I know I shouldn't .... but ....

[Gerry Attrick]

I want to adjust the fuelling on my flapper type air flow meter fitted to a 350i. No, I don't want the tame adjustment from the screw outside the box. I want to mainline by taking the cover off and getting the real thing.
Various threads have suggested that this is as dangerous as holidaying in Basra, but I have a problem. Having suffered from instability on light throttle, I took my prized Wedge to an 'expert(????)' TVR specialist, who has basically tried to mask the problem by making it over rich. Now, in addition to the instability, the car won't idle, the fuel consumption has increased by 25%, and I generate more smoke than a Pink Floyd rock concert when I start up from cold . I was told that the 'mechanic' had adjusted the flapper during his repair work, and I now want to get it back to standard. I've got the black cover off, but I can't see any way of adjusting it . Any help would be gratefully appreciated.

[wedg1e]

Now that's at least two of you that have mentioned flap problems: I was thinking that the way to establish what the 'correct' or basic setting should be, is to apply a spring balance to the flap and see how much force is required to move it. Then it would be a simple (ahem) matter to return to that setting once you'd fiddled with it to your heart's content. Of course one would have to take the measurement BEFORE fiddling, which is where I suspect you may have come unstuck.
As far as I know, there is a ratchetty-type tensioner thing under the black plastic cover, but never having been daft enough to pull my airflow meter apart, I can't say more than that.

Ian

[Gerry Attrick]

wedg1e said:

Of course one would have to take the measurement BEFORE fiddling, which is where I suspect you may have come unstuck.

You're a wise man, Ian. Unfortunately, I trusted unwisely.

Don

[19560]

I have tried various settings of the ratchetty thing. Fairly simple to do. V8 developments gave me the settings which I can dig out if you get really stuck but it might take me a week. Ask your mechanic how much it was altered by, it shouldn't have been more than 3 or 4 clicks. Just a question of trial and error with trial runs inbetween to see which setting runs best. One other note - the black plastic is sealed with silicone (very neatly) so the cover can be difficult to lift off and time consuming; you only want to do it once. Good luck. J

[rev-erend]

I would have recomended marking the ratchet wheel before adjustment... the only real way to know it's right - is with a co meter attached to the exhaust..
I managed to talk a local mechanic thru it at MOT time
a few years ago... as most are not keen on what they don't know about.

[dickymint]

I may be the other one that wants to fiddle with his flapper
After fitting a new cam for me,my mechanic couldnt adjust the co below 5% (on the mixture screw).He thinks my flapper is knackered but im not convinced!
somebody on here suggested tinkering with the base adjustment on the springy/ratchet jobby.
Ive been trying hard not to fiddle but I just cant resist it-its got to be done! & soon cos it ticks over like a bag of spanners especially when cold and stinks of petrol. Everything is fine after about 1/2 a mile except for the fuel consumption...pass the monkey wrench.

[wedg1e]

Aye, my 390 is a little reluctant to idle smoothly (especially when the weather is cold): I do have a CO meter (albeit one with Gunsons on it ;-) and found that fiddling with the fuel pressure had a marked effect on the CO - which wouldn't come down below 3.7% until I dropped the fuel pressure. Now it's about 1.5% or so. I can get it lower at the expense of throttle response: low CO is hardly the point of a tuned engine though, is it!
My engine hunts quite a bit till it warms up, then it idles at around 750, rock solid.
As for fiddling with yer flaps: what the hell, go for it! The worst that can happen is it costs you money to put right

Ian

[Gerry Attrick]

Hello Guys. Thanks for the information and encouragement. I appreciate it. I will put it to the test over the weekend and let you know how I get on. If I learn anything, I'll pass it on.

[DICKYMINT]

wedg1e said:

Aye, my 390 is a little reluctant to idle smoothly (especially when the weather is cold): I do have a CO meter (albeit one with Gunsons on it ;-) and found that fiddling with the fuel pressure had a marked effect on the CO - which wouldn't come down below 3.7% until I dropped the fuel pressure. Now it's about 1.5% or so. I can get it lower at the expense of throttle response: low CO is hardly the point of a tuned engine though, is it! My engine hunts quite a bit till it warms up, then it idles at around 750, rock solid. As for fiddling with yer flaps: what the hell, go for it! The worst that can happen is it costs you money to put right Ian

Had two sleepless nights thinking bout flaps
Decided you're right again Ian. Leave well alone.
Lowered my fuel pressure a couple of weeks ago and it did improve things so will play with it some more. What pressure you running at Ian?

PS. Still got a spare headlamp motor if you need it.

[Gerry Attrick]

I know how you feel. However, I've got to do mine as I think the garage screwed it up trying to fix the hesitation fault. All I want to do is get back to normal (if normality is a word you can associate with Wedge ownership).

[2 sheds]

Good advise to mark the ratchet wheel before fiddling, of course this may be too late if somebody has made adjustments.
Its possible that the base idle speed is also set too low, especially with cars with hotter cams, try 850 rpm for a standard 350 and around from 1000 for modified cars, I used to have a 4.2 with a 234 cam that was happiest at around 1300, below this and it over fuelled due to the cam profiles.
Its not a bad idea to tinker but be careful and use decent measuring equipment.
Tim

[wedg1e]

DICKYMINT said:

Had two sleepless nights thinking bout flaps Decided you're right again Ian. Leave well alone. Lowered my fuel pressure a couple of weeks ago and it did improve things so will play with it some more. What pressure you running at Ian? PS. Still got a spare headlamp motor if you need it.

About 2.8 bar. Pull the feed off the cold start injector and hang a pressure gauge on there (my CSI is removed anyway).

Thanks for the headlamp motor offer: I did manage to find a couple (thanks Steve!); ironically my mate had two in his shed all along (I got one of those as well, but it's a bit rough!). I was thinking of going into the reconditioning business...

Ian

[dickymint]

wedg1e said:

DICKYMINT said: Had two sleepless nights thinking bout flaps Decided you're right again Ian. Leave well alone. Lowered my fuel pressure a couple of weeks ago and it did improve things so will play with it some more. What pressure you running at Ian? PS. Still got a spare headlamp motor if you need it. About 2.8 bar. Pull the feed off the cold start injector and hang a pressure gauge on there (my CSI is removed anyway). Thanks for the headlamp motor offer: I did manage to find a couple (thanks Steve!); ironically my mate had two in his shed all along (I got one of those as well, but it's a bit rough!). I was thinking of going into the reconditioning business... Ian

Cheers Ian,
Turned mine down to 2 bar (guage is permanently fixed to valve)this improved cold tickover but yes reduced throttle response. Off outside to see what it starts like with cold sart injector plug off and pressure back to 2.5 as its probably rich enough without.

[dickymint]

Glad I checked cos its set at 2.75 bar (must ave slipped my mind)took the cold start cap off injector but didnt make a blind bit of difference...Houston we have a problem!!!!!