The never ending 700r4 Lockup questions haha

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usar17

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Base info:
1985 Chevy k10 with Carb 305 and 700r4
Tranny is connected to the EGR, Vac Sensor, and Brake Sensor

New Setup:
1987 TBI 350

Lock up worked before engine swap, now doesnt. I believe i hooked everything up correctly, except the plug that when to vac control for the EGR valve. That is currently unplugged. There is no where to place that now with TBI. Is this whats preventing the lock up? I have yet to test the plug at the tranny for 12v with key on/ no brake on pin "A" i believe. I know there are multiple setups for this haha Any insight would be great.
 

Jims86

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Base info:
1985 Chevy k10 with Carb 305 and 700r4
Tranny is connected to the EGR, Vac Sensor, and Brake Sensor

New Setup:
1987 TBI 350

Lock up worked before engine swap, now doesnt. I believe i hooked everything up correctly, except the plug that when to vac control for the EGR valve. That is currently unplugged. There is no where to place that now with TBI. Is this whats preventing the lock up? I have yet to test the plug at the tranny for 12v with key on/ no brake on pin "A" i believe. I know there are multiple setups for this haha Any insight would be great.
Refresh my memory again, what did the TBI engine comeout of?
 

usar17

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well i pulled it from an 87 C20. you think formally a van because of the TBI setup.

Do i need to cut out the connector for the EGR and make it a solid line?
 

Jims86

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well i pulled it from an 87 C20. you think formally a van because of the TBI setup.

Do i need to cut out the connector for the EGR and make it a solid line?

No it will be completely different. The C20 most likely had a th400. To do this the right way, you will need a PROM from a 700r4 truck. Code ASDU will work just fine, then, you can wire the lockup to work properly off the ECM. You can probably find one real easy on ebay, or, 89suburban may have one.
 
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usar17

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UGH haha more electronics. So what do i need to wire up then? I was afraid by doing that I would need to re-pin the ECM connector.

And yes the C20 had a 400 that was trashed or i would have kept it.
 

usar17

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since this may change the prom id i guess i should add this.

It has and AIR pump controlled by the ECM. Also A/C.
#1227747


what other info would be necessary for PROM selection?
 
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Jims86

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Yup, thats it. As far as wiring, the light blue wire(high gear input)from the trans, will wire into cavity C7 on the ECM plug, and the tan and black lockup wire, which is already in cavity A7(for downshifting the TH400) is already there, and you will most likely find the other end of it in the plug that was next to the fuel pump relay.
Is your trans still the 85 model? or is it updated?
Another option is, to have a trans shop install a lockup kit...usually $100 or so, and you dont need to get another chip.
 

usar17

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should still be the 85 model. Says "MD8" behind the passenger side bellhousing. How do i wire the Lt Blue into cavity C7?? ive never messed with making pin connectors
 
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Jims86

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should still be the 85 model. Says "MD8" behind the passenger side bellhousing. How do i wire the Lt Blue into cavity C7?? ive never messed with making pin connectors

Ooofff...thats a rough one. Would have to be there to show you....unless someone else here can 'Splain it....like Retro, or if you know someone that does car stereos.
Is there a pressur switch on the right side of your trans, above the pan? Its been so long since I have seen a 1st gen 700r4... Maybe HR could help us identify some of the older stuff.
Mybe take some pics of your trans?
 

usar17

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Is right side, driver side? Lol

It has 3 wires to a 4 pin connector on the driver side. There is that big round thing behind the dipstick tube passenger side. Only other things I recognize are the cooler lines and TV cable.
 

Jims86

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Is right side, driver side? Lol

It has 3 wires to a 4 pin connector on the driver side. There is that big round thing behind the dipstick tube passenger side. Only other things I recognize are the cooler lines and TV cable.

Pass side...I remember my 86 trans having a pressure switch on the pass side, not sure of 85. I think they have 2 pressure taps on that side, that were done away with in 87.
 

usar17

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there are two bolts that look adjustable bc they are not in all the way and at different lengths out
 

usar17

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I ordered that PROM already....is that an issue?
 

Jims86

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I ordered that PROM already....is that an issue?

Nahh...your ok. Take a look at cavity C7 on your ecm plug, and see if there is something there already.
 

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