1.2 puretech turbo misfire under load

[sjhaycroft]

It only happens when my foot is to the floor.

[sjhaycroft]

and only does it in 5th gear however last night is did it when foot was to the floor in 3rd gear. Prior to last night it's only ever done it in 5th on the motorway and when foot is right down on the accelerator.

[Twig62]

sjhaycroft said:

Twig62, how long your 208 been doing it for?

Anyone any ideas as to the cause of the misfire?

As far as I can remember it's done it since it was new. It's now 20 months old/21,000 miles. Only seems to do it at 70 + MPH and nearly always when I hit the accelerator pedal hard (mines an auto by the way). It can go for over a month without doing it and other times may do it several times in a week. It's due for its second service soon so will mention it to the dealer when I book it in, but as it's intermittent I don't hold out much hope for them finding anything unless it's a common problem.

[Bennachie]

Its only a baby engine with a tiny turbo so does not produce prodigious torque. Sure you are just asking too much of it in too high a gear? Cruise tin 5th on m-way is pretty lazy rpm. Slot it down one and try it........... does not really get into its stride until 1.8 k

[Twig62]

Bennachie said:

Its only a baby engine with a tiny turbo so does not produce prodigious torque. Sure you are just asking too much of it in too high a gear? Cruise tin 5th on m-way is pretty lazy rpm. Slot it down one and try it........... does not really get into its stride until 1.8 k

Mine is a 6 speed automatic but is still turning over at around 2300 rpm at 70 MPH. I would imagine that the OP's manual Cactus is doing more than that in 5th.

[sjhaycroft]

So are we saying it's normal for the engine to do this?

[Bennachie]

No

[sjhaycroft]

Twig62, did you ask about the issue at your second service?

Regarding reducing the spark plug gap that mignon mentioned. I was on a parts website looking at spark plugs and it said 2 bosch plugs were compatible with this car, the only difference was that the spark position was 5mm on one and 4mm on the other. What would using one of these over the other do to the engine?

[E-bmw]

sjhaycroft said:

2 bosch plugs were compatible with this car, the only difference was that the spark position

What exactly do you mean by "spark position"?

[sjhaycroft]

[sjhaycroft]

[E-bmw]

OK, I can see an arrow pointing to 4mm & 5mm but that doesn't tell me what you mean by spark position.

It is not a term I have ever heard before, what is meant by spark position?

[sjhaycroft]

I'm guessing it's the spark plug gap?

This is from NGK website

[E-bmw]

No, that is electrode gap in your information posted earlier.

4 or 5mm would be MAHOOSIVE for a spark plug gap, most are 0.6 to 1.2mm.

[sjhaycroft]

Sorry, my mistake. When I had a look at the plugs that were taken out of my car when it was serviced I thought 4/5mm would be big. What would the difference in those 2 types of spark plug on the engine performance (if any)?

[GreenV8S]

The distance that the electrode projects from the body can vary. It isn't usually listed as a dimension in plug specs, but it's possible this is what the measurement is referring to.

[Mr2Mike]

The number relates to how far the centre electrode projects past the end of the body. However if you use this pdf to decode the Bosch part numbers for those two plugs (ZR 6 SPP 3320 and ZR 5 SPP 3320) then the only difference is the heat rating.

[Bennachie]

As it is an auto and it only does it when your foot is to the floor..................its not kickdown activating, or trying to activate is it? Have you tried pushing the pedal down until it reaches the kickdown switch and no further?

These are brilliant little engines.

[sjhaycroft]

Mines a 5 speed manual. Is's twig who's got the 6 speed auto.

[Bennachie]

What a mistaka to maka...