AEM Infinity on S52 with M50 OBD1 Cam sensor

**flexer** · 09-12-2019, 04:31 PM

I am stuck.....

I am trying to convert a buddies car from an AEM V1 box to an infinity. It's S52 motor, but with the cam sensor from an OBD1 M50 vanos head I believe. The car starts right up on the V1 box, but when I switch it over to the infinity box I can't get a cam signal.

BORIS ARE YOU AROUND BUDDY?!!?!?!

I found a thread by boris where he ran into the exact same problem, but on his thread he never describes how he solved it or fixed it.

Is anyone else running an infinity ECU on a M50 or M52 or S52 motor? Did you have any problems with the Cam Signal?

I will shoot Boris a PM as well and see if he ever figured out how to solve this.....

**NOTORIOUS VR** · 09-12-2019, 05:13 PM

it's not seeing the Cam signal at all? Post up a log and your settings from the Diagnostics screen.

**Kevin325i** · 09-12-2019, 07:16 PM

No problem once it was swapped to a 93-95 cam sensor. I've got all the colors and positions in my build thread.

What did you do for wiring to the cam sensor?

**Def** · 09-12-2019, 11:48 PM

Is it wired up to the right pins of the Infinity?

**flexer** · 09-13-2019, 09:03 AM

Originally Posted by Def

Is it wired up to the right pins of the Infinity?

I have 12v supply coming out of the AUX plug and play plug harness which I can see is C1-63.

The Ground wired to pin C1-23

and the input wire to pin C1-26

Now there is a difference on the V1. The V1 runs power and ground the same, but on its cam input it is a 5v pull up, while on the infinity its a 12v pull up. I figured it wouldn't matter since its pulling it to ground anyway. It really is identical to what boris ran into. Scoping it got a good clean signal, but infinity never picked it up. It looks like he hasn't been active since 2016 though so I have the feeling he won't be coming back :-) Let me see if I can find that thread again.

I will attach the log. Whether I set it up with the universal 60-2 trigger, or use the wizard for the 1995 M3 I get the exact same results. It does see something, and it see's it rhythmically.

Hmm...Its not letting me upload the log and tune file. Anyone that wouldn't mind taking a look I will email it. Let me go dig and find boris's old thread.

J. R.

**flexer** · 09-13-2019, 09:14 AM

Let me add a little more info. When checking the cam sensor plug with the AEM V1 wired in I get 12v on pin 1, 5v pull up in the middle on pin 2, and ground on pin 3.

Because I was having problems, I made a separate harness for the cam sensor and ran it directly to the infinity Pins to make sure I wasn't having anything else splicing into those wires and causing me problems. Tried it, and the log is identical. I then measured each of the wires to make sure, while cranking, they were getting what they needed. Pin 1 had 12v while cranking. Pin 3 had ground while cranking, and pin 2 was jumping up and down so I assume it was working till I get my scope.

**Kevin325i** · 09-13-2019, 09:16 AM

You can pm me for an email, or Def has my contact too.

I really think you should take a look at the cam sensor wiring at the sensor. Maybe there's an additional pull up resistor someone put in the harness for the V1?
Edit: You already were doing this.

There is nothing else needed other than being sure you are NOT using the 92 sensor. If you've scoped it you have seen a nice clean square wave that's enough to assume it's working and is a hall effect sensor.

My next question is are you sure you've got the pins in 23 and 26? Those molex connectors get people sometime on counting from the front or back.

**flexer** · 09-13-2019, 09:23 AM

OK here is Boris's thread.

https://www.bimmerforums.com/forum/s...am-crank-seors

**flexer** · 09-13-2019, 09:39 AM

Originally Posted by Kevin325i

You can pm me for an email, or Def has my contact too.

I really think you should take a look at the cam sensor wiring at the sensor. Maybe there's an additional pull up resistor someone put in the harness for the V1?
Edit: You already were doing this.

There is nothing else needed other than being sure you are NOT using the 92 sensor. If you've scoped it you have seen a nice clean square wave that's enough to assume it's working and is a hall effect sensor.

My next question is are you sure you've got the pins in 23 and 26? Those molex connectors get people sometime on counting from the front or back.

I thought about that, that i could have pined it wrong. I've done 8-9 infinity installs, but anything is possible when it comes to making mistakes, but let's talk it through together. If looking at the back of the connector the top row is 1-20, with 1 starting on the right. You then move to the next row from the top if looking at the back of the plug. That row would start with pin 21 on the right again, since there are 20 pins per row, so the cam sensor input would be the 3rd pin in on the 2nd row.

You agree?

When I flip the plug over and am looking at the face of the plug (the side that pushing into the infinity) pin 1-20 are now on the bottom and pin C1-23, the cam sensor input, would be the 2nd row 3rd pin in from the right. I then did a continuity test from that pin to the middle pin of the cam sensor and I have continuity.

**Kevin325i** · 09-13-2019, 10:17 AM

Ecu connector sounds right.

I'll double check sensor side but I do not remember if pin 2 at the sensor was signal. You may have always had signal and 12v supply flipped with the v1.

**Def** · 09-13-2019, 10:55 AM

Originally Posted by flexer

I have 12v supply coming out of the AUX plug and play plug harness which I can see is C1-63.

The Ground wired to pin C1-23

and the input wire to pin C1-26

Now there is a difference on the V1. The V1 runs power and ground the same, but on its cam input it is a 5v pull up, while on the infinity its a 12v pull up. I figured it wouldn't matter since its pulling it to ground anyway. It really is identical to what boris ran into. Scoping it got a good clean signal, but infinity never picked it up. It looks like he hasn't been active since 2016 though so I have the feeling he won't be coming back :-) Let me see if I can find that thread again.

I will attach the log. Whether I set it up with the universal 60-2 trigger, or use the wizard for the 1995 M3 I get the exact same results. It does see something, and it see's it rhythmically.

Hmm...Its not letting me upload the log and tune file. Anyone that wouldn't mind taking a look I will email it. Let me go dig and find boris's old thread.

J. R.

You might try grounding the sensor to the engine and see if you can get a signal. I've seen some wonky things happen when you overload the sensor ground plane and it drifts off true ground.

Also, does the sensor need a pullup resistor to 12V?

Like this: https://www.diyautotune.com/product/...sition-sensor/

**Kevin325i** · 09-13-2019, 10:59 AM

No it's pulled up to 12v internally.

I agree that taking the sensor off the conditioned ground is probably the next logical step. I run the bmw grounds for cam and crank signals to pin 46 on the Infinity 8h and 6 units.

**flexer** · 09-13-2019, 11:00 AM

Originally Posted by Kevin325i

Ecu connector sounds right.

I'll double check sensor side but I do not remember if pin 2 at the sensor was signal. You may have always had signal and 12v supply flipped with the v1.

About A week ago I was sitting at work and that thought came to me. Maybe the 5v is the sensor supply in the middle (pin 2) and that 12v I was seeing was actually the pull up and so I had wired it wrong.

To test the theory I looked up what the cam sensor input was on the V1 and measured its voltage. Crap, it was 5v. Hmm..... Just to double check I did a continuity test and it had continuity to the center pin. I thought for sure that was it, but it appeared that the center pin was the cam sensor input after-all.

I really thought I had it that time as well and that that was the issue. I even then plugged the V1 all back in and the car fired right up.

With the way the sensor is behaving I really did think it was just me switching the 12v and signal wire or with the ground wire so I thought for sure that was it and it was just a dumb error. I was very surprised when I measured it the way I did.

OH DAMN WHILE I AM TYPING THIS I just had a thought. The V1 box is for an acura integra. You modify the box to go from a VR to hall sensor. When doing this who really knows if the pin marked "cam sensor" really is cam sensor anymore. Granted.....it would make sense that it is, but it is possible that that is the 5v supply. Although the only other pin that goes into the ECU goes to what is marked the "sensor ground". SO I really doubt it.

Lets just get to the bottom of it. Would someone mind checking the voltage on there cam sensor with the key on? Do you have 12v on pin 1? Cam sensor output on pin 2? And ground on pin 3?

**Kevin325i** · 09-13-2019, 11:09 AM

Originally Posted by flexer

Lets just get to the bottom of it. Would someone mind checking the voltage on there cam sensor with the key on? Do you have 12v on pin 1? Cam sensor output on pin 2? And ground on pin 3?

My car and a couple others have 3 pin replacements for the cam connector. The other people I've made adapters for I rewired OBDI hall sensors to match OBDII harnesses and those are different still

.

Looking at the bmw wiring diagrams. I don't have it documented that I needed to deviate from this.
Pin 1: supply
Pin 2: signal
Pin 3: ground

I would remove your ground from C1-23 and put it to chassis ground wherever is convenient for a test.

**flexer** · 09-13-2019, 11:33 AM

Originally Posted by Kevin325i

No it's pulled up to 12v internally.

I agree that taking the sensor off the conditioned ground is probably the next logical step. I run the bmw grounds for cam and crank signals to pin 46 on the Infinity 8h and 6 units.

Pin C1-46 is listed as just a battery ground

I wired it to pin C1-23, listed as a signal ground, just because that's how I've always done it on other cars. I will try switching it to a chassis ground.

Another question. My cam sensor harness from the cam sensor itself is female, and the engine harness connector is male. When you type in 1995 M3 cam sensor online I see some of the sensors are male connectors and some are female. Maybe its possible that I think I have the correct OBD1, single Vanos cam sensor, but I don't. Although it does work just fine with the aem V1 box

**flexer** · 09-13-2019, 11:47 AM

My problem really does look identical to Boris's. Does anyone have any contact info for him or maybe an email?
You look at his thread and its exactly my issue.

**TheJuggernaut** · 09-13-2019, 12:05 PM

Were you able to confirm what type of sensor you have? When you scope the signal, is it zero crossing or not?

**Kevin325i** · 09-13-2019, 12:08 PM

Woah pump the brakes on my side.

Are you using
Hall Effect- Crankshaft
Hall Effect- Camshaft

Which AEM Infinity ecu are you using? Boris was using a series 7 if I remember correctly (the pin they're telling him to use in the other thread is NOT correct for a hall signal in the series 5). I have use series 5 stuff.

Not that it should effect a sync routing but I use 12v supplied Hall Effect sensors on both cam and crank sensors for OBD II vehicles. I do not use the VR sensors on the crank.

**flexer** · 09-13-2019, 03:26 PM

Originally Posted by TheJuggernaut

Were you able to confirm what type of sensor you have? When you scope the signal, is it zero crossing or not?

I will confirm with a scope this weekend.

- - - Updated - - -

Originally Posted by Kevin325i

Woah pump the brakes on my side.

Are you using
Hall Effect- Crankshaft
Hall Effect- Camshaft

Which AEM Infinity ecu are you using? Boris was using a series 7 if I remember correctly (the pin they're telling him to use in the other thread is NOT correct for a hall signal in the series 5). I have use series 5 stuff.

Not that it should effect a sync routing but I use 12v supplied Hall Effect sensors on both cam and crank sensors for OBD II vehicles. I do not use the VR sensors on the crank.

I'm using an infinity 506. I believe I am using a hall effect on both the cam and the crank, but honestly I cannot remember off the top of my head if the crank sensor is a VR or Hall. When I get off work I will grab my tuning laptop and take a look again.

**TheJuggernaut** · 09-13-2019, 03:46 PM

If you're using the sensor in the back of the block, it's Hall, if you're using one on the front of the engine, that's VR. M50 cam sensors vary, there's a Hall version from later years, early ones have something else, I'm not even sure if it was VR or something else.

**NOTORIOUS VR** · 09-13-2019, 03:53 PM

OBD2 Cam sensor was some hybrid sensor that CANNOT be used.

OBD1 M50 cam sensor is the one you need. It's a hall sensor.

**Kevin325i** · 09-13-2019, 06:32 PM

Hey JR,

Pretty sure you're working with a Hall effect sensor on the crank or incorrect wiring with a VR on the front of the motor. Please visually identify which is in the car.

Currently your log does NOT pass any sort of base plausibility as the crank sensor never sees a missing tooth on a regular interval. From the log it looks like it get's a sync signal about when the missing tooth appears and having a big spike in engine speed. The crank angle signal should roll from 0 to 720

**flexer** · 09-17-2019, 10:15 AM

Originally Posted by Kevin325i

Hey JR,

Pretty sure you're working with a Hall effect sensor on the crank or incorrect wiring with a VR on the front of the motor. Please visually identify which is in the car.

Currently your log does NOT pass any sort of base plausibility as the crank sensor never sees a missing tooth on a regular interval. From the log it looks like it get's a sync signal about when the missing tooth appears and having a big spike in engine speed. The crank angle signal should roll from 0 to 720

Heading over and will confirm today. I believe I am using the front VR sensor for the crank. Going to scope the cam sensor as well.

**flexer** · 09-17-2019, 02:10 PM

Well My scope was able to pick up a good signal with the V1 box running the car, but when cranking the car with the infinity hooked up it was tough to get my scope to display a nice clean signal. Sometimes I was getting something and sometimes not. My scope is trash though so I ordered a new one so should be here by the weekend. I needed an excuse to upgrade. While it has got me by all these years it was time to retire it.

**flexer** · 10-07-2019, 12:13 PM

OK,

So I'm going to stop trying to use the front VR crank sensor and instead use the rear HALL crank sensor. Would anyone know the pin outputs from top to bottom of the following pic I have attached? The top pin is closest to the starter motor and bottom, well, its on the bottom.

And I assume it is a 60-2 crank tooth wheel on the crank?

IMG_4101.JPG