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jump starting =burned computer?

Danno

NAXJA Forum User
Location
Lawrenceburg, TN
my secretary has a Mitsubishi Montero and the battery went out on it. She had it jumped started to get home and then the car started to run rough. she had it put on the computer and it said that the MAF was burned out. A couple of folks said that they had that problem after jump starting their Explorer. Anybody have this problem? It's hard to believe that the MAF got burned out. Maybe the computer got tweecked? What do you think? TIA, Danno
 
It's not so unusual to see that -- especially in the Ford system (haven't heard of a Mitsu doing that)...

Lots'a folks are still going battery to battery and the spikes there are readily transmitted to the PCM since the PCM monitors battery for charge -- this is compunded by the fact that a lot of these folks are leaving the key "on" in the jumpped car so the PCM is "right there"...

The manuals talk all th time about proper jumping procedures - some even recommend disconnecting the "victim" battery so that you're really just charging it for a while ...

Spikes are a good way to kill of most anything, but I can imagine that the heated MAF's are fairly susceptible since the PCM would be trying to get that hot for the the ride's starting breath...

for my part - I always recommend leaving the parking light and dome lights (even headlights in many cases) "ON" for the victim car then making the positive connection battery to battery then picking a ground on the victim car before finding one on the running car -- ALWAYS key full-off on the vicitm - that way the spikes are attenuated as much as can be expected -- once connections are made the load on the victim car (lights) can be reduced to speed things along... and let em "catch-up" before trying to crank anything...
 
Lots of oppinion, on jump starts. Even most manuals say find a good chassis ground, not to the battery. Good luck finding a good chassis ground, most every thing is covered in paint or preservative.
The safest way, I´ve found, is to hook up with both vehicles turned off. Try and start with just the battery, forget about the engine running and using the alternator. Leaving the batteries hooked up with a dome light or parking lights turned on, in the car with the dead battery, will help load the dead batttery somewhat (if it´s a healthy battery). On the old Delco SS type alternators, a run away regulator, was not uncommon and would often burn out every bulb in both cars, not to mention smoking the alternator and messing up the electronics. I´m not willing to trust the electronics in both vehicles to a voltage regulator.
As a side note, the OBD I computer is expensive and hooking up the jumper cables backwords, will sure enough kill it. The local auto parts stores, used to sell a bunch of OBD I´s, every time a ship would dock. They´d jump them, to get them off of the ship and the scortch marks on the battery lugs, attested to the fact they weren´t to careful about polarity.
 
I am assuming that the poor running is occurring with a good battery in it. Many vehicles (Chryslers a prime example, including Mitsu-powered minivans) will run really rotten if the battery is bad, even if a boost got it started.
 
On the few occasions I have had to jump start another vehicle off my XJ I make sure I have the other cars keys in my hand and the owner is standing next to me. I use my XJ to do a fast charge on the dead battery then remove my jumpers and allow them to see if theirs will start now. Twenty minutes seems to do the trick. I also use heavy cables and clamps that cost me over $70 for the set and are weighty enough to make you wal lop sided if carrying them in one hand.
 
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