Fuel System Upgrade Needed?
My battery is in the trunk, and I've got a pretty big wire running from the alt back to the battery.
There's a large power distribution block in the back that runs the fuel pumps, trans cooler and A2W pump.
When I check voltage at the alt and then back at the battery there is no difference.
No worries about the filter?
I wouldn't think so but thought I'd ask.
How would I do that?
My battery is in the trunk, and I've got a pretty big wire running from the alt back to the battery.
There's a large power distribution block in the back that runs the fuel pumps, trans cooler and A2W pump.
When I check voltage at the alt and then back at the battery there is no difference.
No worries about the filter?
I wouldn't think so but thought I'd ask.
My battery is in the trunk, and I've got a pretty big wire running from the alt back to the battery.
There's a large power distribution block in the back that runs the fuel pumps, trans cooler and A2W pump.
When I check voltage at the alt and then back at the battery there is no difference.
No worries about the filter?
I wouldn't think so but thought I'd ask.
Quick and dirty? Stuff the DMM leads into the fuel pump wires and have someone watch. A multimeter is an RMS reading so it won't catch transients but if you're flat out dropping battery voltage under WOT, it'll show up with a DMM. You can even run a pair of wires off the fuel pump to the DMM and run it up to the front seat to watch it. It'll be high impedance so you dont have to worry about high current or dropping voltage at the DMM to read it. If you have good voltage to the pump then you can start focusing on filtering/sizing of the pump/etc.
I'm not having any fueling issues or issue of any kind really, just something I noticed and thought I'd bring to tech for some discussion.
I know the factory ECU will vary Alt. output based on demand which I don't really like but I don't think there is anything I can do about it?
Oh well hell I can do that for sure.
I'm not having any fueling issues or issue of any kind really, just something I noticed and thought I'd bring to tech for some discussion.
I know the factory ECU will vary Alt. output based on demand which I don't really like but I don't think there is anything I can do about it?
I'm not having any fueling issues or issue of any kind really, just something I noticed and thought I'd bring to tech for some discussion.
I know the factory ECU will vary Alt. output based on demand which I don't really like but I don't think there is anything I can do about it?
I've been digging and there's a lot of vary info on how the alternator circuit works so its hard to know what is correct.
It's still the one wire in the four-pin plug which from what I'm reading simply turns the alternator off/on.
I've been monitoring voltage off the Control Module Voltage through HP tuners and here's what I'm seeing:
14.0-14.1 volts on cold start up at idle.
13.4-13.6 volts in closed loop and driving around, will hit 13.4 at idle and 13.6-13.7 cruising at 35 mph.
During a WOT 20-110 mph pull the voltage will drop to 13.2 and vacillate between 13.2 and 13.3 volts during the pull and as soon as I lift it jumps back up to 13.5-13.6.
I do have quite a few loads running once the car is warm during a pull with the engine coolant pump, fuel pumps, A2W pump, air compressor, trans cooler fan and injectors etc.
It looks like once my cooling fans kick on is when I see the .5 volt loss.
The one wire Exciter is why I don't think it's variable. It's either generating current or not. Your symptoms don't sound like variable voltage control, it sounds like as the car warms up youre losing battery voltage and during WOT it drops more.
The alternator is a brand-new JS unit so I know the alt is good.
The wire running to the battery is 1/0 and its #2 from there to the disconnect and to the power distribution block so I'm not sure where any improvements can be made.
The only question is the battery, I have to keep a tender on it, or it goes dead.
There's no excessive draw on the system while sitting and Autozone tested the battery, but I'm not sure I trust it.
Really tempted to just bite the bullet and get an Odyssey PC1500 battery.
What about Optima yellow top batteries, are they any good?
Last edited by Black_Sunshine_99; Mar 22, 2024 at 12:13 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo I'm hesitant to believe some of these parts store battery tests. Just because it passes a test doesn't mean it's actually good for a car like yours. Optima is supposed to be good stuff but I haven't ran one.
The battery has a tender on it 24/7 when in storage and currently the voltage is sitting at 12.2 volts which is a 60% charge, so my suspicion is growing.....
The belt only goes around the crank pulley and alternator with a spring-loaded tensioner and a grooved idler pulley, no WP or PS or anything else.
Well and I come from the material handling world where a large majority of the equipment is powered by large, industrial deep cycle batteries and when we tested those, we had a massive load bank where we could actually load test a battery because as you know, slapping a voltmeter on it doesn't test jack.
The battery has a tender on it 24/7 when in storage and currently the voltage is sitting at 12.2 volts which is a 60% charge, so my suspicion is growing.....
The battery has a tender on it 24/7 when in storage and currently the voltage is sitting at 12.2 volts which is a 60% charge, so my suspicion is growing.....
TECH Enthusiast
Joined: Feb 2020
Posts: 734
Likes: 209
My experience, optima is not as good as what you'd expect at that price. Most of the AGM type with conventional plates ( not spiral ) are pretty good though and sealed ( no gases coming out so safe for in trunk or hatch use ) those little parts store battery testers with 14 gauge leads are a joke and shouldn't be trusted. My advice would be to shop around for an AGM battery with the best warranty and or a trusted review
Quick update gents, Summit just so happened to be having a good sale on XS Power D3400 AGM batteries, so I've got one of those coming.
A very well known battery in the racing community and comes with a 3-Year warranty.
People have good things to say about their customer support as well.
Fingers crossed.
A very well known battery in the racing community and comes with a 3-Year warranty.
People have good things to say about their customer support as well.
Fingers crossed.
So, this is weird, I pulled the old wet cell battery out of the car and set it in on the ground, put my voltmeter on it and it read 12.41 volts after being on the tender (Noco Genius 2) so about 60-70% charged.
The new XS Power battery directions stipulate charging up the battery before install, so I set my tender to AGM and have it charging up for install this weekend.
On a whim I put the voltmeter back on the old battery this morning and it read 12.73 volts, so fully 100% charged after sitting on the concrete floor overnight.
Any thoughts?
The new XS Power battery directions stipulate charging up the battery before install, so I set my tender to AGM and have it charging up for install this weekend.
On a whim I put the voltmeter back on the old battery this morning and it read 12.73 volts, so fully 100% charged after sitting on the concrete floor overnight.
Any thoughts?
So, this is weird, I pulled the old wet cell battery out of the car and set it in on the ground, put my voltmeter on it and it read 12.41 volts after being on the tender (Noco Genius 2) so about 60-70% charged.
The new XS Power battery directions stipulate charging up the battery before install, so I set my tender to AGM and have it charging up for install this weekend.
On a whim I put the voltmeter back on the old battery this morning and it read 12.73 volts, so fully 100% charged after sitting on the concrete floor overnight.
Any thoughts?
The new XS Power battery directions stipulate charging up the battery before install, so I set my tender to AGM and have it charging up for install this weekend.
On a whim I put the voltmeter back on the old battery this morning and it read 12.73 volts, so fully 100% charged after sitting on the concrete floor overnight.
Any thoughts?
. The old battery would show 14.0 volts on the tender and immediately drop to 12.4 when unplugged so its odd that went back up after sitting.
I just thought it was very odd the old battery went up in voltage overnight while sitting on the cold concrete floor, it was 38 degrees last night so you'd think the cold would have brought it down.
I don't think the tender is no good?
It's a newer Noco Genius 2 which had great reviews and I just leave it plugged in all the time.
Oh no the new battery is at 14.04 volts and when I pull the tender it drops to 13.9 and slowly starts to drop where it should rest at 13 volts for an AGM battery from what I've read.
The old battery would show 14.0 volts on the tender and immediately drop to 12.4 when unplugged so its odd that went back up after sitting.
I just thought it was very odd the old battery went up in voltage overnight while sitting on the cold concrete floor, it was 38 degrees last night so you'd think the cold would have brought it down.
I don't think the tender is no good?
It's a newer Noco Genius 2 which had great reviews and I just leave it plugged in all the time.
The old battery would show 14.0 volts on the tender and immediately drop to 12.4 when unplugged so its odd that went back up after sitting.
I just thought it was very odd the old battery went up in voltage overnight while sitting on the cold concrete floor, it was 38 degrees last night so you'd think the cold would have brought it down.
I don't think the tender is no good?
It's a newer Noco Genius 2 which had great reviews and I just leave it plugged in all the time.
All kidding aside, that does seem a bit odd but for all we know its the DMM that was varying with the cold temps.
Quick update, I think I'm in good shape now power wise gents.
Got the new XS Power D3400 battery all charged up and installed.
The starter even sounds different, it wings up and starts so quickly now.
With a DMM on the alt at idle with everything running I'm seeing 14.7 volts at the alternator, at the back of the car at the battery I'm seeing 14.58-14.67 volts so I'm losing very little through all that cable.
The fuel pumps pull voltage from a bus bar right next to the battery which has the same 14.58-14.67 volts, so I know my pumps have an excellent supply voltage.
The voltmeter on my Davies Craig controller shows 14.1-14.2 at idle with everything running so there's a slight discrepancy there but never goes below 13.9 and when it does it doesn't stay there long and goes right back up.
I'm wondering if HP Tuners is monitoring from the same or similar location since it reads the same as the DC controller but since I know the pump voltage is where it should be this doesn't concern me as much now.
Cruising around town the car even idled better, and voltage was never below 14.1 on the DC controller screen, before cruising around it would get down around 13.3-13.5 volts.
I haven't made a pull yet as its still cold and the car won't hook whatsoever so I'll report back once it gets a little warmer but at this point, I'm very optimistic.
Got the new XS Power D3400 battery all charged up and installed.
The starter even sounds different, it wings up and starts so quickly now.
With a DMM on the alt at idle with everything running I'm seeing 14.7 volts at the alternator, at the back of the car at the battery I'm seeing 14.58-14.67 volts so I'm losing very little through all that cable.
The fuel pumps pull voltage from a bus bar right next to the battery which has the same 14.58-14.67 volts, so I know my pumps have an excellent supply voltage.
The voltmeter on my Davies Craig controller shows 14.1-14.2 at idle with everything running so there's a slight discrepancy there but never goes below 13.9 and when it does it doesn't stay there long and goes right back up.
I'm wondering if HP Tuners is monitoring from the same or similar location since it reads the same as the DC controller but since I know the pump voltage is where it should be this doesn't concern me as much now.
Cruising around town the car even idled better, and voltage was never below 14.1 on the DC controller screen, before cruising around it would get down around 13.3-13.5 volts.
I haven't made a pull yet as its still cold and the car won't hook whatsoever so I'll report back once it gets a little warmer but at this point, I'm very optimistic.