Did the PO swap PCM's?

Once, long ago, I installed heavier injectors, and didn't have a tune to support them.. I was running more than a little rich.. I ordered up a tune from hemifever, and while waiting for it had a conversation with captin (member here) about it..

Mine is an 02, half breed second/third gen.. his is a thoroughbred second gen 01.. my truck ran fine, but guess what didn't work? The fuel gauge.. it was strange.. when hemifevers tune arrived via email, I loaded it up and haven't looked back..

Dan and I talked about it though, and one of the glaring differences with our rigs is the fuse block.. the relays are set up differently, but not so much I couldn't rearrange a few things and have it set just like his, or his like mine..

Point I'm making, and needed to say all that to justify: check your fuse block and reconcile it with a schematic.. if your PCM was changed, it may need flashing to accommodate the differences, or if the PO did all kinds of wiring hooligans, he may have screwed that up.

Dunno why, but my truck ran fine on the '01 tune, but the gauges were whacked, and the gas straight up farted... I tried to haunt my truck, in other words.

 

Spook injection?

 

Been on mcbclj since '04.. never thought I'd put boots on the mothership again, but life is funny like that.. I'm a dreaded defense contractor, and do mostly training type stuff now..

You wouldn't believe the changes I've seen just in the last five years.. there used to be nothing but God's soggy country between marston pavilion and the commissary, but now there are tons of huge battalion areas.. all the barracks are being rebuilt/finished.. its crazy.. my head shack is across from the combat pool, behind the base theatre.. used to be an armory back in the day (which happens to be about two years ago, but will remain 'back in the day' for the purpose of this conversation)... Stone bay is floggin huge now with MARSOC, courthouse bay is brown water navy now, French creek is still the ghetto and men don't walk through there unarmed.. so, some things don't change..

 

Dunno, could have been..

The gauges were the critters I could see... I wondered about the differences I couldn't see, ya know?

 

The PCM doesnt have a flash sticker on it so I was excited about that. I was hoping it didnt get the death flash back in the day like our other 2 trucks did. I will cross ref the part number to the truck and see if it should work. i do have another pcm sitting around so I may try that......just for shiz n grins.

Ill be down in Lejuene area next year (spring) visiting. Im sure Ill be in awwww of what has changed. I thought Id be happy after I got out but damn I miss the shiz in the worst way. Maybe I just miss being a Marine among Marines. Not to many hear in the frozen tundra, lol

I spent some time with 2nd recon......it was a fluke but they caught me at the range one day and asked if wanted to try out. I said ok. I guess they like my shooting skills........yeah I was pretty good back then. Dont know why.....never hunted or anything before I went in. Just loved to shoot........still do.

Semper Fi!

 

It's with great misfortune I inform you, sir, that your truck came from the factory with the flash of death.. the death flash.. grrrrrrrr... Mine did too...

I was an 8541.. they call it 0319 now I think.. primary was 0311.. I've plenty of trigger time.. .. the guys without the hunting background are actually easier to train.. no bad habits.. I was an exception.. I'd shoot anything that moved when I was a kid.. when I went into the woods, rocks stood deathly still..

 

I'd be thinking about a hemifever tune JUST to be sure and scare those goblins off...but that's just me being a happy hemifever tune customer....

 

The trick with the fuel gauge is that if the signal goes completely away it'll hang in the last position it was commanded to. So, with the last position being pinned during the self-test, hanging up there makes sense -- the gauge sweeps low to high during the self-test, then with no signal at all the PCM says fuggit and turns on the low fuel indicator.

The wiring is all on page 8W-30-42 of the FSM, pretty straightforward stuff. Straightforward to look at, not so easy to get at on the Fuel Tank Module end of things. That "Joint Connector No. 1 (In PDC)" you'll see is where almost all of the sensor grounds gang together. Lots of black/light blue wires jump into a pile there. The only ugly part is that you've got to drop the tank to get at the Fuel Tank Module -- on the up side you might be able to avoid that.

You might want to start by finding C129 which is under the hood, above the frame rail -- page 8W-90-19 in the FSM will show you where it's located. It's the one point most in harm's way where corrosion or bonehead unpluggage might bite you. I'd find that mufker and give it a serious visual inspection before doing anything else. If it looks to be plugged up properly, break it open and look at the parts. You might find corrosion, female pin spread, a broken wire, something like that.

 

I had this problem on my 1996 after it was sitting after a 12 month deployment (Army). Someone said that there is a ceramic plate that gauges the fuel level, and that deposits and varnish can get on it and mess with the reading. Makes sense because of how long it was sitting!!!

Most people replace the fuel pump assembly (Where the plate is) and the problem goes away.

 

BTW, drew is right about the fuse block (I am Dan BTW).

I had a 1996 and the PDC was different than my 2001 in terms of what repays are plugged in. I have two PDC covers, one that has my MSD box taped to it, and another that does not. The spare one was from the junkyard. The relays are different. THey differ not only from year to year, but by options (Engine, 4x4 or 2x4, off road package...).

I remember when I was replacing fuses in my PDC with junkyard fuses in my 1996 after an engine fire. My engine sounded RACIER, like it had a camshaft. Seemed like it had more power, but the tranny was not shifting correctly and the idle would become erratic. The weird part was that they were from a PDC that was a 1996 5.2, 4x4....the same as my truck. SO, you never know.