ok 7.3 gurus lets hear your thoughts

RescueF250 · Oct 26, 2013

Im at stand still with this obs driving me nuts. Motor had head gaskets redone. New manifolds, etc.

Now the truck runs great at idle then starts to hiccup slightly and shut off. No codes, has hpo, batteries are good, replace cps already, added a new water pump.

As for the problem battery light stays on but charging system is good 14.2 v both batteries, hpop is reading 570-605 psi at idle, checked all grounds, and wiring. Still idles and shuts off but fires right up after it shuts off. Again no codes but a battery light. Cant figure it out to save my life. Everything checks out normal whats missing

co04cobra · Oct 26, 2013

What year engine wiring harness? What year truck ? Where is the cps from?

RescueF250 · Oct 26, 2013

95, orginal harness no issues before cps from ford

POWER-STRUCK · Oct 26, 2013

cps wiring chafed on ebp tube? ipr nut loose?

co04cobra · Oct 26, 2013

Def start back tracking all wires on the engine harness and look carefully at the 42 pin for chaffed wires. Recheck and clean all grounds.

RescueF250 · Oct 26, 2013

Checked passenger battery to block. driver battery to frame. Engine to Chassis passenger head, Chassis to frame, driver battery to front clip.

IPR was running at 16-17% at idle. This is all stuff already done still have battery light on, and cut off issue.

Tom S · Oct 26, 2013

I think I would also watch to make sure I had fuel pressure.

golfer · Oct 26, 2013

..interesting.

My 2000 Excursion is doing this exact same thing as of Friday.
New batteries last week...(prior to these issues)
Battery light came on Friday while I was commuting in, got into work, alternator wasn't charging...3 alternators(2 'new'), and then lastly, one known working alt.

Fires up and instantly dies. Over and over.
No extended crank, fuel psi, and ICP are fine..

Did note that mass fuel desired is zeroooooo

Haven't had a chance to look at it(past that)...but when the battery light came on I smelled a decent amount of electrical/burning smell...

I'll keep you updated, but a new PCM didn't change anything either.

PSDEng · Oct 26, 2013

Probably a long shot but are there any marks on the front of the CPS? I had similar symptoms when I had camshaft gear walk

Tom S · Oct 27, 2013

golfer said:
..interesting.

My 2000 Excursion is doing this exact same thing as of Friday.
New batteries last week...(prior to these issues)
Battery light came on Friday while I was commuting in, got into work, alternator wasn't charging...3 alternators(2 'new'), and then lastly, one known working alt.

Fires up and instantly dies. Over and over.
No extended crank, fuel psi, and ICP are fine..

Did note that mass fuel desired is zeroooooo

Haven't had a chance to look at it(past that)...but when the battery light came on I smelled a decent amount of electrical/burning smell...

I'll keep you updated, but a new PCM didn't change anything either.

Did the old alternator smell burnt up? They do that from time to time on Crown Vics when they fail. If it did not then that would make me think the battery light is more of a symptom then a cause.

This is going to be a very interesting one when you figure it out.

golfer · Oct 28, 2013

the old alternator did smell a little very 'electrical'...but I don't think it was anything out of the ordinary (for a big ass electrical 'generator').

the big unknown is what caused the electrical burning smell...

it was definitely much more pronounced in the cab, than it was in the engine compartment (popped hood & 'sniffed' as soon as I pulled in the shop Friday).

update on the start/stall...

we had swapped in the original Excursion PCM...and didn't plug in the PATS module....w/o the chip installed, the PATS was killing the truck.

as of this morning, it starts & is idling fine...but alternator is still not charging.

going to swap in another set of batteries, and see if we can find out what got hot in/under/behind the dash.

golfer · Oct 28, 2013

Alternator(s) were all charging...however the GPCM was staying on...drawing the voltage down...

unplugged the GPCM and chit is fine...

hoping the 'smell' was just the GPCM taking a chit...only way to find out is to drive it...

I'll update if necessary, but as of now...the GPCM was the culprit.

Marty · Oct 28, 2013

Find a broken plug or chaffed wire putting power into the block (a ground)....

RescueF250 · Oct 28, 2013

Engine block to firewall
Passenger battery to block 2 grounds
Driver battery to frame rail
Body to frame ground
Driver battery to front clip

Are the ones i have been all checked

Luke@MillerPerformance · Oct 28, 2013

14.2 is on the high side, alternator could be overcharging. Try another PCM if you have one you can try. Check 5 volt reference with all sensors hooked up.

JoeDaddy · Oct 29, 2013

14.2-14.4 is all mine have run as far back as I can remember.
I had a IPR, FPRpsi, FB heater harness go bad awhile ago. I had ditched the bowl and the left over wiring was laying in the grease in the valley.

Does the CEL flash when it hiccups?

Can you watch the fuel pressure? Does it drop when it dies?