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1965 SPF Terminator Powered 427 Cobra, & 2022 BMW M850
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Depending on how much time you have to devote to this you might want to look at an aftermarket ECU like an MS3Pro PnP or MS3Pro EVO <= clickable. They will start the engine, run the engine and get you away from the problem pit you are currently stuck in. If you use one of the PnP units you can use a factory wiring harness. The MS3Pro PnP supports variable cam timing on as many as four cams so you can keep the VCT feature the engine already has.
 

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Discussion Starter · #42 ·
Has anybody on here successfully swapped a 3v into something else using the stock PCM/Harness, or a Ron Francis? I am at a loss of what to try next. Could there be something in the cluster/BCM/PATS/other modules that the PCM needs to see?

After doing some more research, unplugging both cam sensors puts it into some sort of "failure" mode and will then fire the injectors and spark on both cycles, thus why it will run for a couple seconds but has a bit of a misfire. Also to note, with the cam sensors unplugged, I can press the gas pedal and get a response (engine revs like it should). It still shuts off after about three seconds though.

with the cam sensors plugged in, it will only run for about a half second, and has no response to the throttle pedal.
Finally, here it is giving it some throttle with the cam sensors unplugged
There is a guy that put one in a ford ranger and he used Ron Francis wiring harness.

Why is it that when you make it go into a default mode by unplugging a sensor it will run longer? It makes no sense. It's like there is maybe a wiring piece missing? It's almost like the key gets shut off or the timing table is confused.

The cam sensors control PWM for the injectors, if I remember correctly. So why do we lose the injector pulse? The injectors are 12V constant and the ground is controlled by the ECM, so where is the break down?

BTW glad to hear you got your refund.

D
 

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1965 SPF Terminator Powered 427 Cobra, & 2022 BMW M850
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Injector pulse width is always modulated by the ECM. The cam sensors report to the ECM the cam position for the variable cam positioning messaging to the cam phasers, which is also exclusively handled by the ECM.
 

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Joining the fray here with you guys. I’ve been battling the same symptoms. I get one fuel injector pulse unless cam sensors are unplugged. It will fire on starting fluid, haven’t tried giving it throttle with the cam sensors unplugged, but that was motivating! I started with a custom harness, tried two different ECU’s finally broke down and spent some coin on the Ron Francis kit, a 3rd brand new ECU, and used their tune… same disappointing result. I bought the Ford reference value manual and pinned everything out. I’ve got some weird ones out of spec like the knock sensors and IRMC. A more ambitious version would have changed them out already… just burned out on throwing money at this thing 🤣 how do your reads look against mine?
 

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Discussion Starter · #45 ·
Welcome to the club, sorry. A couple of questions for you. 1) What year PCM do you have? 2) Do you have any engine codes?


I wonder about wire 1140 Pin 46 in harness 175B, mine has no wire there and is the ISP-R location. This is to be hot in start and run, and is what is tied to the fuel pump relay coil hot side when the key is turned on.


It's almost like it fires and then shuts off, but the fuel PW is way too high and is flooding the cylinders so the PCM shuts it down to prevent cylinder wash.

This is kind of where I'm going next.

D
 

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I have a 2005 PCM, and I have P0685 and P0690. Anyone try to clear these or anyone having a 3V running and still have these codes present?

05 and 06 had slightly different pin outs from 07 and up.

My wiring diagram doesn't have a pin for 46 on 175B
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hopefully between the three of us, somebody can get this figured out... I've been working on paint/interior and wiring the rest of the truck, but hoping to start trying to get it running again soon. My 06 also does not have anything in pin 46. I believe that pin was used on the 07 up models. Looking at my wiring diagrams the 1140 circuit is the "Run" circuit that triggers all of the PCM/ fuel pump etc... relays. Are you guys using the factory "BEC" (fuse/relay box)? I am not.
Previously I had all of my grounds going to a single stud. My plan now is the separate some of the ground circuits to be more like the factory. Specifically all the the (570) black/white grounds. I will splice them all together and terminate them to a different location than all of my generic grounds. Same thing with the 1118 power circuit for the coils/injectors/pcm. I will splice them all together this like the factory was. Other than that I really don't know what else to try. I'm really wishing I would have just went with a coyote at this point.
 

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Discussion Starter · #48 ·
Mine doesn't have Pin 46 either but maybe that is the piece we are missing. Once you modify it from the factory setup this may be required. The setup is acting almost like start and then shut down, but why? At this point, there have been multiple harnesses and PCM's tried by all of us and we are in the same place, I think that Pin 46 is worth considering.

Ford Racing swap harness and PCM uses a 2007-2009 engine harness and incorporates Pin 46, I would think that 2007-2009 uses it as well, in the factory setup.

I may be wrong but I think it's worth a shot.

D
 
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