Link G4+ Xtreme - Trigger issue

[Tom H]

Hi guys, 

I have been working with a car that was wired by a reputable person, in the motorsport industry and has start and run without fluids. Since then it has done a few weird things which I would like clarification if possible. The car is not in my possession but its owner can test things as required.  

The car will start and run when the ECU appears to be "cold". This is a new motor/build the car will get shut off after about 5 minutes running or even less. After this initial start or series of initial starts the car will not start again and sounds absolutely flat, like no spark or fuel.

During cranking when it wont start, there is no sign of the triggers being active within the runtime values screen. On the scope provided with the software there is no sign of the triggers most of the time, when its not starting. 

The motor is a v8 Ford 331cu and has an AEM cam/crank 24 & 1 trigger wheels in place of a conventional dizzy. When the ECU is first turned on (cold) and the AEM trigger wheel removed from the engine you can clearly see the triggers working form the Link software and hear the injectors trying to pulse. If put back together at this stage there is a high chance the engine will start. Once started the triggers are ON and active and fine, although the car may die at some stage for a few reasons. 

The owner has switched ECUs, after initially thinking it was the AEM cam/crank sensor and the same thing appears to happen (at least the not starting part). 

Some questions:

1. I'm stumped how the car will seem to run when the ecu is "cold" first powered up and not when its warm. ECU states 35ish degrees max. 

2. The AEM wiring diagram calls for 12V feed for the sensors but it has been wired to pin 6 (8v+) from the ECU. I did try connecting to 12V but made no difference. I accept this as ok but still raise the question. these appear to be hall effect sensors so arming voltages etc shouldn't be an issue? 

3. If I use a timing test light on the engine, while cranking and with out the Triggers being displayed as active within the software I will still get a pulse generated and the light will flash. Should I accept this? I would have thought not? The light could be random, as I couldn't actually time it like this. I can vouch that the car is in time though, as checked when running. 

4. I notice the wiring for the cam and crank triggers has the sensor ground (0v) going back to the B loom on pin 22 I think (green). typically these go back to pin 7 on the A loom, although they appear to be internally connected in the ECU so should be a problem? 8v+ to the sensors as discussed above. 

Any help appreciated. I am struggling with the fact it runs some times and not others. I'm willing to accept noise or even wiring to make something not run at all or run poorly but in this instance we have a situation were it will start and run fine some times, but not all the time. 

211217 Mustang v8. 1.1pclr.pclr

Edited January 1, 2022 by Tom H

[Adamw]

Do us a log and a triggeerscope next time it wont start, that will help narrow down a lot of possibilities.  The 8V will be fine for 99% of hall sensors.  

I would suggest updating firmware also as yours is ~6 years out of date.  

What does it have for an ignition system?

[Tom H]

Thanks for the reply Adam, 

firmware is updated to the latest available in the + range. 

ignition is individual coils on plugs but controlled from 2 x igniter packs, each doing 4 coils. 

I have tried to log and watch the scope during cranking. It really struggles to log anything most of the time...like the signals are not there when the ECU has been on for a while. I will have another attempt when I'm out there again. It makes it slightly harder to log because the car has a push button start that times out the cranking signal after a few seconds. 

 

Cheers, 

Tom 

 

[Adamw]

1 hour ago, Tom H said:

firmware is updated to the latest available in the + range. 

So was it updated after you saved the map above?  That map shows it is on 5.5.3 firmware and it is a Storm ECU, not Xtreme.  

 

1 hour ago, Tom H said:

I have tried to log and watch the scope during cranking. It really struggles to log anything most of the time...like the signals are not there when the ECU has been on for a while.

A trigger scope would still be useful, if there is no waveform coming through it would still show us what voltage is reaching the ecu, that could give clues as to whether it is more likely a wiring or sensor problem.  

[Tom H]

10 hours ago, Adamw said:

So was it updated after you saved the map above?  That map shows it is on 5.5.3 firmware and it is a Storm ECU, not Xtreme.   

Have included the last map I have of the car. Firmware 5.6.7... Initial testing was on a Storm and the owner has since changed to a Xtreme purchased recently for a different project, software was also updated. The swap was after doing a pin to pin check of the wiring for the triggers and only noticed the ground pin positioning mentioned above. no other circuits were pinned out. 

 

10 hours ago, Adamw said:

A trigger scope would still be useful, if there is no waveform coming through it would still show us what voltage is reaching the ecu, that could give clues as to whether it is more likely a wiring or sensor problem.  

Ok cool, makes sense. I will see what I can get done soon.

Thanks for your support. 

211222 Mustang v1.pclr

[Tom H]

17 hours ago, Tom H said:

 4. I notice the wiring for the cam and crank triggers has the sensor ground (0v) going back to the B loom on pin 22 I think (green). typically these go back to pin 7 on the A loom, although they appear to be internally connected in the ECU so shouldn't be a problem? 8v+ to the sensor. 

 

 Is this a concern the way this is wired? Is pin 7 on the A loom intended for triggers and triggers only, or are any grounds for this ok to use? I'm assuming fine, although not typical. 

The way its shielded (if its shielded) I cant confirm as I haven't had the loom apart at this stage. 

[Adamw]

Yeah thats fine.  All the "Shield/Gnd" & "Gnd Out" pins are sensor ground and can be used interchangeably.  Shielding shouldnt matter for start up.