4.2L V8 Swapped B5 A4

[bhusted]

First things First. VSS.

Verify that Pin 54 of the ecu goes to connector a180. From there it goes to the blue 32 pin plug on the cluster, and connects to pin 3 which is white and blue. Verify continuity between these two pins (ECU pin 54, Blue plug pin 3) to ensure the ecu receives the proper VSS signal!


Now, on the ecu side, large plug remove the wires from pins 30, 47, 48, 81. If you don't remove these, the car will not start and if it does it will run like crap. One is for the CEL, but it'll run without for now. I can walk you through hooking that up later.

The wire in pin 23 needs to be moved to 19. That is cyl 2 injector which is different on 01 ecus.

You must supply power to pin 21 on the large ECU plug. The 2000 ecu has no wire here, as it didn't have an immobilizer. You MUST run a diode inline for the trigger for pin 21. I prefer to connect it to fuse 7 (2001-up use this fuse), but any Key-on power source works, including terminal 75x. Then, add a diode. Radioshack sells them, I use this one:

http://www.radioshack.com/product/in...ductId=2062591

Without it, when you turn the key off the car will continue to run for a second or two. This is a big deal because it throws a plethora of codes as everything is shut down. Diode solves that problem.

Now, the small plug on the 2000 ecu. pin 115 has a large wire going into it. Follow it down till it splits. Those are cam adjusters - ground signal trigger. Bank 1 (passenger side) has to go to pin 115 and bank 2 (driver side) goes to 120. Basically the 2000 runs both cam adjuster grounds from one pin, we want to split them to both pins like the 2001 ecu has. If you don't want to do this, I can remove diagnosis in the flash, there are no drawbacks to doing this.

Pin 104 ecu side, small plug needs to go to 48 on the large ecu plug. Intake manifold changeover valve.

Then, we do the clutch switch install.

http://breakoutmotorsports.com/index...clutch-switch/

If you've already done this, skip right to the next step, verifying the clutch switch works properly:

VCDS measuring block 060. It should show your cruise control condition bits. Basically a string of 0's and 1's. When the clutch is out the 3rd bit (from the right) should be 0. push the clutch in, it should change to 1. If it's reversed, you have the wrong model clutch switch. Some are backwards. Not having this properly makes the car rev hang, and makes the driving experience VERY jerky.

http://wiki.ross-tech.com/wiki/index...asuring_Values

This seems scarier than it is, but fear not. The entire process should take an hour!

Any questions?

Doesn't seem bad at all. I'm waiting to hear back from this junk yard on the ECU that they may have for me and then I can dive in.

I think that the VSS is correct already, but I will double check with the test you have suggested. I've done some logging with VAG-COM and the VSS reported by the ECU matches what's going on in the cluster, aside from being in km/hr.

What do pins 30, 47, 48, and 81 do that they need to be removed. I do need to have a CEL to pass inspection, so I'll want to hook that up.

No problem adding the diode to pin 21, though you haven't mentioned the polarity of the diode. Which orientation should it be?

How far into the harness do I have to dig to find where the cam adjuster wires split? I don't mind doing it if it's in the first few inches, but I don't want to de-loom a ton of it. In my current setup, the ECU varies both cams together, whereas the 2001 is able to vary them separately? If I understand correctly, that seems like a much better plan.

Which change over valve does pin 104 control? There are 2 valves on my engine. Does the 2001+ only have one?

I used the clutch switch from my pedal cluster when I did the swap and read the article you referenced. Do you know if the correct switch (you mentioned that some are backwards) is normally open or normally closed? I don't think I can access 060 with VCDS lite to verify the installation with the method you have suggested. The wiring is complete, but I do wonder about the switch.

Once I get the necessary harness modifications completed will I simply be able to load the files you've posted on NefMoto, or will additional changes need to be made? Should I work on gathering pieces to make a bench flash setup, or do you think I'll be able to do this in car?

Thanks for the help!

[revolution337]

^ yeah y u so awuhsumm?

[bhusted]

Just got off of the phone with the junkyard. The ECU from the 2001 they have is 4D0907558F. I'm assuming this is no good. I'm glad you had the part # otherwise I would have bought it.

Looks like I'll be talking to Maroney's tomorrow. Thanks for the link Walky.

[ddillenger]

I'm not familiar with that ecu. If it TRULY is a 2001 ecu, then it'll work. HOWEVER, the only references I see to it online point me towards a 32v a8. I'd look elsewhere. I can give you some alternates that work (4D0907560CL works as well), but the 560AE is plentiful and cheap. It's your best bet for finding one that won't break the bank, that's why I listed it. I can't be explicit enough in my warning NOT to get a 2002-up ecu. If you do, your ecu won't get a VSS signal, and your redline will be limited to 6000 (unless the file is altered). In addition, you can't use the launch control or no lift shift I patched in (I'll post it in the thread later).

Now, for your questions.

1. The Diode allows power to pin 21, but not from it.
2. The cam adjuster split is about 12-18" from the ecu plug. Splitting them isn't for individual control, but rather for individual circuit diagnosis. The 2001 will tell you if you have an open circuit on one of the adjusters, whereas the 2000 would need both to be open before triggering a fault code.
3. The S6 flash uses the second changeover for the intake tract, not the manifold. You will want to connect both pods to the one solenoid to operate like the s6 does in unison. While this may seem detrimental, the gearing is so different there is no detriment to doing it this way, and the flash is modified accordingly.
4. You can load the nefmoto files, but they may need tweaking, or codeouts based on your installed components.

Also, don't forget that you'll need to defeat the immobilizer prior to running the 01 ecu!

[Mad Cow]

You must supply power to pin 21 on the large ECU plug. The 2000 ecu has no wire here, as it didn't have an immobilizer. You MUST run a diode inline for the trigger for pin 21. I prefer to connect it to fuse 7 (2001-up use this fuse), but any Key-on power source works, including terminal 75x. Then, add a diode. Radioshack sells them, I use this one:

http://www.radioshack.com/product/in...ductId=2062591

Without it, when you turn the key off the car will continue to run for a second or two. This is a big deal because it throws a plethora of codes as everything is shut down. Diode solves that problem.

I'm sorry for being kinda off topic, but as I understand it this will bypass the J271 relay? Or does the 2001 harness not have one in the first place?

[ddillenger]

You are correct, there will be a J271 Relay code present after the swap. I remove it from the flash. You could hook it up, but I've found this way to be the simplest.

[bhusted]

I'm not familiar with that ecu. If it TRULY is a 2001 ecu, then it'll work. HOWEVER, the only references I see to it online point me towards a 32v a8. I'd look elsewhere. I can give you some alternates that work (4D0907560CL works as well), but the 560AE is plentiful and cheap. It's your best bet for finding one that won't break the bank, that's why I listed it. I can't be explicit enough in my warning NOT to get a 2002-up ecu. If you do, your ecu won't get a VSS signal, and your redline will be limited to 6000 (unless the file is altered). In addition, you can't use the launch control or no lift shift I patched in (I'll post it in the thread later).

Now, for your questions.

1. The Diode allows power to pin 21, but not from it.
2. The cam adjuster split is about 12-18" from the ecu plug. Splitting them isn't for individual control, but rather for individual circuit diagnosis. The 2001 will tell you if you have an open circuit on one of the adjusters, whereas the 2000 would need both to be open before triggering a fault code.
3. The S6 flash uses the second changeover for the intake tract, not the manifold. You will want to connect both pods to the one solenoid to operate like the s6 does in unison. While this may seem detrimental, the gearing is so different there is no detriment to doing it this way, and the flash is modified accordingly.
4. You can load the nefmoto files, but they may need tweaking, or codeouts based on your installed components.

Also, don't forget that you'll need to defeat the immobilizer prior to running the 01 ecu!

I'll take your advise and find a 560AE. Walky posted a link to a yard in PA that claims to have two for $75 each. I'll give them a call tomorrow and get one on its way.

It sounds like a good practice to split the cam signals for diagnostic purposes later on down the road if necessary. It shouldn't be too bad, but that electrical tape the Germans use on the harness is like kevlar.

So, with your S6 file, both flaps stay shut until the higher threshold is reached? This would seem to make more sense than opening both early.

I'm planning to retain all stock equipment for the moment with state emissions tests to pass. The only thing I've though about trying to remove if everything else goes well is the SAI pump and EGR valves. I'll save that problem for later though.

Can you tell me more about the clutch switch? As I said before, I do have one installed. It's the same one that was used for the DBC cruise control on the V6. I'm just wondering if the switch should be open or closed went the pedal is in the up position. I'll test my current switch in the morning to see what I have.

I need to do some more reading on NefMoto about the immo defeat and flashing in general. Thanks again.

[ddillenger]

There are two switches. It sounds like you only have the one for starting the car, but that's fine with an auto file. Once the manual file's in, that's when it becomes important to to install the proper switch to prevent the previously mentioned issues, as well as have working cruise control. As for the intake flaps, with my file I sort of split the difference and open the flaps a little earlier than the s6, but later than the initial state of the a6. It keeps the load steady and I feel it's a good compromise. The one on nef isn't the one I currently use, but the intake flap maps are defined, so you can alter their mapping to suit your liking.

As for the SAI, it's very easy to delete. I can help you out with that.

[bhusted]

I have both clutch switches. There is the starter interlock switch (push the pedal to start), and the vacuum vent switch at the top of the pedal throw. I have it wired into pin 39 on the ECU as the page from breakout motorsports suggests. The switch I used was the same vacuum vent switch originally used for the cable based cruise control. Since my car was originally DBC, I had to add the wire from the switch to the white plenum plug and then to the ECU.

Does deleting the SAI effect the readiness codes at all? Since the car is already hot when I arrive at the testing center, there would be no reason for the pump to actually run. I would guess that they just look to see that the ECU thinks it's working.

[ddillenger]

There are 2 ways to remove it.

1. Tell the ecu that no flow is normal. This allows you to remove the pump without codes as the ecu never expects any airflow so it isn't disappointed when it doesn't get any. Readiness passes. You must leave the relay in place.
2. Turn SAI off as though it was never equipped. This sets it to PASSED in vcds, but NOT SUPPORTED to all other scanners. Circuit diagnosis can also be removed so as to allow the removal of the relay without stopping fuel trims.

Either way is acceptable.

[bhusted]

New ECU is on its way. I'm excited to get these last few issues figured out.

[rage385]

tracking this thread! I am thinking about picking up my friends 2000 A4 and I would love to put this V8 in there!

[rage385]

is there any difference between this V8 and the V8 in the S5?

[bhusted]

I ended up stuck in traffic yesterday for about 45 minutes and no overheating. I have to admit, I was a little bit worried, but the fans did their job. I ran the A/C at 70 F the whole time. I could certainly hear the hurricane going on outside though

is there any difference between this V8 and the V8 in the S5?

I'm certain that there are other differences, but I think that all of the newer V8s are timing chain instead of a timing belt.

[ddillenger]

is there any difference between this V8 and the V8 in the S5?

The only thing they share is the displacement.

[bhusted]

I got my Chinese center caps today. I've been using the VW caps that came with the wheels for over a year now. Not bad for $13 shipped from China.

[widgget]

Very nice project.

Why did you go with a 4.2 over the 2.7t?

Don't get me wrong, the V8 sounds sexy as hell, but it's a heavy beast and the one out of the B6 S4 at least is expensive as hell maintenance wise, let alone upgrading it, not that a 2.7t is exactly cheap ether but parts are much more readily available.

I'm not challenging your choice of engine, it's just that everyone in the B6 world is going with 2.7t swaps (plan on it myself this winter), and i am trying to understand why the B5 guys are so hot on going to the 4.2 instead.

[bhusted]

This is not the chain driven 4.2 from the B6 S4. Rather an older belt driven engine from a C5 A6. Stock for stock, this engine is more power and more reliable (my opinion) than the 2.7T (fewer expensive parts to break).

Many people have asked about the weight, but when it comes down to it, this engine is lighter than the 2.7T. The 2.8 and 2.7T are both cast iron blocks. This V8 is all aluminum with a magnesium intake manifold. The only real disadvantage with the V8 is that it is a little bit longer than the V6.

[Nollywood]

Very nice project.

Why did you go with a 4.2 over the 2.7t?

Don't get me wrong, the V8 sounds sexy as hell, but it's a heavy beast and the one out of the B6 S4 at least is expensive as hell maintenance wise, let alone upgrading it, not that a 2.7t is exactly cheap ether but parts are much more readily available.

I'm not challenging your choice of engine, it's just that everyone in the B6 world is going with 2.7t swaps (plan on it myself this winter), and i am trying to understand why the B5 guys are so hot on going to the 4.2 instead.

The 4.2 V8 weighs about the same as the 2.8 30V. And way less than the 2.7T.

The 2.7T is easier to install in the B6 than the belt-driven V8. The B6 engine bay is shorter than that of the B5. The chain-driven V8 is notoriously unreliable.

Fitting a 2.7T in a B5 is reinventing the wheel, and is not actually a conversion, the B5 S4 has taken care of that.

I hope this answers your questions.

[widgget]

I hope this answers your questions.

It does. Thank you both.

[bhusted]

New (used) ECU arrived today. Excited to get started on the conversion. Does anyone know if the large ECU plug from a 2.8 will physically fit this ECU? I'm thinking of making a bench flashing harness while I'm at it and need to know what my options are for cars to cut from at the junk yard.

[Mad Cow]

New (used) ECU arrived today. Excited to get started on the conversion. Does anyone know if the large ECU plug from a 2.8 will physically fit this ECU? I'm thinking of making a bench flashing harness while I'm at it and need to know what my options are for cars to cut from at the junk yard.

Best you can do is try, if it fits you'll know. The only difference I can imagine would be the shape of the small tab that protrudes between the 5 thick wires and the 2 rows of smaller wires on the large plug (the only one you need). But it's not really useful anyway, lots of people end up cutting them off. If you're browsing junkyards I would look for an ATW and AWM, ATW's have one style and late AWM's have the other.

[bhusted]

Got my new serpentine pulleys and coolant tank in the mail. Of course this is the same day that the original coolant tank went critical on me. Now I have a nice shiny coolant tank instead of the old yellowed one. I ordered it from partsgeek.com and fully expected a Chinese knockoff for the $56 I spent (everyone else wanted close to $100). The one I received looks to be OEM with the four rings and part number cast into the bottom.





I actually did the tank swap in the parking lot of our apartment (not supposed to work on cars). I didn't want to drive it and have the old one totally explode. Early on a Sunday morning there wasn't anyone around, so I went for it. Used a $4 hand pump from Harbor freight to drain the tank and some plastic line pinch clamps to hold everything else in. Didn't spill a drop. Before someone mentions it, I know I need a new cap...

Later today or tomorrow I'll drive to the garage where I work to pull the bumper/lock carrier and switch out the serpentine pulleys. One of the idler pulleys has gone bad and now sounds like a supercharged V8 without the extra Hp. I hope the noise is the plastic idler or tensioner pulley and not the one that used to drive the fan.

In other news, my wife and I will be moving in October. We bought a place in Kirkland with a garage!

[bhusted]

CEL turned off today while I was on my way home from work. I'm not sure if the ECU finally gave up on the errors, or if the light failed...

[DeltaAlpha9]

Easiest way to tell would be to turn the key to ACC and watch the lamp test.

[bhusted]

Yeah. I'll take a better look at it tonight. It's weird that it just turned off on its own. I'll see if it turns on in the ACC position and scan for codes tonight. It's nice to have it off though if all is truly well. I figured the TCU fault would keep it on until I switched ECUs.

[bhusted]

Today I replaced both the tensioner and plastic idler pulleys. The noise has diminished, but I believe that the now idler that used to be the mount for the viscus fan is the final source. The only problem is that it is rediculously expensive ~$300 for aftermarket. Anyone know of a belt outing on these V8's that would bypass the fan pulley?

[bhusted]

Made this wire harness tonight for bench flashing the new ECU. Hope to have some good progress this weekend. Thanks to "lm0812" for finding the necessary ECU plug in a junkyard for me.

[revolution337]

The only problem is that it is rediculously expensive ~$300 for aftermarket. Anyone know of a belt outing on these V8's that would bypass the fan pulley?

I had that same bearing (the one for the viscous fan clutch) go out on me when I got my car running as well, it made a god awful noise. I also noticed howe insanely expensive an OEM replcement was. After searching for about a week, I was able to find a guy parting out a 4.2 A6 and I picked up a used one for $25. No more noise.

[bhusted]

I had that same bearing (the one for the viscous fan clutch) go out on me when I got my car running as well, it made a god awful noise. I also noticed howe insanely expensive an OEM replcement was. After searching for about a week, I was able to find a guy parting out a 4.2 A6 and I picked up a used one for $25. No more noise.

I found one from a partout on Vortex for $30. I hope that noise goes away. It's getting embarrassing to drive into school. I teach at an independent school where parents drive Maseratis, Ferraris, etc. I sure can turn some heads in a 14 year old Audi that makes some funny noises.

[bhusted]

Still waiting on the fan pulley bearing to show up. In the mean time I got some other goodies.

While I was changing out the other two idler bearings on the serpentine, I noticed that one of the intake flap links was totally missing. I'm not real sure what happened here. I've heard of the them breaking, but there were no parts. Just gone. The Gruven links look pretty nice but rather steep at $90. I ordered up some M5 ball joints to make my own for ~$20. These also have the security pin and dust boots.




I also did some more work on my bench flashing harness. I added a switch to simulate the ignition switch and a ground for getting the ECU into boot mode.



Next up is to defeat the immobilizer and flash the modified S6 file.

[bhusted]

Got my new intake linkage arms made today. Way stronger than the stock plastic ones and much cheaper than the Gruven alternative. Ordered the joints and dust seals from http://www.jwwinco.com/. These joints also include safety locking pins to make sure that they will NOT fall off.

Part numbers:
Joints - 5NXF1/B $3.30 x 4 = $13.20
Dust seals - 12DXF0 $1.37 x 5 = $6.87
Total = $20.07

I ordered the fifth dust seal in case I tore one and it put me over the $20 minimum for free shipping. For the threaded portions to link them together, I went to my local ACE and bought 2 M5x0.8x40mm bolts and cut the heads off for $0.94. I used the nuts that came on the ball stud as the jam nuts and tightened everything down with some blue locktite just to be sure. Total investment $21.01.

[revolution337]

Very cool! Looks to be just as quality as the gruven units.

[bhusted]

Sprung a power steering leak today... I went to pull it out of the garage and the damn pump was whining and there was a puddle underneath it. Great! To top it off, the fan pulley I've been waiting for in the mail got redirected because my fail forwarding took effect today. Hopefully it shows up at the new address tomorrow. I guess I know what I'll be working on this weekend.

[bhusted]

Got some time today to work on replacing that serpentine bearing that had gone bad. In the process, I took some pics of the radiator setup for those that had asked.

Top hose from outside:


Clearance from inside on the top hose:


Lower hose from outside:




Upper hose from inside after moving lock carrier forward:


It's still taken apart while I work on a power steering leak, so if there are any other angles you want to see, let me know.

[bhusted]

And...We're Back! I was gone for a while with a massive power steering leak. With new hoses and some busted knuckles she's alive again. Also had this wicked knocking noise and starting fearing the worst. Turns out that some idiot forgot to tighten these...

[NeedingAnAudi]

And...We're Back! I was gone for a while with a massive power steering leak. With new hoses and some busted knuckles she's alive again. Also had this wicked knocking noise and starting fearing the worst. Turns out that some idiot forgot to tighten these...

You should fire your mechanic lol

[revolution337]

Those don't even appear to be the correct bolts for that pulley, they look way to big. IIRC, they are 10mm heads.

[Vinnie981]

Those don't even appear to be the correct bolts for that pulley, they look way to big. IIRC, they are 10mm heads.

100% correct you are. I have the 4.2L ART motor and those are NOT the right bolts at all!

[bhusted]

100% correct you are. I have the 4.2L ART motor and those are NOT the right bolts at all!

They are the "right" bolts. The originals were in such poor shape that I replaced them with hardened flange bolts. I torqued them down and used red loctite this time.