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see if I can run a single rear O2 sensor with a split return signal to the ECU since the original car had 2 rear o2 sensors. I'll make a splitter dongle and see what happens.
Can you confirm if this worked or not?
 

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When I find out I'll be sure to report back. Just picked up the cat, resonator and muffler last week. I'll get the rest of the parts and hopefully have this done by the end of February. :thumbup:
I'm in the same boat. We thought we were done with the exhaust, running just 1 pre and 1 post CAT 02 sensor (which works for 3.2 swaps), but after talking to the guys who made my harness, found out we need to run all 4 sensors for the adaption to work correctly for the 3.6. Damn
 

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Discussion Starter · #224 ·
I'm in the same boat. We thought we were done with the exhaust, running just 1 pre and 1 post CAT 02 sensor (which works for 3.2 swaps), but after talking to the guys who made my harness, found out we need to run all 4 sensors for the adaption to work correctly for the 3.6. Damn
My hope is that the system can be tricked by having the same O2 sensor feeding the signal line. The ECU shouldn't be looking for both sensors to be powered or grounded. All it'll care about is the heater line and the signal line.

Returning the same signal back to the ECU should work fine. The hiccup i think is whether both heater wires can be joined together or if one heater line will need a dummy load circuit separate from the sensor.
 

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Discussion Starter · #227 ·
Finally getting some work done. mkIV shift components installed, fairly easy swap. Only need a few clips for the cable ends to complete. However, there is some rubbing with the coolant overflow hose so I ordered a mkV Jetta one that looks much longer. Also, need to cut the gear selector shaft as its ~2" taller than the old corrado part.

Also got exhaust stuff ready to go and started laying it all out. I have a small ESAB 95i DC inverter with a lift TIG that I want to finally learn so I'll be practicing that for a bit before doing any final welds...





 

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Finally getting some work done. mkIV shift components installed, fairly easy swap. Only need a few clips for the cable ends to complete. However, there is some rubbing with the coolant overflow hose so I ordered a mkV Jetta one that looks much longer. Also, need to cut the gear selector shaft as its ~2" taller than the old corrado part.

dieselgeek sigma 5 shifter will eliminate the tall shift weight, clear up some space :thumbup:

 

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Discussion Starter · #230 ·
dieselgeek sigma 5 shifter will eliminate the tall shift weight, clear up some space :thumbup:
On the list for the future! At the time, I made some adjustments for everything to clear. The new mkv Jetta coolant tank line is ~6" longer than the mkIV diesel one I was using and doesn't interfere with the shift cables, nice! I did install the rear 02 sensor but haven't played with combining the signals from one sensor to feed both ECU inputs but I'll be getting to that shortly.

Finished the exhaust, the wookie is alive! And the 02J shift linkage upgrades are worth their weight in gold.

 

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Discussion Starter · #232 · (Edited)
Now that the exhaust is done, the rear O2 sensor problem has been addressed. For correct operation you will need to combine the 2 four wire 02 sensor plugs in the wiring loom as such. For reference, I used the brown plug.

Pin 2 of the O2 plug -> T94/7 & T94/29 (brown/white -> brown/white + black/white)
Pin 3 of the O2 plug -> T94/76 & T94/54 (white -> white + white)
Pin 4 of the O2 plug -> T94/77 & T94/55 (green -> green + green)

Pin 1 of the O2 plug white/red wire is +12V from the fuse box which your O2 sensor already has if you wired it in to your fuse panel.

As you can see below, the ECU believes there are 2 sensors, tested and passed.




Up next, Leak detection pump!
 

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Discussion Starter · #233 · (Edited)
Finally addressing the cooling issues. Mocal 13 row 235 matrix oil cooler and thermotstatic sandwich plate. Also added a 5.25" fan in addition to a deeper 12" main fan. Main fan is tied to the low side temp switch and the teeny tiny fan to the high side. Combined can pull ~1600 CFM.

Also switched to the 3.6 secondary water pump. The unit is about half the size and weighs much less. Not a lot of room in here!

Didn't get to do a full test today but that should happen this week. First warm up I did have some oil seepage from one of the right angle AN fittings so it got a little extra torque







 

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Discussion Starter · #234 ·
A few updates.

1.) Cooling systems upgrades aren't leaking and operating as expected! I need to give it a stress test in the summer but so far so good.

2.) Malone tune was 10% off last weekend so the ECU is in transit to ECS for a flash. +10% power is nice but I'm really curious of the drivability differences, hopefully the rev hang is eliminated.

3.) Almost done with adapting the leak detection pump. The passat charcoal filter is probably 3x the size of the Corrado unit so I ditched it and will test a hybrid system with the Passat LDP and Corrado charcoal canister. Luckily the only room in the engine bay is next to the canister so everything fits pretty well!

The SLC has a basic fuel vapor system in the car from the factory. You have the gravity valve at the fuel filler neck and that routes through a nylon tube to the front of the car. What the LDP will do is pressurize the whole system from the N80 valve to the fuel tank and over time the ECU will check the pressure level and determine if there are any leaks in the system. So to adapt the Passat LDP to the Corrado system I am installing a T fitting in the fuel vapor line that is coming from the fuel tank so the LDP can pressurize the system.



For the below picture

Green arrow: output of the LDP
Red arrow: tube from the gravity valve/fuel tank
Yellow arrow: Tube to the charcoal filter

You can see a fatter tube coming out of the charcoal filter in the above picture, that routes to the N80 valve.

 

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Discussion Starter · #235 ·
So through my testing of the EVAP system I did find that the fuel tank seal between the level sending unit and the tank was not sealing properly. I ended up making my own gasket from a sheet of 1/16" buna-n silicone. The gasket ends up sitting on top of the sending unit and is pinched by the plastic tank cap. You MIGHT get away with using 1/8" but because the gasket spaces the plastic cap away from the sending unit, the fuel line quick connect may not line up anymore. 1/16th inch thick works fine though.

I didn't comb the Grainger or McMaster-Carr catalogs for an off the shelf solution. But the dimensions of my gasket are OD 4 15/16", ID 4 1/16". After fitting the gasket the EVAP system now works properly!

Link to the buna-a silicone sheet



 

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Discussion Starter · #236 ·
A few months back I had an issue where the car just quit and would not start back up. A bit of testing led me to not getting 12v at the fuel pump so I started investigating everything in that signal path. What I found was a big face palm.

When I got the relays I has assumed they were all the same. So I looked at the diagram on the side and the switched connection output could either be in the middle of the relay slot or the typical 87 slot on the outside edge of the connector. I thought this was nice so I could split power output directly from the relay and not have to combine too many wires into the crimp connectors.

Well only ONE of the relays had the useable center and outside output tabs. The other three were SPDT with only the middle tab as the switched path! This meant that ECU power #2 and the secondary coolant pump weren't working at all and I have no idea how the fuel pump was working as it's power wasn't correct either.

Anyway, read your relay diagrams kids. Car has been running really solid lately, coolant temp stays at 190F and oil temp rarely goes above 210F!

 
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