PCM: Replace or not?
Thread Starter
|
Senior User
Joined: Jun 2012
Posts: 153
Likes: 1
The misfire is random and the SUV has done the same thing to me, runs perfect one minute stumbles the next. Also I can't remember if I had done any testing with the #1 injector connector off the injector and then not clear the DTC. I know I specifically had taken it off early in my testing to trip a code other than #2 misfire and it did. I believe it was the same result, #1 injector circuit open.
The Tech can only go on what he see's especially when I have requested he perform a specific task!
Anyway I'm no closer to a solution.
The Tech can only go on what he see's especially when I have requested he perform a specific task!
Anyway I'm no closer to a solution.
Cargo Master
Joined: Mar 2002
Posts: 3,132
Likes: 219
From: W (BY GOD) V
Watch this video- https://video.search.yahoo.com/yhs/s...27157a8c8f2a50
SOURCE- http://autodiagnosticsandpublishing....or-testing.htm
A good number of late model ECMs are using the more advanced microprocessors, with 32 bit processor systems on most of them. These computer systems are capable of shutting down the injector driver in the event of a short circuit, a severe misfire, or an overheating engine. The Cadillac Northstar 4.6L engine was one of the first systems to employ such an ECM. The system shuts down the injectors intermittently in the event of an overheating engine in order for it to work cooler and therefore protect the head gaskets. It is important to determine if the misfire or lack of injector pulse is the result of an ECM strategy to save the engine from damage or an actual malfunction.
Thread Starter
|
Senior User
Joined: Jun 2012
Posts: 153
Likes: 1
So, the fact that I have determined #2 pulse driver is not sending a signal (randomly) to the injector may be caused by the PCM doing it purposefully! This would explain why the SUV runs perfect at times. I just need to determine why it might do this. The Tech said "if it was his, he would replace injectors next" and those were already on order before he advised it.
I will do some more troubleshooting tomorrow. Engine temp might be a factor. Highway speed/RPM's it runs perfect 99.9% of the time as soon as the RPM's get below 1200 then it starts misfiring often. Step on the gas pedal as soon as it raises above 1200 no misfire. Engine temp would not explain why it does it sometimes at cold start up.
What a PAIN!!
I will do some more troubleshooting tomorrow. Engine temp might be a factor. Highway speed/RPM's it runs perfect 99.9% of the time as soon as the RPM's get below 1200 then it starts misfiring often. Step on the gas pedal as soon as it raises above 1200 no misfire. Engine temp would not explain why it does it sometimes at cold start up.
What a PAIN!!
Thread Starter
|
Senior User
Joined: Jun 2012
Posts: 153
Likes: 1
yes I had watched that video early on but did not catch that part about the computer shutting things down.
No mine does not have the cylinder balance feature.
Yes I did put a double dose of TECHRON fuel system cleaner in the tank when I bought it but haven't used the tank of gas yet.
Is the 4.0 injection system a "direct" or "multi port" system? What does Ford call it?
No mine does not have the cylinder balance feature.
Yes I did put a double dose of TECHRON fuel system cleaner in the tank when I bought it but haven't used the tank of gas yet.
Is the 4.0 injection system a "direct" or "multi port" system? What does Ford call it?
Cargo Master
Joined: Mar 2002
Posts: 3,132
Likes: 219
From: W (BY GOD) V
yes I had watched that video early on but did not catch that part about the computer shutting things down.
No mine does not have the cylinder balance feature.
Yes I did put a double dose of TECHRON fuel system cleaner in the tank when I bought it but haven't used the tank of gas yet.
Is the 4.0 injection system a "direct" or "multi port" system? What does Ford call it?
Has your Shop Manual arrived yet?
Thread Starter
|
Senior User
Joined: Jun 2012
Posts: 153
Likes: 1
Yes have Manuals. Also working 4pm to 4 am or after, Sat. thru Wed. so don't have much time to do anything.
Briefly browsed thru manuals, WOW a lot of information in a shop manual! Unfortunately, it looks like they emissions and fuel system diagnosis information is in another manual not the shop manual.
I have a fuel pressure adaptor on it's way. It will supposedly connect between the supply fuel line and the fuel rail and is of a quality that permits me to just leave it "in line". I had to pay extra for something Ford should have installed at the factory! I posted a part # earlier in the thread. It's the wrong #, this is the correct # per Ford/Rotunda, "310-180"
Briefly browsed thru manuals, WOW a lot of information in a shop manual! Unfortunately, it looks like they emissions and fuel system diagnosis information is in another manual not the shop manual.
I have a fuel pressure adaptor on it's way. It will supposedly connect between the supply fuel line and the fuel rail and is of a quality that permits me to just leave it "in line". I had to pay extra for something Ford should have installed at the factory! I posted a part # earlier in the thread. It's the wrong #, this is the correct # per Ford/Rotunda, "310-180"
Cargo Master
Joined: Mar 2002
Posts: 3,132
Likes: 219
From: W (BY GOD) V
Yes have Manuals. Also working 4pm to 4 am or after, Sat. thru Wed. so don't have much time to do anything.
Briefly browsed thru manuals, WOW a lot of information in a shop manual!
Unfortunately, it looks like they emissions and fuel system diagnosis information is in another manual not the shop manual.
...sigh...
2008 Powertrain Control Emission Diagnosis Gas Only - Helm Incorporated
I have a fuel pressure adaptor on it's way. It will supposedly connect between the supply fuel line and the fuel rail and is of a quality that permits me to just leave it "in line". I had to pay extra for something Ford should have installed at the factory! I posted a part # earlier in the thread. It's the wrong #, this is the correct # per Ford/Rotunda, "310-180"
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Thread Starter
|
Senior User
Joined: Jun 2012
Posts: 153
Likes: 1
I't certainly pays to shop around. I found the Ford PC/E Diagnosis Manual, used, for $45 shipped. That's on the way! I do like these more technical/specific manuals and easily resealable when I replace the vehicle.
This SUV is frustrating! Currently, in a good way! I decided to drive it to and from work this week to get more detail information on what/when the misfire occurs. It's only a 17 mile round trip but there are several stops. Prime situation for the misfire to occur, only it hasn't! It did twice for about 3 seconds each time but nothing more.
I know! Now I'm pissed because my SUV is running correctly, just can't make some people happy! As long as it continues, I'll be happy.
This SUV is frustrating! Currently, in a good way! I decided to drive it to and from work this week to get more detail information on what/when the misfire occurs. It's only a 17 mile round trip but there are several stops. Prime situation for the misfire to occur, only it hasn't! It did twice for about 3 seconds each time but nothing more.
I know! Now I'm pissed because my SUV is running correctly, just can't make some people happy! As long as it continues, I'll be happy.
Thread
Thread Starter
Forum
Replies
Last Post