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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond

Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
Overview Gallery Discussion
skunked said:
Did you get the fuel pump/tank reinstalled?
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I only have the driver side tank in right now. I want to make sure it works well before putting the passenger tank back in. Plus I still don't really know why the passenger pump was failing. Everything is running through the tank selector valve so I know it won't cause me any trouble.

Still kinda on the fence about the whole fuel tank situation. Both saddle tanks have taken more of a beating than I realized. I could go to a K5 tank and then there are good options for a skid plate. I'd have to redo the tailpipe I just made, LOL. I could also make some pretty simple 1/4" plate skids for the saddle tanks that would protect them from most of the damage they've suffered.
 
You know maybe there's even a chance the tank selector I had in there before was causing the problem. Since I swapped in a new that I knew was rated for the fuel pressure.

Other thought is that pump just took a hard enough knock to jar something. It did happen not long after a trail run but I don't remember hitting anything on that run either.

You know in general tho crawling under the truck I'm surprised at the places I see rock impacts.
 
fuel capacity is the big deterrent with K5 tank.....


I was looking at your taipipe and thought there is no way I could pull that off on my truck. Maybe I'll go with a stack :D
 
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Doh! Finally got through the whole build and assumed it would be running when I got to the latest post. Want to see how the Holley performs.
 
Pretty close! I've been using another type of GM connector, the type that's usually under the dash. These weather pack connectors are WAY easier. The crimp tool holds the terminal securely so it's easier to do them in the vehicle. So from now on probably everything is going to be weather pack.

The other connectors are good for tapping in and modifying factory plugs.
 
What I have now is a kit I bought on ebay that came with the nice crimper. Since the crimper is the expensive part there aren't a lot of the terminals and seals in the kit. I usually order bulk terminals from waytekwire.com. Where are you ordering the GM stuff?
 
mrk5 said:
I only have the driver side tank in right now. I want to make sure it works well before putting the passenger tank back in. Plus I still don't really know why the passenger pump was failing. Everything is running through the tank selector valve so I know it won't cause me any trouble.

Still kinda on the fence about the whole fuel tank situation. Both saddle tanks have taken more of a beating than I realized. I could go to a K5 tank and then there are good options for a skid plate. I'd have to redo the tailpipe I just made, LOL. I could also make some pretty simple 1/4" plate skids for the saddle tanks that would protect them from most of the damage they've suffered.
Click to expand...

I do not know if this is going to be any help at all, depending on what modifications you have made, but if you are using the stock steel GM fuel lines coming from the left side saddle tank the 3/8" fuel feed line had a problem from the factory that caused a restriction coming from the left side tank. Where the feed line goes over top the small support frame cross member, GM bent the fuel line too tight and caved-in the fuel line, thus causing a restriction. I fixed mine by cutting that section out with a tube cutter, then double flaring each side, and then installing a piece of rubber fuel injection line in its place with hose clamps. I am only running a set of pumps that produces a max pressure of 33-PSI, and an adjustable fuel pressure regulator set at 13-PSI, so I was able to get away with this fix.
 
Interesting, I will have to check that out. Right now the left tank seems to be supplying fuel fine. However it's just static pressure right now, no demand is being put on it. Be interesting to see if it works once the truck is running a putting a real demand on the system.
 
Finished up the wiring.

One of the plugs/harness is basically for the auxiliary stuff. There are 10 circuits and I'm only using 3. I pulled the wires I'm not using and plugged them.

2017-05-03%2010.27.51.jpg


The 3 wires are for: Fan #1, Fan #2, and a tach signal wire. The other wires are used for stuff like nitrous and air conditioning idle.

The wires are well labelled.

2017-05-01%2010.05.31.jpg


Hadn't planned it, but the firewall ended up being the location of everything I added.

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From left to right; Starter solenoid, circuit breaker for factory battery power, Sniper fuel pump relay, Sniper power fuse, and coil.

One of my concerns with the Sniper is the length of wiring harnesses since they need to be sure to have enough length to fit multiple applications. I was able to route most of it in round about methods and still be fairly tidy appearing. Below I've marked what I call the "main" harness that had the primary power, 12V switched power, fuel pump power, and ignition connections.

b9a976fd-4cc4-4f40-8fbe-f141a2611ccf.jpg


That wiring runs up to the firewall and across to the other side of the motor with one wire connecting to the coil negative.

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At the other end is the first weather pack plug I posted about above which connects to the factory fuel pump wire and 12V switched with power in RUN and START. Additionally there are the positive and negative connections to the battery. I used side post adapters to make the connections.

2017-05-05%2016.57.59.jpg


Holley emphasizes the power needs to be connected DIRECTLY to the battery.

One of the things I was curious about beforehand was the length of the various wires. Below I labeled the lengths and uses for the wires I think would be most valuable to know.

2017-05-01%2016.17.28.jpg


So there's 20' of fuel pump power wire and 4.5' of the primary wire to connect to the battery.

Probably the most excessively long harness is for the oxygen sensor. I routed it up and looped around the factory bulkhead connection and back across over the valve cover into the throttle body.

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My wiring for the auxiliary is a bit more complicated than it needs to be. As I mentioned above I'm using just 3 wires. The tach wire is a straight connection. The fan wiring I have a wire for each fan that feed back in behind the dash. This is because I have lights on the dash to tell me when the fans are on. I also have a switch to manually turn on the second fan. Without those wires running to the dash, the fan wires off the Sniper harness could be wired directly to the negative on my fan relays.

This is the wiring running along the valve cover.

2017-05-05%2016.57.26.jpg


There is a wire that drops down to the oil pressure sender and another for the temperature gauge sender in addition to the fan control wires. Still need to put loom clamps on connected to the valve cover studs.

Plan is to start it tomorrow morning. I'm going to pull the belt off the power steering pump so that I can bleed it after getting the motor up and running good. Once the belt is off, I'll be ready for initial startup.

The only other thing I need to do is cover the 2-1/4" hole in the firewall from the factory TBI harness.
 
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