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So I’ve got me a 2002 Buick Park Avenue Ultra 3.8L Supercharged. It has the premium 9 speaker with factory amplifier set up. So, issue is, my right side door speaker (speaker not the tweeter) is pulsating only with the key off engine off. It seems to do it sometimes. And only does it with an aftermarket radio. Now my car was recently broken into and had everything stolen so I’ve changed radios quite a bit. Stock radio, everything is fine. They stole a Kenwood double din I had and it did the same thing. I thought maybe the radio was bad. Then I put in another aftermarket radio and the problem persists. I had changed the wiring harness because they cut up my old one, & the radio is brand new. So I’ve canceled out the radio and harness already. Now this car has the factory amp, if the solder got hot or something can something be shorting out internally? I plan to start get into this Friday, im just waiting to get some electrical diagnosing tools together. I’m typically good with electrical stuff. But I’m stumped on this. It works fine with stock, only acts up with aftermarket head unit. & only the key off. & it’s been killing my car every day causing me to jump it every morning which is becoming a pain. Any ideas or anyone had a similar problem? I don’t have a system or anything everything is stock besides the head unit. Also, when I play with the stock radio harness and instrument cluster harness, I get white noise from all of my speakers. Very very weird. I’ve talked to a buddy and he thinks I may have a bad ground. But if anybody else had a similar issue, some advice would be nice! Thanks in advance!
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Factory amp you say?
It sounds like you know your stuff with car audio. You should know then that pretty much any stock stereo equipment just bites and tends to act stupid. If the speakers, harnesses, and dash unit are changed but that factory amp is original and stock, there lies the problem.
Even if it is a good brand name for factory stereo stuff, it is probably the lower end. I have a Bose system in my Acura which is stock and let’s just say when funds permit, that crap is getting ripped out.
I didn’t change the speakers though nor the stock radio harness. I changed the aftermarket radio harness that plugs into the stock one. The only thing aftermarket is the headunit. & if the amp was bad, you would figure that typically it would be more than one speaker that’s acting up. That’s why I asked if it was possible. I’m not saying I’m an expert. But with school and a bit of experience under my belt, im not dumb founded when it comes to electrical not car audio. The basics at least.
One thing – sorry your car was broken into. Had that happen before and damn does it feel violating. Had $1,000 worth of stuff ripped from a lesabre I used to drive.
It might be possible that the aftermarkets are feeding the factory amp more power than it wants?
With one amp channel on any amp acting stupid –
Keep in mind that with any audio amplifier that has more than one channel, each channel is going to have it’s own power transistor (typically a MOSFET).
Therefore, it is very possible for only one speaker/channel to act up.Of course you should first check ALL wiring and especially connections first.
One thing – when you turn the key on/engine off and play the stereo – what happens in that channel at various volumes? Does the pulsating go away after a certain volume?
Yeah man it really sucks but thanks. They stole my radio, amp, subs, & all my tools. I’m the idiot who left them in his car. But it was over $1000 in just the tools alone. but anyways, no as soon as you turn the key on/engine off, it stops. As soon as the radio gets power again, it goes away. When the radio is getting no power is the only time it pulsates. Other than that, it’s normal. I probably wouldn’t have noticed if my car wasn’t dying every night. I have a video, I was a bit cranky this morning so ignore me if I sound like I have an attitude lol.
Well, the best I can come up with is maybe the amp is compatible with only certain GM stock radios. OR, maybe a wire is crossed somewhere in the connections? That pulse sounds like some kind of signal for something. Like maybe something for the alarm system or to retract a power antenna. TBH I am not sure. Just REALLY check the connections at the harness in the dash.
[quote=”Alex0330″ post=115875]I was a bit cranky this morning so ignore me if I sound like I have an attitude lol.[/quote]
Oh if only you could have heard the things I was saying today when I had to do some EGR passage work on my engine today. :angry: The devil blushed a few times. I smoked a whole pack of 120’s, at the same time!
Yeah I’ve checked the connections and can’t find anything in the work I’ve done. I’m gonna pull off the door panel friday and check if it’s getting power when the cars off. I would assume that’s why it pulsates. But I’m gonna get a test light too and check if I have a short to ground somewhere and go from there. I’ve got a plan, I just don’t know where to start. Lol. But you would figure if the amp wasn’t compatible then somewhere on the Internet i can find SOMETHING. But I cant. I’ve got alldata and checked tsbs looked at wiring diagrams and it seems the problem can only be the amp or a short to the speaker after the amp. & btw what engine and kind of car was it? Lol I’ve had those days before too
The engine was my Acura CL 3.0
The exhaust gas passages tend to get clogged up and it is just a PITA basically. Especially when a stud stripped out and I had to stop and deal with THAT crap. It was about as fun as cleaning dog poop out of shoe treads.
But, the CEL no longer stays lit.So what did you come up with for that pulsating?
Well, unfortunately, nothing. Had the whole car torn apart. Checked all the grounds. Checked all connections and wiring. Everything seemed okay. EVERYTIME I was trying to check power and ground on a speaker while it was pulsating the power probe wa pulsating with it. Lol. I imagine it’s because there’s a speaker inside of it. But I tried for hours and I couldn’t find anything. Then I disconnected the negative battery and put a light bulb in series with the ground ( I didn’t have a test light) and it lit pretty bright. I pulled every fuse, nothing. I cannot figure it out.
I did an amperage draw test though with a meter and draw definetely goes down when I pull the radio fuse. (Amplifier has its own fuse) so im not sure. I had to call it a day because I was getting frustrated and my uncle wanted help working on his semi getting a fan clutch out.
hmm. that is a strange thing. I had my car broken into as well it was 4 years ago. TWICE in 2 days nonetheless. Anyways one thing you can try is just unplug the speaker? Even if there is a problem generally if you take the load away the problem doesn’t happen. It does sound like a AMP issue though. Behind the passenger front seat is the wiring harness for the amp. Water tends to get in there and stand in the floor pan. There is a orange wire in the harness that splits into two. that can get badly coroded. The result usualy is no sound at all however its a place to look.
02 does it have onstar? it could be an issue with that, or a wiring issue, i know you have checked them but for some reason its like the amp is staying on and getting signal for that speaker, ive never seen that before, in almost 20 years messing with car audio and electrical ive never seen that.
So, I’m back! Figured out its the amp. It’s not shutting itself off when I turn off the car. That’s why I have my speakers pulsating I’m guessing. Question now is can I just bypass this amp without losing my sound quality? Or should I just get one from the junkyard?
I got here a day late it seems. When speakers pulse like that it’s because they’re receiving a pulsed DC signal. I’m not a fan of integrating aftermarket decks with OE amplifiers (see below), but being that you’ve not upgraded the speakers it does kind of make sense in this case (the stock speakers would likely not benefit much from an aftermarket amplifier).
Here’s a terrifying question. When is a piece of wire more than just a piece of wire, a positive or negative?
When it’s handling communication. 01100011 01110010 01100001 01110000
A series of digital signals.
Try to locate a switched ignition in a newer (turn of the century plus or minus a couple of years and newer) GM vehicle at the radio harness… there aren’t any.
The radio’s receive a CANbus input from the body control module telling them when to turn on and off. That’s why you were supposed to buy that ‘module’ that allows you to connect the switched ignition to your aftermarket deck – the module supplies the switched ignition when it receives the input from the BCM to turn on, and removes it when the BCM says to. Also, If your factory radio stays on with the key in the off position until a door is opened… that’s not done through solid state logic, it’s done via the body control module.
What the heck am I driving at? You may have one heck of a time finding a way to switch the amplifier on and off via your aftermarket deck as it too may be looking for a CANbus signal from the body control module or even worse – the factory deck.
A relay interrupting B+ at the amp using the power antenna signal from your aftermarket deck might be an option, but I suspect you’ll get even more speaker pulsating when you cycle the key on and off as required.
What I’m confused about now is the switched ignition. Are you saying that the red wire off the radio harness isn’t controlled through the actual ignition switch, but rather the bcm? And yes the stock radio even stays on until the door is opened. But the speakers only pulsate with the car off. And it’s not even all the time. Just sometimes. Another thing that threw me off a bit though was that, when I have my aftermarket radio in, my draw is 1.3 amps with the car off. If I put the stock radio in, the draw is around 400 milliamps. Which is still excessive. But lower. And when I just unplug the amp the draw is within spec, for the most part. It’s 70 milliamps. Maximum “acceptable” was 45 milliamps I BELIEVE. It was a while when I looked it up on alldata. But somewhere around there. And wouldn’t you figure then that more people that have these gm stock amps in their cars would have more issues and it would be a more known common issue? I just wanna get this right. I’ve been through 3 optimas in the past year and a half. And my boss won’t warranty them anymore because it’s my fault I haven’t fixed the car yet. Lol.
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