[Diy_efi] Using GM '747 to control TCC lockup only

[Geoff Harrison]

The 700R4 has 2 internal switches, connected in series, such 
that when
the fluid temp is up to normal, and the transmission is in 4th 
gear, ground
is sent back to the GM ECU.

Take that lead, feed it to a delay of say 5 seconds, (to stop 
the clutch engaging
as it shifts into 4th) override that with a signal from the 
brake light switch (to drop
the clutch out so as not to pull RPM below idle speed at low 
road speeds)
and control the TCC solenoid. The only advantage of using 
manifold vacuum
would be to allow the TCC to disengage prior to the transmission 
shifting from
4th down to 3 gear.

Just my 2c worth

Geoff

----- Original Message ----- 
From: "Eugene Pilipanko" <epilipanko at mn.rr.com>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, September 12, 2006 10:20 AM
Subject: Re: [Diy_efi] Using GM '747 to control TCC lockup only


> www.bulkpart.com    part # 74416ak.   Summit racing part # TCI 
> 376600 or Jegs part 3 890-37660 should help you out.
> ---- Original Message ----- 
> From: "Milosz Kardasinski" <miloszk at gmail.com>
> To: <diy_efi at diy-efi.org>
> Sent: Monday, September 11, 2006 5:16 PM
> Subject: Re: [Diy_efi] Using GM '747 to control TCC lockup 
> only
>
>
>> What I have seen in some applications is the use of a vacuum 
>> sensor
>> connected to ported vacuum. You'd have
>> to set the switch point to whatever you feel is the 
>> appropriate vacuum
>> threshold...but all the sensor does is ground
>> out, which engages the TCC below a certain vacuum setting. 
>> Some also connect
>> a switch in series to turn off TCC
>> whenever the brake pedal is depressed.
>>
>> ----- Original Message -----
>>
>>>
>>> I converted a Jeep 4.2 liter to a GM throttle body, works 
>>> well. But, I'm
>>> thinking of purchasing a MOPAR MPI conversion which was 
>>> designed for that
>>> engine.
>>>
>>> My dilemma is that I have a 700R4 automatic in the thing and 
>>> like that the
>>> GM ECU ('747) controls the TCC lockup. I will lose that 
>>> feature in the
>> Mopar
>>> unit.
>>>
>>> Any ideas about the feasibility of using the '747 to just 
>>> control the TCC
>>> lockup?
>>>
>>> I think I can piggy back off most of the sensors the TCC 
>>> logic uses; temp,
>>> speed, MAP, but I'm not sure about the throttle position. I 
>>> saw a cable
>>> throttle position sensor which might work.
>>>
>>> What happens when the ECU isn't actually controlling the 
>>> fuel anymore and
>>> the closed loop logic gets feedback, but isn't controlling 
>>> the system?
>>>
>>> Is there a better way to automatically control the TCC and 
>>> disable the
>> other
>>> processing in the GM ECU?
>>>
>>> I just hate going to a switch on the dash. It's so 
>>> "unelegant".
>>
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>
>
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