Superlight R Misfire- any ideas?

[switey]

Hi- i'm scratching my head over a misfire on my Superlight R. She has been running perfectly, but has just started almost stalling- even when under full throttle at speed. As soon as this happens, it then seems to sort itself out and run OK again for a minute or so. Also when I start her, she idles perfectly for about a minute or so, then the revs drop and she stalls.....any ideas? I wondered if it could be a blocked fuel filter- but not sure if this car has an in line filter, or where it would be.

 

Switey

[k80rum]

Hi Switey. The fuel filter is just behind the rear bulkhead behind your seat. Two bolts secure it to the bulkhead. You can replace it with a Metro one from Halfords. Myles has some very useful info on his site here

 

With regard to the near-stalling, I'd see whether there was any consistency to it at startup and at particular revs when under load/whether it's only before the engine's warm or if it happens when it's up to temperature too. It could be an air leak - It might be worth starting by checking the vacuum pipes that run across the top of the throttle bodies and into the fuel-trap thing on the bulkhead and from there back to the ECU. Any leaks here might cause that sort of unpredictable behaviour. After that, its probably worth checking the HT leads, particularly the one from the coil. Angus has some helpful stuff on his site about a similar problem if I remember correctly. (A search for "Angus & Tessa" on this site should find you an article with a link to his).

 

Edited to say - just found the link: here

 

Best of luck with it,

 

 

 

Darren E

 

With an all-new website

K80RUM Superlight R #54

 

 

 

Edited by - k80rum on 22 Apr 2007 17:41:22

[switey]

Cheers Darren- you have snt me off on a journey of discovery......I will start with the fuel filter I think and progress from there!

 

Switey

[jerrypike]

sounds similar to the symptoms i had when the cable from the flywheel sensor had started to fail in part of the insulation (metal screened?) and sent a 13,000rpm message to the ECU with instant fuel shut-off

very tough to find- required clever man with computer and rolling road to log spike on screen and see cable arcing (it was dark by then ☹️)

suggest looking at the cable very carefully and watching it whilst running engine in the situation it occurs

hope you fix it

 

jerry

[Geoff Dixon]

Flywheel crank sensor

[ruff seven]

Hello Jerry, hope you are well, interesting fault on the cable shielding, I have a odd missfire on a r500, that feels very much like fuel and has given me a bit of a runaround, I must look int that.

[jerrypike]

hi ruff

trust all fitted well

yes, it was a strange and unusual problem, haven't heard of any similar, but i think it was due to the cable coaxial shielding giving way- could see little blue electrical arc at the end

 

jerry