Okay, so I picked up my new to me 2000 Excursion Saturday afternoon in Vegas and about half way home we stopped for gas... I saw this large mound of snow and could see that someone had already gone through part of it so I thought I'd take out another chunk of it.. I took it out, no biggie drove to the pump turned off the truck and filled it up.

Well when I came back she started just fine, I put her in gear to drive away and she just died... I fired her back up, and noticed that the SES light was on and the OD light was blinking... I thougth crap, tranny's going south... UGH... Well I needed to get her home still so I got on the road... The OD light quit blinking rather quickly, and she ran just fine on the highway...

She ran great all the way to my inlaws where I was stopping for the night... I get up to leave this morning, go out and fire her up to let her warm up a bit and melt off the fresh snow... Well I get in to back out of the inclined driveway, I'm trying to go uphill mind you, and she dies again, same stuff OD light blinking and such... Then I have to lock her in to 4wd to get up this driveway because of the snow and she chugs and fights me to get moving but once moving she's fine... Again, OD light goes away quickly...

Well once I get to my dads house for a quick visit on my way home, same thing AGAIN... This time when in park she revs betweek 1-2K until I rev her up, hear some chugging and then she idles just fine...

Well we leave and she runs okay then, we stop at autozone so my traveling partner can get new wiper blades and I have them pull the SES code.

They came up with a "P0720 The PCM has determined that a malfunction exist in the circuit for the output speed sensor"

Well, they didn't know what the heck that was, they told me I'd have to check with the dealer...

Well we have a long haul ahead of us still... We drive for another 50 miles, and get more gas (damn she drinks alot)... No problems other than that freakin SES light...

Another 80 miles later we stop and see a friend of mine for lunch, I pull her into the garage and disconnect the battery to reset the ECU and I disconnected and reseated the speedo sensor wires on the rear dif housing just for giggles since that was the only sensor I could think of having to do with speed... I left the battery off for a good hour durring lunch and such and left the light switch on as to make sure that all the juice drained for sure and reset...

Well the reset went fine, I drove the truck another 70 miles home and no issues have arrisen yet... She's running fine, no blinking no SES light no stalling or sputtering whatsoever...

So can anyone enlighten me as to what I might have screwed up???

TIA,

Heath



PS this is my first SuperDuty based vehicle/First V10/First Triton Engine...

 

most likely when it threw the trans code it went into fail safe and stayed in 3 rd gear. cuaseing the hard take off. heres the help from our companies web site

P0720
OSS
Insufficient input from output shaft speed sensor
PCM detected a loss of OSS signal during operation.
Harsh shifts, abnormal shift schedule, no torque converter clutch activation.
WIRING OR OSS SENSOR
http://www.levelten.com/store/F250_codes.htm

 

CHECK THE WIRING to the tranny!

Also, check the VSS wiring on the rear diff.

Sounds like snow/water got into a connection, or something got disconnected.

 

Well, so far still no problems... The wiring harness connected to the Tranny looks good... And as stated before I reseated the one to the speedo sensor on the rear housing... We'll see how she fares the rest of the week...

 

Try spraying some WD-40 on all the connections or even better yet, take them off and put dielectric grease on them especially if running in deep snow or where they will get wet. Just a quick thing to try. Tim

 

I'm thinking the trip through the snow pile caused your troubles (water in a connection, unseated that sensor you checked).

To the experienced ones:

Would it be a good idea to use some di-electric grease on a connection like that?

 

Absolutely... at the very least, on the rubber seal.

 

art right on again

never inside the plug. to many so called A grade mechanics do that and cause more problems then before. i clean with brake clean. wd40 and compressed air grease the seal only and reassemble.

all the companies seem NOT to leave extra wire in the harrnesses .so there is not enough flex and the wires brake inside the insulation. bending pulling and flexing will usally find the bad spot. then it's time to break out the bare crimps and shrink tube to make the repair. never solder as that makes it stiffer behond what all vechicle builders now want.

i go to walley world and use the new weather proof 3m crimps with the heat shrink and glue allready on the crimp. works very good.

 

Funny how dialectric grease works as an INSULATOR, eh?