Carb to TBI

[foamypirate]

not the 6 wires that go from the ECM to behind the Cluster?

ECM->VSS,ALDL, Fuse Block, Inst Cluster, Transmission Position Sensor

I think Jim was including that with the ECM stuff.

 

[Jims86]

I think Jim was including that with the ECM stuff.

Oh, thought he took the ac dash harness stuff out...lol
Is it separate from the ALDL,P/N,vss?
I have always ran new wires for that stuff, but since you, do have it, your ok....just a little extra work.

 

[usar17]

P/N???


i have a few questions.

The Brown w/White stripe wire that goes from the ECM to the instrument Cluster: I'm assuming that is the Check Engine Light...If so can i cut that and run it to a grounded indicator lamp?


ECM1 & ECMB Fuses: Are they constant hot or ignition hot? And Where do they go after passing into the engine compartment?

The Brown and The Tan w/Black Stripe Wires that go from the ALDL directly to the Firewall junction box behind the fuse block?

And the Transmission Position Switch......Idk if my current 85 has one. If not what do I do?

The Wiring diagrams i have dont show these.

 

[Jims86]

P/N???


i have a few questions.

The Brown w/White stripe wire that goes from the ECM to the instrument Cluster: I'm assuming that is the Check Engine Light...If so can i cut that and run it to a grounded indicator lamp?


ECM1 & ECMB Fuses: Are they constant hot or ignition hot? And Where do they go after passing into the engine compartment?

The Brown and The Tan w/Black Stripe Wires that go from the ALDL directly to the Firewall junction box behind the fuse block?

And the Transmission Position Switch......Idk if my current 85 has one. If not what do I do?

The Wiring diagrams i have dont show these.

PN is the trans position switch. pull the one from the bottom of the 87 column, and it clips in place of the switch currently on your 85, which only operates the reverse lights. 87 unit does both ecm and reverse lights.
EcmB is constant, Ecm1 is switched.
I will have to look at a diagram for the other stuff.
The check engine light is hot when the key is on, ECM operates it via ground.

 

[usar17]

Ok I'm having a brain fart.... this the position sensor?

 

[Jims86]

Ok I'm having a brain fart.... this the position sensor?

Yes.

 

[usar17]

thanks, I thought so. I'm half frozen today. It's very cold and very windy this week. Which brings me to my next question...I really don't feel like pulling this tank and fuel lines haha.

Is there a cheap alternative to hold me till warmer weather when i can swap the tank and sending unit over properly?

 

[Jims86]

thanks, I thought so. I'm half frozen today. It's very cold and very windy this week. Which brings me to my next question...I really don't feel like pulling this tank and fuel lines haha.

Is there a cheap alternative to hold me till warmer weather when i can swap the tank and sending unit over properly?

Not really. an inline pump woul bebaround $100, then a filter...maybe $3. then you need to run the lines.

 

[usar17]

ugh. I wish i owned a garage


hmm what other question did i have...
-I have A/C in my current truck, but it isn't factory. (don't ask) I currently just spliced a idle seloniod into the wire for the A/C Clutch. What would I need to do for the TBI? is there already one on there? The Donor truck has factory A/C

-on the donor truck: what is the single wire that goes down to the driverside of the TH400 tranny? Do i need it? will it cause check engine light?

-with my 700r4: since i'm maintaining the use of vacuum switches to lock up the torque converter, where in the '87 motor should i tie into the vacuum lines?

 

[Jims86]

ugh. I wish i owned a garage


hmm what other question did i have...
-I have A/C in my current truck, but it isn't factory. (don't ask) I currently just spliced a idle seloniod into the wire for the A/C Clutch. What would I need to do for the TBI? is there already one on there? The Donor truck has factory A/C

-on the donor truck: what is the single wire that goes down to the driverside of the TH400 tranny? Do i need it? will it cause check engine light?

-with my 700r4: since i'm maintaining the use of vacuum switches to lock up the torque converter, where in the '87 motor should i tie into the vacuum lines?

No worries. there is a signal wire that you can splice into the same wire for your solenoid. the ecm raises the idle for ac when it sees 12v at that wire.

 

[usar17]

any clue which wire im looking for?
and any clue on the transmission questions?

 

[Jims86]

any clue which wire im looking for?
and any clue on the transmission questions?

you will not bee using the wire going to the donor trans, thats a kickdown wire.
For the AC, its a Dark green wire thats usually wired in to the positive wire for the A/c clutch, but it may be wire in with the pressure switch. I have seen it both ways OEM. The best way to track down these wires, is to get the harness out, and unplugged from the ecm , and then we trace them down with the continuity tester on a digital volt meter.
Since you will neednto add the 700R4 wiring, we need to source some terminals...which I think I can round up for you.

 

[89Suburban]

ugh. I wish i owned a garage


hmm what other question did i have...
-I have A/C in my current truck, but it isn't factory. (don't ask) I currently just spliced a idle seloniod into the wire for the A/C Clutch. What would I need to do for the TBI? is there already one on there? The Donor truck has factory A/C

Don't confuse the dark green wire with the dark green w/ white stripe wire.

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[usar17]

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.

 

[89Suburban]

I don't know about the transmission stuff, those pics are to hook up the ECM to the A/C to get the idle bump.