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Yea, I've checked those 1 billion times. I've physically traced the fronts to each wheel. For the rears, I've traced to the fuel tank, and then must assume that where each line turns 90 deg, one left and one right, that they are going to the corresponding left and right wheel.
Short version, I may have my Brake Light Switch to pin 41 hooked up incorrectly, and it's causing a problem.
Who can confirm the correct circuit for the BLS input, Pin 41?
Much longer version.
I found to a way to re-create a symptom without being on track. Turn ABS off, then on. On first press of brake pedal, if pressed quickly and hard enough, the ABS system "clicks" noticeably AND I can feel a small quick reduction of pressure in the brake pedal. One kinda "crunch" feeling. This "crunch" feeling is one of the few symptoms I've been having on track. With ABS off, this never happens. Never. Dozens of repeated attempts.
So, I start unplugging sensors to see if I can get the crunchy click to stop. And low and behold, unhook the BLS and it stops.
Check BLS connection, and I *think* I have it backwards. I have 2 documents I thought were the same and thought I could trust both. Notes from Racing Harness Technologies, Doug Wardell (MK60 Installation notes for E36), and from "BMW E30 Motorsports Parts".
The RHT document say to hook Pin 41 as follows: "GROUND when the pedal is NOT pressed and open circuit when the pedal is pressed."
The E30 Motorsports Parts documents says: "chassis ground connection in the brake light (pin 41) when the brake pedal is pressed and no connection when it's not pressed"
I connected via the E30 Motorsports Parts document method.
*IF* this is it, it's an odd failure mode. It requires the line pressure to be above about 900PSI, and for that pressure to rise quickly. I had noticed this on track, if I pressed slowly and approached ABS activation slowly (meaning, 0 PSI to high PSI in ~ 1 sec), the brakes seemed to work amazingly well with no weird pedal issues. If brakes were applied smartly and hard, then odd crap would happen. The only thing I can think of, is if Pin 41 is expecting GND when brakes are off, the computer is seeing both a "brakes are off" signal and high pressure sensor pressures.
You can check using the INPA software (the same one you use to trigger the bleed cycle). I forget where, but in some page somewhere, it shows you the status of the BLS in real time. Step on brakes and the circle goes dark, circle is empty otherwise.
You can check using the INPA software (the same one you use to trigger the bleed cycle). I forget where, but in some page somewhere, it shows you the status of the BLS in real time. Step on brakes and the circle goes dark, circle is empty otherwise.
Oh, cool thanks.
I also came across the wiring diagram for that pin 41 input somewhere, maybe in the TIS, but finding diagrams in the TIS software isn't easy to recreate.
I had meant to unplug sensors while I was at VIR to see if symptoms changed, and I got caught up in, being at VIR, So much fun.
Update, Doug Wardell confirmed that Pin 41 (BLS) is supposed to be ground when not pressed and open circuit when pressed.
So I have it wired incorrectly.
You must have some old E30 Motorsports Parts document. They know how to wire the Teves units and it is the opposite.
This is from them - connected to ground when the pedal is not pressed:
Sumbitch...my document has the same thing in the pinout section. But in the text section, it has:
Doug still thinks something else is wrong. I'm hopeful this is it. I don't think I made it clear to Doug that I could reliably create one of the symptoms (crunchy pedal) with the car on the lift, and the symptom goes away when I disconnect the incorrectly wired BLS. So, fingers crossed.
ATEC responded to my email, and stated they could ship to US no problem.
I'm working on the details of shipping/handling fees, etc, and how to actually order them.
Sorry, I got distracted from the fittings. One question I have is the 650.616.
Are we sure that's correct? The catalog lists the female thread size for that as Dash 3, but the MK60 pressure sensor threads are metric (M12x1, IIRC)?
Sorry, I got distracted from the fittings. One question I have is the 650.616.
Are we sure that's correct? The catalog lists the female thread size for that as Dash 3, but the MK60 pressure sensor threads are metric (M12x1, IIRC)?
Per the earlier discussion on the inlet ports, is one 10mm (rear) and the other 12mm (front)? I don't have a module on hand yet (though I technically do have one in the M3 in my driveway, I suppose).
Yea, I'm not at my shop....was trying to remember. I have it written somewhere.... I actually think both the Rear and Front inputs to the MK60 are M12. I'll check in about an hour.
I'm happy to put together a group buy, but I don't know if it'll save money. Shipping from Europe amortized over a handful of parts, then shipping from MD to where ever.
06-09-2021, 03:09 PM
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