1987 GMC V1500 LS Swap help

[NastyBuzzard]

Hey guys, I am in need of some questions answered so I can move forward on my swap.

Here is my build thread.

http://67-72chevytrucks.com/vboard/s...d.php?t=627161

Probably should try and move it here, or I should have made it here to begin with.

Here is my truck:



And here is my donor:



A lot more pics on my build thread.

Anyways, my plan was to take out the LS drivetrain from the 01 donor. Also take out instrument cluster, entire wiring harness, fuel tank and rear end and put all that into my 87. I want to run the entire 01 wiring harness so I can switch everything on my truck to run off relays, also it will make it easier to run the instrument cluster.

I want something like this.






Anyways... I ran into my first problem today.









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.

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?

A friend suggested somehow making a bastard sender from a vortec truck somehow.

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

Also I assume I will need the higher flowing pumps. The selector valve I have now is a pollock brand and is only about 6 months old, I got it as a replacement from autozone, I dont know what psi it can handle, any ideas?

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.

Any ideas on a newer plastic tank that would work?

Also anyone ever swapped out the 16 gal tank (40" or so long) for the 20 gal tank (50" or so long)? I may be more willing to run the one 20 gallon tank to eliminate having to purchase the higher psi selector valve and less fittings.

I am reaching out guys, I really am stumped. This sent my motivation into the pooper.

[Nitis]

Why not an in frame blazer/suburban tank?

[NastyBuzzard]

I don't see how the blazer tank solves my problem to be honest.

I initially wanted to do the blazer tank but decided against it mostly b/c filler neck couldn't be routed to stock location.

The main reason I wanted to use the 01's donor tank was to keep the fuel line/pump assy setup so I could run the stock wiring.

[Houston Ben]

Got this form "Glock" on his Fred Build

High PSI fuel switching valve Pollak ZX812705U $83.00 ea jcwhitney.com 65psi rated.

How hard was it to put that dash in?

[NastyBuzzard]

Originally Posted by Houston Ben

Got this form "Glock" on his Fred Build

High PSI fuel switching valve Pollak ZX812705U $83.00 ea jcwhitney.com 65psi rated.

How hard was it to put that dash in?

Apparently JC whitney doesn't carry that anymore?

Also, I found a pic of that pollack switching valve and it looks exactly the same as the one I am currently running. Any idea?

Which dash in? I haven't yet converted it to have the 01 cluster. That is just a pic I have of someone who has done it.

[Houston Ben]

Ya, I just read your build, guess I should have done that before posting the question, lol. I am only running on side tank so I can't help you on that, sorry.

[NastyBuzzard]

Originally Posted by Houston Ben

Ya, I just read your build, guess I should have done that before posting the question, lol. I am only running on side tank so I can't help you on that, sorry.

What side tank are you running? I am heavily considering buying a 20 gal tank and just running one side. I think that will be easier and save me a lot of cost.

[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.

[Houston Ben]

My fuel tank is on the drivers side, straight shot to the fuel line on the engine. Here is some helpful swap info

[NastyBuzzard]

Originally Posted by Houston Ben

My fuel tank is on the drivers side, straight shot to the fuel line on the engine. Here is some helpful swap info

That the list from Fred/Glock?

I think I have a copy of that somewhere. Thanks.

Just read through your build thread again. I didn't see what size tank you are running though. Did you use the EP381 pump?

[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?

[BR3W CITY]

I THINK if your using the column, then in fact, you may be correct. Unfortunately, I can't verify that first hand, as the trucks use VATS differently than the f-bodies did (where you can actually manipulate it), and I've never pulled a complete harness from a truck to try it.

Please be careful with the airbag on the that column tho dude! I don't want your first-start to result in a concussion from the drivers seat lol.

[Houston Ben]

Yup, that's from Glock build. Im running stock 87' 16gal fuel tank. I bought my fuel pump from NAPA, they said it was the same rating as the one in the EP-381, haven't had a problem with it yet.

[NastyBuzzard]

Originally Posted by BR3W CITY

I THINK if your using the column, then in fact, you may be correct. Unfortunately, I can't verify that first hand, as the trucks use VATS differently than the f-bodies did (where you can actually manipulate it), and I've never pulled a complete harness from a truck to try it.

Please be careful with the airbag on the that column tho dude! I don't want your first-start to result in a concussion from the drivers seat lol.

There is a thread called Captain America 68 short bed fleetside where he has done it!!

I am careful with airbag! Trust me! Also truck is completely apart now except for column. It has no power or wiring to it but I still plan to be super careful. I dont even plan to pull off the steering wheel if I dont have to.

[NastyBuzzard]

Originally Posted by Houston Ben

Yup, that's from Glock build. Im running stock 87' 16gal fuel tank. I bought my fuel pump from NAPA, they said it was the same rating as the one in the EP-381, haven't had a problem with it yet.

16 Gal tank.. Do you have to fill up like all the time? What kind of MPG you getting?

I drive around on one 16 gal tank now w/ the 350 tbi but like ever 120-150 miles I am getting gas, but I dont drive it too far from home b/c it has a few electrical/tuning gremlins.

[Houston Ben]

Im getting around 18 mpg. I only drive it 1 to 2 x a week to work and back for fun and sometimes on the weekend.

[NastyBuzzard]

Originally Posted by Houston Ben

Im getting around 18 mpg. I only drive it 1 to 2 x a week to work and back for fun and sometimes on the weekend.

I want to be able to travel atleast a few hours away and not have to fill up... 16 gal is how I'll go temporarily. After I get a few miles on it once it's done I'll go to a 20 gal tank.

[BR3W CITY]

I have a 16 gallon tank, and can go a little over2.5 hrs on road before considering a fillup

[NastyBuzzard]

Originally Posted by BR3W CITY

I have a 16 gallon tank, and can go a little over2.5 hrs on road before considering a fillup

Nice! Considering what you are running! I am really hoping for 20mpg!

Taking the fuel lines off the 01 donor now... Gonna try and mock up my fuel lines how they are going to be. I think I can make a bastard set with what hard lines I have and some high pressure hose. Trying to decide which side would be easiest to have tank on... D.S. or P.S.

[BR3W CITY]

Originally Posted by NastyBuzzard

Nice! Considering what you are running! I am really hoping for 20mpg!

Taking the fuel lines off the 01 donor now... Gonna try and mock up my fuel lines how they are going to be. I think I can make a bastard set with what hard lines I have and some high pressure hose. Trying to decide which side would be easiest to have tank on... D.S. or P.S.

PS, because its easier to run the lines up the firewall on that side, and you'll already have brake lines on the DS because of where the booster mount is (path of least resistance imo)

[NastyBuzzard]

Here is fuel lines from 01 donor.



Here Is the 01 filter next to 87 filter... Could they be same threads?



I think I may agree with pass but running the 01 ends that connect to fuel rail may be troublesome. Guess I could try n debend or extend them with high pressure hose.

[Mr. 250r]

On my suburban i kept all the original fuel lines and wiring just swapped the pump out for a replacement and put the corvette filter/reg because mines returnless and then blocked off my original return line at the tank i figured an 87 would've already had everything there being FI and all

[NastyBuzzard]

Originally Posted by Mr. 250r

On my suburban i kept all the original fuel lines and wiring just swapped the pump out for a replacement and put the corvette filter/reg because mines returnless and then blocked off my original return line at the tank i figured an 87 would've already had everything there being FI and all

That is true for the most part. Old rubber fuel line hose has to be replaced and smooth fuel injection clamps have to be used instead of the older screw style.

My issue was that I wanted to run all the stuff from the 01 donor, wiring and fuel wise. I ran into the issue of tank just being too damn deep so now I have to find away to make my sender output match what the 01 sender would output as well as figure out how to do the evap stuff and pressure switch.