Running with flat battery and Fuel Injection.

[allan4169]

Here is a question that I need to have answered. My 2002 Dodge truck will not run with a dead battery. I can start it with jumper cables but there is not enough in the battery to run the fuel injection. As soon as you rev it, it runs like crap. Obviously you can't drive it. So what about fuel injected bikes. My 2001 1200 Bandit had a flat battery at work and I just rolled it down  the ramp and bump started it. Got home and the next day bought a new battery and on we go. But what about the fuel injected bikes. Has anyone any experience with a flat battery and a FI bike?

[Red01]

Seems odd about your truck.  I'd think that once you jumped it, the alternator should have put out enough juice to run things. (This has worked on my EFI Jeeps.)  Though it is true that today's electronic controls are more susceptible to the right voltage and are less likely to run on low voltages that would not have affected older ones.

[CWO4GUNNER]

Have you confirmed your findings by swapping out a charged battery (from your other car) into your truck to confirm that it runs smooth again. If not it sound to me that your O2 sensor on your truck is bad which will also run very rough when you depress the accelerator. It happened to me on my 96 Isuzu rodeo when the O2 sensor just down stream of the CAT failed. The dealer wanted $600 to replace it but I opted to buy it at Auto zone for $69 and install it myself in all of about 5 minutes and about as difficult as replacing a spark plug.

[r_outsider]

I've never had a problem with bump starting an FI bike. Unless I stall it and have to push it down the road in the hot sun again!
Seems odd that the truck would have that problem. I've jump started many EFI vehicles and never seen anything like that.

[allan4169]

In the case of the truck, I went and purchased a new battery right away and the truck ran fine with the new battery. Still running fine to this day. There has been no other problems with the truck. I am assuming that the battery may have had a collapsed cell and therefore was not even able to charge once running. Once I got the new battery in it though, it was running great. And thanks r_outsider for your reply. Thanks guys for answering my question.

[DSMoneypit]

Most newer vehicles are more susceptible to surges from the electrical system.  Your battery acts a filter in your electrical system when the vehicle is running.  The alternator produces AC and as we all know your vehicles electrical components run on DC (really have to wonder what Tesla would say about this).  There is a device in the alternator called a rectifire (I believe, its been awhile) that converts the AC to DC but it does not completely convert all of the AC to DC.  Your battery helps to filter the remaining AC.  If the Battery has a fault then the computer will sense the AC and go into limp mode as a default protection mode.  That is probably the reason that the car was not running properly.

[gyrogearcrunch]

Most newer vehicles are more susceptible to surges from the electrical system.  Your battery acts a filter in your electrical system when the vehicle is running.  The alternator produces AC and as we all know your vehicles electrical components run on DC (really have to wonder what Tesla would say about this).  There is a device in the alternator called a rectifire (I believe, its been awhile) that converts the AC to DC but it does not completely convert all of the AC to DC.  Your battery helps to filter the remaining AC.  If the Battery has a fault then the computer will sense the AC and go into limp mode as a default protection mode.  That is probably the reason that the car was not running properly.

Bad rectifier diodes can show all kinds of symptoms, caused by reverse current leakage. You're right about the battery acting like a filter capacitor, but a shorted diode is too much for the battery to handle.