Hi Im Simon

iTrader: (6)

Alright, I'm out of ideas after checking everything. Perhaps you guys can give me some ideas. I'm only getting 12ish volts. Once the Fan kicks on, it drops to high 11s. The tuner can't tune with these voltages. I'm running a lot of electronics though. I've tested resistance for ground on all my electrical components ground and they tested good. The battery has been relocated to the bins running a 2 gauge wire to the front factory battery connection. A separate 4 gauge to the ECU, Coils, Injectors, and sensors that need 12V.

- Brand New Battery - Odyssey Small Battery
- Brand New Alternator - 200 Amp high output alternator
- Davies Craigs EWP
- 3 Walbro 450L Fuel Pumps
- AEM Meth Kit
- AEM Infinity 506
- AEM CD-7 Dash
- AEM Smart Coils
- 6 Injector Dynamic Injectors
- Borg Warner 8374 Turbo.

Any help would be greatly appreciated.

Thanks,

DaleClark

iTrader: (55)

What's the voltage coming off the alternator? Like putting a meter on the main terminal on the alternator.

Also where did this high amp alternator come from?

If you're only getting 12v I would suspect the alternator. Also do you have underdrive pullies? Does the voltage go up with RPM?

How are you reading voltage?

Dale

mikejokich

iTrader: (1)

One thing to check is the main 100A or 120A fuse, I forget the exact amperage. Several years ago I had a short that partially blew that fuse except for a small piece of metal still bridged the gap when it melted. I would get only 12V everywhere and the car would weakly crank and would not start. It took me two weeks of troubleshooting to finally find the problem. I would check the voltage across the battery terminals and then across the negative battery terminal and the main fuse. If less, then it is the main fuse. $8 at AutoZone.
Mike

tiger18

iTrader: (1)

hi i just recently fixed the exact problem,, mine was something stupid, My alternator wasnt earthing with the engine bracket very well. I used meter and tested alternator earth to engine "nothing". Cleaned up mounting points and bracket for adjusting belt tension. Bolted it back up had good earth and bingo voltage was back up to 14v from 11.9.

Hi Im Simon

iTrader: (6)

So the alternator came from Amazon. Eagle High Amp 200 Amp alternator. I checked the voltage coming from the alternator output is 14.3 to 14.4. The resistance from the alternator housing to the closest chassis ground is 0.2 Ohm, which should indicate a good ground. The crank pulley is slightly under-driven. I've checked all the fuses and they all look good, including the main 120 amp. I had one that looked a little dark but was still good. I replaced it anyways.

One thing I just noticed after testing the voltages was that my long 2 gauge wire to the battery terminal is getting 14.4 volts at one end (main fuse box) and is getting 13.98 at the other end of the cable (battery terminal). Does that mean there is a possible pinch in the wire?

Link to Alternator

Thanks,

b3delta

iTrader: (2)

I'd get that Alternator checked out. Reviews on that company are pretty all over the place. Some say it's good, others have fitment issues, parts going bad within 4000 miles etc...They've been around a while on Supra, truck, and other forums with varying success and failure - apparently the guy specializes in Euro alternators and dabbles in Japanese. A couple people even asked em and they said high RPM doesn't mix well with their Alts or something. I'd def get it tested not only for voltage, but amperage as well.

DaleClark

iTrader: (55)

If you are getting 14v at the alternator it sounds like it's doing its job. I assume that's at idle?

The long 2 gauge wire is just getting some voltage drop. This is normal with long runs of wiring. That's not enough to really worry about IMHO. It's not pinched or anything, if that was the case you would have a short to ground and would be blowing fuses left and right.

What is showing the low voltage - is it the PFC commander, a voltage gauge, what?

Dale

Hi Im Simon

iTrader: (6)

The ECU is reading the correct voltage as the battery. I'm also realizing something else. The wire from the main fuse box to the battery in the bins is actually a 4 gauge. That's probably not enough. I looked it up and the max amps that a 4 gauge wire is only 60 amps. That's definitely not enough power to drive 3 pumps, ECU, coils, and EWP. I guess this was fine with my old setup, but after all the new stuff it is not. I'm going to run a 0 gauge wire. I ordered it from Amazon, but it's going to take a month to get. =( Darn you Corona Virus!

Thanks for the help. I'll keep you guys posted.

DaleClark

iTrader: (55)

FYI many times Amazon is giving out 1 month shipping estimates but you actually get it much faster. I think they're erring on the side of caution.

That's definitely a good place to start!

Short term I think that alternator will be fine. Long term you may have problems. The best option for a high-amp alternator is IRP's alternator - it does cost more but it's solid and proven Many of the high amp alternators out there have a lot of issues in how they were designed, IRP's is designed right.

Dale

IRPerformance

iTrader: (41)

Do a load test on the alternator with the fans and a few other accessories on. Many of the super high output alternators are notorious for having charging issues at lower rpms. We have found that 140amps is about the highest you can go in a stock fd case before you start risking charging issues at idle, hence why 140amps is what we offer on our high output alternators. Also make sure the contact points between the alternator and motor are bare metal. Paint or powdercoat will affect grounding. Check the condition of the alternator harness itself.

Hi Im Simon

iTrader: (6)

Thanks for the input. I would have went the IRP route if I wasn't super desperate to get it. My old alternator gave out at the tuner. I bought it on Amazon and got it in two days.

Hi Im Simon

iTrader: (6)

So quick update. I ran a 0 gauge wire to the battery in the cabin of the car. It powers the 3 Walbro 450 pumps, meth injection pump. I reran wires directly from the alternator to a new fuse box for the ECU, coils, injector, and EWP.

I did some Amp checks. I'm not sure how accurate it is. It's using a Klein Amp Clamp. It shows the following:

Fuel Pumps + Meth = 45 Amps (Lift Pump 14, Sender Pumps 12 and 12)
ECU + Coils + Injectors: 20 Amps
Fan: 26 Amps

With everything on 100% (fans, EWP, etc.) at 3000+ RPM, I'm only getting 13.3 volts. It holds steady at 13.3 volts though. At idle it's going down to 12.5. I still don't understand why it's low. Any suggestions?

Thanks for the help.

DaleClark

iTrader: (55)

At this point I'm thinking the alternator isn't able to keep up. One other thing to look at/try is the actual main power wire going to the alternator - if it's stock or undersized it may need an upgrade. That was a common mod on the FC back in the day, it had a really rinky-dink stock alternator wire that barely worked on a stock car. Adding a larger gauge wire from the alternator main terminal to the positive terminal made a substantial improvement.

Also, how are the other primary grounds? I'm assuming the battery negative is grounded to the chassis, does the engine have the stock ground to the body or a beefier ground?

Dale

Hi Im Simon

iTrader: (6)

Thanks for the advise. I'm starting to think the same thing too. I reached out to the manufacture and see what they say.

I have upgraded all the wires coming from the alternator. There's (4) 4 gauge wire coming out of the alternator to the different fuse boxes. The grounds are good. I have multiple engine grounding points. I've checked resistance and there is little to none from the engine to the grounding points. This is to include the alternator as well.