This is in a 1954 Chevy Pickup with a frame off restoration all late model GM V8 rewired etc. I installed an Alpine CDA-9851, a Californian Amp, 2 Sony 5 1/4 inch 3 way speakers and a non- amplified sub woofer tube. Everything works fine except that when I go to idle ( especially with a load like the A/C on) the current seems to drop low wnough that the Alpine starts to cut out and sound terrible. So here's what I've done so far that hasn't helped: Upgraded my alternator to 160 amps with 4 ga. wire, recehecked and added extra grounds between the batt, frame and cab, Rewired the power and ground from the alpine to the batt with 8 ga. wire direct(including a 20 amp fuse). The amp which doesn't seem to be part of the problem is also wireed direct with 8 ga. wire. I have checked with a digital meter and my volts never drop below 13. I would appreciate any suggestions. Thanks.
Replies (12)
UKinstaller on 07/16/2005 22:38:04
where did you tap in for power for the radio at?? try tapping in at your ignition harness if you haven't already.
-UK
Zigrig on 07/16/2005 23:49:50
Thanks UK. I originally had it at the fuse box but moved it to the battery to try to get more power but it didn't help. This is just the yellow and rthe ground. I have the red (switched) at the iginition harness.
swez on 07/17/2005 13:04:18
Have you checked the voltage at the amp to see what it is getting at idle and A/C on? If it drops below 11.5 volts, sound degradation is possible at HU and/or amp.
HU install manual:
http://akamaipix.crutchfield.com/Manuals/500/500CDA9851.PDF
How do you have all speakers wired?
1. HU power
2. Powered off amp
3. Tri-mode, off the amp?
Do you have links on that amp and bass tube?
It sounds like the amp may not be getting adequate power at all times or the way it is wired to speakers may not be optimal. Plenty of ALT power here. (160A) But, how much is actually getting to the amp?
That HU is a pretty solid unit too. It may be part of the issue if not well grounded to body. The power wires sound right, but make sure you have a good bare metal ground for the HU as well.
Finally, what is your engine RPM at idle? If it drops much below 600 RPM in gear with A/C on, may have to bump up the idle speed a tad. ALT output is definitely affected by engine RPM. At idle speeds, the ALT should be putting out close to 50% of full current in amperes. The voltage at idle would ideally be above 13.0 volts.
Swez
PS UK, does this HU have an inline regulator on the power feed wires? I recall ttocs and maybe Less saying it can be removed and performance of the HU will be fine. Comments?
UKinstaller on 07/17/2005 17:29:01
i have yet to see this head unit in person, but the specs say it's 18 watts RMS to each speaker, which shouldn't require an inline regulator on the power wires.
if it does though, you can definitely cut it out with no difference in performance whatsoever. every time i install a head unit with regulators inline on the power wires i cut them out, it's just more clutter to fit behind a dash and it's much harder to make your wires look neat. they're big and hideous.
swez you might be on to something about the low idle RPM, that could definitely cause the problem mentioned.
-UK
Zigrig on 07/17/2005 18:25:27
OK. Re. your questions SWEZ: The speakers are wired Tri-mode off the amp. Does that mean that you think the problem is with the amp and not the HU? The idle speed is set for 600 rpm in drive but I'm not sure if I set it with the A/C on or not I'll check that and the volts at that speed and get back to you. Raising the rpms definately solves the problem but the question will be can I set the idle high enough to avoid the problem at a stop sign and still not have to stand on the brakes with both feet to keep it stopped.
swez on 07/18/2005 09:52:05
Interesting comments here.... Tri-mode works, but we compromise a lot on power and signal quality to the sub(s). The HU has adequate power amps to drive most efficient speakers, right off the HU. (especially rear fill speakers) You may wish to experiment and only power the sub with this amp and let the HU amps take care of full range speakers.
The RPM range will drop when A/C is engaged, unless there is a solinoid actuator to boost RPM when A/C is engaged. Try changing idle speed w/ A/C engaged and in drive to a min of 650, 750 max RPM @ idle. This should help your ALT put out more power.
If that seems to be too much for safe braking, consider using a smaller diameter pulley shieve for this ALT. It will turn the ALT faster at same RPM settings as well.
Comments?
Swez
Zigrig on 07/18/2005 11:25:54
Sounds good. Thanks to you both. I won't be able to get back to it for a couple of days due to scheduling but I will definately try your suggestions and report back with the results. I appreciate the help.
swez on 07/18/2005 16:15:04
Good nuff! Let us know how things turn out as you tweak and such.
Swez
Zigrig on 07/19/2005 19:02:03
Here's the update: Raising the idle helps a lot. However I still had a bit of a problem here and there. I watched closely and during the drop outs the voltage never dropped below 13v. so I think something else is still wrong. Besides, having the idle that high caused the engine to run-on when I turn off the ignition so that's a problem.Here are a couple of things I was wondering abou trying. Let me know your thoughts.
1. I could add an idle solenoid that just kicks in when the A/C compressor is on and that might give me enough bump in RPMs yet still allow me to shut off the engine without run-on.
2. Do you think a bigger battery might help? I tried running the system with the ehgine off and just on Acc. It seemed to work fine so I don't know if that indicates that the battery is big enough.
3. Do you think it would be worth trying removing the amp from the system and running the 3 ways off the head unit to seeif the problem improves? I don't think the HU would have the power to run the sub tube though.
Thanks.
swez on 07/19/2005 22:10:17
The solinoid speed control will definitely help boost idle speed when A/C is activated. Many have adjustment rods that allow user to set idle to desired RPM when A/C is engaged. That's a good, permanent fix. (650-700 RPM should do it, in drive)
The BAT sounds like it's doing its job already if you can get good performance with ACC only. If you have a 600 CCA or higher, should be fine for this smaller system.
Engine run on (dieseling) is common is the throttle plate is open too much when the ignition is shut off. Guess you can't solve the root problem by only changing idle speed. Back to the solinoid idea seems best.
I would suggest running the amp, only for the bass tube. If the bass tube is 4 ohms, you can bridge the amp for MONO bass and double the RMS power to sub. This amp, does it have a good Low Pass Filter? (LPF) If yes, set to 80-100 Hz. That will block all voices and non-bass audio to sub.
At 18 watts (RMS x 4) if you have very efficient speakers, (90dB @ 1 watt) or higher, should get adequate power to drive your speakers to a decent level. Just avoid using too much EQ or Bass Boost to speakers off HU. Setting the bass levels at +3dB is plenty, depending on the crossover frequency you select, (80 - 100 Hz.) and speaker size used. The sub will handle the lows, below 80 Hz.
Finally, the HU should be set to deliver clean mids and highs at about 80% of max volume settings. Much above that number, the HU amps will begin to "clip" and cause harsh sounding mids and shrill highs. Is best to test this outside the vehicle with doors open. Stand to back of vehicle and set your HU to a volume and tone control setting where it's loud, clean and full sounding. Once you have that setting dialed in, bring up the sub amp gain until you get full, clean bass.
Swez
PS Follow these basic steps and I'll bet you $10,000,000.00 Bachese, (10 cents American) the system will sound better than you could have ever guessed. USFLAG
Zigrig on 07/20/2005 09:48:24
Thanks again for the hel SWEZ. I'm sure I will now be able to dial it in.
swez on 07/20/2005 09:57:11
Good luck and keep us posted to your progress OK?
Swez
Replies (12)
UKinstaller on 07/16/2005 22:38:04
where did you tap in for power for the radio at?? try tapping in at your ignition harness if you haven't already.
-UK
Zigrig on 07/16/2005 23:49:50
Thanks UK. I originally had it at the fuse box but moved it to the battery to try to get more power but it didn't help. This is just the yellow and rthe ground. I have the red (switched) at the iginition harness.
swez on 07/17/2005 13:04:18
Have you checked the voltage at the amp to see what it is getting at idle and A/C on? If it drops below 11.5 volts, sound degradation is possible at HU and/or amp.
HU install manual:
http://akamaipix.crutchfield.com/Manuals/500/500CDA9851.PDF
How do you have all speakers wired?
1. HU power
2. Powered off amp
3. Tri-mode, off the amp?
Do you have links on that amp and bass tube?
It sounds like the amp may not be getting adequate power at all times or the way it is wired to speakers may not be optimal. Plenty of ALT power here. (160A) But, how much is actually getting to the amp?
That HU is a pretty solid unit too. It may be part of the issue if not well grounded to body. The power wires sound right, but make sure you have a good bare metal ground for the HU as well.
Finally, what is your engine RPM at idle? If it drops much below 600 RPM in gear with A/C on, may have to bump up the idle speed a tad. ALT output is definitely affected by engine RPM. At idle speeds, the ALT should be putting out close to 50% of full current in amperes. The voltage at idle would ideally be above 13.0 volts.
Swez
PS UK, does this HU have an inline regulator on the power feed wires? I recall ttocs and maybe Less saying it can be removed and performance of the HU will be fine. Comments?
UKinstaller on 07/17/2005 17:29:01
i have yet to see this head unit in person, but the specs say it's 18 watts RMS to each speaker, which shouldn't require an inline regulator on the power wires.
if it does though, you can definitely cut it out with no difference in performance whatsoever. every time i install a head unit with regulators inline on the power wires i cut them out, it's just more clutter to fit behind a dash and it's much harder to make your wires look neat. they're big and hideous.
swez you might be on to something about the low idle RPM, that could definitely cause the problem mentioned.
-UK
Zigrig on 07/17/2005 18:25:27
OK. Re. your questions SWEZ: The speakers are wired Tri-mode off the amp. Does that mean that you think the problem is with the amp and not the HU? The idle speed is set for 600 rpm in drive but I'm not sure if I set it with the A/C on or not I'll check that and the volts at that speed and get back to you. Raising the rpms definately solves the problem but the question will be can I set the idle high enough to avoid the problem at a stop sign and still not have to stand on the brakes with both feet to keep it stopped.
swez on 07/18/2005 09:52:05
Interesting comments here.... Tri-mode works, but we compromise a lot on power and signal quality to the sub(s). The HU has adequate power amps to drive most efficient speakers, right off the HU. (especially rear fill speakers) You may wish to experiment and only power the sub with this amp and let the HU amps take care of full range speakers.
The RPM range will drop when A/C is engaged, unless there is a solinoid actuator to boost RPM when A/C is engaged. Try changing idle speed w/ A/C engaged and in drive to a min of 650, 750 max RPM @ idle. This should help your ALT put out more power.
If that seems to be too much for safe braking, consider using a smaller diameter pulley shieve for this ALT. It will turn the ALT faster at same RPM settings as well.
Comments?
Swez
Zigrig on 07/18/2005 11:25:54
Sounds good. Thanks to you both. I won't be able to get back to it for a couple of days due to scheduling but I will definately try your suggestions and report back with the results. I appreciate the help.
swez on 07/18/2005 16:15:04
Good nuff! Let us know how things turn out as you tweak and such.
Swez
Zigrig on 07/19/2005 19:02:03
Here's the update: Raising the idle helps a lot. However I still had a bit of a problem here and there. I watched closely and during the drop outs the voltage never dropped below 13v. so I think something else is still wrong. Besides, having the idle that high caused the engine to run-on when I turn off the ignition so that's a problem.Here are a couple of things I was wondering abou trying. Let me know your thoughts.
1. I could add an idle solenoid that just kicks in when the A/C compressor is on and that might give me enough bump in RPMs yet still allow me to shut off the engine without run-on.
2. Do you think a bigger battery might help? I tried running the system with the ehgine off and just on Acc. It seemed to work fine so I don't know if that indicates that the battery is big enough.
3. Do you think it would be worth trying removing the amp from the system and running the 3 ways off the head unit to seeif the problem improves? I don't think the HU would have the power to run the sub tube though.
Thanks.
swez on 07/19/2005 22:10:17
The solinoid speed control will definitely help boost idle speed when A/C is activated. Many have adjustment rods that allow user to set idle to desired RPM when A/C is engaged. That's a good, permanent fix. (650-700 RPM should do it, in drive)
The BAT sounds like it's doing its job already if you can get good performance with ACC only. If you have a 600 CCA or higher, should be fine for this smaller system.
Engine run on (dieseling) is common is the throttle plate is open too much when the ignition is shut off. Guess you can't solve the root problem by only changing idle speed. Back to the solinoid idea seems best.
I would suggest running the amp, only for the bass tube. If the bass tube is 4 ohms, you can bridge the amp for MONO bass and double the RMS power to sub. This amp, does it have a good Low Pass Filter? (LPF) If yes, set to 80-100 Hz. That will block all voices and non-bass audio to sub.
At 18 watts (RMS x 4) if you have very efficient speakers, (90dB @ 1 watt) or higher, should get adequate power to drive your speakers to a decent level. Just avoid using too much EQ or Bass Boost to speakers off HU. Setting the bass levels at +3dB is plenty, depending on the crossover frequency you select, (80 - 100 Hz.) and speaker size used. The sub will handle the lows, below 80 Hz.
Finally, the HU should be set to deliver clean mids and highs at about 80% of max volume settings. Much above that number, the HU amps will begin to "clip" and cause harsh sounding mids and shrill highs. Is best to test this outside the vehicle with doors open. Stand to back of vehicle and set your HU to a volume and tone control setting where it's loud, clean and full sounding. Once you have that setting dialed in, bring up the sub amp gain until you get full, clean bass.
Swez
PS Follow these basic steps and I'll bet you $10,000,000.00 Bachese, (10 cents American) the system will sound better than you could have ever guessed. USFLAG
Zigrig on 07/20/2005 09:48:24
Thanks again for the hel SWEZ. I'm sure I will now be able to dial it in.
swez on 07/20/2005 09:57:11
Good luck and keep us posted to your progress OK?
Swez
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