1 Attachment(s)
Warning: Long Post!
Not exactly a Christmas present, but close. Some of you know I dabble in older BMWs. Between my brother and I we have bought 62 of them over the years. Some we bought on Monday and sold on Friday, but many were cars we actually drove for a while. My absolute favorite (even better than any of the early M cars) is my 83 745i, Euro only model factory turbocharged car. I bought it out of a salvage yard with most of the engine in the trunk and a lot of missing pieces. PO’s wife was pissed at him and threw away enough turbo related pieces that he gave up putting it back together. It showed 105,000 miles when I got it in Nov. 1997. Body was absolutely pristine. I had it up and running by Christmas; although the piping from the intercooler to the charge pipe was a temporary PVC set up. Think about how pathetic performance was in 1983. This car would do a true 150 mph in stock trim, with only 6 psi boost.
Fast forward. As this was my daily driver for many years, it now has about 320,000 miles on it. As you can imagine, parts are not cheap and not readily available. Any time you order a “Euro only” part on line, you have to scan and email the title to prove you own a Euro only car. I guess they don’t want someone creating a Euro version of a U.S. model car. I have no idea why.
I have been through a few different iterations of the motor set up. At one time, I was running a solid copper head gasket (there is an adventure all on its own) with 15 psi of boost. Never had it dynode, but kept breaking parts. Chassis and driveline just won’t tolerate the massive torque I was making. Just a guess, but I am guessing between 550 and 600 in torque. I realize lots of late models can do that with ease now, but this driveline just wasn’t designed to handle it. After twisting a driveshaft about 20 degrees, breaking rear axle CV joints, I settled on a slightly milder build. Still running 11 psi of boost. Can’t take off too hard or the IRS wheel hops something fierce even with 265’s out back (by the way, why do those damn rear tires keep wearing out faster than the fronts? I swear, they are all defective).
So, how does this relate to a car part for Christmas? Last spring I noticed the car would intermittently cut out from time to time. So, we just didn’t drive it much. I ASSUMED the ECU was dying. I have been through a few. Last summer, I headed to the car wash with both my 7 year old grandsons (identical twins) to wash it. I noticed it cut out just a couple times on the way to the car wash. After washing, it wouldn’t even get out of the parking lot. How embarrassing. Called Sherri; she came and got us, and we took the car hauler to the car wash, winched it home and it has sat in my garage since then. I could start it, and it would run for five to ten seconds and quit. I keep a spare ECU, but it did the same thing with it. Tried a third. Same thing.
I installed a fuel pressure gauge as well as an oil temp gauge and an aftermarket AFR meter to keep tabs on things. The last thing you want with a turbo car is for it to go lean. I noticed the fuel pressure never dropped, so that ruled out the fuel pump and filter (although I changed the filter anyway). I have a buddy down in Dallas that is a real 745i guru. He can tell you the values on each resistor in the ECU. He suggested it might be my air flow meter (AFM). They are normally good for 200k or more, so maybe he had a point. I mailed two of my ECUs to him to try on his car.
In the meantime, I found a guy on line that rebuilds the AFMs and can even test each one with an oscilloscope. I sent mine to him. Got an email saying he wasn’t sure it could be rebuilt, as the unit had remained unsealed for so long that there was a lot of corrosion in the circuit board. Crap. Found a core on ebay (actually two) but both were obviously unsealed, and no guarantee they would be any better.
OK, we are getting to the “part”. Tried the part number one more time, and found a seller who just purchased a whole warehouse of old BMW and Mercedes parts. He had an NOS air flow meter for my car! These things have been out of production for like 20 years. Got if for $275 (less than the cost to rebuild my old one). Came FedEx in Tuesday. Installed it, and the car runs perfectly. Well, almost. I have to keep the boost under the stock setting as the current ECU in the car is stock, and does not have the performance chip that allows me to run increased boost. My chipped ECU is still with my buddy in Texas. But I will get it back soon. Merry Christmas to me!
|
