A New and Different Issue With CS144 Conversion?

[Hink]

Hello all,

Recently I was told that the CS144 will not work with the 4L80E transmission because "the F terminal output is a different signal ratio than a standard CS144, and the 6.5L relies on the F terminal output for transmission control and a couple of other features.".

Also, "Any high output CS144 unit that you purchase from anyone will likely have a smaller than stock diameter pulley in order for the alternator to charge well at engine idle RPM. This changes the F terminal output to the TCM, and makes the transmission shift incorrectly. "

Has anyone ran into this? It seems that many have done the conversion and I don't remember any problems with the transmission reported.

Thanks!

 

[WarWagon]

The alternator drives the tach. The source of the confusion you were reading they tripped over as now their tach was off... so um yeah... the shift points must be FUBAR (because the tach is screwed up.) I wonder if they were suffering the effects of wearing a mask when they wrote that?

Swap pulleys from the gas engine size to the rare diesel engine size and call it a day. I don't recall if I even had to change the alt plug. I did add a larger charge wire off the alt.

I seriously doubt anything is connected to the F terminal. Tach is the P terminal.

I did have shifting trouble on a 2002 GM due to the remote voltage sense of the alternator screwing with the ECM and trans during a shift: GM's fix was to run that wire that went from the main bus "SNIP" to the output lug of the alternator. In effect making the voltage drop correction of remote sense useless.

Near the bottom of this your head will explode article is a pin out description for the CS series:

BillaVista.com-Alternator Bible Tech Article by BillaVista

www.billavista.com

 

[Hink]

The alternator drives the tach. The source of the confusion you were reading they tripped over as now their tach was off... so um yeah... the shift points must be FUBAR (because the tach is screwed up.) I wonder if they were suffering the effects of wearing a mask when they wrote that?

Swap pulleys from the gas engine size to the rare diesel engine size and call it a day. I don't recall if I even had to change the alt plug. I did add a larger charge wire off the alt.

I seriously doubt anything is connected to the F terminal. Tach is the P terminal.

I did have shifting trouble on a 2002 GM due to the remote voltage sense of the alternator screwing with the ECM and trans during a shift: GM's fix was to run that wire that went from the main bus "SNIP" to the output lug of the alternator. In effect making the voltage drop correction of remote sense useless.

Near the bottom of this your head will explode article is a pin out description for the CS series:

BillaVista.com-Alternator Bible Tech Article by BillaVista

www.billavista.com

Excellent, Warwagon, thank you!
And that's what I suspected.
Exploding heads aside, looks like that article will go a long way in explaining everything. : )>

 

[Hink]

I did have shifting trouble on a 2002 GM due to the remote voltage sense of the alternator screwing with the ECM and trans during a shift

Also, on this, he did say on the specific alternator I was going to use
"that uses 2020 production Denso hairpin internals" and that the transmissions didn't shift correctly "with the Denso based retrofit unit."
Could the newer Denso internals make it specifically incompatible with the 4L80E?

 

[Will L.]

Yup. ND has a long history of doing things their way instead of to factory spec. But no one sues them or other mfrs so they get away with it still being called “oem spec”. SMH

 

[WarWagon]

There may be credibility to Denso having problems vs. Delphi/ AC Delco units. Who knows what rebuilt parts or new parts are used NOW on a unit you buy today that can have trouble.

The 2002 1/2 ton 5.3L 4L60E problem was "noise" screwing up the ECM. It had a Denso alternator on it... An educated guess on how it could affect shifting: Trans goes to shift that uses more amps, voltage drops, alt raises voltage to correct voltage drop, and the interaction over the charge wire wire run to the main bus and voltage sense wire back to the alt caused noise the ECM couldn't handle and thus shifting problems. So to steady out the alt voltage the remote voltage sense was neutered.

Consider triggering a shift solenoid with a spike in amps (=voltage drop) that quickly tapers off. How fast this happens and the delays in changing the field strength of the large inductor in the alternator: you get a voltage drop followed by a voltage spike. Thus it's not mechanical (too slow) but rather a chip going crazy from voltage changes or noise it can't handle. Dealing with the speed of light it's a small timing change to move the sense location so IMO there is more to it, like induction, than just reducing the wire distance. It could have caused an oscillation of the voltage going low, alt correcting, but the wire distance delay making it too late, voltage overshoots high, then overshoots low, than high... Aka noise via an oscillation.

All this would affect the voltage used to set the shift pressure in the transmission and "BANG!" the shifts. Noise, wrong voltage delivered to the shift pressure control in the trans, as the ECM calculated on a different voltage that's no longer true.

As a person who is sensitive to light flicker I can see this kind of "noise" in the electrical systems at night, engine at idle, and dome lights on. The damn dome lights dim (flicker) as the fuel injectors fire. (offhand I recall thin on 2006-2009 GM SUV's for example with the 5.3L and 6.0L LS2.)

 

[Hink]

Yup, I think you guys nailed it. It's the Denso specifically, not just the CS144 in general, and the "output is a different signal ratio than a standard CS144" would be your noise, WW.

Real good stuff to know, I can see going out and getting a great alternator for a CS144 swap, knowing it's a fairly straight forward deal and having all kinds of issues with your auto trans. That would be maddening.

So just make sure you're not getting one with Denso Internals and you're gold.

Excellent, thanks for helping to resolve that guys!