Technical Fast idle - 2001 JTD 110

[MultiPa]

Hi - the multipla has been behaving impeccably of late, although it had a new battery just before Christmas and has since started flashing the glow plug light, although it always starts with no problems.

However, on the way home tonight it seemed to be running away - I thought at first it was running really well; it felt fast. Then I hit traffic and realised it is idling at about 1200 rpm. When you take your foot of the accelerator it seems to carry on accelerating, although there was too much traffic to really tell if it was as I kept having to brake.

Anyway, I've had a search, and found two threads. One suggests it might be a connection in the passenger footwell:

https://www.fiatforum.com/multipla/195065-fast-idle-throttle-sensor-switch.html

Can someone give me a better idea what I am looking for?


The other suggests it might be something to do with driving it with the glow plug light flashing and I need a diagnostic (there is no error light on the dash when you drive it though, once the glow plug light goes out)

https://www.fiatforum.com/multipla/232682-high-idle-revving.html

Any other advice much appreciated. As ever money is of the essence, and I have to drive it to that London on Sunday (although it runs fine, so touch wood it won't be a problem even if it isn't fixed by then)

Thanks in advance for any advice.

 

[Zundapp]

Ignore the flashing glowplug light, that doesn't cause any problems whatsoever.

It's most likely a poor connection at the throttle potentiometer or at one of the electrical connections leading to it. Plenty of threads re this issue.

The joys of Italian electrics! :yuck:

 

[MultiPa]

Thanks for your replies - changed my laptop and lost my password but finally got around to getting a new one.

Just an update on this anyway - it fixed itself. That's my kind of problem

I noticed that you could kill the idle to a more normal level by putting your foot under the pedal and pulling it up. Obviously there is no throttle cable as such, but I guess a few days of doing this has freed off some tension in the mechanism, or caused it to re-calibrate, or cleaned the contacts - or something like that.

It idles properly again whatever has happened, so I'm happy.

Just hoping the worn bushed at the back will mend themselves next ...

 

[MultiPa]

Well, that didn't last.

Yesterday it was like driving a car-possessed.

Sometimes I'd stop at lights and it would be fine. Sometimes the revs would just keep rising to about 3,000. Sometimes they stuck at 2,500.

Engine braking was erratic to say the least.

Anyway, thanks to advice on here I poked about with the white connector in the passenger footwell and it seems fine again. For now.

 

[QinteQ]

"poked about with the white connector in the passenger footwell"

 

[MultiPa]

Works for me

 

[QinteQ]

Works for me

- MultiPa .. .. I wasn't taking the **** I was observing how many times this easy fix helps people

 

[MultiPa]

I know you weren't - I was joining in - I think we were both smiling when we made our posts

(And miraculously it's still working - all I did was jer-jer -jer jiggle it as Arkwright from Open All Hours would say - I didn't even disconnect it and clean it)

 

[QinteQ]

Sorry about that M8.

It even to this day, all this time later, amazes me how many people have spent loads~a~wonka replacing parts that are not needed.

I looked at this once yonks ago, after all a wire is a wire etc and couldn't figure out why this bog standard bit of wire could have such a dramatic disabling affect on the car, there's a post I made in great technical detail somewhere on this site about 2 years ago.

I essence the TPP sends a voltage which is read as Ohms resistance / over / Throttle Position / by the ECU and any - even the tiny-est resistance introduced into the cable sends the 'brain' into protection mode.