Link ECU - issues with crank signal

[cpalella]

I know I'm slightly breaking rules posting a question regarding a non-FI issue, but this sub forum seems to be the best source for information regarding standalone on the S/M5X platform. Hopefully I can still get some advice

I'm running an S52 in my E30 and finally made the jump from stock ECU and "stock" wiring harness from an E36 to a Link G4X extreme standalone ECU and a new "mil-spec" wire harness.

Some basic configuration info:
Link G4X extreme
DBW e-throttle (TB and pedal from E46 330)
TMAP sensor in the IM for speed density tuning (no MAF)
"old style" M50 cam sensor
OE hall effect crank sensor in OE location (below starter)
Bosch 3 channel igniters (x2)
Qty:2 wideband controllers on canbus (one on each exhaust bank)
Injector dynamics ID1050x injectors

So here's the issue we ran into. First, had a problem with crank sensor wiring. When it was pinned out according to all the diagrams, it didn't work. I swapped power and ground and then it worked and car started/runs. Then my tuner started working on the tune and noticed weird issues with detonation/timing. So we check timing and notice that the timing is changing with RPM increase. Seems like the timing change is occurring in a linear relation to RPM increase. Any ideas what's up? Is there an issue with this OEM BMW crank sensor? Do I need to switch to the front timing cover style sensor? We're stumped.

Here's some pictures for fun:

Hardware tucked under passenger glove box



Sensors and wiring on intake side






Exhaust side wiring to be covered with OEM loom coverings from E30 M3









- - - Updated - - -

Here's the link to the full build on R3V for anyone interested

https://www.r3vlimited.com/board/for...ourney/page125

[trthrrt489]

Wow....clean car! I appreciate your attention to detail.

Are you using the stock 60-2 trigger wheel? What's the air gap from the crank sensor to the wheel? Are you sure the parameters you set in the software are correct?

[cpalella]

Wow....clean car! I appreciate your attention to detail.

Are you using the stock 60-2 trigger wheel? What's the air gap from the crank sensor to the wheel? Are you sure the parameters you set in the software are correct?

Thank you. Yes it's the stock trigger wheel on the rear of the crank. 60-2 wheel. Shouldn't have an issue with air gap considering it's an OEM crank sensor. And yes, triple checked software parameters. I have a very experienced tuner working on it. Neel from apex speed tuning if that name rings a bell for anyone. Link also has base maps and configurations for the M52 which we also checked, including recommended wiring diagram - but again when wired and configured according to their diagram (same as oem diagram), car wouldn't start, no crank signal. Thinking I may just purchase a brand new sensor to eliminate that variable.

Can anyone running standalone comment on which crank sensor they're using and why? I've seen an older style sensor also mounted off the front cover interacting with the harmonic damper trigger wheel?

[pbonsalb]

Euro 328i with OBD2 continued using a front mount crank sensor. You could source those parts if that is determined to be what you need.

[cpalella]

Euro 328i with OBD2 continued using a front mount crank sensor. You could source those parts if that is determined to be what you need.

Thanks, yea just pulled the PN for it.

Wondering if the issue may be related to how I was checking timing with the timing light clipped to the cyl 1 trigger wire. Reading maybe I need to put a spark plug extender and clip it around the wire between coil and plug?

Came across this thread with an issue like mine, unfortunately the thread did not end with clear resolution

Many timing lights will fire off the dwell edge rather than spark edge when connected to the primary side of the coil. The correct way to check timing on a COP engine is to pull the coil out and run a short HT lead between the coil and sparkplug, with the timing light attached to that.

https://forums.linkecu.com/topic/978...or-setup-help/

[NOTORIOUS VR]

Wondering if the issue may be related to how I was checking timing with the timing light clipped to the cyl 1 trigger wire. Reading maybe I need to put a spark plug extender and clip it around the wire between coil and plug?

Yes you CANNOT do that - you have to put a lug wire in between the coil and plug and using the timing light clamp there other wise you will see strange things like a drift or swapping of TDC if you measure from the trigger wires. That is likely your issue.

Also the LINK does have a delay adjustment for the main trigger if there is a light drift present with RPM but it will be minimal drift nothing like what you're seeing now.

[trthrrt489]

Does the car start? If not, does it seem to "want to catch"?

[cpalella]

Yes you CANNOT do that - you have to put a lug wire in between the coil and plug and using the timing light clamp there other wise you will see strange things like a drift or swapping of TDC if you measure from the trigger wires. That is likely your issue.

Also the LINK does have a delay adjustment for the main trigger if there is a light drift present with RPM but it will be minimal drift nothing like what you're seeing now.

Thanks for that clarification. Had limited equipment and preparedness while on the dyno - lesson learned. We should have already checked timing prior.

I've got a timing light and the lug wire on order.

Still doesn't explain the backwards wiring on the sensor. Maybe that's just a fluke weirdness and I won't think of it any further.

- - - Updated - - -

Does the car start? If not, does it seem to "want to catch"?

Yea the car's been running and driving. We have a good tune on it now too. Just got weirded out by the timing results and the seemingly backwards crank sensor wiring.

[trthrrt489]

Got it. Are you running stock knock sensors? If so, do you turn them off above a certain rpm?

[cpalella]

Got it. Are you running stock knock sensors? If so, do you turn them off above a certain rpm?

Yes, stock knock sensors. Not sure - I'll have to check with my tuner. Also not sure if we even got to start calibrating/setting up knock yet since we hit these "timing issues"

[trthrrt489]

Look into it.

The stock sensors pick up A LOT of noise above 5000 rpm. I never knew it was thing to turn off the sensors above a certain rpm, but, it's a common thing to do. The reasoning is knock is more prone to happen during the peak torque area. High rpm's have the flame moving fast enough to avoid it.

[NOTORIOUS VR]

Thanks for that clarification. Had limited equipment and preparedness while on the dyno - lesson learned. We should have already checked timing prior.

I've got a timing light and the lug wire on order.

Still doesn't explain the backwards wiring on the sensor. Maybe that's just a fluke weirdness and I won't think of it any further.

not sure what you mean about backwards wiring - did you go by color or by pin number? There's been some revisions to the OBD2 Crank Hall sensor wiring so depending on the version you have and the wiring diagram you used that would be why you had an issue but impossible for someone to tell you why that happened to you as there isn't enough info. But you have that sorted so that isn't something to worry about as it either works or it doesn't with Hall sensors - for sanity now just double check timing sync with the ECU with a plug lead and you're good to go.

Look into it.

The stock sensors pick up A LOT of noise above 5000 rpm. I never knew it was thing to turn off the sensors above a certain rpm, but, it's a common thing to do. The reasoning is knock is more prone to happen during the peak torque area. High rpm's have the flame moving fast enough to avoid it.

That doesn't make any sense - you tune the knock control to listen for actual knock, plus most ECU's (LINK included) have knock windowing so it only listens to the knock sensors during the crank duration where there is knock for that particular cylinder.

[trthrrt489]

not sure what you mean about backwards wiring - did you go by color or by pin number? There's been some revisions to the OBD2 Crank Hall sensor wiring so depending on the version you have and the wiring diagram you used that would be why you had an issue but impossible for someone to tell you why that happened to you as there isn't enough info. But you have that sorted so that isn't something to worry about as it either works or it doesn't with Hall sensors - for sanity now just double check timing sync with the ECU with a plug lead and you're good to go.



That doesn't make any sense - you tune the knock control to listen for actual knock, plus most ECU's (LINK included) have knock windowing so it only listens to the knock sensors during the crank duration where there is knock for that particular cylinder.

When I post an issue I'm having, I look for ideas to try. This is an idea to try.

[NOTORIOUS VR]

When I post an issue I'm having, I look for ideas to try. This is an idea to try.

Sorry your post wasn't clear it was a specific issue you're having - but rather it seemed like you were suggesting people (to) turn off knock sensors because of noise.

That said, TEC3 really isn't going to have any worthwhile knock capabilities IMO (not sure if you're having the issue yourself or elsewhere with a different ECU however).

[trthrrt489]

Sorry your post wasn't clear it was a specific issue you're having - but rather it seemed like you were suggesting people (to) turn off knock sensors because of noise.

That said, TEC3 really isn't going to have any worthwhile knock capabilities IMO (not sure if you're having the issue yourself or elsewhere with a different ECU however).

I wasn't having an issue. I was suggesting the OP turn off the knock sensors to see if that's an issue. Forums are primarily about helping others, trying different things.

Try not to forget that. "Pride goeth before destruction, and an haughty spirit before a fall."

[E30s50dude]

Yes you CANNOT do that - you have to put a lug wire in between the coil and plug and using the timing light clamp there other wise you will see strange things like a drift or swapping of TDC if you measure from the trigger wires. That is likely your issue.

Also the LINK does have a delay adjustment for the main trigger if there is a light drift present with RPM but it will be minimal drift nothing like what you're seeing now.

Don't want to hijack this thread but, can someone send me a link to a good "lug wire" to use while I already have a digital timing light. I had no clue I couldn't just use the signal wire on the cyl 1 coil while checking timing.

[NOTORIOUS VR]

Don't want to hijack this thread but, can someone send me a link to a good "lug wire" to use while I already have a digital timing light. I had no clue I couldn't just use the signal wire on the cyl 1 coil while checking timing.

Just cut up any plug wire that works for your application (Honda wires are usually good for this, or a custom wire kit from MSD if you have something laying around, etc.), plug the boot on the plug in the head and stick the other end with the wire exposed into the coil boot, add some electrical tape to keep it there... doesn't have to be expensive or complicated as there is no load on the motor when you're checking you're just looking to get the spark energy to the plug.