supercharged 5.0 true fire 98 explorer sport

4pointslow · August 4, 2015

Dono said:
Why on earth would the factory want to lower the voltage at wot? I can't help but think its a voltage regulator thing, but Tim has tried a couple of whole alternators already.

One trick used in the muscle car era was to put a wot switch on the alternator field circuit to eliminate the parasitic horsepower loss at WOT. Kind of the same reason some use an electric water pump.

Certain Crown Vics have this feature built in to the PCM which controls charging, and it can be turned on or off in the tune. Our Explorers don't have that feature.

If there is only a small drop during WOT then it is no big deal, how long are you at wot anyway. If the voltage is dropping at other times or you have other symptoms like dimming lights or hard starting then it's time to look into it.

I was more concerned about the TPS randomly dropping out and not reading full WOT during the datalog on Tim's truck. When I saw the battery voltage dropping out I thought that it might have been related, but now it doesn't seem so.

4pointslow · August 5, 2015

Quote

A quote from that post that Tim linked to.....

"I know for a fact that the regulators are the problem in the alternator. They have an overtemp built into them and basically stop producing volts when the temp gets high."

vroomzoomboom · August 5, 2015

if your saying i can put the voltage thing to rest, i will happily do it!!!
as for the TPS, i was thinking today what i might do it go to one of the wreckers when i get a chance and find a 94 and up mustang (more then likely a v6, wont find a v8 in there here) and cut the connector off the body side of the harness, and grab the tps out if it and try it.

4pointslow · August 5, 2015

Voltage

Send me a current datalog of WOT so I can see where it is now.(voltage and TPS).

In the picture below you can see how it recovered, at least you know it is not going to let you down on the road.

The regulator is going into self preservation mode. lol.
With the larger crank pulley it would be spinning faster and hitting high temperatures quicker. Like 2000streetrod mentioned, if you could get a pulley that would keep it at the normal RPM's (not faster or slower) that would be the best.

I like the way it was fixed in the thread you posted, but it does cost a bit more don't it.
If you end up with a lean condition that can not be fixed on the dyno due to under voltage then it would be time to revisit the options on charging system upgrades.

Dono · August 5, 2015

That's the thing, there is nothing 'telling' the alternator to shut down.
I might just buy a 3 pole bridge rectifier off ebay rated for somewhere over 100 amps. It looks super easy to wire in.
Maybe the diodes are over heating in the alternator, and the regulator is still trying to do its job? It would be worth trying, and an inexpensive experiment.

4pointslow · August 5, 2015

Voltage still bad

And this is what makes you go WTF?
In these two pictures the voltage recovers well, but the battery voltage is dropping way to low at WOT. Dropping below battery voltage (12.6) means that not only the regulator has stopped charging to protect itself from overheating, but the battery is being discharged by the excessive loads on the system.

Still a problem here.
Some thoughts
What was the CCA measurement off the battery?
Maybe the battery is weak or needs to be upgraded.
Tim has a capacitor for his stereo amps, I don't know how that would effect the system since it is not a factory item. Maybe disconnect it and do a before and after datalog.
Alternator looks to be charging well before and after the WOT, on other datalogs I swore I saw something different like low charging voltage so maybe the cables helped there.
Kenne Bell boost a pump or boost a spark are voltage conditioners that are supposed to keep things up when at WOT or even if the charging system shuts down.They can even raise the voltages, but are only good for about 40 amps.
Jacobs Electronics systems used to make similar things, they were sold and are located out of Australia, but check out there website. Check out the Race accuvolt which is the first one listed. A little pricey.
http://www.jacobselectronics.com.au/index.html

Dono · August 5, 2015

4pointslow, I agree with you 100%.
There's no way the voltage should drop like that.
I'm not even happy with ahodges, or mine seeing the voltage drop. Tim's voltage drop is terrible. From what I understand, this really makes a difference on injector pulses. I still don't get how such a widely used alternator could behave like this. I guess it just 'is', and we need to look at solutions.
I just ordered this for a test:
http://www.ebay.ca/itm/361143887069?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT
I don't expect to see it for a month though.

4pointslow · August 5, 2015

Post

My last post now has the two pictures I was talking about. I could not upload them a little while ago.

Dono's and Ahodges are not the problem. The regulator is doing what it is supposed to do, protecting itself from overheating.

Look at Tim's voltage dropping below 12 volts, that is bad.

Dono · August 5, 2015

Ok, I see why you are asking about the battery.
Even without an alternator at all, If the battery is charged we shouldn't see a drop to just over 11 volts. I get it.

2000StreetRod · August 5, 2015

diodes vs regulator

My 1973 Volvo 142S had Bosch fuel injection (analog computer) and an electric fuel pump. On my first long, summer trip I began losing power on the freeway. I had to keep depressing the accelerator farther to maintain my speed. When I finally reached an exit ramp and left off the pedal the engine died and wouldn't restart. I walked to a phone booth (before cell phones) and called a tow truck. Eventually the truck driver arrived, he charged my battery for a few minutes, I started the engine and drove to the nearest gas station (they had mechanics back then). My family walked to a nearby diner to eat while the mechanic tested my battery and alternator and fully charged the battery. Nothing was found to be defective so we continued on our trip. A couple hours later I could tell from the voltmeter that the battery was no longer being charged so we pulled into a motel in St. Charles, LA. I called a small foreign car repair shop and learned that the alternator diodes were inadequate for my model. They eventually overheat reducing the output voltage to that of the battery. After cooling for 30 minutes they test fine. I replaced the alternator with one that had better cooling and larger capacity diodes. Our new 2014 Grand Cherokee had the same design deficiency but we never experienced the symptoms. We waited a year for a replacement alternator for the issued recall.

I doubt that your problem is the diodes overheating because it takes several minutes for them to recover. However, it is very possible that your voltage regulator is overheating due to its location in the alternator and the alternator's exposure to the heat from your exhaust headers. If the voltage drop is gradual with engine speed increase and the voltage increase is gradual with engine speed decrease then I suspect the voltage regulator is functioning normally and there is a voltage remote sensor problem. Measuring the voltage at the remote sense terminal of the voltage regulator would be enlightening. If the voltage drop/increase is a large step then I suspect the voltage regulator is overheating. One reason I prefer cast manifolds over headers is because of their lower heat loss. But in the case of the V8 stock manifolds (pathetic) the performance improvement of the headers forces their use. I have less heat with my V6 stock manifolds and a custom voltage regulator. Many high output alternators come with upgraded voltage regulators. Is there room for a heat shield between the alternator and the header?

Dono · August 5, 2015

Dale, Can you find an upgraded regulator for the 4g? I am having no luck.
I'm surprised I can't find anywhere that someone has moved the regulator and rectifier to external. Once external, you have tons of options.

edit:
I have to wonder if this would be whats required to use an external regulator:
http://store.alternatorparts.com/partnof796bnc.aspx
Then, with adding a second heavy duty external rectifier everything would be moved outside of the alternator.

vroomzoomboom · August 5, 2015

Well, I want to believe that as well, and unfortunately I don't have any logs from when the 302 was in, but you would have to think there would have been a problem with it as well. I never saw any problems when that motor was in, even driving to PA and back. However that was also before the m112 was on it to. Keep in mind however, I had mentioned that my old stereo had a setting on it that displayed voltage, and never notice a problem until the 347 went in. I'm not saying by any means your theory is wrong, and I do honestly welcome any ideas. One big problem with me is I have a very hard time understanding anything electrical on any vehicle. Need a quarter panel welded on? No problem. Need panels made? No problem. Need a trans or motor swapped out? No problem. Need a blower mount made? No problem. Need a electric dohicky figured out?.......PROBLEM!!!! I am going to run down to the local auto electic place in town after work with the truck and see if they have any ideas, because all of this confuses the crap out of me lol

Turdle · August 5, 2015

We all want to help, and I know sometimes suggestions made will ruffle feathers when the recipient doesn't understand the "logic" from the contributors head.

Ok, that being said, it sure does seem to me like the TPS is "shorting" the circuit and causing a drain of power.

However, if this was the case all that current would surely burn the wiring.

I still do not understand though, does this occur with the key on engine off also? If the engine is not running, does the voltage drop if you move the TPS to WOT?

Or, is this occurring at an RPM range? Does the rev limiter play a role in this at all?

I wonder what would happen if an old school 1 farad audio capacitor was added in. If the line voltage drops below 12 with one of those installed something real weird is going on. Seriously, a battery voltage drop that low very quickly seems odd to me. That is like a high powered amp hitting deep bass. A lot of current being drawn in a very short time. How many amps does the METH kit draw?

vroomzoomboom · August 5, 2015

If I sound ruffled to some of you, point it out! I don't want anyone to think that.
I guess I could see if it would datalog with the motor not running. Never thought of that. Also, I do have a cap for my amps. Like John said, those logs are with the cap hooked up (I keep forgetting about it). I'm not sure how may amps the meth pump draws. I will have to look into it. If I am not wrong there is a 15 amp fuse on its controller

Dono · August 5, 2015

Jon summed it up. Were all looking for a solution.
Is it the charging circuit at fault, or is there truly that much draw at wot?
I guess we all need to step back a bit and troubleshoot before drawing conclusions.

CDW6212R · August 5, 2015

I'm also setting back and hoping to see a solution.

My one thought is that if the voltage drop was possible to separate from the PCM(it controls so much), then a device like the farad caps could be used to supply the ignition current, or more. I know race cars with older ignition systems have the option to install 16v supply devices. Those are fed with normal main power cables, but the loads(ignition etc) are fed solely by that 16v source. I always thought those were a glorified super regulator, just a more stable voltage source. Racing needs that, ignitions draw a lot of current.

2000StreetRod · August 5, 2015

big load at WOT

Here's a plot of my engine start.

Battery voltage drops to 10.6 v when the starter is cranking. That is comparable to your V8 and we both have 4 gauge wire to the starter. The PCM current increases with engine speed (but not significantly) because of the increase in fuel injector duty cycle. If you had a high resistance connection to the PCM (bad ground, poor diode, bad relay contacts) it would make the voltage reading inaccurate. However, your voltage readings indicate to me that isn't a problem.

The starter probably draws around 200 amps from the battery. When the engine isn't running the alternator isn't providing current. Your PCM voltage dropping to around 11.5 or so at WOT makes me think a load of around 100 amps or more is occurring at WOT that isn't present otherwise.

vroomzoomboom · August 5, 2015

well, making it to the auto electric shop wont happen. raining right now. i will go and do a log of the truck off, and at WOT. i will see if i can do a start up as well (i dont think it will do a start up, something tells me it resets the sct when you do that). i think my next thing might be is to pull the meth pump off and do a datalog and see what it does, or the fans. those are the only 2 major electronic upgrades i have done with the stroker in the truck.

2000StreetRod · August 5, 2015

power sources?

vroomzoomboom said:
. . . i think my next thing might be is to pull the meth pump off and do a datalog and see what it does, or the fans. those are the only 2 major electronic upgrades i have done with the stroker in the truck.

What are the power sources (which fuses) for the meth pump and the fans?

2000StreetRod · August 5, 2015

external diodes & voltage regulator

Dono said:
Dale, Can you find an upgraded regulator for the 4g? I am having no luck.
I'm surprised I can't find anywhere that someone has moved the regulator and rectifier to external. Once external, you have tons of options.

edit:
I have to wonder if this would be whats required to use an external regulator:
http://store.alternatorparts.com/partnof796bnc.aspx
Then, with adding a second heavy duty external rectifier everything would be moved outside of the alternator.

I looked online at Quick Start's high output alternators when I was researching my upgrade. The titles mention an upgraded voltage regulator but I didn't find a model with one when reading the details. Even their 250 amp alternator with the external rectified kit had the standard voltage regulator. After visiting awhile with Tom Coker (Carolina Alternators) I realized he was very knowledgeable and trusted him to assemble mine. He researched each component to determine what was available from suppliers and ordered the best parts to satisfy my desires. I did not want to lose engine compartment space to an external voltage regulator or rectifier.

The solid state voltage regulator in the 4G is fairly sophisticated using pulse width modulation to avoid sudden load on the engine at start and when a large load kicks in. The charge indicator will illuminate when the alternator voltage output is too low and I think when the output voltage exceeds a specific value (maybe 16.5 v). Some of the most sophisticated features are not implemented in the stock voltage regulator but mine may have one or more of them.

supercharged 5.0 true fire 98 explorer sport

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