Technical Euro6 1.2 Throttle Response, Hill Start Issues & Watchdog report

[auditt]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Got an e-mail from Service Manager and there are no updates for this issue.He sent me the printouts of current bulletins.As the revs dont change when you press the brake I wonder if the car would perform OK with the brake pedal switch activated?

 

[jrkitching]

re: Euro6 1.2 Throttle Response & Hill Start Issues

As the revs dont change when you press the brake I wonder if the car would perform OK with the brake pedal switch activated?

Not sure I follow your logic on this one .

 

[auditt]

re: Euro6 1.2 Throttle Response & Hill Start Issues

When you raise and lower the clutch the revs change,press the brake at the same time and the revs stay the same.So the brake pedal switch must overide the clutch pedal switch.If you can simulate this the car may run OK.

 

[jrkitching]

re: Euro6 1.2 Throttle Response & Hill Start Issues

When you raise and lower the clutch the revs change,press the brake at the same time and the revs stay the same.

Ok, I think that's new information.

So the brake pedal switch must overide the clutch pedal switch.If you can simulate this the car may run OK.

Apart from the obvious issue that this would put on the brake lights, I'm not sure what other effect this might have have on the ECU if it thought you were trying to accelerate and brake at the same time. Running OK might not be a good description of what the engine would do if faced with this conflicting information.

But it's useful input which may help us to understand better how the Euro 6 engine actually works, where the ECU is getting its inputs from, and how it's processing them.

If the engine is physically the same apart from the addition of a clutch position sensor (and this is purely speculation right now), then I'm thinking a hack involving disconnecting the new clutch sensor might fix the problem, but I've no idea what else you'd need to do or whether it could actually work.

Right now, given Fiat's apparent disinterest in supporting its most recent customers, I'd say the best workaround for anyone contemplating purchase of a new 1.2 500/Panda and who can't live with this new behaviour is to go test drive a Swift or i10.

Or buy a TA.

 

[Palma500s]

re: Euro6 1.2 Throttle Response & Hill Start Issues

As expected the technician from Fiat tested my car today and gave it a clean bill of health. So they are sticking firmly to the line that these cars operate as intended and meet all the european standards even though you can't do a hill start without burning the clutch. According to the dealer Fiat Spain also said there aren't any software updates available for my car.

 

[jrkitching]

re: Euro6 1.2 Throttle Response & Hill Start Issues

As expected the technician from Fiat tested my car today and gave it a clean bill of health. So they are sticking firmly to the line that these cars operate as intended and meet all the european standards even though you can't do a hill start without burning the clutch. According to the dealer Fiat Spain also said there aren't any software updates available for my car.

B***er.

Can't think of anything more helpful to say right now.

If operating as intended means you can't do a serious hill start without revving the engine to within an inch of its life, I'd buy something else.

 

[ahmett]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Ok, I think that's new information.



Apart from the obvious issue that this would put on the brake lights, I'm not sure what other effect this might have have on the ECU if it thought you were trying to accelerate and brake at the same time. Running OK might not be a good description of what the engine would do if faced with this conflicting information.

But it's useful input which may help us to understand better how the Euro 6 engine actually works, where the ECU is getting its inputs from, and how it's processing them.

If the engine is physically the same apart from the addition of a clutch position sensor (and this is purely speculation right now), then I'm thinking a hack involving disconnecting the new clutch sensor might fix the problem, but I've no idea what else you'd need to do or whether it could actually work.

Right now, given Fiat's apparent disinterest in supporting its most recent customers, I'd say the best workaround for anyone contemplating purchase of a new 1.2 500/Panda and who can't live with this new behaviour is to go test drive a Swift or i10.

Or buy a TA.

whatever happened to the NA TA?

 

[auditt]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Disabling the input signal to the ECU from the clutch pedal could be a fix.

 

[zanes]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Several things to bear in mind here;

1) Permanently switching the brake switch "on" is a very bad idea- the "ECU" will throw a hissy fit, your brake lights will be permanently on and trying to get around this will fail the MOT. It also might well start to interfere with EBD, ABS and ESP functionality. This is not a good idea.

The "improvement" described above might well be due to the assistance servo "loading" the intake manifold with the brakes on.

2) Disabling the clutch switch will also break stop and start and the hill holder functionality, and possibly more.

In both cases, the switch is almost certainly not simply a single switch making and breaking a contact on the ECU connector

I would not want to find myself up in court explaining why my brake switch was disabled and that it definitely did not in any way influence the accident I was involved in, because I read on a forum that it "would be fine".

3) This update is a very, very new one. It's entirely possible (likely, perhaps) that not all dealers are aware, or if the "dealer"/DET are the news hasn't filtered through to the person that answers the phone. We also don't know yet what conditions the TSB (if it is that) stipulates for application of the update- it could be a not-technically-a-recall-but-we'll-contact-all-owners-to-advise-them, routine at service time, on customer request or some sort of "last resort". It also might be country specific.

 

[Palma500s]

re: Euro6 1.2 Throttle Response & Hill Start Issues

I have just had an email from my dealer suggesting that I try a 500 with Hill Holder as my car doesn't have this option. I can't really see how this is going to tackle the problem of the lack of low down torque that we 1.2 owners are experiencing but has anyone here got this option and would it help in any way?

 

[muttleysdad]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Hi Guys

I looked a while back at the switch on the clutch pedal, its actually a slot cam moulded out of yellow plastic that drives a potentiometer and is operated by a pin sticking out of the side of the clutch pedal, so you would assume it's generating a variable input to the ECU for some reason.

You can disconnect the plug to it. This has two effects, stops the rev increase linked to the clutch (as expected) and pops the engine management light on.

The car did drive differently but I didn't leave it too long like this to obtain a true picture.

once the plug is re-connected you have to start the engine 6 times to clear the fault light.

being a variable input you would assume there is some calibration software for it, probably built into the system somewhere.

Chris

 

[jrkitching]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Hi Guys

I looked a while back at the switch on the clutch pedal, its actually a slot cam moulded out of yellow plastic that drives a potentiometer and is operated by a pin sticking out of the side of the clutch pedal, so you would assume it's generating a variable input to the ECU for some reason.

You can disconnect the plug to it. This has two effects, stops the rev increase linked to the clutch (as expected) and pops the engine management light on.

The car did drive differently but I didn't leave it too long like this to obtain a true picture.

once the plug is re-connected you have to start the engine 6 times to clear the fault light.

being a variable input you would assume there is some calibration software for it, probably built into the system somewhere.

Chris

Thank you Chris.

This is new information, and one of most useful posts we've seen on the subject.

I'm thinking along the lines of measuring the rest value of the pot, removing the plug, and replacing it with a fixed resistor, thereby getting rid of the clutch pedal input without putting the warning light on.

Longer term, it ought to be possible to reverse engineer the system to produce a replacement clutch pedal switch that removes the unwanted functionality whilst still retaining the necessary inputs to preserve S/S functionality.

 

[UFI]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Just tried the same but nothing happens when in neutral,but when I put it in first and lift the clutch the revs rise and you can drive off without pressing the throttle.I then did the same with my foot on the brake and it behaves the same as in neutral ie no rise in revs.

As a member of the 300,000 city km on a single clutch club, I always let the clutch out at idle.

Most, if not all EFI cars do this. Clutch out, revs drop, the ECU detects this and bumps the revs up to 1200. My 2005 Wrangler does this (AMC engine from the 70's), my 2007 VW TDi does it. It won't do it with the brake on as a safety precaution.

Nothing to do with EURO6 or drivability issues. I can only assume EURO4/5 1.2's do it too.

 

[muttleysdad]

re: Euro6 1.2 Throttle Response & Hill Start Issues

I'm thinking along the lines of measuring the rest value of the pot, removing the plug, and replacing it with a fixed resistor, thereby getting rid of the clutch pedal input without putting the warning light on.

Longer term, it ought to be possible to reverse engineer the system to produce a replacement clutch pedal switch that removes the unwanted functionality whilst still retaining the necessary inputs to preserve S/S functionality.

That would be an interesting exercise. My first though when I saw it was to unhook the yellow slot cam off the pin as it looks quite flexible, I was then going to tie it up at the top end of its travel (clutch out position), but its too close to the bracket that holds it all together so you haven't got the room to slide it off the pin unfortunately. The potentiometer (or whatever it is) feels loose but I can't see how its fixed to the metal plate behind it, I'm assuming its just clipped in place. I'm wondering if it can be unclipped easily?

Chris

 

[Jazzist]

re: Euro6 1.2 Throttle Response & Hill Start Issues

I am driving a 200 mile old 64 reg 1.2 500 on loan this week and very happy with the engine, not noticed any problems. Anything you want me to look for to tell you if this problem still exists?

 

[jrkitching]

re: Euro6 1.2 Throttle Response & Hill Start Issues

I am driving a 200 mile old 64 reg 1.2 500 on loan this week and very happy with the engine, not noticed any problems. Anything you want me to look for to tell you if this problem still exists?

Yes, please can you try this and report back.

With the car stationary and idling in neutral, slowly depress the clutch all the way and then slowly release it. Watch the tachometer - what happens to the revs as the clutch is released?

 

[Palma500s]

re: Euro6 1.2 Throttle Response & Hill Start Issues

I am driving a 200 mile old 64 reg 1.2 500 on loan this week and very happy with the engine, not noticed any problems. Anything you want me to look for to tell you if this problem still exists?

Could you try making a hill start on a fairly steep hill? Starting from 0, that is to say without any momentum. I would be very interested to hear how you get on.
Thanks in advance.

 

[Mercky]

re: Euro6 1.2 Throttle Response & Hill Start Issues

Yes, please can you try this and report back.

With the car stationary and idling in neutral, slowly depress the clutch all the way and then slowly release it. Watch the tachometer - what happens to the revs as the clutch is released?

hey JR, as the main 'controller general' of this thread, have you considered dropping in to a dealer and taking a recent 1.2 out for a test drive? Pretend your interested in trading up or whatever.

 

[auditt]

re: Euro6 1.2 Throttle Response & Hill Start Issues

On our car the revs dont rise when in neutral,it has to be in gear.

 

[Officina red]

re: Euro6 1.2 Throttle Response & Hill Start Issues

No rise in revs on mine either, a steady 850 revs in neutral.