sensors and controls what the car does, so it's possible that it comes up with a different answer on different occasions. For example, if you are travelling at a different speed it can supply different amounts of fuel, even with the same throttle position depending on what is optimal or best for emissions etc.

I presume the car does this hot or cold and it's not engine temp' related which could be the engine cold-start setting (old style "choke") being too keen?


Ralf S.

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I'm a programmer, I have to think Logically... lol

This only ever happens when the car is at operating temperature, not too hot or cold.

Alanw47 said:

I'm not quite sure what your objection to using Sport Mode for a trip or two is whilst you investigate the problem, but if you really don't want to use you won't get to see the Turbo Boost gauge

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I don't have an objection, but as it happens so infrequently I may be driving for weeks on Sport mode before it happens, and it may not happen at all in this mode. It might be specifically linked to Auto Mode.

Ralf S. said:

Interesting. How many miles has the beast done? The first paragraph sounds like clutch slip.

It could possibly be connected to the 1st gear surge.... if the clutch is a bit slippy but you're at an engine speed range/lower end of a torque curve where the clutch can "grab" then it could give your symptoms that it's having a lunge, whereas it could just be working properly (at that point.. obviously not "overall").

If you're handy with a brake bleed kit, try bleeding the clutch. It won't fix a worn clutch but if there's a small/temporary improvement (bleeding helps whatever clutch is left) then that will point to a new clutch being the answer.

Ralf S.

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Ralf,

Ive done 24k miles so far from new, recently just had it's two year service, just before Christmas, was happening before then and has happened since then...

I'm not sure how a Garage would be able to replicate it..

Starbucks Junkie said:

Ralf,



Ive done 24k miles so far from new, recently just had it's two year service, just before Christmas, was happening before then and has happened since then...



I'm not sure how a Garage would be able to replicate it..

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Can you make it happen to order? If so take the mechanic/technician on a test drive and replicate it yourself. They should be quite accommodating if no fault shows up in the diagnostics

Starbucks Junkie said:

Ralf,

Ive done 24k miles so far from new, recently just had it's two year service, just before Christmas, was happening before then and has happened since then...

I'm not sure how a Garage would be able to replicate it..

Click to expand...

If you've had the beast from new, you'll know that nobody has gone drag racing with it... and 24k isn't really enough miles to wear a clutch out in normal driving... but if there's some slip then it's a possibility.

It could also be something contaminating the plates (e.g. an oil leak)... but even if the clutch is slipping/worn then that doesn't necessarily cause the surging problem, so I'm reluctant to suggest dismantling the gearbox on the off-chance.

Have a look for any oil leak under the gearbox, where the bell-housing joins the engine. If there's some oil there, then there's possibly a leak that could be contaminating the clutch. If it's bone dry then there probably isn't.

Another idea to try is to bleed the clutch circuit. If there's a problem with the slave cylinder keeping the clutch slightly dis-engaged, then it's more likely to slip. Bleeding it might improve that.. and even if the slipping stops only temporarily, then you'll know that something is slightly amiss in the clutch hydraulics.

Once the slipping stops, the surging might stop.. (or they may be completely unrelated). If you can reproduce the surge, then as Alan suggests, take the mechanic for a ride (makes a change ... usually it's the other way round ) and see what they think. I'm a bit short of other ideas at the moment...


Ralf S.

Alanw47 said:

Can you make it happen to order? If so take the mechanic/technician on a test drive and replicate it yourself. They should be quite accommodating if no fault shows up in the diagnostics

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It would be nigh on impossible to replicate this, I have driven the car over the same roundabout where it mostly happens many times and it has not occured, and then out of the blue it will happen..

Ralf S. said:

If you've had the beast from new, you'll know that nobody has gone drag racing with it... and 24k isn't really enough miles to wear a clutch out in normal driving... but if there's some slip then it's a possibility.

It could also be something contaminating the plates (e.g. an oil leak)... but even if the clutch is slipping/worn then that doesn't necessarily cause the surging problem, so I'm reluctant to suggest dismantling the gearbox on the off-chance.

Have a look for any oil leak under the gearbox, where the bell-housing joins the engine. If there's some oil there, then there's possibly a leak that could be contaminating the clutch. If it's bone dry then there probably isn't.

Another idea to try is to bleed the clutch circuit. If there's a problem with the slave cylinder keeping the clutch slightly dis-engaged, then it's more likely to slip. Bleeding it might improve that.. and even if the slipping stops only temporarily, then you'll know that something is slightly amiss in the clutch hydraulics.

Once the slipping stops, the surging might stop.. (or they may be completely unrelated). If you can reproduce the surge, then as Alan suggests, take the mechanic for a ride (makes a change ... usually it's the other way round ) and see what they think. I'm a bit short of other ideas at the moment...


Ralf S.

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All that sounds really mechanically and Techy, and I barely know how to drive a car let alone know how to do any of the stuff you have suggested..

If I was to approach the garage I bought the car from how would you suggest I explain the problem to them in a way that isn't going to make me sound like a nutter?

Starbucks Junkie said:

It would be nigh on impossible to replicate this, I have driven the car over the same roundabout where it mostly happens many times and it has not occured, and then out of the blue it will happen..

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I give up, fresh out of ideas. The last thing I can add that when I first had my car, 2.0 MJ, every time it started from cold it ran rough as a dog until it warmed up. Dealer kept telling me "No fault found" until I drove the car myself with their technician, with a cold start, car covered in frost. FINALLY it was diagnosed as a faulty sensor which did not show up on the diagnostics because it WAS sending information to the ECU, just the wrong information, telling the ECU it was hot when it was cold. Replaced the (very expensive) sensor under warranty, no more problems. Might be an intermittent fault on a sensor that will be a b****r to track down.

When I read "certain places" I started thinking that there might be a ghost who do this lol, sorry but literally I thought that.

Alanw47 said:

Might be an intermittent fault on a sensor that will be a b****r to track down.

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That's what I'm starting to think...

And if I was driving it myself all the time i'd just suck it up and live with it, but my partner was driving it last week and it surged forward at a different roundabout and she nearly crashed into the car in front which had suddenly stopped, really shook her up...

The only time mine ever races ahead seems to be in 4th gear under low load when coasting at about 20mph (auto). I've kinda got used to the little "fault".

It happened to my partner again last night, admittedly it happens more frequeantly with her than myself, different driving styles, she has driven the car twice in two weeks and each time it has happened.

On this occasion she was in 1st gear rolling slowly towards a roundabout, foot on clutch only, then applied the accelerater and the car surged ahead, and she needed to quickly apply the break, luckily this time no near misses...

It is quite hair raising when it occurs, car goes from a couple of miles per hour up to almost 20 in a split second, it really jolts you..

Not sure how to describe that to a garage and have no idea how to replicate it..

Starbucks Junkie said:

It is quite hair raising when it occurs, car goes from a couple of miles per hour up to almost 20 in a split second, it really jolts you..

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No it doesn't.

Starbucks Junkie said:

It happened to my partner again last night, admittedly it happens more frequeantly with her than myself, different driving styles, she has driven the car twice in two weeks and each time it has happened.

On this occasion she was in 1st gear rolling slowly towards a roundabout, foot on clutch only, then applied the accelerater and the car surged ahead, and she needed to quickly apply the break, luckily this time no near misses...

It is quite hair raising when it occurs, car goes from a couple of miles per hour up to almost 20 in a split second, it really jolts you..

Not sure how to describe that to a garage and have no idea how to replicate it..

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Just describe it how you've just described it here.

If it's a Fiat garage then they might already know this problem, if others have reported it (and remember that 500X is more or less identical to 500L and also Jeep Renegade in this respect). If it's a known issue then there be a latest ECU/throttle map which could be applied to reset the car's brains to be less "eager".

It doesn't sound like it should be doing it though.


Ralf S.

Starbucks Junkie said:

On this occasion she was in 1st gear rolling slowly towards a roundabout, foot on clutch only, then applied the accelerater and the car surged ahead, and she needed to quickly apply the break, luckily this time no near misses...

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If rolling towards a junction, why is a foot on the clutch? Take foot off and let the engine just pull gently.

If the clutch is fully down, then there is no drive. So this must mean you are either resting a foot on the pedal, bad practice, or holding the pedal slightly down.
Either of those may cause a little slip, but as more power is applied, the clutch may grab, taking full engine revs to the wheels, instead of losing some with the slip.

This may be a technique issue.
Find a local road with little or no traffic and good visibility ahead and behind. As flat as possible.
Move away in 1st gear, then let go of all pedals. Let the car just roll along with the engine on tickover.
Now gently apply the gas to increase speed. Pickup should be smooth and controllable.
Now change to 2nd, release all pedals and allow it to roll along on tickover again. This will demonstrate the lowest speed it will tolerate in 2nd gear. At or above this speed there is no need to depress the clutch.
Again, from there, gently adding gas should bring a smooth increase in speed.
Many cars will do this in 3rd as well, but will protest at the gentle acceleration.

When moving away, it is easy to be lazy and bring the clutch up before adding any gas. Sadly many instructors teach this way, as it is easier, so lazy. It is poor practice, confuses the engine management computer, and increases cylinder bore wear.
Should always add a little gas to raise the tickover before finding the clutch bite, then gas is added as the clutch is released. Only once moving can the engine be allowed to sit on tickover to pull the car along without gas.
Physics - Basic Inertia rules. It takes more energy to start something moving, than it does to keep it moving.

If the clutch is brought to bite without any gas, the engine computer is trying to maintain tickover against the added load. More fuel is put into the engine to prevent a stall.
As you then push the gas pedal, the first movement tells the computer that you will now decide on fuel input, but the computer is already feeding more than you are now requesting, until you've moved the pedal far enough. The computer responds by reducing the fuel input, which momentarily tries to cause a stall, so the computer adds fuel, discovers it is adding more than requested, and repeats the cycle. Some engines tolerate this better than others. Some will kangaroo, others just push harder than you wished. This is what may be happening.

Thanks for the input guys, when I get paid end of this month I get it into the garage so they can look at it, hopefully it will be a common fault and easily rectified..

portland_bill said:

it is easy to be lazy and bring the clutch up before adding any gas. Sadly many instructors teach this way, as it is easier, so lazy. It is poor practice, confuses the engine management computer, and increases cylinder bore wear.
Should always add a little gas to raise the tickover before finding the clutch bite, then gas is added as the clutch is released. Only once moving can the engine be allowed to sit on tickover to pull the car along without gas.
Physics - Basic Inertia rules. It takes more energy to start something moving, than it does to keep it moving.

If the clutch is brought to bite without any gas, the engine computer is trying to maintain tickover against the added load. More fuel is put into the engine to prevent a stall.

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The problem? with the 500X manual box (which has been discussed before) is that on lifting the clutch off the floor the engine management AUTOMATICALLY lifts the RPM from 850 to 1100/1200 rpm. This is more that I would do in our other cars. Unless on an incline or towing then 1000rpm is enough and reduces clutch wear. With the 500X if you touch the throttle while lifting/releasing the clutch then the engine overrevs. Do this in Sport mode and your clutch will be rapidly worn as the RPM will soar to 2000+ with even the lightest touch.

Personally I've got used to and can switch between our three cars but occasionally on the 500X I do get the clutch and flywheel engagement speeds out of balance. This normally happens at the low speed 1500rpm engagement threshold.

s130 said:

The problem? with the 500X manual box (which has been discussed before) is that on lifting the clutch off the floor the engine management AUTOMATICALLY lifts the RPM from 850 to 1100/1200 rpm. This is more that I would do in our other cars. Unless on an incline to towing the 1000rpm is enough and reduces clutch wear. With the 500X if you touch the throttle while lifting/releasing the clutch then the engine overrevs. Do this in Sport mode and your clutch will be rapidly worn as the RPM will soar to 2000+ with even the lightest touch.

Personally I've got used to and can switch between our three cars but occasionally on the 500X I do get the clutch and flywheel engagement speeds out of balance. This normally happens at the low speed 1500rpm engagement threshold.

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The latest Fiesta does this too. An attempt to make the car do what drivers should be doing, so a good idea in principle, but whilst addressing poor practice also encourages it. Incredibly annoying, and it makes slow moving queues hard work on the left leg, as it won't trickle slowly enough.
This is probably a reaction to issues like the Euro6 Panda struggling to move away, especially uphill, as most will bring the clutch up first, where more power is needed.