Winter & spring 2017 work log

It’s already June…but more progress has been made. The E24 has two fuel pumps. Testing has determined that the in-tank “lift” pump is dead.  I hope to get it replaced tomorrow; with any luck it will solve the running problems I’ve been having. The car starts & runs great, but when it warms up and switches into closed loop mode, it bucks & eventually stalls at idle. Typically that’s due to a fair-sized vac leak in an intake hose, but everything there is new. I haven’t tracked it down yet. I also have a different DME (ECU) on the way. I also checked & cleaned up the flap-type AFM (air/fuel meter) but it was OK. I also jury rigged a check engine light for testing and discovered the largely frustrating code “1222.”

Since I’m stymied by a few running problems, I’ve been cleaning up the bodywork. A few hours of clay bar & Turtle Wax Ice have made a pretty big difference. They’re really nice for thick single-stage lacquers like my Zinnoberrot. I also found a few rust spots around the car. There were a few typical spots under the taillights, and an unusual one under the driver’s door. The taillight seals are OK, but the rust spots might have been letting water into the trunk. I’ve been tidying them up.

It’s Memorial Day weekend, let’s sum up my progress. I’ve FINALLY been able to put a few miles on the car after insuring & registering it.  I’m stuck with two pretty severe problems…tracking down a running glitch and replacing the clutch hydraulics. The master cylinder is too short for some reason, haven’t figured out why yet. The DME also seems to be cutting out randomly. It’s not the main power, and it’s not the unloader relays.

  1.  Classic plate!
  2. Classic insurance!
  3. Rear speed sender
  4. Rear sway bar mounts
  5. A/C belt
  6. Brake, coolant & oil status lights. Install M20B27 coolant sender.
  7. Trunk leak
  8. Sunroof leak

During May, I fixed a few small problems. One was flickering high beams. The turn signal stalk was damaged; I suspect some cola was spilled into the column. Nasty stuff for electronics, isn’t it? Happily, I had a spare. It turns out that the late E24 (mostly) interchanges with late E30 non-airbag parts. I had to swap the turn signal relay socket, and the OBC clicky function isn’t wired up, but at least it’s not flashing the high beams randomly! I also resolved the rear sway bar mount, speed sender wiring, and the coolant status light.

February has been good to the car. I made up a harness to move the WBO2 electronics inside the car. I also tracked down some missing exhaust parts for my OEM BMW exhaust pipes. These are stock US E28 B34 parts…how hard could it be, right? The parts were easy to find but the flange was wrong. Part numbers checked out…the rest of the gaskets were correct…hard to say. Perhaps Bosal had the wrong parts listed? The flange they sent was significantly too small (at least 1/8″) for my 1.75″ OD mid-section pipes. I bought a generic Walker 3-bolt exhaust flange to suit. It cross-references to an ’80s Cadillac Seville (does that mean I’ll have a bit of GM in this car too?). I also tracked down another pressure leak in the cooling system. There is a short bypass hose that was leaking away once the thermostat opened up. It’s on the way. The clutch hydraulics are still a hot mess too. Instead of wasting even more time messing with it, I ordered a new master & slave set. We’ll see if Centric makes half-decent refurbs, their brakes haven’t been awful. The clutch line was overpriced, so I’ll probably have one made up instead. Hopefully this will install itself this weekend.

To finish January up, I paid my friendly local scrapper a visit. The scrap included a cracked M30B35 block, a bunch of worn rotors, a few small lead-acid batteries, and about 100# of scrap steel. Metal has an intrinsic (albeit low) value – knowing a good scrapper is a necessity in this hobby. My next chore was picking up fluids. I needed a little motor oil, coolant and washer fluid. Need more details? Check it out here.

Jan 30: Found a blown H3 bulb in the driver’s side fog light. Replaced it with a used spare, still didn’t work. That bulb had a cracked positive lead. Replaced it with a new part (raided a cheap set of 60 watt H3 Pep Boys lights) and now it’s fine. Headlights are randomly flicking onto high beams, I suspect the turn signal stalk. I also ordered about $100 worth of parts from RockAuto and ECS Tuning for the exhaust pipes and various trim trivialities. I was planning on a clutch slave cylinder too. I changed my mind. I’ll try to bleed it one more time. If that fails it’s time to swap another one in.

Jan 28: The engine temperature gauge hasn’t been working, I’m working on figuring it out. Many other B35 transplants ran into this problem since the chassis wiring does not match the engine harness. The gauge sender had two male spade terminals on the early Motronic cars (’81-’84?), then a two-pin Bosch plug with only one internal male pin on the mid-range cars (’85-’87?). I’m not sure if the E24 B35 is wired the same as the E32 & E34. If it is, it will have a two-pin Bosch plug with two internal male pins on the B35 cars (’88-’89). Why does this matter? Well, the donor car has the terminals switched. So if you have an E34 donor (like me), you’ll need to re-pin the connector for the gauge to work properly. I was curious about why some senders even had two pins, and I found out that the dual-pin senders have two functions. Both are grounded through the block. One pin sends a variable resistance for the gauge, the other is a switch for an overheat warning light. I’m not sure if that overheat light is in the gauge cluster or the “Check Control” board. According to the ETM, the mid-range cars (like mine) have a gauge cluster socket for the overheating light but aren’t internally wired for it. It’s possible that these functions were taken over by the ‘Check Control’ OBD unit. If not, I might see if I can add this function to the car. I’ll be in there anyway when I’m trying to install the CEL. Both functions seem pretty useful. BTW, none of this applies to the earlier E24/1 cars at all (built before ’82). They have a similar harness, but a totally different electro-mechanical gauge cluster.

I also cleaned & reassembled the headlights this week. I’ve upgraded this machine with Hella halogen composite headlights. These are commonly called ‘E-Code’ units; they use an H4/H1 bulb combination. The “E” code is just a letter cast into the lens, it’s an indicator for a European lighting specification. These are one of my favorite upgrades – they fit directly into the US buckets but provide significantly brighter illumination. They only require a bit of wiring and a fuse upgrade. Fuses 1 & 2 were 7.5A, now are 15A. One should be careful with doubling the rated output into a circuit, but it’s been done many times and is just a temporary jury-rig.

I’m also checking into clamp-on exhaust sleeves to sort out the missing hardware on my ratty exhaust center section. That will be handled in a future post. I have high hopes!

Jan 21: Figured out a lot of stuff.

WBO2 wired up. My B35 harness had four wires. Two white wires: from the plug, pin 1 is 12VDC, pin 2 is ground. There are also a black signal wire on pin 3, and a grey floating ground on pin 4. I left the floating ground unwired, since I don’t have a floating sensor ground in the DIY WBO2 controller. I tossed the controller board into a cardboard box and lashed it to the brake line under the car. It reports that the car runs a little on the rich side, around 13:1 AFR.

B34 temp sensor wired up but not installed. I’m not sure the gauge is working; I still have to sort out the wiring differences. The E24 gauge requires a 5VDC feed and floating return, thus the B35 sender won’t work. I’m told the dual pins on the B35 sender feed the gauge and the overheating emergency light, grounding through the block.

Hydraulic booster buttoned up. Thanks to another incredibly helpful MyE28 post from Chris Wright, I managed to sort out some leaks in my booster system. The brake and accumulator return hoses were leaking ; they had hardened up over the years and needed to be replaced. The OEM stuff is incredibly expensive and these hoses don’t see very much pressure. These hoses are odd metric sizes; very unlikely to be in stock at auto parts stores. I chose to use SAE bulk hose from my friendly local NAPA. BMW specifies 6x12mm for the accumulator return; I substituted 1/4″ (6.35mm) I.D. low pressure internally-reinforced fuel line. Likewise, BMW specifies 8x13mm for the brake return, I used 5/16″ (~8mm) I.D. transmission cooler hose. It’s a temporary repair, but I’m happy with it. If it fails in five years, I’ll throw another $20 at it. After purging the accumulator, I properly filled the hydraulic reservoir. The pump now runs quietly and efficiently.

I also put the driver’s kick panel back together.

The last of the vac lines are patched up too. I ran a hard line off the charcoal canister over to a tee at the fuel purge valve. The other leg goes to the interior air temp sensor since I’d run out of intake manifold nipples.

Finally, I chopped off a 3-pin male plug from the Euro E24 engine harness and modified it to meet the seven? pin female C103 plug under the dash. Whoever installed the S38 had already modified the chassis wiring, but I hooked up the tach & economy signal wires anyhow.

I still have to figure out why the clutch is so sloppy. It might just need a new master cyl – but I’ll see if I can’t scare up a spare.