Battery - Jeff?

[Allen-GTR]

Well, start up has been challenging...

Everything is in place, battery charged, loose objects stowed, small children at a safe distance... hit the loud button.... NADA

Spent a week trying to figure out why I get no spark. Engine cranks merrily away, but no spark. Spent a lot of time with the EFI tech on the phone... everything checks out good. All the voltages were right, yada yada... In the end he tells me to pack the whole thing up and send it back for bench testing, assuming it was the ECU. Before I take it all apart (IT RAN ON THE ENGINE DYNO!) in a last ditch effort, I connected the another battery up and VIOLA! SPARK!

So, to make a long story short, the Oddeysy battery does not have enough oomph to keep a spark in the EFI. Plenty to crank the engine, but does not maintain enough starting power to hold the EFI. Who knew???

Anyway, I know Jeff runs a Optima in his car. Jeff, what Optima battery will fit in the same location?

Almost there!

Allen

[usagtrman]

Allen

Check my website under Ultima......I just posted two pictures of my Optima battery installed. I'll check my records to find the model number for you.

Brad Z
www.bradzeman.com

[Allen-GTR]

I believe the Optima 51 (or 51R) will fit. I just want to make certain it will have enough cranking power to do the job. I suspect it will.

I will also have the Odyssey battery checked for proper function where I bought it. I am only getting 12.5V fully charged where I would expect 14V+. It also seems to discharge quickly, (lost a cell perhaps?) so I want it checked before plunking down more cash for a Optima... (and changing the battery clamp/brackets/etc.)

[mkoch1]

you might want to check your alternator, maybe it's not working correctly.

mark

[Allen-GTR]

Well, the engine has yet to fire in the car. At this point the battery does not maintain enough voltage/amps during cranking to support the EFI and associated ECU to induce the spark during cranking to even start.

After I get a good blue spark during cranking, the engine will fire right up. I was there when it ran on the engine Dyno, so I know there is no issue with the engine or tuning. Just one of those funky things I would not have expected. I will post the solution when I know what it is. (either bad battery, or battery too small)

Allen

[USCANAM]

Allen
Check the 12V feed wire going to the engine computer. On my setup, it requires a direct feed using a heavy gauge wire. I have the small battery with no problem starting.
Having said that, I have the Stack Dash which has a built in digital voltmeter. I had machined a larger drive pulley for the alternator to reduce alternator rpm in anticipation of high revving on the track. As a result, my alternator will not "kick in" and start charging until the engine reaches 2000 rpm, at which time it starts to charge even if the rpm drops to idle at 975. But what I do notice, when the engine first starts, and I have not blipped the throttle to reach 2000, the voltmeter shows around 11.8 volts, and the engine does not run smooth. Once the alternator kicks in and the voltage shows 14 volts, there is an instant increase in rpm (up to normal idle) and the engine runs smoother. What this shows is how sensative the computer is to low voltage.
Once again, check the supply feed to the computer. Make sure it's getting ALL the volts it can when cranking with a smaller battery.
Good Luck
Jack

[Allen-GTR]

Thanks Jack!

Here is what I found...

I suspected that maybe I had a bad cell in the battery, so I pulled it to be tested. No need to test it... It was leaking acid out of a hole in the bottom of the case. As it happens, the hole was directly over one of the rubber pads the battery sits on, so it didn't leak until I pulled it out. Anyway, the battery was replaced under warranty last night. I put it in the car and I do get spark now.

I am using the green choke wire to power the EFI. The EFI also uses the heavy lead on the starter for the bulk of the power requirement. The green choke lead is hot on start and crank, and with a good battery (!) supplies a clean 12V. The factory recommended using that lead for the EFI as well. There isn't a high amp load on that lead. The amp load is on the starter lead.

So, I will attempt to start the beast tonight. I think all the kinks are worked out...?

Allen

[jschwartz]

I think mine is the Optima 51 yellow.
With the factory harness I was never able to get decent voltage (10.7-11.2 with ac on 12.3-12.5 wo). After installing larger gauge wires as Mack posted here, I was able to get 13.8 volts most always.
Jeff