RE: misfire under load

[Simon Allcorn <simon.allcorn@cartesian.co.uk>]

Ok So I've found out some more about the mis-fire. It happens in any gear 
(but 1st) at 1.8k under any kind of acceleration, but only goes on till 
2.3k and has full power / no misfire above this. Given this I *think* the 
HT leads are fine (IMHO HT leads / caps / rotor arms can cause intermittent 
mis-fires (which is what this started out like so far point Iian) and / or 
missing on a cylinder all the time)) but a mis-fire that is very repeatable 
and only there for some of the rev range I think is more lightly to be fuel 
or air starvation. Fuel starvation in this case I think is unlikely because 
it is fine under high load above 2.3kRPM. Sooo my thinking is leading to a 
blocked / restricted air filter effectively causing over fueling at about 
1.8k. BTW I've got no evidence to back this up (other than the mis-fire) 
but I'll be changing the air filter in the next few days to see what 
difference it makes (I do know that when I had this car between 96 and 98 I 
never change the air filer - ugly!!)

Simon

87 Coupe Quattro (no turbo!)


On Monday, November 15, 1999 8:41 PM, Iain Atkinson 
[SMTP:iain.atkinson@virgin.net] wrote:
> Simon
>
> How old are the plug leads and dizzy cap/ rotor arm???? My car was acting 
up
> with an odd misfire recently and changed all three items, misfire now 
gone.
> I would use OEM plug leads if I were you. Also pull the spark plugs and
> check their colour, mine had two plugs that were fouling because of bad
> leads.
>
> Hope this helps
>
> Iain