car is running weird

[lito]

Don't mess with that plug, it has a power from coil and injector that doesn't go anywhere, power for the coils come from the second to last (green) block on the BEC but if all other cylinders work I would not mess with power as is the same for all.

Check the ground to the PCM, they go into the E connector (biggest, bottom one) and test pin to pin to the coil ground (the wire at the coil that is not red)

Here is the diagram:

http://iihs.net/fsm/?dir=40&viewfile=Electronic Engine Controls - 4.6L.pdf

 

[06silverbullet]

yeah i got power on the always hot wire.

thats what i'm trying to test, is the ground/trigger wires. i just needed the pin out. and the e clips are the things plugged into the front of the pcm?


whats the easiest way to test the continuity i have the meters and settings ect. my probes are too big to fit in the pin hole, could i put a piece of wire in there and tape in place. and use that to probe off. it fits in the coil side.

almost wondering it i should just get a new/used harness and call it a day.

 

[TexasBlownV8]

I often use a small piece of solid wire and stick it into the connector and then connect the ohmmeter probes or clips to them.

Since you have power on the hot wire, the next logical check is continuity of the other wire to the pcm connector. You can compare to another cop circuit to make sure you are reading the right pins (if you identified the one circuit and am able to successfully get continuity, but the cyl. 8 is showing open, you've found your problem).

 

[06silverbullet]

I often use a small piece of solid wire and stick it into the connector and then connect the ohmmeter probes or clips to them.

Since you have power on the hot wire, the next logical check is continuity of the other wire to the pcm connector. You can compare to another cop circuit to make sure you are reading the right pins (if you identified the one circuit and am able to successfully get continuity, but the cyl. 8 is showing open, you've found your problem).

ok cool thats what i'm about to do, i was trying to tst the cylinder closest to the pcm first to use as a test. then try the 8 cyl ground. wish me luck lol


anyone have the ecm/pcm pinout? not sure which hole to test?

 

[06silverbullet]

ok... the wire is good i have good continuity tested the #1 cyl and 8 both good solid connections.

is my pcm the only thing at this point now?

 

[lito]

Maybe, I've had a couple with damaged drivers now. Didn't you had one another once for testing?

 

[06silverbullet]

no i wish, i did replace it less than a year ago. it was under warranty so i took it back to get replaced.

 

[Len20hun]

Without codes or abnormal engine data it's pretty tough to even hypothesize what "could" be wrong or where/what could be the cause of the problem. There's been some pretty standard suggestions "clean MAF/TB" and check the datalog for anything that may stand out. Just because the car may be setting a new threshold for what you consider to be running rough, doesn't mean that it isn't just learning how to run again. Hell just the weather could be enough to throw off the baseline in closed loop. Depending on how modified, the worse it could be. Until it pops out some codes, I'd just give it the chance to learn. Now if you take it out and do some WOT pulls and it runs like shit, then I would be concerned. Something would have to change fairly significantly to throw off open loop.

Yeah I'm just really anxious and concerned to find out what it is. Everything worked good when I first took it out then soon as I get close to home it began to act up. I need to buy a new programmer to look at codes but now I will have to get it re-flashed to even add the old tunes and diagnose the codes. It's so sad that someone broke into my car and stole my handheld a few weeks ago. Im hoping it's something small and nothing big like motor issues.