I just acquired a '74 2.0 with D-Jet. I'm starting to go thru the motor inpreparation for getting it running. I'm not sure what is in the pictures below. It looks like a socket for a relay. One end disappears into the wiring harness somewhere below the throttlebody. The other end has no connector on it but the wire inside the sheath is red and fairly heavy gauge (power). Any ideas what this is? The car does not have AC and doesn't look like it ever did. I believe the motor is original, but I don't know for sure.

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That looks like one of the two connectors that plugs into the silver double relay thingy.

I'm not sure what he's talking about there, and unfortunately I can't identify it personally, but it might be that it was for an add on that has since been removed. You say the other end has no plug? Did you check in that area to see if maybe the wire had broken off it's original connection? Where does the other end run to- I mean, where did you find it?

W/ a little more info we might be able to figure this out.

Did this car ever have an air conditioner?

It's okay eric- they didn't teach us how to read in school either. Sorry man I couldn't resist.

I think he is referring to the distribution wire that hangs off the side of your battery tray that does have a couple relays and fuses..... i'm not positive where it goes from there though....



You got sauce for that mess of spaghetti??? I hate hacked up wiring!!!

Oops! Obviously a case of a short attention span - my bad

The engine harness is for an L-Jet car. The connector you are showing is for the double relay necessary for the L-Jet system to function. You do not need it for D-jet. If you have another engine harness, I will buy that one for a spare for my wife's 914.

I have an L-Jet car and it doesn't have a plug like that. The dual-relay plug for an L-Jet car is about twice as wide. I also don't see a plug for an airflow sensor.

The motor is a 2.0 and has what appears to be a complete D-Jet FI system in place. I do see a plug at the dizzy for the trigger points and there is a MPS. I can't be certain that this is the original motor. There is an oil-temp sender (taco plate) on the motor, but no center console or oil temp gauge in the car. This mean anything?

I found this just laying in the engine bay. I need to remove a few things to see where the thicker wire goes to. The other wire was found just as you see it, and appears to be the right gauge for a wire connected to the battery. Someone else had mentioned AC. If I had to guess, I would say a relay went there to power something?

I doubt it's A/C. It's got a VW logo stamped in it.

Didn't I say that?

My '75 1.8L L-jet has it. Looks like this:
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Cevan- I didn't see that you were holding the other wire when I first looked at the pic. It almost looks like it might have been in a connector (like an o-ring or butt connector) since it's stripped like that; and if it wasn't crimped properly, it may have just fallen out. Check to see if you can find any of these in the area where you found it. If you can't find any then it is possible it was just an add on that was removed by one of the PO's.

Also try to find out if it's the original engine. If it's not than it's likely it was for something on the original engine and was never removed when the replacement was installed.

I would also look at possible sources if you can't determine for certain where the plug wires and the other wire are leading to. Check the connections at the relay board and fuse panel- if you find a wire of the same color, use a voltmeter to check for continuity- if you have it then you've found the source. As for the big red one, check for continuity at the hook up on the battery if you're sure it's a power wire. Each of these checked is one more possibility eliminated.

The relay board connections are all present. The relay socket is on the passenger side. Are there any relays (other than on the relay board) present in the D-Jet wiring harness? I am no D-Jet expert but I don't think there are. I will follow the wire loom and report back. Thanks for everyone's help.

Just for sh*ts and giggles, what's the VW part number on the plug?

Is that one of AA's hot start relay harnesses?

I think you're right. I got my 15 year old to help me trace the wire. The thicker one goes along the backside of the motor and joins another wire loom. From there, it splits, with a smaller wire loom going thru the rear tin where it splits again, with a yellow wire going to the STARTER and the rest going to the reverse light switch on the tranny. The rest of the wire loom inside the engine compartment connects to the relay board. See pictures below.

How do I bypass this?? There are 2 black wires, 1 brown, and one yellow wire in the black loom.

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Well, normally that yellow wire on the starter goes all the way to the ignition switch.
It may be a hot start relay as stated above.
Draw a picture of what all the wires are doing.
Does not matter what wire loom they are in.

Rich

Here is a diagram, the best I could draw with Photoshop. The wiring harness looks stock, no evidence that it was hacked into.

I also noted that in addition to the dual black wires on the positive terminal of the coil, there was a wire that ran to the supplementary air valve. The Haynes manual shows that wire going to pin #12 of the 12 pin connector on the relay board.

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I'd say just dump it and get a harness from someone else, or a rebuilt harness from Bowlsby.

Zonedoubt and Clay are right. It's the 12 pin plug wiring harness from an L-Jet car!!!!!! I just checked my other car and the extra L-Jet harnesses I have. Exact match.

Now why is it on a 2.0 D-Jet motor??

On 75 or 76, 2L D-jet, the mystery plug is the auto speed limiter that cuts off the fuel for California engines ONLY. It is mounted on the battery tray just like the L-Jet double pole rely. See page 9 of the 75 Factory Dealer information guide. Relay part # is 039.906.021A.

I compared it to an extra L-Jet ignition harness and it's an exact match. It even has the yellow wire that plugs into the quadruple connector at the relay board.

The only difference I can see is that L-Jet uses pin 12 on the 12 pin connector to go to the dual relay and D-Jet uses it to go to the AAR. Seems like an easy thing to modify.