Backfire

Author
Discussion

speed6

Original Poster:

25 posts

265 months

Sunday 2nd February 2003
quotequote all
What causes the speed six engines to backfire?
It has happened about 2 times in the past 7 months of ownership.
First time was because I had standard unleaded in.
The second, which was today.
The funny thing is that I had optimax in which I filled up today.
The past refuel I put standard unleaded in because there was no shell garages around.
When I went to refuel I had 6 litres left of that unleaded fuel left.
So is this what caused it? Is this natural? Is this a problem?

ajvmoore

170 posts

286 months

Monday 3rd February 2003
quotequote all
Never had this - but it sounds great! - methinks something wrong somewhere - I have used all kinds of petrol and variously driven the car with poisoned cats, inoperative Lambdas, mis mapped ecu, wobbling throttle bodies, sleeved cans, carbon can co cans, two cylinders down - but never managed a backfire!

P7ULG

1,052 posts

290 months

Monday 3rd February 2003
quotequote all

What causes the speed six engines to backfire?
It has happened about 2 times in the past 7 months of ownership.
First time was because I had standard unleaded in.
The second, which was today.
The funny thing is that I had optimax in which I filled up today.
The past refuel I put standard unleaded in because there was no shell garages around.
When I went to refuel I had 6 litres left of that unleaded fuel left.
So is this what caused it? Is this natural? Is this a problem?





Seemed to remember from mine that it could run on standard unleaded, so don't think that could be it.Maybe a build up of unburnt fuel?

andyvdg

1,537 posts

290 months

Monday 3rd February 2003
quotequote all
Just to make sure, what do you mean by a backfire ? Is it some occasional light popping on the overrun (when you come off the throttle) or do you mean really, really loud bangs when you're idling or accelerating ?

speed6

Original Poster:

25 posts

265 months

Monday 3rd February 2003
quotequote all
sorry backfire is the wrong name, the right name is Pre ignition.
What it appears to be, is Pre ignition of the mixture prior to a piston getting to near top dead centre and causing the engine to faulter, as if the ignition/explosion was trying to make the engine go backwards. When its happened, the car has been accelerating through (about) 2500rpm in third.



>> Edited by speed6 on Monday 3rd February 16:48