143 replies to this topic

[Dan r]

Hi, I went to the goodwood members meeting yesterday which was a good day out, but on the way down I was at full load for a while on my 2.2 sc and it spluttered a bit, so I backed off and it went into limp home mode and the mil light came up on the dash. I keyed off and back on, the mil light cleared and it ran smoothly but now badly misfires on high load. I had a good look around the engine and couldn't see anything a miss (it's Paul Coopers old lightning Yellow car which has been looked after very well), connected my scan tool when I got home but showed nothing, I plan to connect my scangauge and take it for a drive to check live data to see if anything is obviously going wrong like throttle pedal and MAP later on but wondered if anyone had a similar experience or recommends checking something? Car runs perfectly on light load but I may be hearing a bit more whistling and boost noises on light boost than normal, not totally sure. I'd imagine that the there would be a lambda fault if the fuel pump wasn't supplying enough fuel right? Thanks in advance for any input. Dan

[siztenboots]

Sounds more spark related

[Dan r]

Can higher cylinder pressures effect spark? It only occurs under high load.

[siztenboots]

Yes it is critical point where spark has to be perfect condition

[siztenboots]

Pull fuse 8 to reset fuel trim to 0 in case it has learnt a large negative trim value

[vocky]

possibly the coilpack or rusty coil pack extensions. Might be worth a new set of plugs.

[Nev]

Remember not to overitghten the plugs when they go in !!

 

Also, consider reducing your plug gap a bit, as the spark might be snuffed out by the boost.

Edited by Nev, 21 March 2016 - 09:37 AM.

[PaulCP]

Hope it's something simple Dan. Plugs were renewed 2 years ago but it's probably worth eliminating the easy picks first as suggested above.

Edited by PaulCP, 21 March 2016 - 09:55 AM.

[Dan r]

Thanks all, I'll look into that when I get chance and let you know how I get on. Dan

[CHILL Gone DUTCH]

Seems to be a common problem on SC cars ATM

[smiley]

My last wideband full run up to 7500isch was rewarded with a shutdown, and an eml with code 1271. (Normally lod). Interested in the plugs story.

[oakmere]

It is worth taking the coil pack apart and cleaning all contacts and earth points. I use a contact cleaner/protector when I change the plugs every year.

[Dan r]

Finally found time to take the car for a spin with replacement coilpack and new plugs which made no difference unfortunately. Will try a new MAP sensor courtesy of Martin soon hopefully. Any other ideas??? Engine runs perfectly until about 70% load when it misfires badly and then runs rough until key off and on again but no mil lights on dash or scan tool??

[Nev]

What spark plug gap are you setting?

[Dan r]

Hi Nev, I set them to 0.7mm which was 0.1mm closer than the ones I took out, although they ran fine like that for 2 years.

[Bargi]

So to confirm. All good for years as is. Misfires under heavy load and continues to run rough until you restart it? Sent from my SM-G920F using Tapatalk

[Bargi]

Does sound like something is triggering limp home even if it's not showing the eml anymore. Sent from my SM-G920F using Tapatalk

[Dan r]

So to confirm. All good for years as is. Misfires under heavy load and continues to run rough until you restart it? Sent from my SM-G920F using Tapatalk

Pretty much, it doesn't feel like a calibrated limp home though, more like running quite rough, although saying that I have only had this happen while at speed, so have keyed off and back on to jump start in 5th as there's always been something behind me. Literally feels like it dies under boost, fine driving around at Sunday driver speeds.

[Bargi]

Change the map sensor and then get back to us. Being CS map your getting the right one? Sent from my SM-G920F using Tapatalk

[Dan r]

Will do, thanks for the input.