Took a really quick 1-day trip to NYC for a meeting & I was so tickled as the Disco ran flawlessly! This morning, I tried to start it, and it was like the battery was dead (cranked once & quit). Checked the voltage at the battery & it was just above 12 volts. Tried to start it again with the headlights on just to see if there was a massive draw & the lights stayed bright like the starter was not drawing any of the battery, but again it would crank slowly once and then nothing. Checked the battery again and it was just over 12 volts, and also checked the cables to see if there was a difference, and they read the same. tried to crank it again, and it started right up as it always does with a quick(ish) spinning starter for a second or two and then barked to life. On the way to work this morning, the speedo went to zero for about 5 miles, and then jumped to 50 for about a mile before going to zero. This repeated for about 20 miles till the speedo began to operate normally. VSS is pretty new (about 3 months old) and has never offered anything that would make me thing that's bad, so I doubt that is the issue. My search of the two simultaneous problems don't seem to be connected... Ideas?

 

Just a guess, but could be the alternator and it's associated cables/connections.

 

I thought about that when it acted like the battery was dead and the voltmeter proved otherwise. However once it started the UG showed 13.52 volts, and besides, wouldn't the alternator make the tach inoperative and not the speedo?

 

If you have an Ultragauge you could check the MPH readout when the speedometer falls. If they match, I'd suspect the VSS or its connection. If they disagree I'd suspect the gauge itself may have something loose.

 

Okay, I never thought about the connection to the VSS, but would make more sense than the 3 month old new out-of-the-box VSS going bad. Just stepped out of the office to see if it would start. Started & ran like there never was an issue, so I'm betting something's loose. Just can't seem to tie the VSS to it's acting like the battery is dead. Another intermittent issue to track down...

 

Yeah, seems odd that the VSS and starting issue are related.

I have seen several VSS that have a long zip tie around then holding then snug on the connection. Maybe it's loose?

 

I had the same exact issue and funky speedometer behavior problems right when my alternator was starting to fail its not a do or die part they actually intermittently fail on you as they begin to die. when it finally bit the dust...everything dies in the last thing to go is the fuel injection and your vehicle will be so dead you can't even put the hazards on so get that fixed! I was able to find a rebuilt alternator OEM on eBay for 180 and then did the replacement myself good luck

 

Starter is dying

VSS is unrelated to cranking

 

Okay, call me stupid!! Got thinking about it last evening & went back through the hasty trip to NYC and right after that to see if I could remember anything strange before the issues started. Then I remember washing all of the salt off of the Disco Friday afternoon including the engine bay & the underside with a high pressure hose. Drove it about 1/2 mile & parked it for the weekend, but it was below freezing when I washed it, and remained there all weekend. Crawled under the truck to check the starter and VSS plug. although I didn't see anything with the starter, pretty much everything that didn't heat up while driving yesterday had ice on it. Started fine this morning, and everything is working as it should. Goes to show, if you wash your vehicle to that extent, you might want to wait till it's warmer outside. Well, at least that's the story I'm sticking with. Oh dopey me!!! Thanks for all of your brainstorming on this.

 

If it acts up more probly just do the starter