Check those timing belts, folks

E28 technical advice asked and given! Troubleshooting, modifications and more.
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turbodan
Posts: 9153
Joined: Jan 09, 2007 10:19 PM

Check those timing belts, folks

Post by turbodan »

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Just bought it, I'm lucky it hasn't snapped in the 150 miles I've put on it since.

Also offering a reward for information that leads to the arrest of whoever did this:

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The spring of course goes on the bottom and holds the tube into the intake. As I found it, the tube is sitting a quarter inch below the intake with absolutely no oil making the trip back down into the sump. Huge vacuum leak as well.

Having sorted out all that, I figured I would calibrate the afm bypass setting and spring tension. Still got that wideband 02 sensor from the turbo days:

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No better way to do it. Went about five notches tighter and nearly closed on the bypass setting. AFR at idle is perfect and under load it drops into the 13s, presumably just as BMW intended. Was way too loose when I got in there, no telling if I'm the first one or if it was like this from the factory.
gadget73
Posts: 1176
Joined: Nov 22, 2017 10:30 PM
Location: New Jersey

Re: Check those timing belts, folks

Post by gadget73 »

First thing I did when I got my diesel was replace the belt. It actually didn't look too bad but having zero history and knowing it had sat for a solid decade I figured it was the smart thing to do.
turbodan
Posts: 9153
Joined: Jan 09, 2007 10:19 PM

Re: Check those timing belts, folks

Post by turbodan »

I had to come back to bitch some more about the grossly incompetent, meatheaded dunce or dunces that worked on this car before I got my hands on it. It's been one thing after another, and I found some of the dumbest shit yet this afternoon.

After sorting out the very stupid intake pipe vacuum leak, properly adjusting the throttle cable, calibrating the AFM spring tension and bypass setting I have still had some persistent idle issues. Car has been running quite well and returning excellent fuel economy but the idle quality varies and is never as smooth as it should be. Figured I might as well take a look at the plugs. Chances are the same clown that unintentionally sabotaged everything else on the car had dicked something up with those too.

First thing I notice is that the plug wires fall right off. I immediately tried to reinstall #1 and it would not clip on. It seemed to pivot around and swivel on the terminal but would not snap into place. Upon removal of the plugs I find, of course, the moron that replaced these plugs did so without removing the terminal nuts. All six plug wires were hanging on only by the silicone boot. None of the plugs looked great but 4 and 5 were loaded up with very heavy deposits, presumably from the intermittent spark. I'm always happy to find a problem but not so much when it's a very stupid problem that should never, ever occur in the first place. That one takes the cake.

Coming in a close second place are the wheels. e39 16 inch and that's fine, doesn't bother me a bit. I did have a good vibration at highway speeds though. By this point in the ownership of this vehicle I have come to expect stupid things so I figure I better pull the wheels off and check for centering rings. Imagine my surprise to find that the mystery master mechanic just bolted these wheels on without any sort of hub-centric device. Easy fix but another one that it should have never needed in the first place. While I'm in there I also repaired the LF wheel speed sensor which was left hanging loosely in the wheelwell rather than secured to the original mounting point. Super easy to put the little wire right back where you found it but even that would be expecting too much from this individual.

I also had a slight drip from the rear diff. I had a similar slight drip from a rear diff back in the turbo car days. Knowing full well the diff holds a finite and relatively small quantity of lubricant, I was aware that this needed to be addressed with some degree of urgency. Back in those turbo car days, I let it go a little too long and roasted the diff on the highway. Lucky for me it didn't lock up but in a few seconds it went from perfectly fine to generating an increasing amount of drag and briefly "grabbing" before it loosened up and settled for simply making a horrendous noise. I wasn't about the let that happen again so I crawled under this one and set about cleaning it up and servicing it's rear end.

Always start with the fill plug, that's what I've read. In the event that it's dicked up in some fashion and you can't get it out to fill the diff, you at least want to discover that before draining it and really putting your balls in a vise. I approached the plug cautiously with my 1/2" drive ratchet and a can of brake cleaner. Before I could apply an inch pound of torque this this thing I find that it spins freely, it was less than hand tight, just plain loose. Mystery master mechanic strikes again. Luckily after cleaning, refilling and reinstalling the fill and drain plugs with fresh sealing rings the diff is only oily on the inside.

I should have been so lucky with the oil drain plug. This little guy was hurt. Over-torqued to the point of pulling the threads most of the way off of the plug. Lucky for me I had a spare from my previous period of e28 ownership. The pan wasn't happy but it did thread in and tighten up.

Maybe cars like this have always been out there but I fear this sort of eagerness and incompetence is becoming more and more common. This is the first one for me that has been so thoroughly molested and abused. Simple neglect is one thing, this is even worse.
gwb72tii
Posts: 619
Joined: Sep 21, 2021 4:58 PM
Location: The Great Pacific Northwest

Re: Check those timing belts, folks

Post by gwb72tii »

I'm finding all kinds of worn out/neglected things on my car, but yours takes the cake. man o man.
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