86 Silverado Father and Son project

[rfmaster]

Originally Posted by mcbassin

RF,
I'm a little confused about the pink/black wire in your diagram? Where does it go? I have it tied into the power on during start and run from the fuse box terminal. You show it going to gauge/fuse? I feel like I don't have power hooked up on the ecm somewhere. I can hear the fuel pump relay kick on and pressure up the fuel system. But it won't squirt gas at the injectors.
I think we need to see that we are getting power to them first and then go from there.

Mike

Mike

Attached circuit diagram is my circuit implementation that I have built for my '75 conversion. The pink-black wire is used to power up auxiliary gauges (WBO, Tach, etc). You can omit it if not needed for your build.

Since you can get engine to run by dumping fuel into TB it indicates that you have ignition, but ECM is not firing injectors. Two possibilities - ECM is not getting power during cranking or injectors do not get 12 volts during cranking.

Got to run - will continue.

//RF

[mcbassin]

Thanks RF,
Your right I wasn't getting power to the injectors but I think I found the reason. One red wire from the donor I suspected needed hooked up while the key is on was unhooked. When I put power to it the injectors started squirting. It now kinda runs under it's own power (still has to be wired permanantly).

I was trying to figure the fuel lines and I may be wrong but it sure looks like the original fuel line is 3/8" The return looks like 1/4". I guess I still need to run a 5/16 return? I picked some 3/8 steel line from Autozone and it is the same dia. as the original. Also there was a lot of discussion about the use of dual tanks. I don't understand why we can't just tie into the main line and use one pump? I guess if your driving down the road under a heavy load it may stumble the engine? Maybe a little? If it's unsafe then I may need to consider the small pump to move the fuel from one tank to the other.

Things to do still:
Finish the wiring
Install the new fuel pump
fix all the vacuum leaks
change the starter? it sounds like the gear is hanging on the flexplate
install speedo gear and vss
make it driveable

[rfmaster]

Originally Posted by mcbassin

Thanks RF,
Your right I wasn't getting power to the injectors but I think I found the reason. One red wire from the donor I suspected needed hooked up while the key is on was unhooked. When I put power to it the injectors started squirting. It now kinda runs under it's own power (still has to be wired permanantly).

I was trying to figure the fuel lines and I may be wrong but it sure looks like the original fuel line is 3/8" The return looks like 1/4". I guess I still need to run a 5/16 return? I picked some 3/8 steel line from Autozone and it is the same dia. as the original. Also there was a lot of discussion about the use of dual tanks. I don't understand why we can't just tie into the main line and use one pump? I guess if your driving down the road under a heavy load it may stumble the engine? Maybe a little? If it's unsafe then I may need to consider the small pump to move the fuel from one tank to the other.

Things to do still:
Finish the wiring
Install the new fuel pump
fix all the vacuum leaks
change the starter? it sounds like the gear is hanging on the flexplate
install speedo gear and vss
make it driveable

On electrical
Looks like you are getting close to a working solution. Just be aware that you are dealing with 20+ year old OE wiring harness. Use of auxiliary relay block removes current from old harness (including ignition key) making the overall installation robust. It is extra work, but it provides long term reliability.

On Fuel Lines
I used both 3/8" lines for supply and return. You can go with 5/16" return, but why bother. Do not use 1/4" vapor line for fuel return line. The back pressure will screw up fuel pressure regulator in the TB. This will create fuel delivery havoc!

On dual tanks
I have fully functioning dual tank system. This system revivals the one found on B-737 - no kidding:



The fuel system took me about four month to fabricate (I was not in a hurry) which included a lot of 3/8" fuel line cutting and bending (soft steel).

Tank select valves and low pressure lift pump:


Low pressure pump lifts fuel out of selected main tank and feeds it into surge tank which provides un-interrupted fuel supply to high pressure EFI pump. Surge is needed since I have non baffled (pre EFI) main 20 G tanks:


//RF

[mcbassin]

I really like what you did with your fuel system! That is really nice! I could fab up a tank like that. I'm not sure we need to worry about the fuel supply since this will be a road only 2wd truck. I totally understand why you did yours like that. As far as the lines I am using, I am really thinking about using the original car fuel lines since they are the correct size and they have the correct fittings and have an inline filter setup already. I just have to make fittings to adapt to the truck lines or use the quick connect fittings from the tank.

On the power,
I have thought about the relay setup. I want to build a setup like that and I'm sure with your diagram I can. Right now I'm wanting to get past the mess that I have of the harness. It really looks like a rat got under the hood. I need to have the best reliability possible (it will be driven by a kid). This project when done will move us toward finishing the 69 project we started. I would really like to install a 5.3 or 6.0 in it with matching late model tranny.
thanks for all the help!
Mike

[rfmaster]

Originally Posted by mcbassin

I really like what you did with your fuel system! That is really nice! I could fab up a tank like that. I'm not sure we need to worry about the fuel supply since this will be a road only 2wd truck. I totally understand why you did yours like that. As far as the lines I am using, I am really thinking about using the original car fuel lines since they are the correct size and they have the correct fittings and have an inline filter setup already. I just have to make fittings to adapt to the truck lines or use the quick connect fittings from the tank.

On the power,
I have thought about the relay setup. I want to build a setup like that and I'm sure with your diagram I can. Right now I'm wanting to get past the mess that I have of the harness. It really looks like a rat got under the hood. I need to have the best reliability possible (it will be driven by a kid). This project when done will move us toward finishing the 69 project we started. I would really like to install a 5.3 or 6.0 in it with matching late model tranny.
thanks for all the help!
Mike

Mike

Since you have car fuel lines available I would use them. Just be aware that any bends must be done with a tube bender to avoid collapsing (or worst restricting ) fuel lines.

Tip on EFI harness routing.

Just layout wiring in the engine compartment the best way you can and route all plugs to their respective locations. Take pictures and them play around on a kitchen table with a pencil hand sketch. This way you'll have a good idea how to route wire harness. Wire harness requires protection - hence invest in some 1/4, 3/8" and 1/2" split looms. For individual branches (single connector) I used 1/4" loom which can safely handle 1- 4 wires. When you have to use high temperature automotive grade electrical tape. DO NOT use commonly available hardware store electrical tape as it is not temperature rated for under hood operation. Professional electrical supply houses have this tape - it is a bit more, but it does not leave a black stinky mess. I had decent results using Scotch Supper 33+ electrical tape from 3M. It is rated for 105C (220F) continuous operation and resistant to oil, water and chemicals.