OK, I screwed up by reversing the cables when jump starting a 2001 Ford E250 (4.2 l) van. After correcting the connections the engine turned over fine but would not fire. I suspect that I at least blew a fuse, possibly took out the ECM or other electronics.
Does anyone know what the most likely damage is on this vehicle? Thanks in advance!
I have seen everything from just blown fuses, to smoked relays, to bad ECM/alternator/radio/ignition control unit. That last one was about $2,500 in 1991 dollars.
Thanks Rick, for the quick response. I was searching this site for related info and found a post about jump start risks from approx. 2008. Are you the poster that has 30 yrs plus of auto background?
Anyway, I was hoping for a bit more detail. Did Ford do a decent job of protecting electronics of 2001 model era? A good design might use a fuse ahead of diodes to protect an ECM. Is there a common, usual or typical failure mode? What would be a good troubleshooting sequence?
?starting fluid to rule out fuel system
?looking for Schrader valve to check for fuel rail pressure
etc
most electronic modules have had “reverse battery” protection for a while now. essentially they have a large diode inside connected across the Vbatt and GND pins, and if you connect power in reverse polarity the diode is supposed to look like a dead short and blow the fuse for the circuit.
find the power distribution center underhood and start checking for blown fuses.
Thanks jz. Kind of brainstorming and researching before I dig into this. Sounds like Ford might have provided reverse polarity and inductive kick protection. Hoping to find someone familiar with this model to save me a bunch of time under the hood.
Hopefully it’ll be warm enough tomorrow to start troubleshooting.
It’s over 40 now.
As far as reverse polarity protection goes the more modern the car the more likely there will polarity protection.
I’m not that familiar with this vintage Ford products.
Here is where you start
Connect a known good battery correctly
Check all the fuses. Replace any blown ones.
Try to start vehicle
Recheck the fuses did any blow again?
If so fault trace
If no blown fuses check for spark during crank
Check for fuel pump operation (hint grab the fuel line and have someone cycle the key from off to on you should feel the pump buzz for about 1 second then stop until the car goes to crank then start again)
You will be missing:
Spark
Fuel
Both spark and fuel.
If you are missing both trace spark first.
Once you get the vehicle running check both DC and AC voltage at the battery.
DC should be about 13.5-14.5V
AC voltage should be less than 0.4V
You need to do these checks as you may have damaged the alternator.