4.2L V8 Swapped B5 A4

[Vinnie981]

interesting...ill post some pics of mine in the AM.

[jerrone]

I'm looking into this swap now.The 4.2 bolts up to the 2.8 tranny right?

[revolution337]

I'm looking into this swap now.The 4.2 bolts up to the 2.8 tranny right?

yes

[OldAudiA4]

Awesome project!

[bhusted]

The bushing on the front lower control arm failed and I ordered a new pair from FCP. I went to replace it this morning and discovered that even with my meticulous attention to VIN splits, etc. I got the wrong parts. Fortunately, they are going to take care of me and get a pair of the correct arms out to me ASAP. Notice the difference in the ball joint taper.



Sucks having to reassemble with old parts. While I was under there, I replaced the leaking oil pressure sensor. I don't know about it's location when installed in an A6, but this was a real b$#@h on the A4. The best part was the waterfall of oil when I got the old one out. Glad I wore safety glasses.

[Operator]

Nice work!!!! Really clean and smoothly done thus far it seems!

[bhusted]

Got started on the wiring changes for the modified AWN ECU today. May have time to finish it up tonight after Walking Dead. Super excited to get rid of the ART issues.

[bhusted]

Finished up the wiring changes last night, but it won't start. It seems like a fuel/injector problem. I pulled the plugs on a couple of cylinders and they were dry. I'm going to make an LED test light for the injectors today. Is there a way to test for spark with the coil on plug ignition?

[walky_talky20]

Just like this (skip to 1:10). Stuff a screwdriver in the end of the coil, then hold the shaft about 1/16" from the valve cover or other ground. Have somebody crank the engine.

[bhusted]

Back up and running! With the newer ECU pin 21 apparently needs power through a diode to defeat the immobilizer. I thought that I may have gotten the polarity wrong, but it turns out that the 75x terminal is not hot during start and so the ECU was never getting the signal while cranking. Special thanks to ddillenger for all of his help.

I haven't reassembled anything yet (dash, ECU box, rain tray, etc), but the trip around the block was AMAZING! No more rev-hang, high idle, or SAI noise. Tomorrow I'll put everything else back together and install the $100 DTS I picked up on CL.

[bhusted]

Got the DTS installed and it does make a difference. Under power before I could feel the transmission squirm around now it seems to totally stay put. There is of course some additional NVH, but really only at idle and I can live with it.

Today I also installed the correct clutch switch for the new ECU. How much of a difference could a switch to tell the ECU if the clutch is in or out make? Major improvement! I don't know how to describe how it was before other than "jerky". It made me feel like I didn't know how to drive. Now it's much smoother. For the record, If you're running the ME7.1.1 ECU, the switch needs to be "normally closed". I wrongfully assumed that the switch from the 2.8 would work, but it is "normally open". I ended up using a brake light switch I got from the pick-n-pull.

Last few things on the list to do before buttoning it back up:
- hook up CEL wire. This had to be removed for the new ECU, but I'd like to get it figured out for future reference.
- figure out which of the vacuum solenoids is activated by the ecu. The new ECU only actuates one of the intake manifold flaps.
- move the VSS signal to the proper pin on the ECU. The cruise control stopped working after the ECU swap and I think it's a VSS issue.

[Mad Cow]

The new ECU probably uses the canbus for the CEL, I had this issue when I swapped in my AWM harness which does the same. I was able to connect a wire to the same pin as it was in my ATW harness and it worked. I never knew that there are two different clutch switches, I'm still using my old 2.8 switch too and I wonder if ME7.5 needs a different one.

[bhusted]

I never knew that there are two different clutch switches, I'm still using my old 2.8 switch too and I wonder if ME7.5 needs a different one.

If your cruise control works, then everything is good. If not, this could be one of your issues and causing more issues than just cc not working.

[Mad Cow]

Yea I realized afterwards that it would prevent cc from working, and mine works just fine. As for the VSS issue, I ME7.1.1 might get speed through canbus and have the VSS go to just the cluster.

[bhusted]

Lower radiator hose clamp failed resulting in a nice puddle of coolant on the floor this morning. I also took the opportunity to get the vacuum lines sorted out for the intake change over valves and pull out the hose/solenoid for the combi valves and SAI. I need to get some block off plates on order so I can pull the combi valves too.

[bhusted]

Still no dice on the VSS. I've verified continuity from the pin on the ECU to the cluster. While running the ART ECU, I know it was receiving the VSS because cruise worked. Now when I try to log measuring block 005, speed constantly reads 0.0 km/hr. What gives?

[Mad Cow]

What about continuity between the VSS and cluster? I'm not sure how it's connected, but does it go through the ECU or does the ECU VSS input pin also serve as the cluster VSS input?

[bhusted]

The cluster is good. The VSS feeds directly into the cluster and then there is an output on the cluster that goes to the ECU. There is a separate pin for the output from the VSS into the cluster from the output to the ECU. I think the problem is software with the newer ECU expecting a different type of signal for speed.

[Mad Cow]

Oh so the speedo works but the ECU isn't getting a VSS signal? Like I said before, it might be that the new ECU gets its VSS signal from the ABS unit through the canbus like how the B6 does it. This is just a guess though since I have absolutely no idea if it's actually like that. If that is the case though I don't see how you would be able to do anything about it short of modifying the ECU software.

I think you might have to invoke ddillenger again, if anyone can help you out it would be him.

[bhusted]

I've already be in contact with ddillenger and he's looking into it also. He seems to think that 2001 ECU I'm using will accept the CAN VSS signal or the older pulse VSS signal. I've been pouring over wire diagrams and it appears to support what he is saying. I hope to get it figured out soon.

[Mad Cow]

That's really weird, my diagrams don't show a direct link between the cluster and ECU for the VSS circuit. It shows it going to the cluster, then out on pin 3 of the blue connector to A108 and nothing after that, no other reference to A108. Are you 100% sure the new ECU uses the same pin for VSS? Sorry if these sound like stupid questions, but it's best to cover all the bases no matter how trivial it seems.

[bhusted]

Yeah. I'm certain of the connection. Everything I have suggests that pin 54 is the VSS for my ECU. If you have a diagram that suggests otherwise, I'd love to know.

[Mad Cow]

Everything I've said is based off the diagram found in ELSA, I can't really make sense of the one you posted and can barely read it because of the resolution anyway. I can send you my diagram if it'll help, I wish I could be more helpful but I'm no electrical wizard.

[bhusted]

Had the pleasure of replacing the clutch master cylinder yesterday. I really hope that its failure was not due to the heavier pressure plate because I really do not want to have to do that again. If you have not had the pleasure of changing the master cylinder, it is located inside the car under the dash. The hydraulic connections are on the firewall underneath the ECU box. I managed to not leak any fluid into the interior.

[bhusted]

Started mocking up a new air box tonight. The current situation places the air filter directly over the passenger exhaust manifold. While it seems to run great, I'm certain it would run better without all of that hot air in the intake. I picked up a coupler and a 45 to start.






The filter side of the tube will have to be cut to accommodate the filter. I may trim the MAF end of the tube as well. I plan to utilize the stock air box mounting points on the frame and will have to fabricate some sort of new upper mount.

[MetalMan]

Great idea! While you're at it, may I suggest also finding a viable replacement for the according hose between MAF and (throttle body?)? There are lots of different silicone couplers available, like 45 deg. reducing, etc.

[bhusted]

Great idea! While you're at it, may I suggest also finding a viable replacement for the according hose between MAF and (throttle body?)? There are lots of different silicone couplers available, like 45 deg. reducing, etc.

Yeah, I've looked at replacing the whole thing from the TB to the MAF and 034 makes one for the B6 S4 that is almost a direct fit, but they want $75 for it.

http://store.034motorsport.com/maf-h...4-audi-v8.html

After I get this part figured out, I may look into other options for that.

[bhusted]

MetalMan's comment about the stock accordion hose got me thinking tonight, so I decided to try replacing the stock tube from the TB elbow to the MAF with the aluminum tube I already bought. The fit is actually pretty good.

[MetalMan]

That's pretty cool. So then I'm assuming the MAF would attach to the open end of the pipe?

[bhusted]

That's pretty cool. So then I'm assuming the MAF would attach to the open end of the pipe?

Yeah. I think I would shorten the end of the pipe a bit and then attach the MAF with either a straight or a 45 degree coupler. Using the 45, I could turn it more toward the strut tower after the aluminum pipe. It sort of screws up my plan for the heat shield though. I'm open to other ideas...

[MetalMan]

Maybe a metal pipe with a MAF sensor tower welded onto it? Kinda like this:
http://s8.photobucket.com/user/Dandr...10108.jpg.html
That's obviously extra added expense but it's an idea

How about some of that "Reflect-a-gold" or whatever it's called wrapped around the MAF housing to shield heat?

Another idea: what about a 45" silicone coupler, attached directly to the throttle body or with a short straight section between the silicone coupler and TB?
The MAF housing could hook straight into the silicone coupler, and the silicone coupler could be easily trimmed to size.

[bhusted]

Maybe a metal pipe with a MAF sensor tower welded onto it? Kinda like this:
http://s8.photobucket.com/user/Dandr...10108.jpg.html
That's obviously extra added expense but it's an idea

How about some of that "Reflect-a-gold" or whatever it's called wrapped around the MAF housing to shield heat?

Another idea: what about a 45" silicone coupler, attached directly to the throttle body or with a short straight section between the silicone coupler and TB?
The MAF housing could hook straight into the silicone coupler, and the silicone coupler could be easily trimmed to size.

The aluminum MAF sensor housing would be super classy. You're making this "simple" project escalate very quickly. I have a spare MAF housing that I could experiment with at some point. I'll talk to my buddy with the TIG at some point about making that.

I like the idea of moving the MAF to directly before the throttle body. There is a 90 degree elbow that comes straight off of the throttle body there. I wonder if there would be any detrimental effects to having a bend directly after the MAF. There is also a PCV hose that goes into that elbow and I would hate to see any oil residue from the PCV get onto my MAF.

[tinytim]

Looking good dude... I can't wait to have my engine back in!!

[bhusted]

Looking good dude... I can't wait to have my engine back in!!

Thanks! I think we all want to see what happens when your engine goes back in.

Ddillenger thinks my VSS issues arise from trying to use an older cluster with the newer ECU. I found a partout of a 2000 S4 on CL and went out to meet him today. Super nice guy. Picked up the cluster, wiper switch, and wiring for the DIS. It looks like I'm back to digging through wire diagrams...

[tinytim]

Wiring diagrams... I just love those things. Not!

I'm not running a stock cluster so things may get interesting for me.

[Mad Cow]

Nice, I've been planning on swapping in a facelift cluster too so I'd like to know how it goes. I already did a bit of preliminary work in figuring out what wires go where, it might help you out: https://dl.dropboxusercontent.com/u/...%20pinout.xlsx Note that I already have a DIS so the last connector you'll have to figure out yourself.

[bhusted]

Nice, I've been planning on swapping in a facelift cluster too so I'd like to know how it goes. I already did a bit of preliminary work in figuring out what wires go where, it might help you out: https://dl.dropboxusercontent.com/u/...%20pinout.xlsx Note that I already have a DIS so the last connector you'll have to figure out yourself.

Thanks. Your spreadsheet looks very similar to the one I've created. I've been going through diagrams to identify each pin and the corresponding wire color. There seem to be quite a few to move from the blue plug to the green. Always an adventure with this car. I'll certainly document the process and let you know how it goes.

[Mad Cow]

How are you going to do the wiring? Since so many wires change connectors i'm looking to salvage some female connectors from a broken cluster and making an adapter harness sort of thing.

[bhusted]

How are you going to do the wiring? Since so many wires change connectors i'm looking to salvage some female connectors from a broken cluster and making an adapter harness sort of thing.

I'm just planning to repin the connectors. I would be nice to have some female connectors, but I'm not sure how feasible that will be. Anyone have a broken cluster that they want to send me? I'll pay for shipping.

[bhusted]

Rather than search and wait to find a broken cluster to salvage the sockets from, I took another look at the cluster plugs. They are a standard 0.1" or 2.54 mm spacing. I went down to my local electronics store and picked up some header pins and set to work.




I've now traced each pin for the cluster swap (I think) and soldered each wire to it's corresponding pin. I'm not real happy with how the heat shrink turned out, so I might revisit that later. The additional wires are ones that will get transferred to the green plug. Here is the beginning of my adapter harness. It will plug into my existing harness so no modification of the existing cluster plugs will be necessary.