Thread: A bit of a teaser, start idles won't rev.....

It should be a "flapper" and it is very common to be bent by a backfire and does not open .
Maybe start it up and then manually lift the flapper while opening the throttle simultaneously.
It will not be accuarte but may allow revving to confirm what is wrong.
you can always manually lift the flapper and see if it binds or is stuck.
Regards Philip A

Hi Philip,
It is a flapper and the flap maybe moves 6 mm front to back if you know what I mean, in the closed position everything closed, as soon as the valve moves off the seat the fuel pump starts and we go from there. So yes this does sound possible, you talk about "lifting the flapper up", the internal tolerances look pretty tight, how much do you need to lift the flapper and also how far should it open? When the flapper hits a stop it sounded pretty "metallic" so I didn't want to force anything just in case I broke something.
I did partially disconnect the hose between the MAF and the manifolf to try and replicate what you are talking about doing with the flapper, the engine died in this case. saying that this was a pretty uncontrolled sort of attempt.

It is a flapper and the flap maybe moves 6 mm front to back if you know what I mean,

Geez, its a long time ago but here goes.The flapper has a balanced plate which should rotate around a spindle much more than 6MM.

This moves a potentiometer along a track inside the cover.
It sounds as if it is distorted and catching.
I am not sure now but I think it should move freely until the whole of the inlet tube is open, that is what the diagrams in "Bosch Fuel injection& Engine Management" show, and the text notes damage from backfires is possible.
Regards Philip A

This moves a potentiometer along a track inside the cover.
It sounds as if it is distorted and catching.

Hi Philip,
You're on the money with the potentiometer, the little copper contact doesn't move past the first contact. I'm assuming that as the contact moves over the potentiometer this in turn changes things within the ECU hence the reason I'm having the problems I'm having.
You are a wealth of interest, keep it coming, thanks for the help.

6mm ? you mean 60 MM dont you ? Suggest you backprobe the TPS with a analog meter and see whats happenin !!

Hi There,
It's become apparent the way people are talking that this flap should have a lot more movement than it has. And a lot easier I might add. The flap will only move with assistance in both directions.
Anyway this might sound a bit brutal, it's no more brutal than a minor explosion caused by a backfire!! I placed a screw driver strategically inside the MAF agains the bottom pin of the flap, I gave the screw driver a smart tap. Tried the flap, minor movement and a bit easier, I then gave the flap a couple of better hits. Magic the flap now moves through a complete arc and returns to the rest position unaided.
I put the MAF back on the engine an hey presto everything works as it should the engine revs, runs sweet as a top. Beautiful.
Really appreciate the comments guys, the AULRO site comes good again. Brilliant.

Hi Philip,
As you may read later in the thread I've now got the flap moving freely. I bought this '86 Rangie as a non runner last week for $600 so right at this moment I'm feeling rather leased with myself.
Appreciate the help you definitely pointed me in the right direction. Thanks.

Good result!!
Hope it keeps going.
Regards Philip A