Carb to TBI

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
Wait....what do I need? I was going to maintain the vacuum controlled lock up. But I'm looking at this scratching my head now.....what kicks down the tranny? My 85 uses a TV cable.

Never mind, sorry, nother brain fart....forgot you going vacuum lockup.
This is what happens when you have 6 projects running around in your brain.
Oh yes! Can we get a pic of the throttle cable bracket for the 87? I want to make sure it will acommodate the TV cable.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
ya i just turned the page and saw that. I have the Haynes Manual too.

What has me all confused it:
1. My 700r4 has 4 wire pin to the driver side, which i assume is for the lock up vacuum switches. My 700r4 uses a TV cable to kick down the tranny.
2. 87 tranny has 1 wire to the driverside, which you have stated as an ecm controlled kickdown.and the TH400 doesnt have a lock out so i know there is no present controls in that system.

....so in the Haynes wiring diagram what are the Light Blue and Tan/Black wires for?
Chilton Book only shows a TCC Solenoid with a Light Blue wire then a PPL/WHT wire to the RAWL Diode...???? which makes no sense to me haha


Posted before reading yours^
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
ya i just turned the page and saw that. I have the Haynes Manual too.

What has me all confused it:
1. My 700r4 has 4 wire pin to the driver side, which i assume is for the lock up vacuum switches. My 700r4 uses a TV cable to kick down the tranny.
2. 87 tranny has 1 wire to the driverside, which you have stated as an ecm controlled kickdown.and the TH400 doesnt have a lock out so i know there is no present controls in that system.

....so in the Haynes wiring diagram what are the Light Blue and Tan/Black wires for?
Chilton Book only shows a TCC Solenoid with a Light Blue wire then a PPL/WHT wire to the RAWL Diode...???? which makes no sense to me haha


Posted before reading yours^

1. Correct
2. also, correct. 400 uses electrc kickdown.

At this point, dont worry about the trans. It is already wired up with the Vac lockup.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
So I just need to check in the morning if the throttle plate on the tbi has a kickdown provision.

If not? And will the ecm throw a code bc it isn't seeing the th400?

and where would be a good point to tee in the transmission vac switch?
 
Last edited:

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
So I just need to check in the morning if the throttle plate on the tbi has a kickdown provision.

If not? And will the ecm throw a code bc it isn't seeing the th400?

and where would be a good point to tee in the transmission vac switch?

no, it shouldnt throw a code.
depending onthe throttle body, you may be able to add the pin for the TV cable.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
awesome thanks.

I hate sounding like a broken record through all this...but:
The fuel tank on my truck is new, I swapped out the 16 gallon for a 20 gallon last summer. It also has a new sending unit, but that doesn't concern me as much. How bad would it be to drop the sending unit/pump from the 87 into my 85 tank. I know its baffled vs non-baffled. Just discouraged to toss aside a new $100 gas tank.
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
awesome thanks.

I hate sounding like a broken record through all this...but:
The fuel tank on my truck is new, I swapped out the 16 gallon for a 20 gallon last summer. It also has a new sending unit, but that doesn't concern me as much. How bad would it be to drop the sending unit/pump from the 87 into my 85 tank. I know its baffled vs non-baffled. Just discouraged to toss aside a new $100 gas tank.

ok, so use the 87 sender and pump in the 85 tank, and just try to not let it get too low. with either tank, try not to let it get too low below 1/8th.
and use the 87 fuel lines.
Solved.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Thanks :) was worried about air bubbles and such. I'll pull the lines today and look at that throttle plate.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Tbi throttle plate
 

Attachments

  • 2013-02-01_09-11-45_588.jpg
    2013-02-01_09-11-45_588.jpg
    95.5 KB · Views: 137

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
Tbi throttle plate

Yup, that throttle bracket will work for a TV cable, but you may want to grab a throttle body from EBay. IMann may have one too, but that throttle linkage does not look lik it will work.
Can we get a bigger pic of that throttle body? Whats that bracket?
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Both r from the tbi. When I get home later I'll look at my Carb.
 

Attachments

  • 2013-02-01_11-54-40_3.jpg
    2013-02-01_11-54-40_3.jpg
    95.3 KB · Views: 187
  • 2013-02-01_11-54-45_31.jpg
    2013-02-01_11-54-45_31.jpg
    95.7 KB · Views: 167

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
135
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
Both r from the tbi. When I get home later I'll look at my Carb.

Hmmm...Thats a wierd t body...looks like its from a van.
WTF?! Can we get a more complete t body pic? Not worried about the linkage anymore.
 
Last edited:

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
Grrrr I'm home now lol will have to be tomorrow. This donor truck was a work truck for a local property management company. I was told the engine was rebuilt a few years ago by GM. Then the tranny blew last winter so they said scree it and gave it to my buddy.
 

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
This is my current throttle plate on my truck
 

Attachments

  • 2013-02-01_17-21-47_61.jpg
    2013-02-01_17-21-47_61.jpg
    95.6 KB · Views: 130

usar17

Full Access Member
Joined
May 3, 2012
Posts
596
Reaction score
17
Location
PA
First Name
Shawn
Truck Year
1985/87
Truck Model
K20 Silverado
Engine Size
TBI350/700r4/NP208
I'm pretty certain that spacer for the air cleaner isn't factory lol. I found in the cab a plastic one that was taller.
 

Attachments

  • 2013-02-02_11-26-06_294.jpg
    2013-02-02_11-26-06_294.jpg
    98.7 KB · Views: 164
  • 2013-02-02_11-26-13_53.jpg
    2013-02-02_11-26-13_53.jpg
    99.5 KB · Views: 125
  • 2013-02-02_11-26-20_489.jpg
    2013-02-02_11-26-20_489.jpg
    100.3 KB · Views: 132
  • 2013-02-02_11-26-36_367.jpg
    2013-02-02_11-26-36_367.jpg
    100.8 KB · Views: 123
  • 2013-02-02_11-26-40_595.jpg
    2013-02-02_11-26-40_595.jpg
    99.3 KB · Views: 125

Forum statistics

Threads
44,173
Posts
950,851
Members
36,288
Latest member
brentjo
Top