Drew's TBI Q&A/install thread

[TUDrewser]

Ok, VSS arrived yesterday and adapter plate should be here today...getting real close to testing everything on the bench. Think I have everything except fuel line, but enough to bench test.

Now, time for more questions!

1. Fuel pump...I have a green wire (F6 Fuel Pump Relay Control) going to it and a gray wire (B12, Fuel Pump Signal). The gray wire looks like it has a factory splice that goes into two gray wires. Any reason I need two gray wires? Assuming the same signal, can I cut one off?
2. Fuel pump...what's the difference between the green "Fuel Pump Relay Control" and the gray "Fuel Pump Signal"? What do I connect where?
3. Battery power...Pin E16 is orange wire that follows the fuel pump wires. Factory splice splits this into three wires, with one cut, one going to fuel pump relay (per label) and one going to battery 12v (assume fused). I assume this is to provide the 12v to the fuel pump...but do I want constant 12v to the fuel pump relay? I realize it will only pump when it gets the signal to activate the relay...just didn't know if that splice/labeling is right and if I want that relay always hot.
4. Ignition relay...where do I pull the 12v from for power side of the relay? I THINK I run a signal wire from starter to activate the relay, but do I run supply straight from the battery and have it only activated by ignition, or do I run it from a supply that is only live when ignition is on?

IOW, should the relays (power and fuel pump)have a hot lead wire that's hot all the time?

5. 4wd...I have a wire for 4WD indicator...can i cut that off?
6. Brake switch...pin E13 is the Brake Switch indicator...do I connect this to something? Ground it out?

[babywag]

1. See #2
2. Fuel pump relay is energized by pcm signal wire, relay is always hot, but fuel pump only gets power when running.
Fuel pump relay control goes from pcm to relay, fuel pump signal goes from relay to fuel pump *and* pcm fuel pump signal.
3. Relays are generally always hot. Think of them as a light switch the power is there but doesn't complete the circuit until switched on.
4. If a latemodel easiest spot is factory duraspark module connector(2 prong plug) one wire switched ignition power(run), other is switched ignition power(crank and run) you want the one that is also hot while cranking.
5. don't need it.
6. don't need it.

Do you have a wiring diagram?

[TUDrewser]

I do have a wiring diagram. Text version posted in first post. But I have the diagram as well too, just seems to be missing some of these things...

[babywag]

The text thing is simply a pinout conversion chart for 7747 to 7427 it is mostly useless for starting with a 7427 harness.
It won't show you anything other than the pcm connections.

Fuel pump relay is on the 3rd page of wiring diagrams from gearhead that I linked in a previous post IIRC

[sgtpoliteness]

I think Blake may have posted the 16197427 diagrams on my build thread too.

[TUDrewser]

Also, my post on the front page is a full pinout for the 7427. I took the conversion list, put it next to my wiring diagram, and went through tracing every wire and confirming/correcting the list.

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[TUDrewser]

Ok all, so for my distributor. I'm buying this cap to put on my stock distributor: http://m.summitracing.com/parts/smp-al482

I will weld the weights in my stock distributor and drill a hole in the original cap to set the phasing. I'm running the GM coil and 8 pin ignition module off the truck. I still need a set of HEI spark plug cables, but no biggie.

So with that cap, new cables, and GM coil, I have everything I need for the ignition part, right?

[babywag]

Yep...that cap uses the stock rotor. So you're all set w/ it & plug wire set.
I used a set I already had for a 5.0 mustang, length was good, and they fit well.
Some people recommend 351 truck wire set, or 460 truck wire set.
Jegs sells some nice universal cut to length sets for pretty cheap.

Only thing w/ this cap is you'll need to do is file out the locator notch.
It's marked/indented in the cap just have to make the notch. Takes a couple minutes w/ a cutting tool/knife & small file/sandpaper.

[TUDrewser]

Cool. Getting ready to order. Also, this may sound dumb, but what bolts/studs do I use to mount the TB to the Performer intake and adapter plate?

[babywag]

Stock bolts that TB used, or equivalent...I forget the size but they are metric

Adapter should come with hardware to attach to intake.

[TUDrewser]

Yeah, it came with the bolts to attach to intake, I just don't have the ones to attach the tb to the adapter plate, and don't know what size to get.

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[babywag]

I bought metric hex head cap screws from Lowe's...if you google probably find the right size?

[babywag]

Week later I found the stock GM bolts..... my garage is a mess.

[Manimal70]

Hey Drew, did you get the fuel pump relay figured out? I had the switching wire and output to pump wire there....It still needed the power and ground for the relay circuit.

[TUDrewser]

Yeah, just need to get the relays. In fact, that is the ONLY thing I need, and it's a quick pickup at OReilly. In the coming weeks I should be able to start, though may wait until after the Tucson fab day so I don't get stuck without a drivable vehicle

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[Renodemona]

Glad to see progress. Interested in seeing how the timing system works for you. Did you get the bolt size for the throttle body figured out?

[TUDrewser]

Nope, still don't have the bolts. Figure I'll just take the tb and plate to the hardware store.

Btw, should I use any kind if loctite on any of the bolts? How about the bolts for the new intake manifold?

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[FSJ Guy]

I have never found a need for locktite on those bolts. Go easy on them, especially the ones going into the aluminum intake.

[Renodemona]

Nope, just RTV for the bolts going into the manifold. 23-25 lbs torque is plenty going into aluminum.

[FSJ Guy]

Why do you put RTV on the adapter to manifold bolts? Just curious.