Strange hiccup on heavy acceleration

[tigerdog]

And you are running the correct plug-gap of 0.8mm … right?

This is worth checking even when everything else is sorted. If running NGK plugs, last I looked they didn't make one pre-gapped to 0.8mm, so it needs to be manually set. At greater than stock boost, Smaug had a similar misfire until I double-checked the gap on the plugs (NGK iridium.)

[LeedsMike]

And you are running the correct plug-gap of 0.8mm … right?

This is worth checking even when everything else is sorted. If running NGK plugs, last I looked they didn't make one pre-gapped to 0.8mm, so it needs to be manually set. At greater than stock boost, Smaug had a similar misfire until I double-checked the gap on the plugs (NGK iridium.)

@tigerdog - after a 30 minute search for some feeler gauges and an SP socket, I eventually got the plugs out and tested. Guess what, they were all between 0.85 and 0.9 - so I made the adjustments and went for a test run and the problem appears to have gone away.......the annoying thing is that the car has been 3 times to a Lotus specialist since I've had it and I naively assumed they would check things like that.... anyway, a lesson learnt...

Hi, sorry busy for the rest of the week.

The injector pulse width is briefly constant (that means that there is no increase in fuel) as it switches to open loop. zoom in to one of the peaks and plot Pulse width and closed loop.

Also plot secondary throttle and rpm or throttle position - you lift off just as it opened hence the suggestion to change gear later - did you notice the difference?

Thanks @Simon_P I had a good look through that data and will record some more runs tonight when there is less traffic. Notwithstanding the above good news, I need to repeat the same runs I was doing before and compare the data. I will share in this channel as it gives a good before/after I guess....

Thanks so much to everyone who has helped on this one....I learnt quite a bit along the way which is always a bonus!

[HJ2]

Not sure if the gap difference is large enough to explain all of this…

[Tuga2112]

I agree with HJ
i would expect something like that to be more noticeable with hard starts than high revs (lower voltage while cranking would have more dificulty to spark than the while the alternator is pumping out health amounts of pixies