C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

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justajolt
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C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

The engine turns over.

When in gear, the engine pulls under it's usual tick-over and the car moves.

When the accelerator is depressed, there is ZERO increase in revs. The motor keeps turning over at the same speed.

Any thoughts as to how to diagnose the cause welcome from anyone who's seen this before!

wheeler
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by wheeler »

What engine do you have?

justajolt
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

It's petrol

wheeler
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by wheeler »

Will the engine rev up when stationary?
you really need to get it on a diagnostic first & check the live data of the throttle pedal position sensor & check the actuation of the throttle body.
That would be my first steps.

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GiveMeABreak
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by GiveMeABreak »

Pop your VIN up for us so we can determine exact engine and options.

justajolt
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

Engine ticks over, but doesn't increase revs when accelerator pushed, so it's not limp mode (which I think would at least rev a little?)

Update: Removed old pedal unit and opened it up to have a look (I modify Nerf blasters, so I'm not afraid of cracking stuff open!) found and removed dead spider near sensor, replaced it and plugged it in again to see if the arachnid was the issue but still no joy.

Garage wanted scan it but couldn't find the OBD2 connector. Guy who had it before me seemed to love DIY, so the already dubiously wired French car goodness has been subsidised with all manner of other quirks! I had a feeling, removed the lining on the footwell under the glove compartment where it should have been located and out fell not one, but two connected OBD2 interface connectors. I have no idea...

Garage now coding it as I type (we've been meaning to buy our own machine for ages, so I ordered one of those today as well).

Also found a guy on ebay who's going to let us go and get a new pedal unit from him at some point tomorrow. Same guy says that the pedal units tend to break more frequently than other similar models for some reason. Might just have been saying that, but hey! Worth a crack.

I'll put the VIN in later this evening.

RichardW
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by RichardW »

The OBD connector is in the globe box, right hand side, vertical, behind a clip out cover.

Edit, as shown here:


rmunns
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by rmunns »

Not something stupid, like it being set to speed limiting at 10mph?

justajolt
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

RichardW wrote:
22 Mar 2019, 17:54
The OBD connector is in the globe box


That's where it should have been!

Update: New pedal hasn't worked (same part number and re-set electronics after installation)

It ticks over but doesn't rev.

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GiveMeABreak
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by GiveMeABreak »

We have asked for your VIN so we know exactly what you have and do not have.

Without knowing what has been done to it previously, it is hard to comment, but some end up doing a hatchet job - you can't just splice into the wires on these new vehicles without the possibility of interfering with the data network signals on the CAN buses. This can cause signal problems and ECUs dependent upon getting the right data to go into a backup mode.

justajolt
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

VIN is VF7**************[VIN obfuscated, can be read by forum staff]

It might be a case of letting an electritian take a look then. I'm confident the motor's strong, so it'd be a shame to lose the whole vehicle...

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GiveMeABreak
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by GiveMeABreak »

Ok so this is a 1.6 VTi 16V 120 (EP6) petrol with Manual gearbox 5.

There are quite a few technical service bulletins concerning this engine, especially with regard to idling and lack of power, flat spot at 4000 RPM and engine speed not exceeding 1500 RPM etc. So I bet you'll probably have a few fault codes logged, so if you can get those read, preferably by somebody with a Lexia and Diagbox software, it should help point us int he right direction.

Dibber
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by Dibber »

Disconnect air intake from throttle body. Get someone to sit in car with ignition on and ask them to depress accelerator to floor. Check to see if throttle body butterfly opens fully.

justajolt
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by justajolt »

I got an Auto electrician to take a look. The guy who had it before me did a lot of creative diy on the wiring and the ae just said it would be a nightmare to try and work out what was going on! Scrapping it and bought another Citroen Picasso! Thanks for your help anyway guys!

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GiveMeABreak
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Re: C4 Picasso Grande 2008... motor turns over, but does not increase revs when accelerator pressed...

Post by GiveMeABreak »

Yes some people are totally bl**dy clueless with modern vehicle electronics and think they can just bu**er about with the wiring, cutting, splicing and generally bodging everything, rendering the vehicle effectively useless.

A point I make here for any future ‘bodgers’ considering installing any Carlos Fandango gadgets and the like in future!

Really sorry you had to scrap her; seems a total waste, but I hope the next one you have is relatively unscathed from any DIY electricians of the same ilk.