I don't know what's up with my car but under 800rpm/idle my electrical system surges. I don't know what the heck is going on. The alternator works I'm sure of it. I'm just not sure it's the correct alternator. Here's the deal, my car broke down last year about this time and I had to get a new alternator so at a local rink dink texaco I had an alternator installed with it's own pulley. I'm going to check the pulley size to my old alternator but I can't figure out why it turns on and off at low rpm. It's really bad, all my friends point it out and you can even feel the rpm dip a little and come back up etc. I have a brand new red top battery so that couldn't be the problem. Any ideas? Anything you can sugest I check? I have a multimeter and am very comfortable with it so please tell me what I can do to pin point this annoying voltage drop. Thanks in advance.

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

Jp, Sounds like we are having a Similar problem. I suspect My alt but Im not sure, check out My thead if you get a chance.

Mine goes to the extreme of dying at idle occasionally however, And I am experiancing some slow Starting.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

My starting is great, engine starts great and the car runs great except when the rpms get too low. It's even worse when I turn on my indicators. It just dips way down to 11 volts and then comes back up when the engine surges a little (probably the IAC) but still, it's been doing this before and after the engine swap. Nothing is wrong with it above 1000rpm but it's when I'm at a stop light and have an indicator on the thing just dips so low and my lights all dim. I don't even have my stereo in yet.

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

So does anybody think there is a problem or is this normal operation? I don't remember it being this bad when I had the older alternator.

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

Well after getting a test on the Chargeing system in Mine, My alt is working perfectly.


It still does it, So Im out of Ideas, Someone help me and JP out )

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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Anybody have any ideas or past experience with the low idle low volts surge thing?

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

Go thru and check all the ground wires for engine/battery. Clean them up nice, and see if that does not help some.

Good luck

 

Already did that when I did the engine swap. This alternator was doing the same thing with my old engine. All the grounds are good, I checked with a multimeter. Like I suspect before, could it be that the alternator is turning off at low rpm? Then starting back up after 1000rpm! Is that normal to have such a surge in voltage increase? It's just really pissing me off when I'm indicating at a stop light and my volts dip to 11 every blink! So I guess NOBODY has every had this problem before or what?

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, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

sounds like the same thing mine is doing. i have a 91 z28 5.7 and have went through 4 alts in 1.5 years. if you find the answer please let me know

 

I know you probably checked this already, but, since you asked..... yes, I had alternator problems before. Once it was just an old belt that needed to be replaced (even though the old one was nice and tight and didn't squeal). Another time it was the electrical connector coming off the alt, which was worn, and I had to shove it in a certain way to get a good connection, at which point you could actually hear the idle increase.

 

It really sounds like a short somewhere. Extreme current draw creates strain on the alternator, it exhibits this as a braking force on the engine, causing the rpms to drop, ECM sees a drop in RPM and uses the IAC and maybe a little extra gas from the injectors to bring it back up, often overcompensating so you get a mild surge. if you are 100% that no wires have been cut, and cuold be making a short, and all your wires are sparkling clean, the alternator is new or tests OK, try checking the voltage regulator. Easy way (Maybe not, I think as soon as I get my service manual back, I'll actually check how easy this is) Get a can or air, hold it upside down so the cold stuff comes out, spray it on the reg, not to the point of condensation, but cooling the reg. If the problem goes away, you definatly have a bad reg, if it doesn't help, you still may have a bad reg. Otherwise, are you sure the electrical system is the problem and not the engine, if the engine stumbles your voltage will to and you could be barking up the wrong tree. My cars lights dim, radar detector resets, etc, when I slow down due to the still bad FPR. (just an example) Anything above idle, it's ok.
Hope this helps ya. Post the results


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Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
SLP 1 3/4" headers, 3" cat back (stock cat )MSD ignition. MSD Blaster SS coil. More soon when funds are avail...

 

I had the same problem on my RS. When it warmed up (after about 10 minutes) it started doing it. The volts were low (around 12 sometimes 11) and the headlights would dim. As soon as you touched the gas the lights flared and volts went up to 14. I lived for years with this as the cheapie rebuilt alternator I got... I figured it was good and this was normal. Finally the bearing were squealing terrible after it rained so I replaced it anyway (hoping to kill 2 problems) with a Duralast from autozone. Never had a problem yet and volts stay at 14.4 no matter what I do. They do something to them because on the box it stated they charge well at idle unlike many other rebuild brands....

Well I believe them now. Unless you have performance pullies you might want to check into one. They're lifetime warrented so it'll be the last one you buy (as long as autozone stays open)

Don't get their lower priced one!!! It's $40 less but there's a reason!!!