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[cheapshots]

Hi guys,

My wife was driving the ForFour 1.3 Pulse (semi-auto), whilst stationary at a traffic light, it turned green so she pressed the accelerator pedal however the rev counter did not move from its idle position (around 1000 rpm) and more worryingly neither did the car!

She said the steering felt really heavy also. She switched it off and then back on and it was working fine after that.

Any idea's?!

[Ocracoke]

Did the engine warning light come on? Did anything display where the gear indicator should be?

If I had to take a guess from the symptoms described, it could be the throttle body that needs cleaning up (there are plenty of posts on here as to how to do that).

[cheapshots]

I should have mentioned this in my initial post, sorry.

No engine light came on or is currently on. The gear selector was stuck on '3'

She then put it in N, turned it off, back on and it was fine.

[Ocracoke]

Right, OK, that sounds more like the clutch actuator, possibly like it could do with some lubrication and then perhaps a reteach.

[cheapshots]

Hmmm... I recently took it in for a service at a smart specialist and specifically asked them to lubricate the clutch actuator, which they said they did.....I might give the throttle valve a clean this weekend anyway, seems easy enough !

[Ocracoke]

Ah, ok. I guess the specialist was S2Smarts? If so, I'll take their word for it that it was lubricated.

Yes, give the TVA a clean - it is worth doing anyway as a preventative nature. As for what happened... the fact that the gear indicator got stuck on "3" and then refused to move (and if it tried, it would likely stall)... still leads me to think that the problem may be around the actuator area but get the small stuff done first (like the TVA) and see if it happens again.

[cheapshots]

Yep, S2Smarts

Your thought process makes sense, I'll clean the TVA this weekend and report back if it happens again. Thank you for your much appreciated help

P.S I've got an iCarSoft i980 diagnostic tool, I'll plug it in this evening and see what lovely error codes it throws up

[CrazyG]

Actuator problems can be intermittent....l remember seeing the
car at S2...and the actuator was working fine after lubing.

Try theTVA clean first and see how it goes from there. If the
problems then re-occur, it could well be time for a new actuator.
Ebay is the place to go/look for the best price for a new one
(usually from Germany), as per the info in posts l've made
on that subject.

[cheapshots]

Thanks CrazyG, I'll clean it this weekend and keep a close eye on it. I ran the diagnostic on the car and there were no relevant stored error codes

The iCarSoft i980 had a live datastream section too with lots of data on the throttle valve actuator and clutch actuator too. Out of interest would we be able to diagnose a problem using the live data stream?

[Alex]

Also check all electrical connections associated with charge and drive systems.

If the throttle didn't move at all even when floored it's probably not a dirty TVA, and the steering being heavy means EPS was cut, like when the battery is discharged or the alternator isn't charging. Clutch actuators also trigger faults and display lines instead of gear position.

When the valve is dirty the car enters limp mode, you can rev it to 2000rpm and even drive it like that, you reach around 60kph by using full throttle.

AMT's are power hogs, maybe the voltage sagged to below operating values and the car just froze before the alternator had a chance to step up?

If the refresh rate is good enough on the data logger maybe you can spot the voltage drop, otherwise an analog voltage meter, car stationary, lights on, ac or at least fan on, simulate waiting at the lights and then wanting to drive off, and see how much the voltage drops when you drive off.

[cheapshots]

Thanks for the helpful post Alex. You thought process also makes sense!

I recently bought an in-car iPhone charger which is permanently attached to the cigarette lighter. I wonder if it's faulty and somehow set the electrics off, hmmm.... I'll check voltage drop like you mentioned, hopefully my data logger refreshes fast enough.

[Ocracoke]

Hmm... After noticing that my dipped lights visibly drop when I was parking up, I changed the battery and earthing leads in my 1.3 and even after doing this, it still does it (Alex, am I correct in thinking that you are using a different battery to the standard one in the 454 1.3?). Whenever I get into the car, the COMAND unit I can hear still spinning the CD in it.

On the subject of earth leads, it could be that in theory that might be causing this. The ones in my car were pretty crusty and got to the point where I could be driving along, go over a pothole or something and the whole thing cuts out or where I park up having got to where I was with no issues at all, lock it, unlock it a few minutes later, turn the key and everything in the speedo cluster just vanishes with the engine not starting.

[CrazyG]

Hmmm...Ocracoke there should be no power to your Comand head unit
until the unit is turned on, or the key is turned to or past position 1.
I'd check into that if I were you.

[Alex]

My nav also chews discs when it should be off, but since i only used the nav dvd in it i just popped that in the glovebox. I know Danny's did it as well. Aux lead made CDs obsolete. Not ok but haven't had the interest to investigate further.

The headlights will always dim to some extent when heavy electrical loads step in. Halogens burn brighter or dimmer based on supplied voltage, they aren't voltage regulated like leds or hids i think are.

So at 12.8v they are dimmer than at 14.4 so with the engine on, and when a fan kicks in or something else loads the alternator, for a brief moment the voltage will drop and the headligths will dim for a sec. If the revs also dip dangerously or the check engine light comes on, that's when you have a problem. When mine had a weak battery if i turned the HID headlights on too quick after turning the engine on, it stalled or check engine light came on.

I use a MOL lead acid battery, 55Ah. I chose it for the 5 year warranty because the last two batteries were short lived. I also charge it whenever i get the chance, i have a ctek 7A charger that tops it up in no time.

[cheapshots]

Update: I've has a really busy period and not cleaned the TVA yet  . The car has been completely fine so far though, will update this thread as I go along