1z swap wiring questions.

[BoostedOne]

Hello all!
After doing several late model gasser swaps I am working on a 1z 96 passat TDI into an early Rabbit('80) diesel for a guy. We are not converting to CE2. Being an early westy D the car doesn't have a tach, early style, nc oil pressure warning system etc.

1)For oil pressure warning I tied the blue and black wires from both together, correct?

2)VSS.. we arent going to tear up the dash for the b4 cluster. Owner for now is content to have no speedo. It appears output of vss goes to cluster then cluster sends a speed signal to the ecu. Is this the same signal thats teed in the cluster or different? Im wondering if I should tie the wire from the vss to the speed signal wire of the ecuor leave them unconnected...

3) From the diagrams G60ing posted, there is a wire that goes to pin 26 on the cluster from pin 9 on the ecu. Its labeled "injection signal t1". What is this for? Does it need to connect to anything?

4) the ecu gets a signal from the brake lights to pin 44.. again any need to connect that?

5) finally, what do I do with the clutch and brake switches in the engine harness if cruise control isnt needed? I think I read leaving them unconnected the ecu will have codes or limp mode?

Thanks for the help!!!

 

[Alchemist]

A few changes would be a good idea.

1 Oil Pressure switches work opposite, one is NC and opens on rise. The other is NO and closes on rise. Connecting them together will act as if there is no switch.

2 I would connect the VSS signal to the ECU just in case it is needed.

3 Sorry, no help here.

4 Yes, connect this. The ECU uses this to monitor brake lights and brake pedal. If the ECU doesn't see a ground through the brake lights, it thinks the bulb is burned out and starts flashing the GP light. If this line is at 12V, the ECU thinks the brake is on and cuts throttle output to the IP.

5 One of the clutch switches interrupts the crank signal to the starter, so you need to do something about that. The other one turns off cruise if it senses that the clutch is disengaged.

 

[Abacus]

Alchemist is on the money, as usual. However:

2. VSS to the ECU isn't needed. I have one of mine disconnected and another on a manual switch for back when I was trying to eliminate low speed shudder. It just results in an inoperative cruise control and a Scangauge or other program won't be able to read it.

5. Passats only have one clutch switch to disengage the cruise control, there is no second one since they have no clutch safety interlock.

 

[BoostedOne]

Thanks for the replies. I tried to reply last night and my phone locked up

One thing I see is I probably could have worded my original post a little better.

1) On the Passat there are two oil pressure senders, the low low and the high low. One is NC and one is NO. From my interpretation of the Passat harness the NC is blue with a black stripe, and NO is yellow with a stripe that I forget the color. Anyhow this early rabbit only uses one switch, thats NC(according to the diagram) and the wire is blue with a black stripe. So what I was trying to say is I tied the blue with black stripe from the Passat harness to the rabbit harness. Left the other wire unconnected.

2) So just so I am clear on the VSS... From the factory VSS output goes to G1/11, thru the fuse box to U/11 to pin 27 on the cluster.. Then Pin 7 on the cluster sends a speed signal back through the fuse box U2/1 to W/1 to pin 43 on the ECU.. Just to make sure Im clear yall are recommending I tie the VSS output directly to the wire that goes to pin 43 correct? Thats what I was thinking to do, but wasn't sure if the cluster manipulated the signal or something.

3) I guess thats still an open issue.

4 and 5 combined) Just to be clear, being an early car there are no provisions on the pedal cluster for the factory ECU tied brake light switches. I can easily tie the pin 44 wire to the brake lights. However, if the brake light switches aren't connected, will it freak the ECU out when it sees the signal go from ground to 12v every time the brakes are applied but does not see a change on the F47 brake switch to pin 47? Or is the brake switch on pin 47 only for the cruise control and thats it?

THanks a bunch!

 

[Alchemist]

1 Try it like that. If it works backwards, use the other one.

4&5 The following information is based on an AHU engine in a Jetta, so it may not be an exact fit for you.

ECU Pin 17 White/Red Clutch Switch F36
ECU Pin 20 White/Yellow Brake Switch F47
ECU Pin 44 Black/Red Brake Lights
Connect all of the above to ECU Pin 33 Brown/Blue Sensor Ground. This will simulate clutch engaged and brake released.

 

[Lug_Nut]

Item 3: T28/26 on the cluster is identified as having plug connector T1e in the circuit. The notation at the bottom of that diagram sheet identifies terminal T1e as the "single connector, multi-function indicator signal". Unless you intend to use a B4 GLX cluster you won't need this connection into T28/26.

 

[BoostedOne]

Great thanks! Definitely no MFA on this early westy cluster.

Alchemist, what you say makes sense. Switches are closed with the pedals up and one side of the switches is grounded in the harness. So I lopped the plugs off and soldered each pair of wires together. Then tied that brake light sensing wire to the same ground.

I think I am pretty much there but one thing.. does this ecu have no constant 12v feed(sometimes referred to as keep alive power)??? All other ecu's I have worked with have this wire to keep the memory and adaptation stored. But for the life of me in 3 different diagrams I can't find one. Just one from track 15.. Nothing from 30.

 

[Alchemist]

No constant power is needed. VW is the only one I know of that doesn't use keep alive.

 

[BoostedOne]

Thanks again. Since the advice was spot on, I got a new one, and one of the issues is related so I am just going to revive this thread..
NEW CAR NEW CAR NEW CAR
So I just finished wiring up another friends Mk1, this time a 98 AHU into a late westy. I remembered this thread from the fall, and when I had the wiring harness stripped I did go ahead and solder the brake and clutch wires. Upon driving the car, the glow plug light blinks.
Did a code scan. I get one for the CEL being open or short to ground(its open, car doesnt have a CEL), and one is for brake pedal implausible signal(or something of the sort). So thats why I pulled up the thread to double check.. Apparently I forgot about the grounding of the brake sensing wire for pin 44... Its just somewhere in the loom cut and insulated, so I guess I need to pull the harness back out and ground it.

So I guess what I am looking to know is while I have this loom unwrapped, is there something I need to do with the CEL wire? I don't recall hooking it up in the last car, but honestly I am not sure. There's really nothing suitable to hook it to in the late westy I do know that. I just dont want to get the brake light wire grounded, wrap it all back up and the glow plug light starts blinking because of the CEL light not being there.

 

[Agent13]

So, I was looking for some wiring info on Google -and landed on this thread..... I'm reviving it because of the unresolved brake switch issue.
In my 83 Rabbit Gti, I came up with a nice little solution. I didn't want to add an additional switch to my pedal cluster. According to some, the ecu wants to see both brake switches acting simultaneously. So I didn't want to have to adjust (and synchronize) the second switch. My solution? I used a standard 5 pin automotive relay. The normally closed second switch wires are connected to terminals 30 and 87a, 85 connects to ground, and (the best part) 86 taps into your brake light output wire (which you already had to connect to the ecu). The ecu gets what it wants, and the relay can be wherever you have the ecu -because every connection is there! This is assuming you (at least) connected the black/red brake light wire. Every car has brake lights -so why wouldn't you?
Another tip. If you don't want to hear the relay -use a small reed type relay, or wrap the relay with dynamat (or something like it). The relay is only receiving power when your brakes are on, and not handling much current - so you don't need to worry about it overheating.
Hope this little switch hack helps someone.
Cheers!

 

[Hasenwerk]

So, I was looking for some wiring info on Google -and landed on this thread..... I'm reviving it because of the unresolved brake switch issue.
In my 83 Rabbit Gti, I came up with a nice little solution. I didn't want to add an additional switch to my pedal cluster. According to some, the ecu wants to see both brake switches acting simultaneously. So I didn't want to have to adjust (and synchronize) the second switch. My solution? I used a standard 5 pin automotive relay. The normally closed second switch wires are connected to terminals 30 and 87a, 85 connects to ground, and (the best part) 86 taps into your brake light output wire (which you already had to connect to the ecu). The ecu gets what it wants, and the relay can be wherever you have the ecu -because every connection is there! This is assuming you (at least) connected the black/red brake light wire. Every car has brake lights -so why wouldn't you?
Another tip. If you don't want to hear the relay -use a small reed type relay, or wrap the relay with dynamat (or something like it). The relay is only receiving power when your brakes are on, and not handling much current - so you don't need to worry about it overheating.
Hope this little switch hack helps someone.
Cheers!

The 1Z / AHU needs both F and F47 wires connected to the brake light - that's it - no relays or MOSFETs required as they both switch in the "same direction". It is the ALH / BEW that switch opposite of each other.

 

[Rockwell]

So, I was looking for some wiring info on Google -and landed on this thread..... I'm reviving it because of the unresolved brake switch issue.
In my 83 Rabbit Gti, I came up with a nice little solution. I didn't want to add an additional switch to my pedal cluster. According to some, the ecu wants to see both brake switches acting simultaneously. So I didn't want to have to adjust (and synchronize) the second switch. My solution? I used a standard 5 pin automotive relay. The normally closed second switch wires are connected to terminals 30 and 87a, 85 connects to ground, and (the best part) 86 taps into your brake light output wire (which you already had to connect to the ecu). The ecu gets what it wants, and the relay can be wherever you have the ecu -because every connection is there! This is assuming you (at least) connected the black/red brake light wire. Every car has brake lights -so why wouldn't you?
Another tip. If you don't want to hear the relay -use a small reed type relay, or wrap the relay with dynamat (or something like it). The relay is only receiving power when your brakes are on, and not handling much current - so you don't need to worry about it overheating.
Hope this little switch hack helps someone.
Cheers!

Oldie but goody. A compact mini relay and some spade terminals work perfect for this. I grabbed a few off a Volvo on my last trip to the bone yard.

 

[Agent13]

The 1Z / AHU needs both F and F47 wires connected to the brake light - that's it - no relays or MOSFETs required as they both switch in the "same direction". It is the ALH / BEW that switch opposite of each other.

Actually, if there are two brake switches... Where one is NC, while the other is NO -that would suggest that the two circuits should be isolated. Even though a test light would show that the wire going to the brake lights is showing a ground when the brakes are not applied -and positive when applied... Wouldn't the "sensing" circuit be feeding a small amount of current to the brake lights when the brakes aren't engaged?