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Discussion Starter #1
Why does the 2.7 l trep seem like it has such a weak electrical system? Does anyone know a remedy to this problem? Mine is an 04 es if that is any help....
 

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What you mean by weak?

If you're referring to the headlight flicker when you step on the brakes, I find the LH has a "laggy" voltage controller. Meaning when voltage drops from a load, it takes a split seconds before it ramps up the alternator to compensate.

The alternator itself is not weak. My 160 amp police alternator still flickers...
 

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Discussion Starter #3
Exactly what I mean. When you roll a window up and it comes to close the motor Boggs down and it doesnt ramp the motor up to compensate. I bought my car used and haven't replaced the alternator yet (but plan to) but im pretty sure its a stock alt at I believe 130 amp. The highest I could find at any napa or hardware store is136a. I actually found a place online that would rewire the alt to put out 200amps. They are asking over 600$ for it. From what I've read though, it seems the voltage regulator would not be able to handle it. Or would it? If not is there anyway to upgrade that without replacing the ecm?
 

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I don't think it has anything to do with the 2.7 or the alternator that comes with it. If you measure the alternator's voltage output while the window motor was stalling, it would probably be in spec. IOW - the alternator isn't bogging down - it's more likely that the window mechanism is binding a little. The window motors are the same regardless of the engine, and they are a little on the weak side (and the window mechanisms can get draggy).
 

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I actually found a place online that would rewire the alt to put out 200amps. They are asking over 600$ for it.
there are places on ebay, etc that have amps of up to 250. and cheaper than $600.
i have a 250 amp in my lhs.
 

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Discussion Starter #7
you talking about AMPS, or ALTS HRM?

He neeeds a new alternator.

Idk how to add the fancy quote thing but thats what i was thinking. I put a new battery in it thats probably bigger than should be in it. 1000 cca, not a deep cycle but will get eventually. Peva, Im not worried about the window motor either. Im talking about anything that runs off the electrical system I.e. cooling fans, multiple window operation, heater, radio...anything that puts any stress on the alt that makes the rpm's drop. (An obvious sign that the alternator is being worked but non of these should put that kind of stress on it. I plan on replacing the alt with a high output(if I can find one cheaper than 600$) I guess what im asking is if I do get a h.o. alternator will it fry the voltage regulator in the ecm?

Hrmwrm

Where is this 250 amp alternator? Can u post a link? Remember this a 2.7 trep...smaller motor than the Lhs 3.2's and 3.5's. Thanks everyone for the input!!
 

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...Idk how to add the fancy quote thing...
Click the >QUOTE"< button at the bottom of the post you want to quote. You can delete what you don't need between the 'quote' bookends to leave only what you're going to comment about. I always put '...' before and/or after any part remaining when I delete part of the complete quote - just like I did on what I quoted from your post.

Peva, Im not worried about the window motor either. Im talking about anything that runs off the electrical system I.e. cooling fans, multiple window operation, heater, radio...anything that puts any stress on the alt that makes the rpm's drop. (An obvious sign that the alternator is being worked but non of these should put that kind of stress on it....
If the alternator were not able to handle the load, that would cause the voltage to drop and the load on the engine would be less than if the alternator were maintaining the system voltage under that added load. I don't know how much drop in rpm you're seeing, but if it's significant, that is an indication that the IAC (Idle Air Control) motor (the thing that closes the loop on engine rpm based on the set point programmed into the PCM) is not working properly - usually needs cleaning.

You're saying that the idle drops simply from turning the radio on? Unless you have the volume turned up, I wouldn't expect the radio to be enough of a load to affect the idle noticeably. The engine cooling fans and cabin fans, yes, but not the radio.

I plan on replacing the alt with a high output(if I can find one cheaper than 600$)
If you do and nothing else is changed, I predict that the same thing will happen because the turning on of additional loads will still be transferred to the engine, and the "beefier" alt. will do an even better job of transferring those loads to the engine.

I guess what im asking is if I do get a h.o. alternator will it fry the voltage regulator in the ecm?
I don't think the higher power alt. demands any more field current, which is the load on the regulator circuit of the regulator circuit. I could be wrong, but I think at a given field current (controlled by the regulator circuit), the higher amp alt. puts out a higher current than the standard alt. for the same field current. But even if that's not true, I haven't read of any problems with the regulator when people have put in the higher current alts.

...Remember this a 2.7 trep...smaller motor than the Lhs 3.2's and 3.5's.
Exactly. That means that for a given added electrical load transferred to the engine, that's harder for the 2.7 to compensate for. *But*, the IAC motor is supposed to close the loop and add more air for more power (fuel) to keep the idle steady. That's why I wonder if your IAC needs to be cleaned.

I'd be curious to know what the system voltage is with minimum loads turned on (1) with the engine at idle, and (2) with the engine at about 2000 rpm, and what happens to the system voltage when you turn on a heavy load (cabin fan to high speed) (3) with the engine at idle, and (4) with the engine at about 2000 rpm. If the voltage is to spec. (between 13.5 and 14.5), then that would confirm that the alternator is doing its job.
 

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I had some gremlins in my electronics recently...One day, out of the blue, the rear drivers' side door locked (the lock has been dead for years). The passenger door wasn't unlocking all the way, so when you go to open the door, the lock snaps back shut. Then, the right turn signal blinked really rapidly, indicating a short or blown relay somewhere. The next morning, everything was a-ok...still need to replace a couple bulbs, but everything is back to normal.
 

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Dujack,

IMHO your alternator is not at fault - the window "bogging down" is the weak motor / mechanism common with a lot of Chrysler cars. It's your money, but I'd hate to see you spend a couple hundred and come back saying the window is not fixed.

If you're planning on extra lighting or sound system that's one thing, but stock, the alternator is perfectly capable of running every option on the car. I'm telling you from experience - a HD police 160A alternator still lags.

You can blame the lag on a laggy voltage controller (built into the ECU, can't change) or thin gauge wires (can fix), but it has nothing to do with the alternator being underpowered. 120A is a healthy size alternator.
 

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Kind of what I've told him, RJ. I also told him how to prove or disprove that the alt. is the problem by measuring the system voltage with and without loads applied at idle and at 2000 rpm.
 

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Where is this 250 amp alternator? Can u post a link? Remember this a 2.7 trep...smaller motor than the Lhs 3.2's and 3.5's
actually got it off of ebay. just search around. don't know if there are higher amp alts for 2.7's, but i assume somebody must make them.
when i upgraded my stereo, i went for a higher output amp.
 

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Discussion Starter #13
I'm back

Click the >QUOTE"< button at the bottom of the post you want to quote. You can delete what you don't need between the 'quote' bookends to leave only what you're going to comment about. I always put '...' before and/or after any part remaining when I delete part of the complete quote - just like I did on what I quoted from your post.

If the alternator were not able to handle the load, that would cause the voltage to drop and the load on the engine would be less than if the alternator were maintaining the system voltage under that added load. I don't know how much drop in rpm you're seeing, but if it's significant, that is an indication that the IAC (Idle Air Control) motor (the thing that closes the loop on engine rpm based on the set point programmed into the PCM) is not working properly - usually needs cleaning.

You're saying that the idle drops simply from turning the radio on? Unless you have the volume turned up, I wouldn't expect the radio to be enough of a load to affect the idle noticeably. The engine cooling fans and cabin fans, yes, but not the radio.

If you do and nothing else is changed, I predict that the same thing will happen because the turning on of additional loads will still be transferred to the engine, and the "beefier" alt. will do an even better job of transferring those loads to the engine.

I don't think the higher power alt. demands any more field current, which is the load on the regulator circuit of the regulator circuit. I could be wrong, but I think at a given field current (controlled by the regulator circuit), the higher amp alt. puts out a higher current than the standard alt. for the same field current. But even if that's not true, I haven't read of any problems with the regulator when people have put in the higher current alts.

Exactly. That means that for a given added electrical load transferred to the engine, that's harder for the 2.7 to compensate for. *But*, the IAC motor is supposed to close the loop and add more air for more power (fuel) to keep the idle steady. That's why I wonder if your IAC needs to be cleaned.

I'd be curious to know what the system voltage is with minimum loads turned on (1) with the engine at idle, and (2) with the engine at about 2000 rpm, and what happens to the system voltage when you turn on a heavy load (cabin fan to high speed) (3) with the engine at idle, and (4) with the engine at about 2000 rpm. If the voltage is to spec. (between 13.5 and 14.5), then that would confirm that the alternator is doing its job.
Hey guys, I'm back. Been a crazy busy summer. I appreciate everyone's input and advice on this issue. Haven't had the time to do any of the upgrades unfortunately. I'm in search of a high output alternator that will put out at least 200 amps and will bolt into and work on my 04 2.7. Idk if that will solve the issue or not but I have a large sound system right now that could use the extra power so I figure why not. Thankyou peva. I'm banking on your wealth of knowledge on the matter at hand and I think you may be right about the IAC possibly being the problem or at least partially at fault. I recently replaced tps and the map sensor and now(only occasionally and at random moments) when I'm at an idle or in park the rpms will start to fluctuate bouncing from 100-1000. It did this till it stalled only once. Most the time I just shut it off and turn it back on and it's fine. So my question to you peva (or anyone else that has experience in this area) is what would be the process of cleaning/replacing the IAC? I'm pretty sure you have to remove the upper intake manifold which will require a new plenum or gasket....possibly other seals??? Thankyou again everyone!!
 

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...So my question to you peva (or anyone else that has experience in this area) is what would be the process of cleaning/replacing the IAC? I'm pretty sure you have to remove the upper intake manifold which will require a new plenum or gasket....possibly other seals??? Thankyou again everyone!!
You do not have to remove the plenum to remove the IAC motor. On the 3.2/3.5, you have to remove the throttle body to remove the IAC motor, but on the 2.7, you don't even have to do that. Just remove the IAC screws and remove it. Clean the IAC plunger and tip and the air passage in the throttle body with a good fuel injector-safe throttle body/intake cleaner.
 

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Discussion Starter #15
Haha I feel like such a moron lol. I can't believe I didn't see those bolts. Well this just got a whole lot easier lol. Thanks a million peva!!
 
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