1987 GMC V1500 LS Swap help

[BR3W CITY]

Originally Posted by NastyBuzzard

So now I need to come up with a fuel system. I really wanted to eliminate the saddle bags for the one 26 gal tank but since thats not possible, it looks like I am stuck with them.

Fuel Cells are awesome. Light weight, any capacity, fit wherever.

However, problem is the sending units put out a 0-120ohm signal for older fuel gauges, the newer gauges run a 90-240ohm signal... How do I jump that hurdle?

You'd have to search for the exact part #, but "late model" sending unit can be made to work with a resistor (or is it a pull-up resistor? I can't remember). Cheap, easy.


Also some how to mount the pressure sensor and the evap tank from the 01.

Don't bother, even on stock wiring you can just remove that circuit. The ECU will need to be tuned no matter what, and setting EVAP to OFF and no DTC is just another button click.


Also I have no clue what an fitting I will need, how many I will need, size or type or whatever. I know I need the expensive high pressure fuel hose with the smooth clamps.

3/8 is -6AN

:

the Bold may or may not be helpful, depends on which direction you want to take. I get the idea of wanting to use the stock wiring, but because of the labor and nit-picky-ness of pulling factory wiring out of a salvage truck, IMO it just ends up being easier to have a custom harness made. I also think the stock dash is more work than its worth, but thats just me.

[NastyBuzzard]

Originally Posted by BR3W CITY

the Bold may or may not be helpful, depends on which direction you want to take. I get the idea of wanting to use the stock wiring, but because of the labor and nit-picky-ness of pulling factory wiring out of a salvage truck, IMO it just ends up being easier to have a custom harness made. I also think the stock dash is more work than its worth, but thats just me.

Thank you!! Any fuel cells you recommend that will be able to route to a stock filler neck area???

It seems that there may be a possibility of taking the parts I need off the 01 pump assy. I am going to look into that later.

For now it seems my plan is to run only one 16 gal tank with the right pump/sending unit and then later go back and replace the 16 gal tank with the 20 gal tank. I plan to move the tank to the d.s. mostly to use the fuel line setup/routing from the 01 donor if I can. This will save me from having to purchase AN fitting... I think... All I need is high pressure hose w/ smooth clamps.

I already have pulled the entire harness from the 01 donor. I labelled everything and was very careful. So I already have it out and labelled

So you say just don't worry about the pressure switch at all? What about the tank needing to be pressurized with a non vent cap?

So remove pressure switch & remove evap. Will the truck initially start/crank like this or will PCM have to be tuned first?

If I don't need it, I dont want to keep it. But if its necessary for first start up I may go ahead and just throw it in.

The PCM will eventually be sent out after I have it all together and running enough to move around my house. It will be sent to remove cats, rear o2s and whatever else plus to get a decent power/mpg tune.

[BR3W CITY]

Originally Posted by NastyBuzzard

Thank you!! Any fuel cells you recommend that will be able to route to a stock filler neck area???

Depends if you decide on one of the pre-designed cells from someon like Boyd, or if you get a universal or custom one. Most of the time, you can just use parts-store universal filler hose and exhaust piping to make a decent run at whatever tank you want. As long as gravity can let the gas flow downwards, it should fill just fine (but won't have the auto-stop thingy for pumping)


So you say just don't worry about the pressure switch at all? What about the tank needing to be pressurized with a non vent cap?

You can get a vented cap, or just run a rollover valve and breather tube on the tank. The computer doesn't need signal from that sensor, iirc its just an emissions thing (signalling failed gas cap or leak in evap). It might trigger a dtc, but wouldn't impede starting.

So remove pressure switch & remove evap. Will the truck initially start/crank like this or will PCM have to be tuned first?

The evap etc gets set to "no error, or no DTC" in the tune, and won't cause any problems. Even with it disconnected, it shouldn't prevent the truck from running.

The PCM will eventually be sent out after I have it all together and running enough to move around my house. It will be sent to remove cats, rear o2s and whatever else plus to get a decent power/mpg tune.

You won't be going anywhere without sending the computer out first. VATS will prevent you from running it for more than 2-3 seconds (if your lucky). It needs to be removed first...and thats usually the same time when emissions stuff is all pulled out.

[NastyBuzzard]

Originally Posted by BR3W CITY

You won't be going anywhere without sending the computer out first. VATS will prevent you from running it for more than 2-3 seconds (if your lucky). It needs to be removed first...and thats usually the same time when emissions stuff is all pulled out.

Vats will not be need to be removed initially. I am carrying over the entire 01 donor harness, as well as body control module, steering column etc. Vats wont detect an issue as long as all the parts are there for it to detect. Am I right?