2010 SHO pcm issues

[shawnmccart]

I have a 2010 Taurus SHO purchased new. 115k. Garage kept. All maintenance kept up and log kept every mile. Last 6 months have experienced several cylinders primary/secondary circuit malfunction. Replaced all COP, plugs and had refurbished ECM installed and flashed by Ford. Ran 2 days, Primary/ secondary circuit malfunction E cylinder. Replaced COP and plug. Did not fix. Sent ECM back. Fixed. Ran 2 more days and several primary/secondary circuit malfunctions. Got an engine wiring harness from boneyard. Replaced. New ECM from Flagstaff. VIN installed. All new plus and COPs. Ran 2 days and primary/secondary circuit malfunction on E again. Any help before she goes for sale as is? Maintenance mechanic says issue in cylinder due to direct injection. Says valves shot. All COPs and plugs are Motor craft.

 

[Texas Marauder]

Have you done a compression and cylinder leak down test? A problem with either wouldn't necessarily throw a circuit code but, I've seen circuit codes in similar situations that actually had a mechanical problem.

 

[kryptto]

Welcome listen to Texas

 

[SHOdded]

when you replaced the pcm, coils and plugs in the last round, was it all done at the same time? you can get caught in a vicious cycle if you don't.

at this point you have changed everything from plugs to pcm and all connections in between. if the fault is electrical, check ignition fuses and relays next.

injectors are known to fail on gdi engines. so could be facing feedback from that cylinder burning up the injector driver in the pcm. i would verify the integrity of the injector driver. if the driver proves compromised, best course is to replace all 6 injectors. test the injector also against the remaining injectors.

you can borescope to see if the valves are a possible issue. usually due to carboning. your SHO has not been driven much over the years. depending on whether it is soft or hard carbon and how much, you can either use pro gdi induction cleaning or walnut shell blasting to resolve it.

 

[shawnmccart]

I changed all parts same time. Had it borescope. Mechanic said valves were coked up and severe. I could not corelate the electrical issue to valves so i went electrical way. Back to same spot. I have not compression checked cylinders yet. All of this is great information and help. Thanks to all.

 

[shawnmccart]

Have you done a compression and cylinder leak down test? A problem with either wouldn't necessarily throw a circuit code but, I've seen circuit codes in similar situations that actually had a mechanical problem.

How do I conduct a leak down test? Thank you

 

[Texas Marauder]

A leak down test is probably not needed if the compression test shows all cylinders equal.

Test with one of these:

Amazon.com : cylinder leak down tester

 

[kryptto]

A leak down test is probably not needed if the compression test shows all cylinders equal.

Test with one of these:

Amazon.com : cylinder leak down tester

 

[SHOdded]

I changed all parts same time. Had it borescope. Mechanic said valves were coked up and severe. I could not corelate the electrical issue to valves so i went electrical way. Back to same spot. I have not compression checked cylinders yet. All of this is great information and help. Thanks to all.

if valves are badly coked up, then i would frankly go straight to walnut shell blasting to clean them up. if the valves are a problem, you should have noticed rough idling as an initial symptom, which when let go over time could certainly lead to bigger issues. the most publicized ones of which are on german gdi engines - bmw, audi and bmw. you can look up the humble mechanic yt channel to see.

 

[shawnmccart]

It never idled rough. It ran great right until i went up a hill. Shuddered and threw code. I got home and got the primary/secondary code. Fixed it with new pcm 1st time and all new parts, Happened again this Friday. It only ran 2 days. Threw code again primary/secondary. I'll get the valves walnut cleaned but do you think this will clear code? It will not clear with my scanner at all. Thank you in advance. Do you think PCM is trashed again?

 

[luigisho]

What pcm did you put in? Used salvage? If so, how old? Double failure is uncommon especially at the same failure point. Not impossible but..

Does it run even poorly now? If so is there a way to check the circuit from the plug, coil, back to pcm pin, out to see if signal is correct? Also will a problem with injector/injector wiring fail trigger this code (maybe in addition to others)?

spitball--What about potential vacuum leaks or faulty cam sensor messing up firing order?

 

[shawnmccart]

What pcm did you put in? Used salvage? If so, how old? Double failure is uncommon especially at the same failure point. Not impossible but..

Does it run even poorly now? If so is there a way to check the circuit from the plug, coil, back to pcm pin, out to see if signal is correct? Also will a problem with injector/injector wiring fail trigger this code (maybe in addition to others)
spitball--What about potential vacuum leaks or faulty cam sensor messing up firing order?

I bought a rebuilt one from FS1 with the vin burned in. It was $300 bucks with a lifetime warranty. Run poorly now. CODE P0355. Won't clear. Wiring harness is new. Its order of firing seems fine. I am interested in testing from PCM to coil. Any ideas on procedure. You have been a great beacon of hope thus far.

 

[luigisho]

Do you have a code reader or a scan tool? There is a difference.

I would start from the beginning disconnect the battery get all the current codes clear and swap plug,coil, and injector from one cylinder to the next to see if misfire moves. I know ignition parts are new but i would change all 3 see if it runs and if the fault moves. That takes into account any possible faulty replacement parts in that area and adds injector itrself (not it's wiring or injector driver fault at the computer) to the mix. I would also want to know if there is a

If it stays at the same place leave those swapped parts there and look more at electrical/signal and other cylinder specific failure,
If failure moves then you swap the coil back. If failure stays at the changed cyliner then move plug again, then injector if needed.

Generic cylinder 3 test English subtitles

 

[SHOdded]

i really can't say, and this is all on your dime, makes it doubly hard for me to push you in any particular direction.

if you did not have rough idling or anything prior to this event cascade, then its back to basics. check compression in case there are 1 or more piston rings compromised.
since the problem is occurring even with all new ignition parts and pcm, check fuel injection - injectors, and the injector drivers in the pcm. usually we have the injectors fail outright and flood the cats w fuel, which you can then smell from the exhaust.

Gasoline Engines PCED
Fuel Injectors — Direct Injection

The gasoline direct fuel injection fuel injector delivers fuel directly into the cylinder under high pressure. Each injector is controlled by 2 circuits from the PCM.

A boosted voltage supply, up to 65 volts, is generated in the PCM and used to initially open the injector. The injector driver controls three transistor switches that apply the boost voltage to open the injector and then modulates the current to hold the injector open. If boost voltage is unavailable, the correct injector opening current may not be generated in the time required.

The PCM contains a smart driver that monitors and compares high side and low side injector currents to diagnose numerous concerns. Each fuel injector high side circuit is paired inside the PCM with another fuel injector high side circuit. All injector concerns are reported with a single DTC per injector.

Typical Direct Fuel Injection Fuel Injector​

Item	Number	Description
1	—	Connector
2	—	Solenoid Coil
3	—	Fuel Filter Screen