S8 crank sensor isssues

[Dave A]

Hi there,
Currently installing an S8 on a BMW M62/M60 hybrid engine. IOts all wired up fine, have no errors being logged at all. However the ecu is not picking up any RPM signal/crank signal. i have scoped the cam and crank signals at the ecu, and the signals are there and working fine. The cal is set to both sensors being 5v bipolar, and the scope is showing a peak to peak voltage of around 4.8volts.

But i have nothing even in Sync Scope. I've check and double checked the pin allocataions and thats all right too.

Anyone here have a idea of something else i could check.


Thanks alot.

[pavlo]

You have presumably done something wrong!

Have you checked the IO config to ensure that you are connected to the correct inputs?

I would suggest you open up gauges showing a trace of all the inputs (makes them easy to see) and see and check all the inputs.

What about your other inputs? Have you successfully got other inputs working?

With bipolar inputs the AN inputs will be biased to near 5volts by a soft set pull up. So if you check the voltage in a gauge (not in sync scope) and you're seeing 5 volts then you don't have a proper physical connection. You can also check all the AN inputs and connect/disconnect the sensor and see if you get any activity.

My money is on a poor crimp, wrong pin on input, wrong pin on AN ground or at a push a wrongly configured input.

[stevieturbo]

Hi there,
Currently installing an S8 on a BMW M62/M60 hybrid engine. IOts all wired up fine, have no errors being logged at all. However the ecu is not picking up any RPM signal/crank signal. i have scoped the cam and crank signals at the ecu, and the signals are there and working fine. The cal is set to both sensors being 5v bipolar, and the scope is showing a peak to peak voltage of around 4.8volts.

But i have nothing even in Sync Scope. I've check and double checked the pin allocataions and thats all right too.

Anyone here have a idea of something else i could check.


Thanks alot.

Can you post a screenshot of the scope trace ?

Can you apply a voltage to the ecu input to see if you actually receive any sort of reading ?

[pavlo]

Good point, from the post I was assuming that the sync log had been brought up and no signals seen.

So what's really happening? Is it no actual change in voltage seen? Or is the ECU getting voltage signals and the ECU isn't properly configured to turn that into a crank trigger setup?

[Dave A]

Thanks for the fast reply guys. I know i've got something wrong but cannot see it for looking.
I have attached a crank and cam trace of the signals recieved at the ECU pins.

bmw 6csl crank and cam trace.png (191.44 KiB) Viewed 30068 times

I have check the pin allocation angain and its right.
i have also attached my Cal file so you can see it if there is something im missing?

bmw 6 back up.SC

(423.11 KiB) Downloaded 1082 times

Really dont see the problem but im sure its something really simple!

[pavlo]

Not that it matters because you can trigger on a rising or falling edge but the crank sensor has the wrong polarity.

Anyway, I would really need to see the sync scope output to confirm the crank and cam are properly assigned.

If you gave cranked the engine with the ECU powered, it should have saved it. Go to "Device->Sync Scope" from the pull down and it should display the crank signals stored in the ECU at last cranking. It's important we see this as well as your scope output as the ECU needs to be configured to be looking for crank and cam on the correct pins otherwise nothing at all will happen.

I'll look at the cal file too.

Cheers

Paul

[pavlo]

Crankshaft sensor was set to falling edge, now set to rising edge due to inverted polarity on crank sensor wires (you can see this in the gap where the falling transition isn't well defined) this will require a timing let to confirm the base timing.

Not sure on crankshaft thresholds as no sync scope trace (which will show the voltages as read by the ecu after being biased to 2.5 volts to read the bipolar signal). HOwever they will often set at rest at 0.3-0.5 volts, so at low cranking speed it may struggle to get down to zero volts, so I've raised that. I've also lowered the high threshold to ensure the output exceeds it at low speed cranking.

Camshaft sensor thresholds set incorrectly. Low threshold set to zero, many hall sensors will never actually reach zero volts.
Camshaft sensor input filter was set to ON, turned to OFF however with the input being on 7 it's already filtered. Due to the filtering I've also set the low and high thresholds to 3.0 volts and the low threshold to 2 volts to help minimise any delays caused by the decay that may result from the filtering. To stop the filtering, move the cam sensor input to inputs 9-16, however for a single tooth it really isn't a problem.

Gap definitions are all okay, but you may want to tweak the max and minimum gap widths if you run it problems on cranking and first fire up.

I also see you have ignition outputs defined but the ignition is set to "Normal". If you are using COP ignition with build in ignition amps you will need to change that to TTL on 1-8.

You also seem to have wired the car in firing order, there is absolutely NO need to do this! Exactly what cylinder is wired to what? Because the firing order is also set, so you need to be sure you're doing both and totally mixing it up.

Cheers

Paul

[Dave A]

Wow, thanks for the help Pavlo.

Re the wiring/firing order. i wired that up then programed the S8 so that is just coinsidence. BMW order there engines 1-4 on the left bank and 5-8 on the right, and the firing order is 15486372...

I've corrected the max/min gaps as well. Now just trying to get the thing to start. Seems to fire no1 coil, then the others, then fires no1 off rapdily before shutting down the ignition complete. Currently have no injection at all either.

Thanks again for your time.

[pavlo]

You absolutely need to provide a sync log from the ECU itself. Do you even know if it's getting then losing sync? The sync log will show you the exact point at which it's loosing sync, or the point it which it achieves 720 sync (full sequential ignition and fuel). Is the logging set to log regardless of RPM and TPS? If you set it to do that it will generate a lot of logging but tell you important information,

You are asking for help, but not answering the questions required to give that help.

[Dave A]

How do i get more inputs in the SyncLog? I thought it was only for cam and crank.

Here is the trace and print screen.

Thanks