Random misfire whilst on idle & other faults including limp mode.....

[Chris205]

Hi chaps,

As my car has just been put back on the road after having 3 months off from the daily slog, it's now decided to develop a fault. Brace yourselves as I've got a few things

First of all heres what I've had off the car since i last used it daily:

Inlets both top and bottom
All associated sensors for the inlets,
Injector rail
Throttle body (Routine clean carried out)

Now after I'd fitted the inlets, I ran the car and it had an irratic (sp) idle which was going up and down, fluctuating between 1250-1650 rpm. It kept doing this which I felt was strange, possible a seal/gasket not quite sitting right. Any how I left the car for a week or so, went back, drove it for 2 miles and ever since the idle has been fine, never fluctuated etc.

Last night after around 50-60 miles the electical fault light came on, it went into limp mode, turned the car off, full power back, everything was great, on the return leg of that very journey it did it again. Never done it today though, and only seemed to do it when on full throttle, I had this problem before which turned out to be the throttle body, which I replaced and has been fine for the last 6 months.

Next, today the car decided it didnt like to have the standard exhaust attached, one of the bolts worked its way loose and the exhaust came out of the centre hanger and got dragged unwillingly accross the floor for a mile or 2. I arrived at my brothers work for it to be sorted out and he said when he came to start it, it began to misfire, run very very low on idle (it usually sits around 900-950rpm, now it was struggling to hold 600rpm. Under light throttle it was misfiring, giving the car more throttle seemed to clear it but once you let off the throttle, the idle had settled and it started again.

It's done it again around 3 hours later, I started it up, let it sit on the drive for a few minutes to get the oil/water temperature up when I heard it do it again, so I gave it some throttle and it cleared its throat.


I'm really unsure what it can be, as the car is always ran on vpower, all the sensors have been checked and are all the same as they were 3 months ago, albeit with a different inlet manifold on.

I'm starting to lose patience with it already, so any help or ideas would be great.


One thing I did want to question was atm I'm running a de-cat with a standard cat back, I cant avoid this, I'd prefer to run it with a performance cat back, however the specialist I've got it booked in with cant do it until the beginning of march.

Could the smaller bore size/extra flow created from the de-cat be choking up the cat back, causing the ecu to be confused and throw a tantrum?

Sorry for the essay, want to get to the bottom of this before I put an axe through it

 

[Wayne-G]

When your cars going into limp mode on full throttle it sounds like you have a Faulty throttle potentiometer, my 1.2 was doing exactly the same, did it 4-5 times withing the space of a month then hasnt done it since :S Think there about £20-£30 ish, i havnt replaced mine, if it does it again i definatley will. If you look have a browse on the tinterweb there quite common to go on the clios. Hope this has helped with one fault anyway! The joys of owning a french car Wayne.

 

[Dan519]

it'l be something not plugged in, something wet, or the throttle body playing up. When you clean the TB, did you lubricate it? If you didn't then the degreasing chemicals will dry out the bushes the spindle sits in and create friction, this will potentially stop it reacting how the ECU wants and throw it into fault

 

[MR.172 Cup]

This is exactly the same as mine, on the diagnostics meter it said "df002 throttle potentiometer circuit track 1 and 2 " and then it went on to say incoherence between throttle track1 and track 2! I'm gona take it to Dan soon to sort out and hopefully it stops this. Does yours come up with the engine management light on the bottom right hand side of the speedo?

 

[Chris205]

The EML is always on anyway due to the de-cat.

That sounds like the throttle body mate, wonder if mine is doing the same, not sure why it started misfiring though

 

[MR.172 Cup]

Oh fair enough. Have u had the fault codes read?

 

[MR.172 Cup]

Like Wayne said it could be a faulty throttle potentiometer which wouldnt be too much of an expense!

 

[Dan519]

Like Wayne said it could be a faulty throttle potentiometer which wouldnt be too much of an expense!

all part of the throttle body. ~£315 new

 

[Chris205]

Had it on the diagnostics, came up with pre and post cat lambda sensors and problem with throttle

 

[gti6steve]

I've had a decat on mine for six months and no eml light for me I changed both lambda sensors for new ones when I fitted my yozza what Danny said sounds right though you do need to lubricate the throttle body after cleaning it

 

[MR.172 Cup]

Sorry, got confused with throttle pedal lol! I haven't done anything to mine yet and the lights have gone off and it hasn't been in limp mode for a while! Going on a drive tonight so shall see if it comes up!