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Check and clean your battery terminals and cables. I had a weak start issue for a few weeks and come to find out, my terminals were dirty. I had put terminal protector on the clamp while connected to the battery and it somehow sank into the connector and acted as dialectic grease preventing them from charging and discharging properly.
Battery terminals are clean, checked and cleaned every oil change.
The batteries are Motorcraft 850 and were replaced January 2014. The alternator is a stock OEM re-man and was replaced November 2014.
I find that the SGII is off by about 0.5 Volts
at the batterie post with a DMM. You might
check the voltage at the posts and also do
a voltage drop test on the cables during a startup.
Sean
Agreed. Just y/day got my VOM and Dashboss out and made the comparison. OBD Scangauge 13.6, VOM at alternator 14.3, VOM at pass batt 14.2, VOM at driver's side batt 14.1.
All VOM readings showed line voltage drops due to line resistance. OBD just seems to show .5 volts lower but I'm not sure it's pure resistance, just "diagnostic interpretation."
Maybe a new phrase?
Part of the problem with the voltage differences is from the fact that we are taking an
analog signal and making it into a digital reading. In this case we are doing A/D. The
speed of the conversion circuit does what is called "Sampling" and then there is the
"Rate" that the "sample" is taken at. The Fluke should be at a higher rate than the PCM
or the SGII.So that is part of the reason that the Fluke is less jumpy. The best reading would
be with a high accuracy analog meter or better yet with a 2 channel oscilloscope with one lead
on the battery and the other one the pin at the OBD2 port in the cab. This would be BIG TIME
over kill for most people at home.
Also there is the resistance of the smaller wire between and the OBD2 port the batteries to the
PCM. This all adds up. Smaller wire will carry less current over distances. Then add all the connections
into the mix and you have more loss. BTW most sockets are tin and the PCM has gold pins. Gold being
the better connector and tin not as good. Tin to tin even worse for corrosion. Gold to gold is the best. But
that is pennies than the bankers want to spend on each.
I didn't read where anyone mentioned that to complete a circuit you HAVE to have a GOOD ground. YOur truck is about 10 years old now....remove your block grounds and sand/clean them good and reinstall the wires. You may be a nice difference.
I didn't read where anyone mentioned that to complete a circuit you HAVE to have a GOOD ground. YOur truck is about 10 years old now....remove your block grounds and sand/clean them good and reinstall the wires. You may be a nice difference.
I recently did this on The Monster and wow....the truck runs that much better.
Rudolph is next this evening after The Monster gets a bath.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
