[urq] suddenly lean

[spot.ontheroad]

Brandon
Funny you should say that because I have been racking my brains (both cells) 
trying to solve this and had come to the same conclusion. I have no apparent 
tears in hoses, no apparent air leaks, at least none that would cause such a 
drastic drop in fuel/air ratio. So all it leaves is the fuel supply itself. 
The only thing affecting fuel supply under accelleration is the flap. I'm 
wondering if when I do a quick change the pressure built up surges back 
through, slamming the flap shut and at this point it is sticking. I will 
investigate at the weekend.
Thinking about it I have noticed that for some time when I pull up at the 
end of a trip sometimes the A/F meter shows it rich at tickover and 
sometimes it shows lean which with hindsight suggests it is not returning to 
exactly the same position at rest.
Anyway the flap is looking favourite at the moment.
Many thanks for your thoughts.

All the best

Keith
----- Original Message ----- 
From: "Brandon Rogers" <brogers at terrix.com>
To: "spot.ontheroad" <spot.ontheroad at virgin.net>; <urq at audifans.com>
Sent: Tuesday, January 31, 2006 10:29 PM
Subject: Re: [urq] suddenly lean


> Wouldn't that be caused by the sudden shutting of the air plate whan you 
> shift (presuming you let up on the gas pedal), and hence dramatic decrease 
> in fuel supply?
>
> Doe sthe AFR catch up as it revs?
>
> my initial thoughts...
>
> Brandon
>
>
> ----- Original Message ----- 
> From: "spot.ontheroad" <spot.ontheroad at virgin.net>
> To: <urq at audifans.com>
> Sent: Monday, January 30, 2006 3:57 PM
> Subject: [urq] suddenly lean
>
>
> I have a problem that has occurred suddenly. It's early days trying to 
> identify the culprit but the symptoms are as follows:
> If I accellerate hard in second, it pulls like a train and will continue 
> to do so for as long as I hold the revs, the air fuel meter reads rich, 
> showing the necessary enrichment is occuring. Then when I shift in to 
> third the power goes, the engine stumbles and the air fuel meter shows 
> suddenly lean.
> The same happens when suddenly accellerating in third. It pulls well and 
> is enriched, then when I shift to fourth the power goes, it doesn't want 
> to rev and the mixture goes lean.
> I have tonight had all the intake hoses off to look for splits that may 
> open under boost. None found. The only thing I have done to it recently is 
> change the oil and filters and put a new set of plug leads on it.
> The motor is a WR with 7.20 CR, zener diode mod and a 1 bar WG spring. My 
> boost gauge with tell-tale says it is hitting 1bar boost as expected.
> Any suggestions gratefully received.
> Many thanks
>
> Keith
>
> '87 WR
>
> p.s. the 1988 TransAm footage was excellent.
> I
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