Formula 1 teams will be informed on Saturday morning about whether the FIA intends to take any further action over the off-throttle blown diffuser issue, after controversy erupted on the eve of the British Grand Prix.
Red Bull Racing team principal Christian Horner and McLaren boss Martin Whitmarsh clashed in public at an official FIA press conference at Silverstone over concessions that have been given to engine manufacturers to ensure their reliability is not hit by the ban on the off-throttle use of blown diffusers that is coming into force this weekend.
Whitmarsh was unhappy that a technical directive issued by the FIA on Friday morning left the way open for the Renault-powered teams - which include Red Bull Racing - to use 50 per cent of throttle blowing while the drivers were braking.
Horner responded that the decision, given to Renault on reliability grounds and relating to exhaust valves, was only fair because the Mercedes-Benz outfits were allowed to use engine over-run under braking to help with crank case pressure.
The situation rumbled on over Friday evening and FIA race director Charlie Whiting met with engine representatives for a lengthy meeting to discuss their concerns and try to find a solution that was fair for everybody - and prevent a situation where other engine makers try and find grounds to justify a similar 50 per cent limit.
AUTOSPORT understands that Whiting will decide overnight if further action needs to be taken, and the teams will be informed before the start of final free practice about the FIA's view on the matter.
Horner and Whitmarsh both expressed frustration at the situation during the FIA press conference when they were asked for their views on the matter.
Horner said: "There was a technical directive which effectively turned it all off. That was obviously with reticence by the manufacturers and it has been very much a manufacture issue.
"Certain teams were then allowed to have fired overrun, to fuel their over-run, of which there are also, obviously, secondary benefits through the exhaust plumes and thrusts that that creates. But that was permitted."
He added: "It would be unfair to allow fire over-run and not allow the same parameters for another engine manufacturer. I think it's a very, very difficult job for the FIA to pick their way through this and I think all credit to them, they've looked to try and be as fair, balanced and equitable as they decreed that they would be through the technical directive, to come up with the solutions that they have.
"We're not totally happy with the solution that we have, that's for sure. I'm sure Martin isn't with his and I'm sure there are a lot of conspiracies in the paddock that these are the reasons why Red Bull is performing or McLaren is performing, or some cars aren't performing. That's just circumstantial at the end of the day. The fundamentals are that the engine manufacturers have been treated in a fair and equitable manner."
Whitmarsh responded: "When the goalposts are moving partway through a practice session, then I think it makes it quite difficult. I think that with the benefit of hindsight, it would have been better to make changes at year end which I think Christian would agree.
"I think that to do this and to do it a fairly cloudy and ambiguous and changing way inevitably, in a competitive environment, every team feels that it's been hard done by.
"At the moment, I think potentially a lot of teams will end up making an argument to cold blow. Renault have been in that domain for some time, other teams haven't and don't have that experience but we're talking about a very substantial performance benefit here..."
He added: "It's messy and I think the intention people believed was that we were going to stop exhaust blowing when the driver didn't have his foot on the throttle. I think that was the simple concept but that concept has been deflected and therefore it hasn't been clear. And the fact that these things were only coming out during the course of today is fairly extraordinary.
"But nonetheless, I'm sure we will remain calm and pick our way through but I think it's probably better to make changes to the regulations between seasons, not in season and also make changes to regulations which are clear and unambiguous.
"I think at the moment, a lot of people are clearly getting emotional about the situation and I can understand why: it's frustrating for the engineers not to know what it is that we're allowed to do, because these changes... by cold blowing you're getting 30, 40 points of extra rear downforce in braking and that's quite an attractive thing so if you can do it, then you're going to try and do it aren't you?"