924Board.org

Svobodin · Joined: 08 Oct 2013 Posts: 67 Location: Colorado

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!

Svobodin · Joined: 08 Oct 2013 Posts: 67 Location: Colorado

You can see the connector here:

xanderdeg · Posted: Wed Nov 06, 2013 4:23 pm Post subject:

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.

Svobodin · Joined: 08 Oct 2013 Posts: 67 Location: Colorado

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.

larchie · Joined: 19 Jun 2003 Posts: 297

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.

scm924s · Joined: 22 Oct 2010 Posts: 268 Location: Gloucester UK

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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1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

Svobodin · Joined: 08 Oct 2013 Posts: 67 Location: Colorado

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.

dubrict · Joined: 22 Apr 2011 Posts: 150 Location: Horseheads NY

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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1979 924 NA
2009 Chevy Impala
2005 Dodge Dakota

!tom · Posted: Thu Nov 07, 2013 4:41 pm Post subject:

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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78 924 NA
5-lug