Clewett cam sync sensor and AEM Infinity 6

[IROC 912]

Hi All,

I am running a 3.2L with AEM Infinity 6 in semi sequential mode. I have installed the Clewett Cam sync sensor per instructions, but could never get the signal to be consistent enough to reliably run in sequential mode.

I was reading the instructions carefully again and noticed the requirement for a 1K 1/2 watt pull up resistor in the wiring between the 12v+ and signal
wire.



The infinity has a 10K pullup to 12V on pin C1-26 (Camshaft Position Sensor 1 Hall) but I was wondering if I need that 1K 1/2 watt pullup ?

Hoping anyone who has run this combination successfully can answer as I'm planning my list of winter improvements. Also, did you have to make any noise value adjustments in the wizard from the standard 10 / 10 settings ?

Thanks

Sandeep

[jons911]

Just the person I needed! I'm having the same problem you were with the trigger offset and trying to get my AEM conversion started up. What offset did you end up using and was it the stock distributor location? When I checked with the timing light, I raised the offset all the way to 296.5 before the TDC mark lined up.

[IROC 912]

Originally Posted by jons911

Just the person I needed! I'm having the same problem you were with the trigger offset and trying to get my AEM conversion started up. What offset did you end up using and was it the stock distributor location? When I checked with the timing light, I raised the offset all the way to 296.5 before the TDC mark lined up.

Using a rothsport 36-1 trigger wheel and sensor with CSA value = 29 and trigger offset = 7. 29 x 10 degrees per tooth + 7 = 297.



Let me know if you need any info ... car runs awesome for me. This setup was for semi sequential operation ... I'm now trying to get the system running sequential so those #'s may change.

[jons911]

Thanks! When I was adjusting the cam sync, 30 got me really close, so those numbers match what I was expecting. Also, sorry for hijacking your thread. I checked my installation instructions for my cam sensor as I'm also running Clewett's, but it says that it is an internal pull up resistor hall effect sensor. So the wiring for it was a direct hot, signal, ground, with no resistor wired in.

[IROC 912]

No problems !

And thanks for that bit of information. The car idles ok for a few seconds and then the system trys to resync becuase of dropped pulses. I'm using the foil wrapped wire provided with the Infinity 6 so assuming noise is not a problem.

Will try that resistor and see what happens.

Cheers,

Sandeep

[jons911]

Thanks again for the help. I tried at 296.5, but it didn't like it. So I was thinking it was probably on the wrong stroke, and went to 656.5. It liked that and fired right up. I've been giving some more thought to your cam sensor question, and I think you're right, add in the resistor. I'm assuming both our infinities are wired similar, so I would have the resistor at the ecu and at the cam sensor.

[IROC 912]

Due to the COVID19 19 Pandemic, I am stuck at home with nothing to do but try and get this cam sync issue working.

I ripped out the existing crank VR and hall cam wiring and rewired properly with twisted/shielded cable like the piece that shipped with my Infinity mini harness (DIY).

Looked at AEM wiring diagrams and terminated the wiring properly with the shield drain to ECU ground, and got rid of that resistor as shown in the original diagram from Clewitt ... maybe that resistor had something to do with the TEC brand of ECU's ?

Loaded up the sequential firmware, started and still have the same problem

Can someone share their noise cancellation values from the diagnostic tab of the software ? The car starts and idles on sequential but I am now getting crank timing errors ?? I reloaded the semi sequential firmware and unplugged the cam sensor and all is fine again. ??

I am hoping it is a noise cancellation value in the software so looking for guidance from someone who is running a VR crank and Hall Cam sensor.

Thanks

Sandeep

['76 911S 3.0]

Since the ECU already has a pullup resistor on the signal wire, the external pullup is not required. I have seen issues in the past with the bolt used for the sensor to trigger off of being non-ferrous and causing sync issues.

[IROC 912]

Thanks for the reply. I recall I used red locktite on that bolt

Would that bolt cause the issue in the screenshot below ? The car does start and run, but I keep getting these crank sync errors now which were not present when I was running semi seq firmware ?

[IROC 912]

some parameters along with the log shot above.

[IROC 912]

Diagnostic page from wizard

[IROC 912]

Noise cancellation values

['76 911S 3.0]

I'll take a look at my cal settings this evening and let you know, I think it may have to do with the sync response settings.

[3rd_gear_Ted]

ECU's that get hooked up to a Porsche engine have electrical noise issues that affect the cam and crank sensor.
Suggest a inline electrical noise suppression unit for the crank and cam sensor voltage source along with noise suppression on the ECU source voltage too.

Mount ECU behind driver seat away from starter motor which is a huge electrical noise source

BTW; The -044 fuel pumps use up to 15 FLA, so voltage drop is a factor too.
AND, some fuel cell set ups need two fuel pumps...

[IROC 912]

Thanks for all the responses so far.

[IROC 912]

Another day of quarantine ... so another day in the garage

I changed out the cam sync bolt with another bolt ... the new bolt seemed to stick a little harder to the magnet on the hall sensor and adjusted it to 33.0mmdepth per the instructions. No difference, unfortunately ... still get crank errors even though I have no crank errors when running semi seq firmware.

Also reloaded the diagnostic firmware to check that coils and injectors are wired sequentially. No issues with the wiring.

The car does start and run but in an 8 minute idling session, I get about 20 to 30 crankTimingError0 hits.

Would the car run if the crank + and - were wired backwards ? I don't think that is the problem though

Also wired up a CANBUS gauge with a 120 ohm terminating resistor / twisted wire per instructions and guess what ... no go on that front either Gauge just says no can data available

Sandeep

[Dr J]

I am successfully running the Clewitt cam sensor on the Infinity in sequential mode. Here is my setup.

1. I did not add a resistor.
2. The locktite does not affect the reading of the sensor.
3. I did not touch the values you are showing in the software. All of my values for sync error are like yours. My values for noise cancellation are also like yours except the one you have highlighted that has a value of 5. I have 10.
4. When I was setting up my car I had the + and - vr backwards and could not get my car to start.

My only suggestion is to check the Cam sync adjustment and Trig offset. I put a piece of blue painters tape to make the crank pulley 0 position obvious.

[IROC 912]

Thank you for the continued feedback. I put the timing light on the engine again to verify my crank settings and trigger offset for the 36-1 wheel and its bang on.

I noticed another issue, not sure if its relevant or not ?? I cannot get the car to idle for longer than about 200 seconds of after start time after the first start of the day. For the second start, the battery is too weak and needs to be boosted ? Perhaps time for a new battery. Hoping it's not the issue though.

Edit ... car continously stalls now after each crank error.

Sandeep

[IROC 912]

Another few days of testing and no firm solutions to the issue

I have noticed that the engine starts consistently on the first cold start of the day and then reliably and consistently dies when the coolant temp hits about 85C. The coolant temp sensor I am using is the stock head temp sensor for the 3.2 Carrera.

I have no errors of any sort until the coolant temp hits 85c, then I get crank errors.

I'm wondering if the cam sensor is getting too hot and then momentarily craps out throwing the errors I see. If I let it cool down (relatively) below 85C it starts up again with no errors unit coolant hits 85C again.

Looking for a compatible crank sensor on Digikey / Mouser now as I think the sensor may be the issue as it is the only item that has not been replaced.

It does run awesome on semi sequential though

Sandeep

[Peter M]

I'd suggest you replace your battery before you do anything else.