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Discussion Starter · #1 · (Edited)
If you are thinking about sticking a tdi into a gas car…….. don’t



Still reading??? Hmm ok well I guess I’ll add to the tex and do a proper write up of it. The car and the write up are a work in progress so updates will be added on a weekly basis until the car is running again. I have done some searches on vortex and the tdi club forums and there really isn’t a definitive write up in it more of a log of the random pitfalls. A helpful but a step by step process is needed for future texters. This write-up is both good for b4 Passat and mk3 Jetta/ golf. There really is little difference between these cars.

Back story. The car is owned by my friend. In November during an early snow storm a tree fell and crushed his car. This just a few months after I got it running properly, leaky ecm vacuum line. He had disused doing repair with a body guy he knew, but I suggested that doing a swap might be easier and safer given the extent of the damage. I also noted that “sedans’ are lame” and if we could find a wagon “with a strait body but major engine or transmission issues” that would be ideal. A glx would be perfect, he wants leather. Ten minutes and a quick search on craigslist later we found our car. A blue passat wagon vr6 tan leather in perfect condition but with a bad transmission. A week later he had the car and I was committed.



I have found the key so far with the swap is to think big. Pull the cars apart in big components whenever possible. Example…We pulled both motors via the sub-frames. In both cases the power steering, transmission, axels, and front suspension at the knuckles are all intact. Really disassembly is the easy part and I won’t really touch on it here. I’m more concerned with are answering the following questions.

1. How much of the wiring will we need to pull from one car to the other to get it to run?
2. Instrument clusters??? Glow plug light is in the cluster.
3. How will I solve the differences between the fuel pump and level sensors?
4. How will going from sedan to wagon affect the build?
5. In this build we are going from auto to manual how is that going to affect wiring and the build?
6. The wagon has abs the sedan doesn’t and he wants to retain abs. How am I going to do that and make sure the cluster functions? I’m I going to run into serious wiring problems?
7. Four to Five lug swap? Are the axels the same dimensions or am I going to have to use tdi Axles or a hybrid of vr6 and tdi?
8. There are part number differences in the sub-frame but are there really any differences between the sub-frames?
9. Fuel delivery and fuel lines? Differences in tanks from sedan to wagon and tdi from gas.
10. Intercooler mounting piping?
11. Ac, power steering, function and components compatibility from one car to the other?
Trough the process of the build and the write up I hope to have all these questions answered. When all these questions are answered the car will be running and ready to be inspected by the California B.A.R. East coasters you guys can cheat but since we have to go by the book in Cali hopefully this will be the write up to refer to when the job needs to be done right.
 

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Discussion Starter · #2 ·
Week one. Research and TDI disassembly.

Looking at part numbers I can answer some of my questions. Being that this build has to be legal we need to get a new TDI wagon tank, fuel lines and sender/pickup. We are trying to see if one turns up in a junk yard but if all fails we will have to get one at the dealer. I have checked they are on backorder so it will have to come from Germany.

Reading on previous swaps seems two methods are taken with the wiring. Cut and splice or complete harness swaps. I have yet to decide. Trough the research I have learned one thing. There is no comprehensive write up on doing a swap. I figured I will take on the project and solve problems as they arise.
Actual work on car, we pulled the motor via sub-frame and most of the parts that make it an tdi.
 

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Discussion Starter · #3 ·
Week two. VR6 disassembly

Did everything to the VR6 that we did to the TDI expect I was much more careful with the body components.

 

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Discussion Starter · #4 ·
Week Three. Further disassembly of both cars.

After talking to a tech friend and researching I have decided to go the wiring route of swapping complete harnesses and keeping the splicing to an absolute minimum. I have separated and identified all the warring in the engine compartment. After reading I have found that there is additional wiring for the ac/heater box required to make a tdi system work. My guess is that the wiring is to make the recirculation circuit work being that the vr6 recirculation flap is vacuum actuated. FYI that vacuum line going into your firewall is for that purpose. I’m thinking that the tdi system is entirely electronic being that diesels don’t generate vacuum that well. I have yet to confirm this. I have taken the entire dash out of the VR6 much easier a task compared to pulling the dash in my Jetta. With the dash out I will start to indentify and label all wiring in the VR6 and start to pull the appropriate harnesses as assemblies. I do know from my initial inspection that life will be easier if I leave as much hooked up to the fuse block as possible. I will have pictures up of all this next week.
 

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the hvac systems are the same. The cooling system for the motors is different. There are several good threads on the TDI club about what you are doing. If you post up in the TDIclub classifieds you might even be able to get the 25gallon B4 varient tank. There is no reason at all to purchase the lines and tank new from vw unless the price is so low that you don't mind. Worst case scenario I would run the gasser tank until the correct used tank finds its way to you. :thumbup:

The swap is fairly plug and play. Most of the wires under the hood can only go to one part within reach of the wire. Its the work under the dash that can get tricky as there are so many wires that are so closes to each other. This is where the labeling or use of colored wire ties is helpful. Also you might want to read lugnut's swap thread as he ran into a little difficluty on doing the wiring for the hvac system as there is a minor differance.

If you pull the dash for the pedal cluster I highly recomend that you replace the heater core and foam on all of the trap doors in the hvac system. :thumbup::popcorn:
 

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Discussion Starter · #6 ·
the hvac systems are the same. The cooling system for the motors is different. There are several good threads on the TDI club about what you are doing. If you post up in the TDIclub classifieds you might even be able to get the 25gallon B4 varient tank. There is no reason at all to purchase the lines and tank new from vw unless the price is so low that you don't mind. Worst case scenario I would run the gasser tank until the correct used tank finds its way to you. :thumbup:

The swap is fairly plug and play. Most of the wires under the hood can only go to one part within reach of the wire. Its the work under the dash that can get tricky as there are so many wires that are so closes to each other. This is where the labeling or use of colored wire ties is helpful. Also you might want to read lugnut's swap thread as he ran into a little difficluty on doing the wiring for the hvac system as there is a minor differance.

If you pull the dash for the pedal cluster I highly recomend that you replace the heater core and foam on all of the trap doors in the hvac system. :thumbup::popcorn:
Good info... Thanks. I prefer to do new lines. Price wise they aren't that bad. Tank is expensive and finding a used on would be ideal, but being that they are plastic I wonder if it would survive a trip on yellow truck. Dealing with CARB and the BAR scares me. If they find one shady thing on the car like using the old tank then they will go over the car with a fine toothed comb. With that said I will most likely still be going new on the tank. All in all its the only real expense of doing the swap. Small price to pay really.

lol your sig has all then info I need.

that wiring difference in the hvac has me worried. Makes no sense but I have read the same thing that there is a wiring difference. When I have it solved I will do a good write up in that part of the solution.

Thanks

ohh ya doing the heater core is a given, come on man I work with thies cars for a living :D
we are revamping as we work. Goal is to make this old car like new
 

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sounds good.

The tanks on the Corrados and mk3 TDI Jettas that I've had my hands on could certainly handle all the abuse that UPS or fedex could toss at them.

Post up on craigslist or even the TDIclub and you might get lucky on a used tank. As for the fuel lines I don't blame you. Get those while they are still available new. I know everytime I'm able to get new parts for a mk3 tdi or corrado from the dealer I feel very fortunate. Soon they will all be NLA.

I look forward to a good detail of the HVAC wiring. If I find anything I'll post it up. Soon I'll add your thread to the swap list.

Also I'd love your you to post up about your SMOG referee experiance as I have a friend with a 16V Golf that I might be converting to TDI, he lives in San Diego:thumbdown: here it would be soooo simple. From what I've it really boils down to the smog referee and what type of person they are.

I know they will want the VIN of the TDI donor
will not allow an older motor into a newer car
the smog equipment for the engine has to be present and 100% operational
Then it just has to pass the typical smog check for the engine donor's car which for 1997-1998 TDIs if I'm correct is a visual and diagnostic scan and maybe a snap throttle check for smoke.
 

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Discussion Starter · #8 ·
Week Four day 1--- The Rats Nest



I started the day further disassembling the TDI interior. I pulled the dash and pretty much got it to the same point of disassembly of the VR6. The wiring still remains. Then It was time to move on to the VR6 and get engine wiring out. In this part of the write up I deviate from what would be the standard wiring exchange and into the much more complex job of not only doing a tdi swap but also a sedan to wagon and manual to automatic swap. I decide to disconnect the under dash fuse and relay block entirely. If you are doing a simple tdi swap do not I repeat DO NOT do this. Simply isolate the connectors at the back of the fuse panel that deal directly with the engine harness and disconnect. This can be done with a little light and a lot of patients.

I separated the cluster harness, the column harness, the abs-airbag-break harness, center console switch pack harness, from the body harnesses and set them aside. I did this because I'm still figuring out the integration of things like abs abs and the automatic trans.


I read in a post before that there are three harnesses that need to be transferred from one car to the other. Those harnesses are as follows

1. ECM harness
2. Radiator Fan harness
3. AC load reduction harness.--- this harness is pictured below.



It plugs into the hvac and also into the radiator harness and engine harness. There is enough differences that it is absolutely necessary to change this out .
I then removed the hvac unit from the car. An relatively simple task. It is bolted into the fire wall in about six locations. It is important to note that it is bolted down in the rain tray with two 13mm bolts that are on each side of the air inlet. I did this because I wanted a clear view of the wiring and I wanted to replace the heater core because I was that deep anyway.

I finished the day by pulling the pedal cluster. It is held in by about 10 13mm nuts. The two places that really gave me trouble was the nuts that are below the carpet and the bottom of the steering column is connected to the bracket for the pedal cluster.

 

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Discussion Starter · #9 ·
Week Four day 2. First major obstacle

The idea was to get the wiring out of the way. This was not to be. I stared on the tdi and pulled the pedal cluster. An easier job when I don’t care about the column being in the way. The real issue was the clip that holds the cutch rod into the pedal is a total pain in the ass. After bending the pedal and a good strong tug the cluster was free. When I went to get the slave I realized that it is attached to a bracket that is attached to the break booster.


Half hour later and after I pulled the booster with the abs pump attached I had the bracket swapped and was ready to reinstall the pedals.

A husk of a car
Fifteen minutes later


And I am officially in the going back together phase of the project. A huge mental triumph.

Though it was short lived. I was cleaning up the fire wall plugging holes that needed plugs and prepping for the clutch master install. I moved to get rid of the automatic transmission harness which I cut in week two when I stopped to think. At first I was like hmm that is a lot of wires just to run the transmission. Then I went to the VR6 Trans and when I looked at the neutral safety switch my heart sank. I realized that the reverse lights controlled buy that switch. That harness goes to the back of the car. That signal passes through the TCM and goes to a relay that inhibits the starter. 175 relay. The body harnesses is intrinsically different because of it being an automatic. Now I’m stuck.

The new vortex search function is terrible. I need to figure out how to eliminate the TCM from the car entirely. I can’t remember what wire plugs into the reverse switch on the TDI. I’m not sure if it was the engine harness or the fan harness. I have read and one method is to jumper a couple wires in for the range switch connector. I don’t want to go that route because I don’t want the tcm to back feed into the ecm and make the car limp. I can’t have a check engine light if I want to pass smog. Another method is to rewire the reverse light switch and jumper it into the 175 relay. If all fails and I don’t have a concrete solution that is what I am going to do. As far as the body wiring goes I still need to indentify and separate all the wiring so I can ascertain which connector that goes into the back of the fuse panel deals with the transmission.

I moved on and removed all the wiring from the tdi. Pics below are of the tdi fuse block being unplugged layer by layer.







I separated the wiring and found compared it to the vr6 harnesses that I removed. The ABS indicator light harness was different. The instrument cluster harness were obviously different. Column harness was different due to mfi and rear wiper. I kept that harness.

Any help with the automatic trans delete wiring end will be very helpful.
 

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Discussion Starter · #10 · (Edited)
Pre Week Five---- picking up the pieces

Spent the week juggling my job duties and scouring the Internet for answers to my questions. I found a wite-up that is for Mk4 with a 01m and dealing with there 175 relay. In that one they hard wire the backup light switch and put a 53 relay to work as the started relay. I talked to "VW-TDI" a dude in Vancouver about his experience with dealing with the automatic transmission wiring. He told me that he bypasses it completely. I looked at ETKA's picture of the harness and it in-fact is a totally stand alone harness, so I should be able to eliminate it entirely. I believe that the reverse light switch is piggy backed on the radiator fan harness. I have to confirm this. If that is the case wiring the revers-lights will be a snap.

I was doing the research this morning on how to get the cluster mfa to function. I found a picture of the back of the fuse panel. One google search led to another and I found this on the Bentley wed site.




here is the source for the above pictures

immensely helpful information for those trying to sort out what all the plugs do in the back of that mess. I'm thrilled that I'm able to post it here. I have the complete wiring diagram and I'm ready to tame that bitch. I will be prepping the car for mfa and keyless entry during the process. I hope to have the car ready for engine install by sun down on Sunday. A write-up and pics of my progress on Monday.

Thanks to

VW-TDI for your help and thanks to Big Richard for fumbling his way through is build like I am.
 

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Discussion Starter · #12 ·
I would think that you could pull the entire automatic transmission harness out.

Installing the the MFA cluster is fairly straight forward and its been outlined several times: http://forums.tdiclub.com/showthread.php?t=101455

This guy has done many conversions of VR6 clusters with MFA to TDI clusters with MFA and the correct milage and a power supply cap : http://forums.tdiclub.com/showthread.php?t=268798
Cool thanks........the GLX cluster has a third lcd screen. Any idea what it is for???
 

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Discussion Starter · #15 · (Edited)
Week Five day 1--- FU auto

I needed a week away from even thinking about this car. Last Saturday was a relatively nice day but chilly. Armed with information that I got from VW-TDI a good dude on the tdi club forums, I set forth on isolating and eliminating the Automatic harness from the car. The harness is in fact a totally standalone harness that is connected to the chassis harness in only a few spots. The automatic trans harness doesn’t connect to the back of the fuse block though there are a couple jumper connections. The harness communicates with the ecm via an eight pin connector that is connected directly to the engine wiring in the rats nest behind the fuse block. The 175 relay does interrupt the starter circuit, when you remove this harness you need to find a jumper on the donor car that is attached to the thick black and red wires that are behind the driver kick panel. Pic below


The other connectors that you have to really worry about are some green and black wired ones. Not sure what they do, revise lights maybe. It’s pretty simple to figure out at any rate.

I traced the trans harness down the side channel then it goes under the driver seat. Why??? I assume because Volkswagen hates me. I wasn’t about to pull the carpeting so snip snip and now the car is a stick


Here are pictures of the reverse lights circuit

Connector to the reverse lights on the engine wiring harness


Engine harness to the back of the fuse panel


Out of the fuse panel out to the body


Weather was closing in. As it got colder I started moving slower. I didn’t want to start the under dash wiring just to run out of time mid way. So I decided to get the engine bay wiring ran and secured. That was more time consuming that I thought. I finished the day mounting the abs pump and hooked up the clutch master. Bolted it all up called the pedals totally done. Stuck a fork in the day.


Side note. Dieder out did himself with the clutch pedal. There is a white nylon bushing that keeps the rod for the clutch master attached to the pedal. I "mongoed" it out during disassembly. Bent the crap out of the pedal, ugly ugly ugly. I struggled like an idiot trying to get it back together before I started to think like a German and figured out the trick. When servicing that bushing

First press cutch pedal to the floor and notice that angle of the rod is such that it is now out of the way

Second pinch stupid ass nylon thingy together

Third keep in mind that the bushing is engineered by the same people that are responsible for lederhosen and the holocaust, with said hate bushing pinched raise pedal up and, presto it is free.
 

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Discussion Starter · #16 · (Edited)
Week five Day 2---- Taming the Rats nest.

Started the day with a laundry list of “need to do’s” to get out of the way. I wanted to finish the day ready for engine install. As fate would have it, this was not to be for a few reasons. Firstly getting all that wiring back together is an imposable task on the quick unless you have done it many times. I spent the day trying to think like an assembly line man keeping the process as simple as possible. Even then it is an complex jumble of wires and I have a few connections that I’m just not sure on. I made two failed attempts at getting the fuse panel wired. Sometimes I would get it wired half way then I found that connectors wouldn’t reach or that inter-connecting wires would block off the larger connectors for the cluster or ecm or whatever. And then when I finally got it all sorted out there are a few orphan connectors that I don’t know what to do with. Not to mention the jumpers. Ohh god the jumpers. Some with one color connectors but different color wires, some with blue connectors but plug into white jumpers. I am not comfortable with those at all. I have a Audi tech fried and wiring guru that has needed a running vr6 for quite some time. I’m going to trade to him that to sort out the rest of the wiring. As it is I’d say it’s about 90% right. What I thought would take a couple hours ended up taking all day. An I’m no where near ready to get the motor in. No matter because as of writing this, the clutch has still not showed up but the fuel tank from Germany has.



So here is a tentative thumbs up to the fuse panel technically it is in.



The menu for this weekend consists of getting the donor car back on its wheels. With the fuel tank here I guess I will pull the sedan tank and swap over hoses and crap to prep the wagon tank for install. I still have to get the intercooler mounted and get the shifter box swapped. Get all that done, then I can watch the Super Bowl and get drunk.

Side note. I hate you dieder for coming up with the A3/B4 wiring. I imagine that the poor sob that had to put that crap together on the assembly line day in and day out lasted for a maximum of three months. After that it was either a long trip to the funny farm or a short trip to slit wrists.
 

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Discussion Starter · #17 ·
Week Six day 1--- preparing the Black Passat for its’ last mile

Beautiful weather this weekend and I spent it in a tee shirt and worked up a sweat. Saturday and Sunday both where in the low 70s with no wind. The sun was warm with a kiss of spring and I was more focused and moved to get as much done while the weather held out. My goal for the day was to strip the sedan of its final offerings and prep it to be moved to its final resting place. First on the menu was the shifter box. The front heat shield has to be removed past that the shifter box is held in with two 13mm bolts from the bottom and one 13mm nut on the inside. Zip zip clunk, and it was out. Few minutes later I had it bolted into its new home.



Next I had to get the intercooler swapped. In the frame horn there is a plate that is welded where the top of the cooler comes through the sheet metal. Not to worry it is tack welded in two spots. A couple good hits with the butt of a screw driver and it broke away from the car. The cooler is easy enough to mount. As with everything else the holes are all there it’s just a matter of swapping a few bits.

There is a square hole pictured below. That is the bottom mount.



Swap the grommet and the nut. The top of the cooler is bolted to the bumper retaining bracket. I removed the cooler with the ducting and mounting brackets intact and put it back together as such. Easy job



Then I had to strip the sedan sub frame of everything but the essentials. Kinda heavy and I was working alone. I bolted it up to the chassis. Got the knuckle bolts hand tight, then got the wheels back on. With that done the sedan is back to being a rolling chassis. Moved to the rear and ripped and tarred the rear apart exposing the bolts that hold the tank in. There really wasn’t a part of pulling the tank that was complicated. There is two 10mm bolts that holt the filler neck to the body. Aside from that I just let gravity do all the work. What sucked was the old tank was full of fuel but I guess there is no convenient way to plan for your car to be crushed by a tree. I had to transfer over a aux tank and some lines. I got a new rollover valve.

Here is the uber new tank ready for install. Really the only real expense to this whole project.


With the tank out the car is ready to be towed out and put in the back yard. Side note at this point my friend is perilously close to being the punch-line to a ******* joke.

The last picture of a very cluttered garage.
 

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Discussion Starter · #18 ·
Week Six day 2--- Getting ready for the big install

Goal for the day must get heap of a car out of garage and be totally prepped for install of TDI motor. Little bit of towing and bruit strength we had the car out of the garage and laid to rest in the back yard. Though it is outside there are a few bits that we need off it, interior trim. After that we hauled the VR6 back into the garage and started the task of breaking it away from the sub-frame.

With that done It was a matter of getting the hvac unit bolted back up and the AC lines bolted back up. Fuel filter is in. Radiator is replaced and ready for install. As of writing this clutch just showed up. So next weekend we are ready to rock. Goal by 6pm Sunday I want to be ready to fire it up.

A VR6 and a pile of broken bits


A TDI waiting for

This



One last pic of the Wagon torn apart and a now roomy garage
 

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Discussion Starter · #19 ·
Week Seven day 1---- Four Bolts and In

It was about when I pulled the tierods off the VR6 rack that I realized that I was working much slower than I needed to. I started the day prepping the subframe for the TDI. I wanted to get the tierods and replace the boots. They were ohh so exposed. I didn’t have a wrench big enough for the tierods so I had to make a trip to the parts store for a adjustable wrench or as I like to call it a “Mexican Wrench Set”. After I got the tierods on I moved to get the clutch on and transmission bolted up. Decidedly lame job trying to line up the flywheel bolt holes lying on your side. After a few minutes the ring gear tends to dig into the skin. Overall the clutch was easy but time consuming. Then I had to figure out where all the bolts went and how the front motor mount was attached. Mad easier by having my car nearby to compare. Once the engine and trans was together I mounted to up to the frame. Not an easy task but with the help so floor jacks everything bolted up. I was pleased to find that the axels bolted up nicely.

This is what i ment by "think big"


Then it was just a matter of getting the whole affair into its new home. The cherry pickers wheels are kind of bad. The enormous weight of the assembly effected the cherry picker in such a way that it wouldn’t roll forward as much as it would jerk and lurch. This made for a couple tense moments when trying to align the motor that it lurch spastically and would hit the car almost hard enough to knock it off the stands. After a little bit of patience and a whole lot of muscle I rolled in the four main bolts for the sub frame and was able to call it a day.


Car is now a TDI Variant
 

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Discussion Starter · #20 · (Edited)
Week Seven day 2---- “That’s an odd looking bracket. I wonder what it’s for?”

With the motor in the first order of the day was to get the cherry picker out of my life. I bolted up the cat, much easier given the angle of the motor. Then I mounted up the front cross member and just like that the cherry picker was a thing of the past. With it out of the way I set to the task of setting up the fuel system and intake system. I didn’t take the passenger side apart. The tree did most of that, what wasn’t obliterated my friend pulled apart. With that said there was a lot of scratching my head and puzzle solving. It wasn’t too bad thankfully we took the fuel system out in chunks. With the right side situated I moved on to the more complicated left side.

I guess you could say I built the car back up in layers. I stared with the shift cable bracket and clutch slave and worked my way up. Everything was going together simply until I came across this bracket.

I didn’t remember what it was for or where it mounted. I began mounting the intercooler pipes and speculated the bracket was used to secure them. This proved to be right.

The holes in the body for that bracket


The nutserts out of the old car for that bracket.


Not really much to say. The wiring wasn’t difficult to deal with. The clutch line needed a bit of an adjustment due to the abs pump. The cooling system spring clips made me question the validity of life. The vacuum lines almost found their own routing. I had a lot to do and the process was taking longer than I anticipated. I wanted to get the bumper and headlights on but, night was closing in. I was in a race with light and because I spent the day figuring out which bolts went where I was losing the race. The weather had taken a turn for the worse. I got the radiator in but I in for shuffle I lost the bolts. I had spent the day looking for bolts and with those missing exaustion and frustration was at a all time hight so I called it a day.

Ya this pic was more of an afterthought
 
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