Captain Obvious

Got it. I did a little digging and found people on BMW forums talking about installing different thickness shims or multiples to adjust the tension. Really seems like an un-German "afterthought" design. Looks like they included a tensioning device in later years, but the early ones used shims? And to design the system without interlocks or locating pins or something such that you can easily do exactly what you did. Just surprising. Could they at least have put the shims on other feet that don't have oil holes or do all the feet port oil? Certainly not poka-yoke. Haha! It's always easier to second-guess someone else's design decisions. Anyway, glad you found a smoking gun. I would have never been comfortable with the engine ever again if I hadn't found something definitive. The guy with the Viper will be happy to see your rear again.

Wow. Glad you found something! It always makes me nervous not to have what I believe is the smoking gun. So that shim is supposed to just stay in place with no locator pin or pressed in boss or anything? Just pinched by the bolt nearby? I don't like it. What's that shim's purpose? That's a gasket between the block and the oil pump?

Once you write the program to do the cutting on the table, knocking these things out will be a piece of cake. Good luck with the project! Once you get to the point where you have the outline perfected, let me know and I'll pull one of my originals off and do a more thorough material analysis if you are interested.

Neat! Here's my impressions after reviewing the dots: The general price seems to have gone up from roughly centered around 15K to roughly centered around 20K. There are a bunch of people out there that think their hunk-o-junk is worth around 10K (7 to 13), but the market clearly disagrees. There is one guy out there with deep pockets who hopefully got a fantastic car for his $40K!

LOL. Or cardboard painted with wrinkle finish paint...

Zed Head, Don't remember exactly how, but I found the Beck/Arnley part number first and started digging into the "used on" applications list. That's how I turned up the Wagner number. One bread crumb that leads to another and hopefully eventually leads to something (hopefully) usable. Cross referencing from other vehicles, and all that. Thanks for guinea pigging for us. Hope they work! PS - If they work and aren't made out of cut up black jeans, can I have your old rusty dented originals?

225's on a inch wide wheel? Looks nice, but I can feel that sidewall roll from here!!

For the energetic experimenter, there may be options. A little digging turned up what some people consider replacements for the factory shim. And cross referencing has turned up a couple part numbers. There may be others as well, but I didn't dig too deep. Here's some numbers to start with: Beck/Arnley 084-2008 WAGNER SH14025 The look a little different than stock, but the differences appear to be in areas that shouldn't really matter. Mainly... They are cut straight across the piston instead of having a circular cut out in the middle. Since the piston doesn't contact there anyway, I'm thinking it shouldn't matter. And I don't know if the coating would help or hurt, but I think they would be worth a try if you're desperate. Here's a pic: And here's a couple pages with more info: http://www.rockauto.com/en/moreinfo.php?pk=156573&cc=1274745&jsn=10619 http://www.ebay.com/itm/Disc-Brake-Pad-Shim-Front-Beck-Arnley-084-2008-/232361458677?epid=75309807&hash=item3619d27bf5:g:sA4AAOSwhvFZNeBE&vxp=mtr

Your temp sensor readings look well within tolerance: I agree with the crowd however and say that your fuel pressure looks high. Also, are you running aftermarket injectors? I'm convinced that some of the supposed "correct" replacements put out more fuel than stock.

Haha!! I'm disappointed! It's solid state and not tubes!! Hope none of your neighbors are listening to the radio or they're gonna hear you testing your injectors.

Chas, That's exactly what I did as well. I used the starter for about ten seconds and decided I needed to do something different. That's when I got the signal generator out and used it to drive a relay that pulled the lower side of the coil to ground. That way, I could also test the ignition system and verify the one injector opening for every three sparks, as well as vary the frequency. A little crude, but it worked. I only mentioned the sig gen because I'm sure Dave has one. Probably vacuum tube, but I'm positive he's got one there somewhere.

Zed Head, Now that I think about it, I bet you are right in that they are steel and not aluminum. I was jumping to conclusions because I don't think they rust. And with that in mind, I bet they are stainless. I suspect the rust you have seen is "embedded" into the shim by the piston, but not growing out of it. I don't have any spares and the only ones I have are on my car. Next time I'm in there I'll investigate a little deeper. Do you have any spares laying loose? Are they magnetic?

Haha! Well the arrow doesn't necessarily point towards the front of the vehicle (because the caliper doesn't mount exactly on the top of the rotor), but it does point in the direction of wheel rotation (when the car is moving forward). When the calipers are mounted on the car, the shims contact the piston from approximately the 8:00 position to the 4:00 position. (Does that make sense?) I don't know for sure what material they use for the OEM shims, but I don't think they rust, so they are probably stainless steel or thin aluminum. I don't know what grade, but it is not one of the dead soft malleable grades. There's a temper to it. They would be a breeze to cut using water-jet or laser. You could mill them on the CNC, but water-jet or laser would be much faster and easier.

EdwardZ (David), Welcome aboard!! I hope you like it here. You got a wonderful car, and I hope you enjoy it as much as the previous owner did!

When I first got my car, the front brakes squealed. When I dug into it, I found that my PO had put the anti-squeal shims in backwards. I switched them around to the proper direction and the squeal went away like magic. Poof.... One way they squealed, the other they did not. The point being... Yes, which part of the piston that is covered by the shim DOES make a difference.

Dave, Yeah, it's not as bad as it sounds. You can get the whole rail off as a unit, and that will also give you the opportunity to take a look at your lower injector seals. If they're dried out and shrinked up, they might not be sealing well. And that certainly isn't going to help a lean misfire at idle when the vacuum is so high and the amount of fuel is so low. Chas, Haha! That sure does look familiar! I don't remember, but I probably got the idea from seeing what you did! Out of curiosity, how did you get the injectors to fire?

And about injector testing... I checked my injector balance a little while ago. I bought a pack of small plastic containers. I think it was an eight or twelve pack of containers from the dollar store. I used a small hole punch to cut a hole in the lid of six of them: I weighed them empty to get the tare weight. Thankfully they were all the same (at least to the resolution and accuracy of my cheapo HF digital scale) at seven grams empty: Numbered them up so I knew which was for each cylinder: Disconnected the fuel rail from the head and thankfully there was enough flexibility to get the cups onto the ends of the injectors: fired the injectors a bunch (I used a sig gen tied into the ignition system) and collected samples: Weighed them up again and verified they were the same (again to the resolution and accuracy of my cheapo HF digital scale), so I'm happy:

Dave, I don't know if there was an ignition problem or not, but I was just pointing out something different on the two videos. Maybe it was just different indexing of the colortune when threaded into the two holes. Maybe on cylinder 2, the spark gap was on the visible side and hidden when installed in cylinder 1? There's a dark spot in the ring on cylinder 1 video. Maybe that's the shadow cast by the ground strap electrode strap? If that's the case, then the spark would be 180 degrees from that and would be hidden by the plug boot? Would be neat to have two (or six!) colortunes installed at the same time for easier comparison in real time.

Well I certainly would try to get it out without pulling the dash first. Maybe you'll get lucky and can manage to get enough stuff out of the way. That copper tube goes about three inches or so into the airbox and then is formed into a coil about an inch in diameter. The point is, you need direct straight on access, not only to get the two screws out, but also to pull the assy out of the airbox. It's incredibly easy if there's nothing in front, but like you said... you have to disassemble so much to access two tiny sheet metal screws. Good luck and keep us posted!

I've never used a colortune so it was neat to see one in operation. Neat. I can provide one potential answer about one thing... There is an "after start enrichment" that adds a little extra gas for a little bit after the starter stops spinning. Lasts maybe thirty seconds or so? I found and poked around with the section of the ECU that performs that task, and it tapers off over the first 30 seconds or so. That might be why you aren't seeing the misfire until a little bit after you start the engine. (For those of you that geek out about this kind of stuff... It involves PNP transistors, film caps, and high value resistors. In other words... Bosch analog voodoo.) So about the colortune... On the video of #2. When you rev the engine and then release the throttle, I can see the bright blue ignition spark when the ignition spark is still occurring, but the mixture is too lean to ignite. The whole plug circle doesn't light up, but the narrow strip of the ignition spark gap still does. But on the video of #1 when you rev it and then release the throttle, I can't see that same phenomenon. Is there a healthy spark during deceleration that I just can't see? I'm just making sure we're hunting a fuel problem and not anything possibly having to do with ignition.

One heck of a shine? A huge ball?

Yeah, like I said, I would be happy to be wrong, but the A/C cars are really packed in there. I know I could take the control head out of my non-A/C car without pulling the whole dash, but I'm skeptical about the ones with A/C. I haven't tried. But pulling the dash isn't the end of the world. Gets easier every time. IMHO, draining the Freon out of the A/C system if necessary would be more of a problem...

I would be happy to be proven wrong, but I don't think you will be able to get enough stuff out of the way to get it out. I think you need to remove the whole heater control head at minimum. You have A/C, right? That makes it worse. I think even the evaporator box might be in the way.

Haha! Maybe next time we'll start with the beer. Might make troubleshooting a little more difficult though!

Yeah, the diagram for the 75 and 76 are the same, and what you suggested is exactly what I think happened. The original battery cables are long gone, and the replacement cables did not have provision for the pigtail firewall ground connection. That left only one tie point built into the body wiring harness that runs along the pass frame rail along the engine. One end or the other of that wiring harness tie point wasn't making good connection, so the body (and everything on the entire car that uses a body connection as ground) was floating. Stuff don't work so good like that.