Misfiring - Changed Coil and Plugs - No Errors On The Scanner!

[MrBox]

1.2 16v D4F

This is driving me up the wall! Wouldnt start one morning so changed the coil, started fine but then went to drive it up the road for a blip and begins spluttering, sounded like it was firing on 2. Waited half hour started it again and got about 5-10miles down the road then goes into Limp Mode! So get it plugged into the scanner and im getting Throttle Sensor. Gave all the connections a good clean with some WD and the Engine Management Light goes off, get it plugged in again and 'No Errors', But is still misfiring but if i am light with accelleratioin its not so bad, if i floor it, she splutters like a B****. Is worse on pull-away and on inclines! Help would be greatly appreciated .

 

[MicKPM]

Live data/resistance check on the pedal tracks required to ensure conformity. Also, the 1.2 16v is plagued with electrical gremlins of which a poor motorised throttle body is an issue... they are problematic so should be ruled out. Other issues are mainly wiring related so inspect the main loom at the rear of the engine/airbox for signs of damage... specifically the security tab over the ECM multiplugs as this rattles about and is known for cutting thru the PVC sheathing creating a short to ground path.

Does it only do it under load (As in when the vehicle is moving) or does it also misfire when you're sat revving it?

Mick

 

[Rob.]

Does it rev up high or is it limited to about 3 - 4 k

 

[MrBox]

Hey Mick i have checked the ECU and the black box is not on there and there is no wiring damage to the loom, also it will missfire when i rev on a standstill and it is not limited it will let me rev too 5.5k ish, so you rekon i should check the throttle bodies? Thanks guys!

 

[Rob.]

I've seen one with same problems with a blocked cat.
Was hard to find the problem

 

[MrBox]

Oh Oki Doke, but it had a new cat last year ?

 

[Rob.]

It's not very common for the cat to block and and make problems, But we have seen it a couple of times

 

[sideways danny]

Oh Oki Doke, but it had a new cat last year ?

I've seen it. The car i found it on had had a new cat the previous year too

 

[MrBox]

Right! So new cat, maybe swap the lambda sensors over? Then if not check for any air leaks/inlet?

 

[MrBox]

Hey Mick i have checked the ECU and the black box is not on there and there is no wiring damage to the loom, also it will missfire when i rev on a standstill and it is not limited it will let me rev too 5.5k ish, so you rekon i should check the throttle bodies? Thanks guys!

 

[Rob.]

Right! So new cat, maybe swap the lambda sensors over? Then if not check for any air leaks/inlet?

Most likely not the cat so check it 1st. If there shagged it will normally all be rattly.

We sell the cats for £70 posted

 

[MrBox]

Haha thats good to know cheers Rob ! .. i think its okay too be honist doesn't appear to rattle! Just stuck in a rut now as to what to do next !

 

[Rob.]

What plugs are misfiring its normally 1.4 or 2.3 if its coil pack problem.

 

[paul6]

had this exact problem bud, changed my HT leads to Magnecor, runs smooth as a dream now

 

[Rob.]

Plugs are part of the coil pack on the D4F

 

[paul6]

ahhh sorry fella

 

[mw51/bl172]

tried the tdc sensor??

 

[MrBox]

Haha yeah so thats no good . May get on it tomorrow and try swapping the lambda sensors! if not have a wack with taking the inlet and airbox off and give it a good clean! May be a moisture issue?

 

[MrBox]

Yeah the TDC is finee

 

[MrBox]

What plugs are misfiring its normally 1.4 or 2.3 if its coil pack problem.

Im not sure too be honist! but i have put a brand new coil pack on?

 

[mw51/bl172]

my 172 was doing what urs is doing changed no faults came up so changed coil leads plugs then it came up fault on the tdc thats why i said that also are all your relays clean and have no corrosion on them??