Throttle body, throttle pedal or something else?!

[Djw John]

Been chasing an odd fault on a 2001 1.2 16v, bought it as a non runner, replaced the top loom and the main earth (with one from a working car we previously broke) and got it running.

The problem is, if you press the pedal slowly it drives fine, you can take it up to the redline and its fine. However if you hit the pedal hard, not even all the way down, it revs all on its own.

This video shows what I mean. The first rev is pressing the pedal slowly and has you can see it goes to the redline, in the second rev I hit the pedal hard down to the floor and kept it there, the fluctuations are all of its own doing.

The 2 points of note are that fault code p0440 is the only one showing and the dogbone is shagged so there's a bit of engine movement, otherwise I've not spotted any other issues.

All ideas are very welcome!

[video=youtube_share;XaqY1E9jkOc]http://youtu.be/XaqY1E9jkOc[/video]

 

[Alan]

Limp mode mate, plugs, happened to my old 1.2 x

 

[Dan@SJM]

Usually the pedal causes that

 

[Djw John]

Brand new plugs 40 miles ago Al, that was my first thought to, should've said!

Cheers Dan, I'll go find one then and try it out

 

[Toastfrenzy]

Mine did this, turned out to be the crank sensor....Dan at 519 replaced both the bit of loom and the crank sensor itself....

 

[Alan]

Idle control valve?

 

[Djw John]

I'll give the pedal a bash first as it was my gut feeling earlier, will update once I've tried everything. Probably with pics of it on fire

 

[Djw John]

New pedal, crank sensor and carbon canister solenoid fitted. No change. At all. f**k.

 

[Djw John]

Btw also left the carbon canister solenoid plugged in but removed from the canister itself, defo working as you can feel it sucking air but the symptoms are exactly the same with it hanging in fresh air

 

[Djw John]

In between clutching at straws I've cleaned up all the earths and decided to put a new tb on it, won't be able to do anymore to it for a few days though

 

[Mar172]

Djw John
Where did you get the tb from . Mine is sticking an the idle flutters between 1k to 1.5 an told it's worn out
Thanks

 

[Djw John]

I see you've got a 172 mate, this is a 1.2! However, I also know 172s well! Before you go replacing your tb I would clean your idle control valve, then replace the throttle cable and if its still playing up then clean the tb and if its still doing it then you'd maybe have to replace it but its usually one of those fixes that sorts the problem. For me it was a new cable last time round.

 

[mr.pink87]

Faulty tb or pedal would trigger the electronic fault light. Coilpack and leads fine? Had the same symptoms on my 1.poo but with electronic fault light on and it was a faulty loom connection (main engine loom to ECU).

 

[Djw John]

Picked up a tb today but not had a chance to fit it yet, not holding out much hope but its worth a shot. Its just had a new loom fitted as it had got so bad it wasnt even starting before! Once I've fitted this tb if it doesnt work then I'll have to give it to an auto spark and admit defeat!

 

[fraz101]

It's probably the TB but i have also seen ECU's throwing up errors like that too.

 

[Joe#]

It could be the TB if its the earlier 1.2 16v engine. It's inside the inlet manifold itself isn't it? Mine was really dirty when I first bought mine.

 

[incy-spider]

ECU

 

[Djw John]

Mine did this, turned out to be the crank sensor....Dan at 519 replaced both the bit of loom and the crank sensor itself....

A well done to you I replaced the crank sensor and it made no difference. Then I realised that he plug was rattling around by a mm or 2. Fixed that and all seems well now.

Anyone want to buy a pedal or tb?!

 

[Toastfrenzy]

Any how, glad you're all sorted......

 

[Dan519]

A well done to you I replaced the crank sensor and it made no difference. Then I realised that he plug was rattling around by a mm or 2. Fixed that and all seems well now.

Anyone want to buy a pedal or tb?!

that's exactly why the loom has the updated section available

 

[Djw John]

Yeah I know, had to do it on my 172 last year but this was different symptoms which threw me!