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2008 Challenger SRT8 #1101
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Discussion Starter #1 (Edited by Moderator)
So a last fall I was driving my Challenger and the entire Dash was flashing on and off and the engine power dipped and then seemed to go back to normal.

It has done that a couple times now sporadically but this year when I took it out of winter storage (on a battery tender),
It felt like it was running kind of "choppy" when idling. 2 days later from that drive and my battery was dead.

I'd just finished replacing all my spark plugs and boots on her previously.

Went ahead and replaced/upgraded my battery to:

Exide 800CCA Marathon Max AGM

I thought I had it licked as it seemed to drive pretty well after that. Then I tried to take it out today and the choppiness resumed so I believe it's probably my alternator.

I plan to be adding later on an additional trunk subwoofer with amp so thought I'd ask.

What is the best alternator to get knowing I might be adding some more power requirements?

Mopar or Aftermarket?
Amp Ratings?

I see that on Steve White Parts shows my replacement to be a 4896805AE for $281.88.
Other sites have spec'd this at 160Amps but I thought I'd read on other threads that there were 220amp models for the SRT's.

Luke, (or anyone) can you shed any insight?

I could go to the same original one but I always like to take the opportunity at the same time to see if an upgrade is in order.

Additionally, while I'm changing this out, are there any related ground wires/straps that I should consider changing or upgrading in some way?


She's only at around 36k miles btw

Thanks,
Jeremy

20200712_212346_HDR.jpg
 

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Have only had to replace one alternator in a car.

The options wer:

Buying a rebuilt alternator. I'm talking about you hand over your alternator as a core and get someone else's alternaotr -- rebuilt -- in exchange, plus of course you have to pay money too. Years ago my auto tech buddies told me this is generally the worst way to go for reasons I won't elaborate on unless asked.

Next is having your bad alternator rebuilt. Generally there are shops -- at least one -- in every major metro area and even smaller metro areas that specializes in rebuilding alternators. (Other shops may specialize in starters, power steering pumps, A/C compressors, etc.) As long as the alternator hasn't shredded itself generally rebuilding it is best. But not cheap.

Next is a factory rebuilt alternator. This is generally a better quality rebuild than one can get from a place that just takes your alternator as a core and gives you somebody else's rebuilt alternator. Plus with a factory rebuilt most of the time they come with a warranty.

Another option is a new one, OEM (but probably not OE). These can be pretty expensive too and may or may not come with much warranty.

Last is an OE alternator. $$$$ but almost certainly with a warranty. If done at a dealer parts and labor.

My two choices were factory rebuilt and new (OE). I went with the factory rebuilt alternator. Techs told me these were of high quality but of course not cheap. But less money that a new OE alternator. The factory rebuilt unit came with a 2 year 24K mile warranty.
 

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The Pork Wagon (‘14 Cop Charger)
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So a last fall I was driving my Challenger and the entire Dash was flashing on and off and the engine power dipped and then seemed to go back to normal.

It has done that a couple times now sporadically but this year when I took it out of winter storage (on a battery tender),
It felt like it was running kind of "choppy" when idling. 2 days later from that drive and my battery was dead.

I'd just finished replacing all my spark plugs and boots on her previously.

Went ahead and replaced/upgraded my battery to:

Exide 800CCA Marathon Max AGM

I thought I had it licked as it seemed to drive pretty well after that. Then I tried to take it out today and the choppiness resumed so I believe it's probably my alternator.

I plan to be adding later on an additional trunk subwoofer with amp so thought I'd ask.

What is the best alternator to get knowing I might be adding some more power requirements?

Mopar or Aftermarket?
Amp Ratings?

I see that on Steve White Parts shows my replacement to be a 4896805AE for $281.88.
Other sites have spec'd this at 160Amps but I thought I'd read on other threads that there were 220amp models for the SRT's.

Luke, (or anyone) can you shed any insight?

I could go to the same original one but I always like to take the opportunity at the same time to see if an upgrade is in order.

Additionally, while I'm changing this out, are there any related ground wires/straps that I should consider changing or upgrading in some way?


She's only at around 36k miles btw

Thanks,
Jeremy

View attachment 998030
You should verify the current alternator is unable to adequately power the car while running plus keep the battery charged before replacing it.

If the electrical/charging system is the culprit for the episodes you mentioned, I would expect one or more DTCs (P0622, P0623, etc) to be stored in the PCM in relation to those episodes.

If you have none, or you have no charging system related codes, and you never saw the red battery light illuminate on the dash during all this, I would not suspect the alternator as being bad or going bad here.

If you do end up replacing the alternator, you can upgrade to a 180 amp or 220 amp alternator if you wish, but you won’t necessarily need a bigger one just because you are adding an aftermarket amplifier to power a sub.

If the amp is sufficiently power-hungry that it is causing headlight dimming during heavy use, then a beefier alternator could help, but so can other things.
  • adding another (or replacing with a bigger one altogether) ground cable for the negative battery post to chassis ground connection.
  • adding/upgrading the engine to chassis ground straps.
  • cleaning/replacing the B+ connection part of the wiring harness that plugs into the back of alternator.
But all of this is theoretical without knowing the output of your alternator now. Check it with accessories off and engine idling, and check it with accessories on and engine at 2000 RPM. And make sure to measure the voltage at the battery posts too.

If you see less than 13.5v at idle or less than 13.8v at 2K RPM, there a problem somewhere in the charging system probably. Isolating it and fixing before continuing would highly advisable at that point.
 
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Premium Member
2008 Challenger SRT8 #1101
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341 Posts
Discussion Starter #4
You should verify the current alternator is unable to adequately power the car while running plus keep the battery charged before replacing it.

If the electrical/charging system is the culprit for the episodes you mentioned, I would expect one or more DTCs (P0622, P0623, etc) to be stored in the PCM in relation to those episodes.

If you have none, or you have no charging system related codes, and you never saw the red battery light illuminate on the dash during all this, I would not suspect the alternator as being bad or going bad here.

If you do end up replacing the alternator, you can upgrade to a 180 amp or 220 amp alternator if you wish, but you won’t necessarily need a bigger one just because you are adding an aftermarket amplifier to power a sub.

If the amp is sufficiently power-hungry that it is causing headlight dimming during heavy use, then a beefier alternator could help, but so can other things.
  • adding another (or replacing with a bigger one altogether) ground cable for the negative battery post to chassis ground connection.
  • adding/upgrading the engine to chassis ground straps.
  • cleaning/replacing the B+ connection part of the wiring harness that plugs into the back of alternator.
But all of this is theoretical without knowing the output of your alternator now. Check it with accessories off and engine idling, and check it with accessories on and engine at 2000 RPM. And make sure to measure the voltage at the battery posts too.

If you see less than 13.5v at idle or less than 13.8v at 2K RPM, there a problem somewhere in the charging system probably. Isolating it and fixing before continuing would highly advisable at that point.
Thanks, I'll check the things out you mentioned starting with a code diagnostic..
 

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2008 Challenger SRT8 #1101
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341 Posts
Discussion Starter #5
Finally located my obd reader and these were my stored codes:

(I think I would rather replace my alternator than figure all of these out).

P0300 - Random Multiple Misfire Detected

P0302 - Cylinder 2 Misfire Detected

P0031 - HO2s Heater Control Circuit Low (Bank 1, Sensor 1)

P0037 - HO2s Heater Control Circuit Low (Bank 1, Sensor 2)

P0051 - HO2s Heater Control Circuit Low (Bank 2, Sensor 1)

P0057 - HO2s Heater Control Circuit Low (Bank 2, Sensor 2)

U0100 - Lost Communication with ECM/PCM

More history:
Everything was completely fine when I put her up for the winter. (Although one time while driving last fall I had a very momentary flash of every dash light and then returned to normal. Thought maybe that was a 'twitch' in the voltage regulator or something)

I started her up this summer and idle seemed low and "choppy" feeling. I already had new plugs and boots so got all those changed hoping it was a fouled plug or something. Kept on a trickle charger while in storage. Despite this, after my first drive this year, tried to start 2 days later and battery was too low so I thought there might be a charging issue. Not knowing if my charger might have caused some I'll effects or how old the BATTERY really was, decided to start with replacing the BATTERY. Also freshened up the fuel in case any issue there.

20200712_212326_HDR.jpg
 

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Finally located my obd reader and these were my stored codes:

(I think I would rather replace my alternator than figure all of these out).

P0300 - Random Multiple Misfire Detected

P0302 - Cylinder 2 Misfire Detected

P0031 - HO2s Heater Control Circuit Low (Bank 1, Sensor 1)

P0037 - HO2s Heater Control Circuit Low (Bank 1, Sensor 2)

P0051 - HO2s Heater Control Circuit Low (Bank 2, Sensor 1)

P0057 - HO2s Heater Control Circuit Low (Bank 2, Sensor 2)

U0100 - Lost Communication with ECM/PCM

More history:
Everything was completely fine when I put her up for the winter. (Although one time while driving last fall I had a very momentary flash of every dash light and then returned to normal. Thought maybe that was a 'twitch' in the voltage regulator or something)

I started her up this summer and idle seemed low and "choppy" feeling. I already had new plugs and boots so got all those changed hoping it was a fouled plug or something. Kept on a trickle charger while in storage. Despite this, after my first drive this year, tried to start 2 days later and battery was too low so I thought there might be a charging issue. Not knowing if my charger might have caused some I'll effects or how old the BATTERY really was, decided to start with replacing the BATTERY. Also freshened up the fuel in case any issue there.
Have you checked wiring for any signs of rodent damage?

What is the freeze frame code? This is the code that caused the CEL to come on and the code which can provide a clue to the underlying problem.
 

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2008 Challenger SRT8 #1101
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Discussion Starter #7
I hadn't heard of the freeze frame code before. I will look tonight and see if my reader can pull that up.
 

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2008 Challenger SRT8 #1101
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Discussion Starter #8
I found my reader on Amazon and it's the app that shows that information. I will purchase Torque Pro to view that data and report back. Thanks for mentioning that might be of help!
 

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Hope you don't mind a different question, Ashoka, but seeing the spark plugs, are they hard to change ? I think I remember seeing the coils. You take those off and the spark plug is under there? Cool pics.
You know, i thought my alternator was going bad on my 1998 Jeep Wrangler. It was wonky and fluctuating power. I send the ECM off to be tested, $25 bucks, but it was certified as fine. I started messing with the ground wire to the frame to the alternator. I made a new ground wire and connected to another spot on the fender, bare metal, and voila. 13.8 volts.
Cleaned all my grounds, and added two. That was two years ago, and still no issues. Alternator is a Denso on the Jeep, 22years old and 136k miles , rock solid. It says made in USA on the alternator.

Maybe you have already set up a new ground wire, as a test?
I hope it works out and you don't have to buy a new alternator,
best regards
Parrott
 

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The Pork Wagon (‘14 Cop Charger)
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6,861 Posts
Finally located my obd reader and these were my stored codes:

(I think I would rather replace my alternator than figure all of these out).

P0300 - Random Multiple Misfire Detected

P0302 - Cylinder 2 Misfire Detected

P0031 - HO2s Heater Control Circuit Low (Bank 1, Sensor 1)

P0037 - HO2s Heater Control Circuit Low (Bank 1, Sensor 2)

P0051 - HO2s Heater Control Circuit Low (Bank 2, Sensor 1)

P0057 - HO2s Heater Control Circuit Low (Bank 2, Sensor 2)

U0100 - Lost Communication with ECM/PCM

More history:
Everything was completely fine when I put her up for the winter. (Although one time while driving last fall I had a very momentary flash of every dash light and then returned to normal. Thought maybe that was a 'twitch' in the voltage regulator or something)

I started her up this summer and idle seemed low and "choppy" feeling. I already had new plugs and boots so got all those changed hoping it was a fouled plug or something. Kept on a trickle charger while in storage. Despite this, after my first drive this year, tried to start 2 days later and battery was too low so I thought there might be a charging issue. Not knowing if my charger might have caused some I'll effects or how old the BATTERY really was, decided to start with replacing the BATTERY. Also freshened up the fuel in case any issue there.

View attachment 998732
Having all 4 O2 sensors throw low voltage codes is telling...if you can retrieve the freeze frame data, do that and then clear all the codes. Drive the car and watch the voltage output with your ODBII reader. Make sure it never dips below 13.8 while running. If at any point it does, replace the alternator.
 

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2008 Challenger SRT8 #1101
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341 Posts
Discussion Starter #11
Freeze frame report generated by Torque for Android
=========================================================

Vehicle VIN: 2B3LJ74W98H291723
Vehicle Manufacturer: Dodge
Vehicle Calibration ID: 68004368AD
3

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 42.353 %
Engine Coolant Temperature = 86 °F
Fuel Trim Bank 1 Short Term = -10.938 %
Fuel Trim Bank 1 Long Term = 0 %
Fuel Trim Bank 2 Short Term = -10.938 %
Fuel Trim Bank 2 Long Term = 0 %
Intake Manifold Pressure = 6.962 psi
Engine RPM = 229 rpm
Speed (OBD) = 0 mph
Timing Advance = 6.5 °
Intake Air Temperature = 78.8 °F
Throttle Position(Manifold) = 15.686 %
Run time since engine start = 48 s
Fuel Level (From Engine ECU) = 91.765 %
Barometric pressure (from vehicle) = 14.214 psi
Voltage (Control Module) = 14.144 V
Engine Load(Absolute) = 28.235 %
Commanded Equivalence Ratio(lambda) = 1
Relative Throttle Position = 5.49 %
Ambient air temp = 80.6 °F
Absolute Throttle Position B = 15.686 %
Accelerator PedalPosition D = 8.627 %
Accelerator PedalPosition E = 4.314 %


End of report.
 

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Premium Member
2008 Challenger SRT8 #1101
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341 Posts
Discussion Starter #12
Hope you don't mind a different question, Ashoka, but seeing the spark plugs, are they hard to change ? I think I remember seeing the coils. You take those off and the spark plug is under there?
Yep they are under the coil packs. You just remove the 2 bolts and when you pull up, the entire boot pulls up off the plug.


These tools helped me immensely while doing this:

GEARWRENCH 3 Pc. 3/8" Drive Impact Locking Extension Set 3", 6" & 12" - 84927N

Neiko 02486A Impact Universal Joint Socket Swivel Set, 3 Piece, Cr-Mo, 1/4, 3/8, 1/2" Drive, Black

GEARWRENCH 3/8" Drive 6 Pt. 5/8" x 6" Magnetic Swivel Spark Plug Socket - 80546
 

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2008 Challenger SRT8 #1101
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341 Posts
Discussion Starter #13
Having all 4 O2 sensors throw low voltage codes is telling...
And what does that tell you if I might ask?
 

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The Pork Wagon (‘14 Cop Charger)
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And what does that tell you if I might ask?
That there was/is a problem with the electrical system as opposed to all 4 sensors going bad at the same time.

If the alternator were bad I would expect it to stay bad, not have a hiccup and then work right. That B+ connecter on the back of the alternator can develop corrosion in the wiring harness and cause the connection to have excessive resistance, to the point it causes problems with the rest of the electrical system, but only intermittently. I would suspect something similar to that over a bad alternator right now.

You can always pull the alternator off and take it somewhere to have it tested. That should rule it out (or confirm it’s the problem) once and for all.
 

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2008 Challenger SRT8 #1101
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Discussion Starter #15
That there was/is a problem with the electrical system as opposed to all 4 sensors going bad at the same time.

If the alternator were bad I would expect it to stay bad, not have a hiccup and then work right. That B+ connecter on the back of the alternator can develop corrosion in the wiring harness and cause the connection to have excessive resistance, to the point it causes problems with the rest of the electrical system, but only intermittently. I would suspect something similar to that over a bad alternator right now.

You can always pull the alternator off and take it somewhere to have it tested. That should rule it out (or confirm it’s the problem) once and for all.
Thanks for pointing that out. I will check that connector first.
 
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