I'm hoping there's some experts in here that know about Mopar PCM's or are better troubleshooters than I am. I've built a 2013 Dodge Charger RT AWD with 392 stroker and Whipple Supercharger, currently running ~11 PSI on 92 octane. New everything, fully forged, my 2nd Hemi build (did a 392 stroker NA in my Ram 1500 prior). I have a weird/frustrating issue I can't figure out. I am getting a cylinder 7 misfire and I've tried everything I know and have run out of smarts. You can hear it misfire louder when it's cold, and currently I have misfire detection set to 2500 RPM in the tune (Use HPtuners) due to false misfires detected at idle likely due to 227/235 - Cam​​​​​Motion Titan 2 VVT Hemi camshaft. Whenever you rev it ~3K RPM it throws a Cyl 7 misfire code and then shuts off the cyl 7 injector, but even then sometimes it just misfires but doesn't shut off the injector. Prior to breaking down and buying bi-directional scanner and seeing that injector shutting off/ zero PW I checked mechanical, rocker, pushrod, valvespring, lift all good (no wiped lifter/cam etc...) I swapped around coils, swapped Injectors, swapped spark plugs, issue didn't move cylinders. Fuel pressure/pump etc all good too. I checked compression, leakdown, both great. After seeing scanner showing injector shutting off the I replaced the injector plug and wiring all the way back to PCM plug (well about 2" from PCM anyway), no change. I bought a brand new PCM (not reman) and same issue. Also when it shuts it off my wideband on that bank goes full lean and it runs like crap because it's trying to compensate. However if you shut the engine off and restart the injector is back firing until you hit certain RPM and your right back to the issue. No other codes besides cylinder 7 misfire P0307.

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I'm at a loss, what could cause the PCM to shut off the injector to that cylinder and why would it do that, I thought for a moment the PCM may detect something and shut it off to protect a "dead cylinder" in its mind but that makes no sense especially since it then leans out the o2 sensor and causes the other cylinders to run rich.


I've been fighting this for months as I don't have a lot of time to try and fix it with work and life demands, but I've ran out of ideas and it's killing me not driving my extremely fun DIY Hellcat type power, without the traction issues, AWD Charger. This thing even hauls *** in the rainy NW WA and I miss it as my daily driver!


I'm hoping someone knows and has solved this type of issue before, please help me figure out what I've missed. Thank you!


Jason

 

I had an issue with my ECM and after losing some hair, I found a less than tight female pinout connector in the ECM plug. The car would go rich under load but show no fault with no load. I had to take all the female pins out of the master plug and try them one at a time onto the male pins until I found one that was loose and fell off! Replaced female pin, problem solved! Good luck.

 

Appreciate that, I hope it's not something so simple yet a pain like that. I spliced the new injector plug right before the PCM plug so I didn't have to tear it apart, LOL. It looked fine, but yes it could be JUST loose enough it loses connection...

I'll have to tear into that plug, it seems, in case that's where are the issue lies. If you happen to know what pins to order let me know.

I'm still hopeful someone will have had the same issue with the injector shutting off and know the solution.

Appreciate the help!

 

Mine was an aftermarket ECM so I do not know a part number for an OEM pin! But any good dealership parts department should be able to get them for an exhorbitant price.

 

Maybe run the question by Arrington Performance?
https://www.shophemi.com/

Hope you find the issue and report back......

 

Bought another ECM/PCM plug, repinned my cylinder 7 injector and same issue unfortunately. New pin, new wire all the way to new injector plug.

I'm starting to think the computer senses enough misfires in cylinder 7 in a short period and then shuts off the injector to that cylinder as part of its backend protection so a "dead" cylinder isn't being pumped full of fuel when it's not burning properly?

I'm also thinking I possibly have a lifter that's not holding pressure at higher RPM (have high volume pump, pressure is great) and that's causing the misfire that then causes the injector to shut off. At lower rpm it's okay and doesn't register misfires but when the rpm gets over 3k for a few seconds it starts misfiring and then the injector shuts off.

Weird thing is the engine was torn apart because cylinder 7 lifter was not holding pressure and ticking like crazy (thought I had wiped a lobe) and now same cylinder. Everything besides the block and head castings is new (and no MDS lifters now) so has to be coincidence unless pressure isn't making it to cyl 7 lifter properly somehow, cracked oil passageway etc? All looked good when I had it apart but can't see in every nook and cranny.
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Just remembering I was going to try jumpering cyl 5 injector signal to cyl 7 too and see if the misfires stop and if they don't I'll know it's likely the ECM/PCM shutting off the injector because of the misfire. If the misfires stop the it's something very weird with cyl 7 injector control...

Hoping I don't have to tear this apart again to replace lifters, so if ya'll got anymore thoughts on things to try let me know. Thanks!

 

Have you checked the injector flow on all injectors, it’s more than possible that you have a bad injector.

 

No I haven't had the flow checked, however I swapped cyl 7 injector to another cylinder and the issue remained at cyl 7 and cyl 5 that I swapped with didn't start having issues.

 

I just saw an article were the Demon 170's were dropping power and needed the spark plug gap reduced to 0.024 . Worth a try? Maybe????

 

You certainly gave it your best. You checked compression, (leak down), injectors and PCM but same issue at #7. The only 2 things I can think of are intake leak causing a lean mixture or the very off possibility a valve is hanging up. I would use the oxygen/acetylene torch brazing tip with just oxygen flowing and sweep around the intake. I can't tell you the number of leaks I found doing that. Running it with the valve cover off will be very messy but maybe a short mess may be all you need to see the operation.

 

Did you ever get it figured out?