Laymaster

I accidentally drained my battery over the past two weeks while I waited for the weather to warm up to change my fuel injectors. I did that today and tried to jump my car unsuccessfully. While attempting to crank I did notice that the tach did not move much. The only things I touched mechanically were the fuel rail and injectors which I replaced with new bosch injectors.

Is this just a case of a pretty poor dead battery or does the minimally moving tach have anything to do with an issue with the new injectors?

Injuneer

Were you able to charge the battery? A battery with an internal short is going to cause problems when you try and use a jumper start. Next time you hook up the jumper, disconnect the positive battery terminal, and hook the positive jumper cable directly to the positive battery cable. See if that helps.

The tach is driven by the PCM, based on the optical cam position signals from the Optispark.

Laymaster

I plan on swapping out the battery directly.

The jumper is attached to the positive battery cable through the bolt. Are you suggesting to unbolt the battery and connect the alligator clip onto the cable without the cable on the battery? The car would shut down when I would disconnect the cable then, no?

Injuneer

All we are trying to do is see if the car will start without the load from a possibly internally shorted battery. If it starts easier without the cable connected to the battery, you've found the problem. If it doesn't start easier, the battery may be OK. The objective is not to keep the engine running.

GaryDoug

It isn't clear from your descriptions ("...attempting to crank") whether the engine is cranking or not. Does the engine starter crank normally? The tach isn't going to move at all if the engine isn't turning. Then in your second post, you note that the car "...would shut down". Is it running now?

Injuneer

"The car would shut down" I believe is a reference to what the engine would theortetically do IF it started without the positive cable attached to the battery, and he then removed the jumper cable.

Laymaster

Yes the engine cranked but it was a little sluggish. I also did not get the put-put I usually would get from a poor crank.

Fred is right the second post was theoretical. I did not get a chance to jump or swap the battery yet today.

Laymaster

I took the battery to autozone today and had it fully recharged as it was completely dead. I was surprised to get zero charge in the battery from the jumper cables the other day. Anyway car started right up without much of any issue.

Injuneer

Might want to check for a parasitic load on the battery, even when the ignition is off.

Laymaster

I know what the parasitic load was...

I left my Valentine One in the on position for 2-3 weeks while the car sat. Ooops.