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I lost a wire?

 
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Svobodin  



Joined: 08 Oct 2013
Posts: 65
Location: Colorado

PostPosted: Wed Nov 06, 2013 3:33 pm    Post subject: I lost a wire? Reply with quote

I don't know how it happened, but after putting my 924 all back together I seem to have lost one wire and its a pretty important one. Pics to follow, but try to follow me here. It attaches to the mass air flow meter, behind the fuel distributor. my question is, where does this wire come from? I know it must still be in the engine bay, since I did not cut anything out. Help me find it please!
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Svobodin  



Joined: 08 Oct 2013
Posts: 65
Location: Colorado

PostPosted: Wed Nov 06, 2013 3:44 pm    Post subject: Reply with quote

You can see the connector here:




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xanderdeg  



Joined: 08 Jul 2012
Posts: 286
Location: Vancouver, BC, Canada

PostPosted: Wed Nov 06, 2013 4:23 pm    Post subject: Reply with quote

I'll look at my engine bay tomorrow and try to figure it out for you. By then somebody else will have given you the answer though i'm sure.
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Svobodin  



Joined: 08 Oct 2013
Posts: 65
Location: Colorado

PostPosted: Wed Nov 06, 2013 11:37 pm    Post subject: Reply with quote

Thanks, please do. I spent an hour all over and under the engine bay looking yesterday after everything was back in place. I'm going to try again tonight with a fresh set of eyes. we'll see. I'm so close to getting her up and running, yet so far away.
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larchie  



Joined: 19 Jun 2003
Posts: 297

PostPosted: Thu Nov 07, 2013 2:31 am    Post subject: Reply with quote

It's an air flow sensor plug (see Hanes Fig. 31.70) which should not be on a '79 924 -- only '78 and earlier. So maybe it was never used because the PO mixed parts or maybe it was used on the early VIN '79s. My later VIN '79 does not have the plug. It's the plug (not numbered) at the bottom left in this image:

If the sensor plate gets stuck for any reason, I think the air flow sensor is there to cut fuel delivery. Hopefully xanderdeg can verify it's on his '78. So if the plug is meant to be used on your model, from the plug, there should be a black/yellow wire to the fuel pump relay terminal 31b via the seven-pole connector in the engine compartment and also a brown wire to ground.
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scm924s  



Joined: 22 Oct 2010
Posts: 232
Location: Gloucester UK

PostPosted: Thu Nov 07, 2013 5:23 am    Post subject: Reply with quote

It triggers the fpr/fuel pump on the early cars when the flap lifts under inlet vacuum, this method of operating the pump was changed, probably as larchie said, in '79 when it was triggered from the ignition (I think).

Maybe someone has swapped in a later AFM.
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Svobodin  



Joined: 08 Oct 2013
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Location: Colorado

PostPosted: Thu Nov 07, 2013 11:52 am    Post subject: Reply with quote

Will this earlier MAF unit change how the car operates without the connection? The car was running before I took it apart to change the head gasket, I hope it runs now that its done.
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dubrict  



Joined: 22 Apr 2011
Posts: 148
Location: Horseheads NY

PostPosted: Thu Nov 07, 2013 1:08 pm    Post subject: Reply with quote

Posting to confirm what others have said. You have an air flow meter from a 77 or 78. I also have one from a 77 installed in my 79. It works just fine with nothing plugged into it. (of course there is nothing TO plug into it, because the fuel relay operates differently on the 79)
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!tom  



Joined: 28 Aug 2006
Posts: 1912
Location: Victoria, BC Canada

PostPosted: Thu Nov 07, 2013 4:41 pm    Post subject: Reply with quote

Also, a car designed with that plug will operate without it connected. When it is connected, the fuel pump is turned off when the flap is completely closed, such as if the engine stalls in a car crash. When it is disconnected, the fuel pump will continue to run.

Given that you have a '79, you don't have this wiring for your fuel pump and relay, so it's of no use to you.

Further discussion here.
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