Dmch alternator issue

[Dontilgon]

Just installed there alternator,when all
Was said and done I now have this problem. I cant think of anything I did wrong that would case this issue https://youtu.be/_OWN-zleySwm.

[dmcnc]

Appears to be more likely an idle issue...was the idle like that prior to your alternator swap?

[Jonathan]

Belt slipping? Not tight enough?

[Dontilgon]

Appears to be more likely an idle issue...was the idle like that prior to your alternator swap?

I did not have this issue prior to the swap. The previous alternator was oem and still working.i believe the belts are tighten properly being I put the stainless alternator adjuster on. If anything I was concerned I may of over tighten.Alternator appeared to be straight forward install: cleaned mounting bracket , 3 red bunch wires to alternator and single alternator wire to single wire from factory harness.Also needless to say when the fans kick on it gets worse.
List of things I did at the same time

Dmch starter
Dmch alternator
New interstate battery mtp-78
Pressure regulator
Oil change
Remove catalytic convertor and replace with test pipe

[dmcnc]

You could do a voltage drop test between the alternator and the battery on both the ground and + sides of that circuit and/or reinstall the old alternator (is it a Motorola?) to see if the issue continues.

[Michael]

A slipping belt would be worse as the rpms rose. It looks like a dead battery to me but you said it was new.

Get your mulitmeter and watch the voltage. Check it at the battery and at the alternator. If the battery is showing less than 12.8v while running, charge it and try again. It is possible you just got a bad alternator with a bad diode.

[Dontilgon]

Okay I will check voltage and report back. Sad was looking forward to taking it out tonight thinking with all the “upgrades” I would feel more confident driving it. Anyways prior to these installs, it would sometime chase idle for a couple of second on start up when smooth out perfectly. When first started after install it immediately sounded totally different. Okay out to the garage .....

[Bitsyncmaster]

I did not have this issue prior to the swap. The previous alternator was oem and still working.i believe the belts are tighten properly being I put the stainless alternator adjuster on. If anything I was concerned I may of over tighten.Alternator appeared to be straight forward install: cleaned mounting bracket , 3 red bunch wires to alternator and single alternator wire to single wire from factory harness.Also needless to say when the fans kick on it gets worse.
List of things I did at the same time

Dmch starter
Dmch alternator
New interstate battery mtp-78
Pressure regulator
Oil change
Remove catalytic convertor and replace with test pipe

I bet the test pipe has caused the idle hunt. You need to adjust your mixture now.

The idle hunt is probably causing a low voltage condition when the idle drops below 700 RPM.

[Dontilgon]

14.9 at the battery but It obviously fluctuates with the idle.Interesting thing I started it this morning and it idled perfectly for a good minute or two,opened up the engine bay and noticed the cold start unplugged. Plugged back in and it stayed the same. I noticed has the car started heating up it seemed to have gotten worse and then it was back to its old tricks

[David T]

Some hunting is normal. To reduce it you must make each cylinder as balanced (equal) to each other as possible. You also have to find and fix all vacuum leaks. Your car sounds pretty normal.