sohctodohc

Setup is as follows:
Meziere electrical pump
Walboro 400lph pump
Factory sized battery
Factory alternator
Aem v2 tuner
Battery is relocated into the trunk

I'm running into issues of my voltage being low during a pull, but after idling for a bit it comes back up to 13.7ish volts. During the pull I'm only seeing 12.0-12.5 volts.

The main problem with this is its throwing our tune all over the place and we are chasing our tail because of it


To me this sounds like the eld is doing its job, do people get rid of the eld to get away from this?

Do I have something wrong with my charging system?

Any help is appreciated!

luck4rmkc

iTrader: (2)

Well 12 volts during a pull is less than what you would hope for but all tuning softwares have a battery voltage offset table so that you can compensate for that situation should it arise...

Sounds like you have two problems
1) Your alternator is not providing adequate voltage during the pull
2) Yout battery offset table (injector dead time) needs some adjustment at the 12v area of the table.

Gunmetal_B20_Hatch

iTrader: (9)

belt slip? Try disabling ELD.

sohctodohc

How do you "disable" the eld??

boostontheD

iTrader: (3)

What crank pulley are you running?

sohctodohc

Factory f20b which is a single belt pulley

crucian

1. If it's an old alternator, replace it with a brand new one. I had the same problem.
2. Like someone stated above, change your dead times.
3. Where is your ground wire located? Make more than 1 ground coming off of the battery.
4. If your battery is relocated to the trunk, replace the factory battery with one with high cranking amps. eg. Optima

Your entire setup is affecting your voltage read out. Everything is pulling a lot of amperage. Having the battery relocated to the trunk doesn't help it.

What's your ignition setup?

TegraGsR

Upgrade to a 130amp alternator. We had the same issue on two different setups, one a b18c and the other h22. Upgraded both cars and problem went away. Tracked that issue for a while with no luck, as soon as we upgraded we hold steady throughout pulls now.

sohctodohc

Dead times are spot on from the paperwork I got with the I.D. Injectors, we currently have two grounds coming off the battery. I think we are going a size bigger on the wire and grounding it to the engine itself on the next go around.

I'm not sure of age on the alternator but I hate to replace it and then realize I need a hire amperage one, so I'm gonna go through and figure my actual amperage from accessories and go from there.

Ignition setup is k series coils with an aem epm.

Garage 808 Hatch

What size wire do you have with the battery relocate? Is the Alt wire ran back to the shut off switch?

sohctodohc

I think it's 0 gauge? We just picked up some 1 ott cable. We actually don't have a shut off switch.

sohctodohc

So doing some quick math at minimum I'm only drawing about 65amps for everything. What do stock honda alternators put out?

2k.civic.si

They claim 80amps...most measure around 70amps. I would have the alternator tested and the battery assuming the wiring is up to par.
The 99-01 v6 honda odyssey alternator is rated at 130amps...wonder if it will bolt up without to much work.

sohctodohc

I might have to look into that, I'm a machinist and I have a good fabricator as a friend so we might be able to rig something up

JJsMotorsports

iTrader: (1)

When we had this problem we upgraded the amps from stock alternator from a local alternator repair shop, cost me 120 bux it did work but I eventually I just went to 16v system and was done with voltage issues

0xenocron

I would bet belt slip and current loss from the alt to the battery in the rear are combined your two major issues

sohctodohc

How does one prevent belt slip besides tension? And we have a f20b alternator we have laying around which in those cars they had electrical power steering plus all the other accessories tied in were hoping it has a higher amperage output. So we shall test and see

crucian

Dead times from a person not working on your car will not help you. Use those dead times from ID to get you in a round-about area then adjust them yourself. I had to do it. Just got of the dyno yesterday and the tuner used my dead times. They were spot on. Plus my new alternator kept the voltage up anyways. Always stays around 13.5+.

georgecastaneda

Hey guys!

I'm having a problem with my 01 civic lx while driving at night i can see the dash board light looking really poor but once i either put the turn signal light or wiper blades on the light's intesity will increase to normal then will they drop down again. im not sure if this is alternator or something else if anyone know about this, i will really appreciate it

thanks

sohctodohc

A little update we swapped alternators and the voltage is much more stable at idle and cruise, but we logged a couple pulls and right at vtec crossover 4200-5000 area we see voltage just plummet and it's consistent every time. So it leads me to believe one of two things a) it is the power wire being to small and to long so we are going to go bigger with it or b) it's belt slip. Which again I ask how do you prevent belt slip minus tension on the alternator?

pb16b

perhaps a better or newer belt? old supercharger belt trick i believe was hairspray

sohctodohc

Will have to try that, I guess it can be a bandaid for tonight at the track

sohctodohc

Little update, I bought a used 99-01 honda odyssey alternator the 130amp one. I am currently in the process of making it fit the factory alternator bracket. Looks like a few spacers and some milling on the alternator case and it should fit just fine.

I will update later when it's on the car working, so far I have a total of 50 bucks in this. Much better price tag then an aftermarket alternator.

1FASTHF

Have you checked voltage at the battery during a pull for comparison? Maybe even going into vtec with light throttle to keep any possible slip to a minimum?

sohctodohc

I haven't but I have asked several times on how to prevent belt slip and no one days a word. Obviously an idler would be awesome but looking at it, it looks impossible to fab something up to help keep tension