Not Charging after Madd bypass.

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Coyote Jack

Coyote Jack

Member #55, I'm old
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I recently installed a new Intellitronix digital a-body cluster in my 72 Demon. At the same time I did the Madd ammeter bypass. Before I did this the car was charging perfectly. It now is not charging. I have 27 volts coming from the alternator at idle. I have traced the wires a half dozen times and I come up with the wires being correct every time. I tried another voltage regulator and nothing changes. Has anybody else that has done the Madd bypass had this problem?

Jack
 
A total guess.....if it's a 2 wire alt. You have the field wires reversed and it's full fielding.
 
The new gauge panel you installed uses a volt meter. How did you do a Madd "bypass" of the amp gauge if there is no longer one in the car?
 
If you are measuring 27V out of the alternator stud then it is not making it to the battery. Unfortunately I have no idea what you've done or the mistake you've made.

Do you have a service manual?

Maybe I should say are you sure the battery is not getting that high voltage? That is dangerously high for the system if so.
 
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Burnt fuse link, maybe?
Did you check the continuity of the wire from alternator to starter relay?
 
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A couple of things to check here. I have been to busy to even look at the car but hope to get back to it in the next day or two.

Jack
 
Hi Jack
I applied the Madd Electrical modification two days ago to my Demon and the charging circuit works well.
In your case, the first thing I would control is the continuity between the alternator and the starter relay. If this wire is ok, the battery will charge. The other wires can only cause malfunctions into the dashboard harness.
Did you replace the ammeter with a voltmeter?

Here's my modification schema (in french, but easily understandable)

Schéma3.jpg


François
 
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I finally got a chance to look at it again today. I checked my wiring again and all looks as it should.

To do a quick test I ran a wire from the alternator to the battery. Still no joy but the voltage did go up from 11.5 to 12.4 when I revved the engine up to 3500 rpm. After shutting down the engine after a 1 minute run the alternator was very hot as in I could not hold my hand on it. I am leaning towards it being a bad alternator.

Jack
 
You sure you did not somehow ground the output stud?
 
That does not seem likely. You might try just charging the battery, and if you have a 'bigger' charger like an 8 or 10A see if you can determine if one cell is bubbling more than others (bad cell) and see if the terminal voltage "comes up." It might just be "that dead."
 
Step one in any electrical diagnostics is testing the battery. If that was me, I'd grab a known good one, just for testing.
Didn't change anything?
Step 2: Verify every connection. Describe to us your ammeter bypass. Did you just bolt the two wires together under the dash and tape 'em up? Did you bypass them in the engine bay? Did you hook one to ground and the other to the light in the ashtray? What exactly do you do?
This also includes.....what voltage regulator you got? What alternator are you running? Is the case of the regulator grounded? Is the alternator case grounded? Is the battery grounded? The regulator is plugged in, right?

Step 3, disconnect the direct line to the battery and see what it does for charging voltage. I run mine from the output stud on the alternator to the stud on the starter relay. Why? Because that's what Rick E. said to do years ago. Electrically, it shouldn't matter, but the E-dogg sayeth it for a reason. You DO have a fusible link in this direct line, RIGHT??? Not a fuse, not a breaker, not 'I'll do it later', but an actual fusible link. Test the continuity of said link.

Do all that and get back to us.
 
jos51700 said:
Step one in any electrical diagnostics is testing the battery. If that was me, I'd grab a known good one, just for testing.
Didn't change anything?
Step 2: Verify every connection. Describe to us your ammeter bypass. Did you just bolt the two wires together under the dash and tape 'em up? Did you bypass them in the engine bay? Did you hook one to ground and the other to the light in the ashtray? What exactly do you do?
This also includes.....what voltage regulator you got? What alternator are you running? Is the case of the regulator grounded? Is the alternator case grounded? Is the battery grounded? The regulator is plugged in, right?

Step 3, disconnect the direct line to the battery and see what it does for charging voltage. I run mine from the output stud on the alternator to the stud on the starter relay. Why? Because that's what Rick E. said to do years ago. Electrically, it shouldn't matter, but the E-dogg sayeth it for a reason. You DO have a fusible link in this direct line, RIGHT??? Not a fuse, not a breaker, not 'I'll do it later', but an actual fusible link. Test the continuity of said link.

Do all that and get back to us.
Click to expand...

I printed this off and I am going to go through each step. I have already done most of them but will do them all just to make sure.

Jack
 
Looks like I jumped the gun a little on thinking I had a charging problem. Today, after charging the battery over night I checked it again. I had 12.68 volts with the car just sitting there. I took the car for a drive and kept an eye on the volt meter gauge. It started at 11.6 volts at idle and when I put the car in gear with my foot on the brake and idling at 900rpm I had 10.9 volts on the gauge. While driving the gauge returned to 11.8 until I turned the car off. I believe I may have a bad reading on my gauge. I am going to check and reseat all my grounds. and see what happens.

Jack
 
I'm sorry I have no ideas at the moment, other than

Get another (multi)meter and check readings at both the battery and the alternator output stud.
 
I don't want to Hijack this thread, but what is the advantage(s) to bypassing the ammeter?
Thanks.
 
harrisonm said:
I don't want to Hijack this thread, but what is the advantage(s) to bypassing the ammeter?
Thanks.
Click to expand...

Mostly, avoiding a possible in-board fire (by rerouting a "hot" wire into the engine bay and not the dashboard).
And secondarily, replacing this useless gauge with a more useful voltmeter. A voltmeter is a low amperage and harmless gauge ...

This by-passing also eliminates the bulkhead connector weakness.
 
if your ammeter is sound and everything works ok. the easiest route to avoding overload of ageing connectors is just to run a fat cable with a fuse in it from the altenernator stud to the stud on the starter relay which is the closest component to battery +...... most of the benefits for the least hassle.... ammeter will not move anymore BUT the main current flow for charging the batery and supplying the car now goes via the new short cut, you are taking the full load (battery charge and supplying the car) out of the route via ammeter and bulkhead connector. car supply still goes that way but is dicated by what is switched on. in theory everything swicthed on in a standard car is less than the current capabilities of the wires..... Battery chargeing however is a variable, and it depends on alternator capacity battery capcity and how flat the battery is.... but current for that will now invaribly take the new route.... i.e you cater for the fact that your battery and potentially your alternator are no longer standard items limited by their "just good enough" factory specifications, that were just good enough to cause bulkhead connector and ammeter problems when standard and with the wires and connector components aged by 50 years.
 
French demon said:
Mostly, avoiding a possible in-board fire (by rerouting a "hot" wire into the engine bay and not the dashboard).
And secondarily, replacing this useless gauge with a more useful voltmeter. A voltmeter is a low amperage and harmless gauge ...

This by-passing also eliminates some of the bulkhead connector weakness.
Click to expand...

Fify
 
jos51700 said:
Fify
Click to expand...

Jos, I don't know what does mean "Fify", but you're right. :)
The ammeter bypassing eliminates some of bulkhead connectors problems. More precisely, the weakness of the little terminals of the two big wires of the ammeter which easily burn or melt the plastic connector under the alternator charge current amperage.

amp-ga23.jpg

(picture from Madd Electrical website)

François
 
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