Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

good idea!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Been busy the last two days figuring out wiring, here's some background on what exactly:

http://67-72chevytrucks.com/vboard/s...d.php?t=517217

I did get it to catch, but it shuts off after a few seconds:


Going to locate a scanner tonight to see if there are any codes that are affecting things...

Anybody have any ideas??

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

You did have VATS removed right?

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

OR! Sounds like the fuel pump is only running while the key is in "start". I think with the key in start, the fuel system pressurizes and then when in "run" the fuel pump shuts off and the system loses pressure. Betcha.

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

I think thats what i would do first is stick a fuel pressure gauge on the fuel rail and see if its staying at the 58ishpsi that it needs to be.

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

I got the PCM from PSI Conversions and told them to remove all the VATS....not that it would surprise me if it was not done with all the other problems I've had with their harness.

I did put in a new Compcam camshaft though....

As for the fuel pumps, that might be it....I can hear them pressurize the fuel system when I first click the key on but the way I wired them was stock to 1987 --- spliced them into the wire off of the tank selector switch and had the tank selector switch provide power to them.

I'm not sure if I should be powering the fuel pumps off of the fuel pump relay that was included with the PCM fuse block as I have two fuel pumps / one in each tank.

Ideas??

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

The way it dies slowly like that, i wouldnt expect it to be VATS actually. Its either loosing fuel as the system looses pressure, or there is a problem with either the computer or cam as it comes off the "starting" peramiters. There is a certain set of timing/fuel peramiters it uses as it starts and it "slides off" of those into normal as after it starts. With that i guess i would try opening the throttle just a little bit as its starting and see if that will keep it running. And also the fuel pressure thing.

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Thanks for that, I will definitely try that after I get the motor to run better.

Am trying to figure out how to match up the duel 1987 in-tank fuel pumps and wiring the fuel system into the LS / PSI fuel relay.

Here's what I was sent from PSI...

Now on my Painless harness, neither power wire that can be used for the fuel switch have power to them during cranking.

However, I checked the PSI fuel relay and it seems to have power when cranking, but not just when I first click on the key to go through the cranking sequence.

That leads me to believe that the PSI relay is only powered when the truck is running.

Does anyone have any thoughts on whether:

1. I should bring power into the supply side of this relay from the battery and then have it go through to the fuel tank selector switch?

2. If I did that would it be pushing too many amps through the fuel tank selector switch and possibly melt the wires?

3.Is there a way to bring less power through the PSI fuel relay, send it to the fuel tank selector switch when the engine is running, then put a relay on each of the wires powering each of the in-tank fuel pumps so power is delivered directly from the battery to the pumps when their respective relay is engaged by the tank selector switch?

I read somewhere that the tank selector switch has a strange set-up inside where it grounds one pump out when the other is engaged or something...

Any thoughts??

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Ok... This is a long shot in the dark as its late, i am tired and your post is only making half sense to me but i have an idea


Some where on this site IIRC some one was running into a problem where after putting in a new motor into their truck (either and LS or cummins i think), they could not get the tank switch to work. The truck would run fine on one tank but when the switch was flipped it would sputter and died.

Now like i said I am tired so my memory might be a bit off, but i DO know that was he came to find out was because the truck was TBI before there was a module under the dash related to the tank switch. What it did was got a signal from some where (this is where my memory fades) that then allowed the the switch/valve and pump to work properly. Without that signal he was pretty much hooped for fuel. I forget how it managed to work on the one tank but i think he managed to luck out and had the right wires crossed... it just did not allow him to switch

This was on a swap though using stock wiring... you have completely gutted every thing so i am not sure if this even applies anymore... I could just be rambling

I got a new HDD in my hard drive and all my book marks went with it. I am headed to work for a couple days but when i get back i'll toss it in and look threw it and find it. See if it sheds any light on the issue

Again though its been a long week and a very long day... if this is just mindless rambling just ignore me haha

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Thanks everybody for the advice!

Hick, you were on the right track b/c when I tore the cab down last year I saw that the previous owner had a couple new fuel selector switches under the seat.

When I took out the wiring harness I also noticed that his harness behind the switch was melted a bit.

So like a robot I just went out and found a new harness connection at the scrap yard thinking that was all it needed....well I was wrong.

What it actually needed was the 1987 TBI fuel selector switch that stays engaged and allows power to flow through it at all times with the key hot.

What the prevous owner had done was just shove the wrong switch into the wrong harness connection that he must have replaced as well at some point.

Anyways, long story short, it runs!

http://youtu.be/xmzyti6QwF8

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Sorry, can't get video to load on here...

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Nice work!!!Sounds good!!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Sweet!!!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

sounds great dude! congrats!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Congratulations Gordon! It sounds good.
Posted via Mobile Device

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Nice man! Good job figuring it out! BTW, The motion on that video had me trippin balls! Looked like it was on a robotic arm! Madness i say!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Thanks guys!

Had it running a bit today....fixed the blower motor on the heater .

A few more little electrical things and should be okay to start putting some more things back together on it.

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Thanks to Eric (LS1Nova71) for helping me with fixing my tach signal.

http://www.csgnetwork.com/resistcolcalc.html

For those with the same problem, the signal from the PCM is usually set to a 4 cylinder signal (but I hear it can be reprogrammed to send a V8 signal to the tach) and the signal needs to be boosted with the help of a 680 ohm (or so, may differ with different engines) resistor sautered in between the signal wire and a fused 12V ingnition-on power source.)

http://www.lt1swap.com/lsx_tach.htm

Anyways, it looks like this. It works a-okay now when the tach is in 4 cylinder mode.

Still working on the oil pressure gauge though.

Getting good signal to the gauge, it is getting a good 12v power supply, grounds seem to be good...will check one more thing tomorrow then I'm going to get another gauge to see if the one I currently have is faulty.

<iframe width="420" height="315" src="http://www.youtube.com/embed/YtmhBGLlw-k" frameborder="0" allowfullscreen></iframe>

http://youtu.be/YtmhBGLlw-k

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Video:

http://www.youtube.com/watch?v=YtmhB...ature=youtu.be

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Put on the fenders today to see what my spacing is and figure out where I can run my harnesses.

Some adjustments will be needed (of course).

Rims look good but will probably rub so I will need to look at that down the road.

Engine bay looks pretty bright with all that white in there!

Definitely needs a good wash when it warms up here.

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

sweet man! lookin good. that is a heck of a lot of white! what engine cover are you going to run?

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Wow lookin and soundin good !

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Awesome!!! Looking so clean!

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

I like those wheels Gordon what are the spec's on them? They set that Cadillac paint off nicely...Vernski:metal:

Re: "The Ayatollah of Rusty Hole'a 1987 SWB 6.0 4L80E
 

Thanks guys! It's nice to hear that some people like the truck!!

I have the usual Vortec MAX cover, not sure what I am going to do with it yet.

Thanks! I hope to have it on the road this summer so I can catch up to your build!

Thank you sir, I like your quad / ATV!

Thank you Vernski, they are Foose 22" Speestars. I'm still not sure if I will keep them on the truck though....might be a little too big.

I hope to have an update tonight on the truck.