As the title says. Ls2 427 runs great runs fast 1 problem.....it wont start. I have tested battery, battery is good(12.7 resting volts). I even tried a diff battery and same thing no start. I had a volt dropping problem(stock alt bad) and the truck 145amp fixed that. Now out of no where it wont start. Noticed my fuel pump went out on me so i installed the racetronix pump and wala still wont start(yes the pump works you can hear it kick on and I have fuel pressure) Here is what has me scratching my head. The car wont start on its own but will start with a battery charger on it or a jump box.? Once the car runs it runs great not missing and volts are at 13-14 volts. But it wont start on its own seems to need help but I dont know why. Checked all grounds and +'s all good all hooked up right.
Im stuck lost and frusterated. PLEASE help...

 

Ppppllllleeeeeaaaassssseeeee...................... ..........

 

Have the starter checked. Had a similar issue some time ago.

 

sounds like a bad battery
or poor connection at the terminal.

 

but it turns over just fine. Why would the starter affect it if it was in working order?

 

Poor connection somewhere.

 

nope checked rechecked and checked again.

correct if im wrong but if I had a poor connection why would a jump box or battery charger get it started?

 

It gives it that extra voltage to bridge the loose connection.

 

Oh where to begin. I hate chasing electrical stuff. endless....
good place to start?

 

Most likely in the battery wires. Either the ground wires or the power wires heading to the starter or alternator. I've seen ground terminals look fine from the outside but once you pull the bolt out of the terminal and remove the rubber boot the terminal and wires are all corroded causing a poor ground connection. I've also seen the AUX (+) on the driveside be loose or corroded underneath.

 

Man...can you imagine how fast it's going to be once it starts???

I'm sorry...that added no value at all to this thread, but I couldn't help myself.

 

If the starter is drawing excessive current, the electronic ignition may not be able to fire. The additional current source would make up for the excessive starter draw.

 

So how would I tell if the starter is drawling to much?

 

so you tested the battery with a volt meter?? im guessing you put the jump box at the battery... id get the battery load tested

start with the simple stop over thinking it. connections

 

Remove it and take it to the local AutoZone/OReillys type parts store. They have the equipment to load test it.

 

yes. 12.7 resting volts and when car is running 13.7/13.8 volts. When cracking the car over the battery only drops down to 10/11 volts. And yes connected battery charger/jump box to the battery. Load test shows or proves what exactly? load test the battery or the starter?

 

A starter load test would show if the starter is drawing so much current that battery voltage dropped during cranking. If the battery voltage is staying above 10 volts during cranking, it should probably operate the ignition OK.

 

which it is. never goes below 10 volts while cranking

 

Have you checked cranking voltage with the battery charger/jump box connected or does the car start too quickly to check it?

 

yea basically the car fires right up. Never tried to see what it reads with a box connected while cranking